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Fooling around with floppies this week, I know
you can put a MSDOS-type partition table on them,
did it with gparted, but it uses up about 1.2mb.
Groovy hepcat c186282 was jivin' in comp.os.linux.misc on Sun, 28 Sep
2025 04:17 am. It's a cool scene! Dig it.
Fooling around with floppies this week, I know
you can put a MSDOS-type partition table on them,
did it with gparted, but it uses up about 1.2mb.
That's very odd! An MSDOS partition table occupies a small (64 bytes)
part of the MBR (master boot record - the first sector of the disk).
Perhaps you were looking at the size of th partition itself, not the partition table.
On 2.10.2025 11.28, Peter 'Shaggy' Haywood wrote:
Groovy hepcat c186282 was jivin' in comp.os.linux.misc on Sun, 28 Sep
2025 04:17 am. It's a cool scene! Dig it.
Fooling around with floppies this week, I know
you can put a MSDOS-type partition table on them,
did it with gparted, but it uses up about 1.2mb.
That's very odd! An MSDOS partition table occupies a small (64 bytes)
part of the MBR (master boot record - the first sector of the disk).
Perhaps you were looking at the size of th partition itself, not the
partition table.
The partition table for MS-DOS sits on the very first sector
(track 0, surface 0, sector 1) of the disk. It is part of the
first startup boot program, called Master Boot Record (MBR).
The very limited space on the MBR limited the DOS partition
table to 4 partitions maximum.
Groovy hepcat c186282 was jivin' in comp.os.linux.misc on Sun, 28 Sep
2025 04:17 am. It's a cool scene! Dig it.
Fooling around with floppies this week, I know
you can put a MSDOS-type partition table on them,
did it with gparted, but it uses up about 1.2mb.
That's very odd! An MSDOS partition table occupies a small (64 bytes)
part of the MBR (master boot record - the first sector of the disk).
Perhaps you were looking at the size of th partition itself, not the partition table.
On 2.10.2025 11.28, Peter 'Shaggy' Haywood wrote:
Groovy hepcat c186282 was jivin' in comp.os.linux.misc on Sun, 28 Sep
2025 04:17 am. It's a cool scene! Dig it.
-a-a-a Fooling around with floppies this week, I know
-a-a-a you can put a MSDOS-type partition table on them,
-a-a-a did it with gparted, but it uses up about 1.2mb.
-a-a That's very odd! An MSDOS partition table occupies a small (64 bytes) >> part of the MBR (master boot record - the first sector of the disk).
Perhaps you were looking at the size of th partition itself, not the
partition table.
The partition table for MS-DOS sits on the very first sector
(track 0, surface 0, sector 1) of the disk. It is part of the
first startup boot program, called Master Boot Record (MBR).
The very limited space on the MBR limited the DOS partition
table to 4 partitions maximum.
On 2025-10-02, Tauno Voipio wrote:
On 2.10.2025 11.28, Peter 'Shaggy' Haywood wrote:
Groovy hepcat c186282 was jivin' in comp.os.linux.misc on Sun, 28 Sep
2025 04:17 am. It's a cool scene! Dig it.
Fooling around with floppies this week, I know
you can put a MSDOS-type partition table on them,
did it with gparted, but it uses up about 1.2mb.
That's very odd! An MSDOS partition table occupies a small (64 bytes) >>> part of the MBR (master boot record - the first sector of the disk).
Perhaps you were looking at the size of th partition itself, not the
partition table.
The partition table for MS-DOS sits on the very first sector
(track 0, surface 0, sector 1) of the disk. It is part of the
first startup boot program, called Master Boot Record (MBR).
The very limited space on the MBR limited the DOS partition
table to 4 partitions maximum.
Any chance this was partition alignment to the 1 MiB boundary?
On 28 Sep 2025 10:21:15 GMT, St|-phane CARPENTIER wrote:
Le 28-09-2025, Lawrence DrCOOliveiro <ldo@nz.invalid> a |-crit-a:
Having a separate /home partition makes things more convenient, in that
you can replace the OS installation without impacting your home files.
Yes, I know the theory. Now that's not that magical nor that good. If
the OS replacement haven't the same applications or the same versions
deployed things will have to be handled manually.
If both distros are of about the same age, they should do.
OK, with two OS installed at the same time, the /home partition is
mandatory. But not everybody want two OS to try things. Some may prefer
the VM way.
Then you have to copy user stuff back and forth. Not so convenient.
On 2025-09-28 12:21, St|-phane CARPENTIER wrote:
Le 28-09-2025, Lawrence DrCOOliveiro <ldo@nz.invalid> a |-crit-a:
On 27 Sep 2025 22:31:34 GMT, St|-phane CARPENTIER wrote:
Le 27-09-2025, c186282 <c186282@nnada.net> a |-crit-a:
Well, partitions can be used for "organization" purposes, which can
be useful.
Give me a real example in the real world. On a personal computer, I
don't see any reason to have more than three partition: one for Linux, >>>> one for the swap and one for the UEFI which requires a FAT partition.
And for the swap partition, I'm even not that convinced that it's better >>>> than a swap file. I'm certainly not convinced by the /home partition for >>>> example.
Having a separate /home partition makes things more convenient, in that
you can replace the OS installation without impacting your home files.
Yes, I know the theory. Now that's not that magical nor that good. If
the OS replacement haven't the same applications or the same versions
deployed things will have to be handled manually. I'm not saying it
shouldn't be done, I'm saying I'm not convinced it's the best way.
It is magical when doing upgrades of the same distribution. If it
doesn't, said distro is garbage.
Indeed, I would recommend having two OS partitions, one left unused toOK, with two OS installed at the same time, the /home partition is
begin with. That lets you install a second OS later, just to try out,
without having to wipe your existing one. And they can both share the
same /home partition. And the same swap partition, while theyrCOre at it. >>
mandatory. But not everybody want two OS to try things. Some may prefer
the VM way.
Not two oses to try things. To do updates. You put the new version on
the second partition, then change which boots by default.
Some people have an extra partition for data, and put links to it from different homes, so that the configurations are separate for each system.
On 10/2/25 04:28, Peter 'Shaggy' Haywood wrote:
Groovy hepcat c186282 was jivin' in comp.os.linux.misc on Sun, 28 Sep
2025 04:17 am. It's a cool scene! Dig it.
Fooling around with floppies this week, I know
you can put a MSDOS-type partition table on them,
did it with gparted, but it uses up about 1.2mb.
That's very odd! An MSDOS partition table occupies a small (64
bytes)
part of the MBR (master boot record - the first sector of the disk).
Perhaps you were looking at the size of th partition itself, not the
partition table.
Insert floppy. Run 'gparted'. Select to create
a new MSDOS-type partition table.
You will find almost ALL of the disk has been
used up.
When doing upgrades of the same distro, I see no difference between
having /home in a designed partition or not.
St|-phane CARPENTIER <sc@fiat-linux.fr> wrote:
When doing upgrades of the same distro, I see no difference between
having /home in a designed partition or not.
The two reasons most often quoted for having /home on a separate
partition are:
1) Doing so makes it impossible for a user in /home to fill to 100%
capacity the root partition. Arguably, this reason is more credible in
a multiuser system where one of the set of users could accidentally or intentionally fill the disk. Things go really wonky if the root
partition is 100% full.
2) Having /home separate makes it easy to upgrade the system without worrying about erasing /home in the process. Unmount /home, perform
upgrade (naturally, being careful as to which partition is actually the
root partition), then remount an otherwise untouched /home partition. Arguably, the rolling release type distros have made this less of an
isssue with their ability to upgrade in place.
Le 29-09-2025, Carlos E.R. <robin_listas@es.invalid> a |-crit-a:
On 2025-09-28 12:21, St|-phane CARPENTIER wrote:
Le 28-09-2025, Lawrence DrCOOliveiro <ldo@nz.invalid> a |-crit-a:
On 27 Sep 2025 22:31:34 GMT, St|-phane CARPENTIER wrote:
Le 27-09-2025, c186282 <c186282@nnada.net> a |-crit-a:
Well, partitions can be used for "organization" purposes, which can >>>>>> be useful.
Give me a real example in the real world. On a personal computer, I
don't see any reason to have more than three partition: one for Linux, >>>>> one for the swap and one for the UEFI which requires a FAT partition. >>>>> And for the swap partition, I'm even not that convinced that it's better >>>>> than a swap file. I'm certainly not convinced by the /home partition for >>>>> example.
Having a separate /home partition makes things more convenient, in that >>>> you can replace the OS installation without impacting your home files.
Yes, I know the theory. Now that's not that magical nor that good. If
the OS replacement haven't the same applications or the same versions
deployed things will have to be handled manually. I'm not saying it
shouldn't be done, I'm saying I'm not convinced it's the best way.
It is magical when doing upgrades of the same distribution. If it
doesn't, said distro is garbage.
When doing upgrades of the same distro, I see no difference between
having /home in a designed partition or not.
Indeed, I would recommend having two OS partitions, one left unused to >>>> begin with. That lets you install a second OS later, just to try out,OK, with two OS installed at the same time, the /home partition is
without having to wipe your existing one. And they can both share the
same /home partition. And the same swap partition, while theyrCOre at it. >>>
mandatory. But not everybody want two OS to try things. Some may prefer
the VM way.
Not two oses to try things. To do updates. You put the new version on
the second partition, then change which boots by default.
For a rolling distro it would be a waste of time. For a versioning
distro, why not. For what I saw, I'm not that convinced because it means
you must have unusable disk partition just to be able to upgrade. Ok, by
now, you can resize your partitions so it can be managed but I'm not
that convinced.
Some people have an extra partition for data, and put links to it from
different homes, so that the configurations are separate for each system.
Yes, that I understand.
St|-phane CARPENTIER <sc@fiat-linux.fr> wrote:
When doing upgrades of the same distro, I see no difference between
having /home in a designed partition or not.
The two reasons most often quoted for having /home on a separate
partition are:
1) Doing so makes it impossible for a user in /home to fill to 100%
capacity the root partition. Arguably, this reason is more credible in
a multiuser system where one of the set of users could accidentally or intentionally fill the disk. Things go really wonky if the root
partition is 100% full.
2) Having /home separate makes it easy to upgrade the system without
worrying about erasing /home in the process. Unmount /home, perform
upgrade (naturally, being careful as to which partition is actually the
root partition), then remount an otherwise untouched /home partition. Arguably, the rolling release type distros have made this less of an
isssue with their ability to upgrade in place.
A third reason I've seen, but it is not anywhere common, is for folks
who like to play "distro hopping". They might have two or more
partitions that are each the root partition of a different
distribution. Having /home be a separate partition means that single
/home partition can be mounted onto whichever of the plural root
partitions is the one they have currently booted.
Le 28-09-2025, Lawrence DrCOOliveiro <ldo@nz.invalid> a |-crit-a:
On 28 Sep 2025 10:21:15 GMT, St|-phane CARPENTIER wrote:
Le 28-09-2025, Lawrence DrCOOliveiro <ldo@nz.invalid> a |-crit-a:
Having a separate /home partition makes things more convenient, in that >>>> you can replace the OS installation without impacting your home files.
Yes, I know the theory. Now that's not that magical nor that good. If
the OS replacement haven't the same applications or the same versions
deployed things will have to be handled manually.
If both distros are of about the same age, they should do.
No. Updated versions of debian, ubuntu, archlinux and guix sure haven
the same versions of the programs they run. And for ubuntu, you have the
snap which brings a difficulty to replace ubuntu by another distro.
OK, with two OS installed at the same time, the /home partition is
mandatory. But not everybody want two OS to try things. Some may prefer
the VM way.
Then you have to copy user stuff back and forth. Not so convenient.
I'm not saying the other way is better. I'm just saying that if the
partition fix some things, it has issues too.
On 2025-10-04 17:22, Rich wrote:
St|-phane CARPENTIER <sc@fiat-linux.fr> wrote:
When doing upgrades of the same distro, I see no difference between
having /home in a designed partition or not.
The two reasons most often quoted for having /home on a separate
partition are:
1) Doing so makes it impossible for a user in /home to fill to 100%
capacity the root partition. Arguably, this reason is more credible in
a multiuser system where one of the set of users could accidentally or
intentionally fill the disk. Things go really wonky if the root
partition is 100% full.
2) Having /home separate makes it easy to upgrade the system without
worrying about erasing /home in the process. Unmount /home, perform
upgrade (naturally, being careful as to which partition is actually the
root partition), then remount an otherwise untouched /home partition.
Arguably, the rolling release type distros have made this less of an
isssue with their ability to upgrade in place.
Yes, unless they fuckup. Then you need to install from scratch, or
install a second partition.
A third reason I've seen, but it is not anywhere common, is for folks
who like to play "distro hopping". They might have two or more
partitions that are each the root partition of a different
distribution. Having /home be a separate partition means that single
/home partition can be mounted onto whichever of the plural root
partitions is the one they have currently booted.
I know one chap that does distro testing, has dozens of the same distro
in a single disk, plus other distros.
St|-phane CARPENTIER <sc@fiat-linux.fr> wrote:
When doing upgrades of the same distro, I see no difference between
having /home in a designed partition or not.
The two reasons most often quoted for having /home on a separate
partition are:
1) Doing so makes it impossible for a user in /home to fill to 100%
capacity the root partition. Arguably, this reason is more credible in
a multiuser system where one of the set of users could accidentally or intentionally fill the disk. Things go really wonky if the root
partition is 100% full.
2) Having /home separate makes it easy to upgrade the system without
worrying about erasing /home in the process. Unmount /home, perform
upgrade (naturally, being careful as to which partition is actually the
root partition), then remount an otherwise untouched /home partition. Arguably, the rolling release type distros have made this less of an
isssue with their ability to upgrade in place.
A third reason I've seen, but it is not anywhere common, is for folks
who like to play "distro hopping". They might have two or more
partitions that are each the root partition of a different
distribution. Having /home be a separate partition means that single
/home partition can be mounted onto whichever of the plural root
partitions is the one they have currently booted.
I've never trusted the idea as /home/user being for user controlled
data, distinct from the installed system. This folder standardly
contains user preferences/config for the OS and installed
applications.
If you install a difference OS or different applications, the
configuration files might not be consistent. I wouldn't assume I could
take /home from one system and drop it onto a different system.
So if I have important data files, documents, spreadsheets, etc. I try
not to store them under /home. Really speaking I only use /home/user
as a cache, I accept it is under the control of the system, rather
than under my control.
Maybe I have misunderstood something?
I've never trusted the idea as /home/user being for user controlled
data, distinct from the installed system. This folder standardly
contains user preferences/config for the OS and installed applications.
Pancho <Pancho.Jones@protonmail.com> writes:
I've never trusted the idea as /home/user being for user controlled
data, distinct from the installed system. This folder standardly
contains user preferences/config for the OS and installed
applications.
It does, but it also explicitly intended for the userrCOs own data.
On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with his >>floppies kept safe (the train was electric). We told him to try wrappingrCLFaraday cagerCY.
in aluminum kitchen foil, or perhaps in a cookie tin box. I don't
remember what he did exactly, but it worked.
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or
quoted:
On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with
his floppies kept safe (the train was electric). We told him to
try wrapping in aluminum kitchen foil, or perhaps in a cookie tin
box. I don't remember what he did exactly, but it worked.
rCLFaraday cagerCY.
And it seems that, in practice, a Faraday cage can possibly protect
to some extend against fast changing magnetic fields, but less
against slowly changing magnetic fields.
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or quoted:
On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with hisrCLFaraday cagerCY.
floppies kept safe (the train was electric). We told him to try wrapping >>> in aluminum kitchen foil, or perhaps in a cookie tin box. I don't
remember what he did exactly, but it worked.
In a perfect conductor, inside the material itself (such as
the cage walls), the electric field E is zero because free
charges move to cancel any applied electric field.
Faraday's law then implies that within the conductor, the magnetic
field B cannot be changing with time.
Changing magnetic fields induce currents (eddy currents).
These induced currents generate opposing magnetic fields
that cancel the time-varying components inside the conductor,
effectively shielding against changing magnetic fields.
But this does not imply zero magnetic field inside the conductor's
hollow interior (the cage's interior space). Static fields do not
induce currents because there is no changing magnetic flux within
the conductor to generate an electromotive force. Consequently,
these magnetic fields penetrate the cage interior unaffected.
Also, real materials might not be perfect conductors. And it
seems that, in practice, a Faraday cage can possibly protect
to some extend against fast changing magnetic fields, but less
against slowly changing magnetic fields.
Pancho <Pancho.Jones@protonmail.com> writes:
I've never trusted the idea as /home/user being for user controlled
data, distinct from the installed system. This folder standardly
contains user preferences/config for the OS and installed
applications.
It does, but it also explicitly intended for the userrCOs own data.
If you install a difference OS or different applications, the
configuration files might not be consistent. I wouldn't assume I could
take /home from one system and drop it onto a different system.
Configuration files for (say) your desktop environment might not work,
if the desktop environments available on the two systems are genuinely different (like KDE vs Gnome).
But for the most part there is very little real difference between the software on any two Linux distributions - perhaps little more than
compiler version & flags, and maybe some details of system file
locations.
So if I have important data files, documents, spreadsheets, etc. I try
not to store them under /home. Really speaking I only use /home/user
as a cache, I accept it is under the control of the system, rather
than under my control.
IrCOve no idea what difference you think that will make to anything. The location of your spreadsheet file makes no difference to whether your spreadsheet application can use it. If you use a _different spreadsheet application_ (e.g. Libreoffice vs Excel) then that will make a
difference but the file location is irrelevant.
On 10/6/25 06:29, Stefan Ram wrote:
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or quoted: >>> On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with
his floppies kept safe (the train was electric). We told him to
try wrapping in aluminum kitchen foil, or perhaps in a cookie tin
box. I don't remember what he did exactly, but it worked.
rCLFaraday cagerCY.
In a perfect conductor, inside the material itself (such as the
cage walls), the electric field E is zero because free charges
move to cancel any applied electric field.
Faraday's law then implies that within the conductor, the
magnetic field B cannot be changing with time.
Changing magnetic fields induce currents (eddy currents). These
induced currents generate opposing magnetic fields that cancel
the time-varying components inside the conductor, effectively
shielding against changing magnetic fields.
But this does not imply zero magnetic field inside the
conductor's hollow interior (the cage's interior space). Static
fields do not induce currents because there is no changing
magnetic flux within the conductor to generate an electromotive
force. Consequently, these magnetic fields penetrate the cage
interior unaffected.
Also, real materials might not be perfect conductors. And it
seems that, in practice, a Faraday cage can possibly protect to
some extend against fast changing magnetic fields, but less
against slowly changing magnetic fields.
It would take a fairly extreme static/slow-changing
field to erase floppies. You can do it - I just did
a couple weeks ago - using a neo magnet at point blank
range - but fields from train motors, I just don't
see it. High-frequency mag fields are more dangerous
but even THEN would need to be pretty strong.
My guess is that we're hearing an "urban legend"
here.
c186282 <c186282@nnada.net> wrote:
On 10/6/25 06:29, Stefan Ram wrote:
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or quoted: >>>> On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with
his floppies kept safe (the train was electric). We told him to
try wrapping in aluminum kitchen foil, or perhaps in a cookie tin
box. I don't remember what he did exactly, but it worked.
rCLFaraday cagerCY.
In a perfect conductor, inside the material itself (such as the
cage walls), the electric field E is zero because free charges
move to cancel any applied electric field.
Faraday's law then implies that within the conductor, the
magnetic field B cannot be changing with time.
Changing magnetic fields induce currents (eddy currents). These
induced currents generate opposing magnetic fields that cancel
the time-varying components inside the conductor, effectively
shielding against changing magnetic fields.
But this does not imply zero magnetic field inside the
conductor's hollow interior (the cage's interior space). Static
fields do not induce currents because there is no changing
magnetic flux within the conductor to generate an electromotive
force. Consequently, these magnetic fields penetrate the cage
interior unaffected.
Also, real materials might not be perfect conductors. And it
seems that, in practice, a Faraday cage can possibly protect to
some extend against fast changing magnetic fields, but less
against slowly changing magnetic fields.
It would take a fairly extreme static/slow-changing
field to erase floppies. You can do it - I just did
a couple weeks ago - using a neo magnet at point blank
range - but fields from train motors, I just don't
see it. High-frequency mag fields are more dangerous
but even THEN would need to be pretty strong.
The drop off of magnetic field intensity by distance can be
**approximated** as 1/(d^3) (inverse cube drop). So yes, the field
from the train motors would need to be extremely strong, or the OP's
floppies would have had to be very close to the motors, for the
electric train motors to have any impact on the floppies.
My guess is that we're hearing an "urban legend"
here.
Yes. There are a lot of those that go around. And since the "foil
wrap" did nothing, but the floppies were undamaged (and the person did
not do an A-B test with some wrapped, some unwrapped) they delude
themselves into belieiving the foil wrap actually did something.
On 2025-10-07 17:16, Rich wrote:
c186282 <c186282@nnada.net> wrote:
On 10/6/25 06:29, Stefan Ram wrote:
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or
quoted:
On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with
his floppies kept safe (the train was electric).-a We told him to
try wrapping in aluminum kitchen foil, or perhaps in a cookie tin
box.-a I don't remember what he did exactly, but it worked.
rCLFaraday cagerCY.
-a-a-a In a perfect conductor, inside the material itself (such as the >>>> -a-a-a cage walls), the electric field E is zero because free charges
-a-a-a move to cancel any applied electric field.
-a-a-a Faraday's law then implies that within the conductor, the
-a-a-a magnetic field B cannot be changing with time.
-a-a-a Changing magnetic fields induce currents (eddy currents).-a These >>>> -a-a-a induced currents generate opposing magnetic fields that cancel
-a-a-a the time-varying components inside the conductor, effectively
-a-a-a shielding against changing magnetic fields.
-a-a-a But this does not imply zero magnetic field inside the
-a-a-a conductor's hollow interior (the cage's interior space).-a Static >>>> -a-a-a fields do not induce currents because there is no changing
-a-a-a magnetic flux within the conductor to generate an electromotive >>>> -a-a-a force.-a Consequently, these magnetic fields penetrate the cage >>>> -a-a-a interior unaffected.
-a-a-a Also, real materials might not be perfect conductors.-a And it
-a-a-a seems that, in practice, a Faraday cage can possibly protect to >>>> -a-a-a some extend against fast changing magnetic fields, but less
-a-a-a against slowly changing magnetic fields.
-a-a It would take a fairly extreme static/slow-changing
-a-a field to erase floppies. You can do it - I just did
-a-a a couple weeks ago - using a neo magnet at point blank
-a-a range - but fields from train motors, I just don't
-a-a see it. High-frequency mag fields are more dangerous
-a-a but even THEN would need to be pretty strong.
The drop off of magnetic field intensity by distance can be
**approximated** as 1/(d^3) (inverse cube drop).-a So yes, the field
from the train motors would need to be extremely strong, or the OP's
floppies would have had to be very close to the motors, for the
electric train motors to have any impact on the floppies.
Well, some trains have motors on every carriage. Then also there was the thought that the overhead cable carried large currents and perhaps
produced large fields.
It was just the fear that something might happen to the floppies, and
what should we do to prevent hypothetical damage. We had no experience,
and there was no internet to ask other people.
-a-a My guess is that we're hearing an "urban legend"
-a-a here.
Yes.-a There are a lot of those that go around.-a And since the "foil
wrap" did nothing, but the floppies were undamaged (and the person did
not do an A-B test with some wrapped, some unwrapped) they delude
themselves into belieiving the foil wrap actually did something.
I don't remember if we used just foil, or a tin box, or both. Also, I
don't remember if there was another floppy outside. I might ask the
other chap if you people are that interested.
c186282 <c186282@nnada.net> wrote:
On 10/6/25 06:29, Stefan Ram wrote:
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or quoted: >>>> On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with
his floppies kept safe (the train was electric). We told him to
try wrapping in aluminum kitchen foil, or perhaps in a cookie tin
box. I don't remember what he did exactly, but it worked.
rCLFaraday cagerCY.
In a perfect conductor, inside the material itself (such as the
cage walls), the electric field E is zero because free charges
move to cancel any applied electric field.
Faraday's law then implies that within the conductor, the
magnetic field B cannot be changing with time.
Changing magnetic fields induce currents (eddy currents). These
induced currents generate opposing magnetic fields that cancel
the time-varying components inside the conductor, effectively
shielding against changing magnetic fields.
But this does not imply zero magnetic field inside the
conductor's hollow interior (the cage's interior space). Static
fields do not induce currents because there is no changing
magnetic flux within the conductor to generate an electromotive
force. Consequently, these magnetic fields penetrate the cage
interior unaffected.
Also, real materials might not be perfect conductors. And it
seems that, in practice, a Faraday cage can possibly protect to
some extend against fast changing magnetic fields, but less
against slowly changing magnetic fields.
It would take a fairly extreme static/slow-changing
field to erase floppies. You can do it - I just did
a couple weeks ago - using a neo magnet at point blank
range - but fields from train motors, I just don't
see it. High-frequency mag fields are more dangerous
but even THEN would need to be pretty strong.
The drop off of magnetic field intensity by distance can be
**approximated** as 1/(d^3) (inverse cube drop). So yes, the field
from the train motors would need to be extremely strong, or the OP's
floppies would have had to be very close to the motors, for the
electric train motors to have any impact on the floppies.
My guess is that we're hearing an "urban legend"
here.
Yes. There are a lot of those that go around. And since the "foil
wrap" did nothing, but the floppies were undamaged (and the person did
not do an A-B test with some wrapped, some unwrapped) they delude
themselves into belieiving the foil wrap actually did something.
On 2025-10-07 17:16, Rich wrote:
c186282 <c186282@nnada.net> wrote:
On 10/6/25 06:29, Stefan Ram wrote:
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or
quoted:
On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with
his floppies kept safe (the train was electric).-a We told him to
try wrapping in aluminum kitchen foil, or perhaps in a cookie tin
box.-a I don't remember what he did exactly, but it worked.
rCLFaraday cagerCY.
-a-a-a In a perfect conductor, inside the material itself (such as the >>>> -a-a-a cage walls), the electric field E is zero because free charges
-a-a-a move to cancel any applied electric field.
-a-a-a Faraday's law then implies that within the conductor, the
-a-a-a magnetic field B cannot be changing with time.
-a-a-a Changing magnetic fields induce currents (eddy currents).-a These >>>> -a-a-a induced currents generate opposing magnetic fields that cancel
-a-a-a the time-varying components inside the conductor, effectively
-a-a-a shielding against changing magnetic fields.
-a-a-a But this does not imply zero magnetic field inside the
-a-a-a conductor's hollow interior (the cage's interior space).-a Static >>>> -a-a-a fields do not induce currents because there is no changing
-a-a-a magnetic flux within the conductor to generate an electromotive >>>> -a-a-a force.-a Consequently, these magnetic fields penetrate the cage >>>> -a-a-a interior unaffected.
-a-a-a Also, real materials might not be perfect conductors.-a And it
-a-a-a seems that, in practice, a Faraday cage can possibly protect to >>>> -a-a-a some extend against fast changing magnetic fields, but less
-a-a-a against slowly changing magnetic fields.
-a-a It would take a fairly extreme static/slow-changing
-a-a field to erase floppies. You can do it - I just did
-a-a a couple weeks ago - using a neo magnet at point blank
-a-a range - but fields from train motors, I just don't
-a-a see it. High-frequency mag fields are more dangerous
-a-a but even THEN would need to be pretty strong.
The drop off of magnetic field intensity by distance can be
**approximated** as 1/(d^3) (inverse cube drop).-a So yes, the field
from the train motors would need to be extremely strong, or the OP's
floppies would have had to be very close to the motors, for the
electric train motors to have any impact on the floppies.
Well, some trains have motors on every carriage. Then also there was the thought that the overhead cable carried large currents and perhaps
produced large fields.
It was just the fear that something might happen to the floppies, and
what should we do to prevent hypothetical damage. We had no experience,
and there was no internet to ask other people.
-a-a My guess is that we're hearing an "urban legend"
-a-a here.
Yes.-a There are a lot of those that go around.-a And since the "foil
wrap" did nothing, but the floppies were undamaged (and the person did
not do an A-B test with some wrapped, some unwrapped) they delude
themselves into belieiving the foil wrap actually did something.
I don't remember if we used just foil, or a tin box, or both. Also, I
don't remember if there was another floppy outside. I might ask the
other chap if you people are that interested.
On 10/5/25 09:51, Richard Kettlewell wrote:Look ... you're kind of treading the line between
Pancho <Pancho.Jones@protonmail.com> writes:
I've never trusted the idea as /home/user being for user controlled
data, distinct from the installed system. This folder standardly
contains user preferences/config for the OS and installed
applications.
It does, but it also explicitly intended for the userrCOs own data.
Yes, I understand that. I'm questioning if it is best to follow that intention, or to instead create my own data area.
On 10/7/25 20:34, Carlos E.R. wrote:
On 2025-10-07 17:16, Rich wrote:
c186282 <c186282@nnada.net> wrote:
On 10/6/25 06:29, Stefan Ram wrote:
Lawrence =?iso-8859-13?q?D=FFOliveiro?= <ldo@nz.invalid> wrote or
quoted:
On Thu, 25 Sep 2025 13:04:59 +0200, Carlos E.R. wrote:
At some point in the 80's, a friend at uni wanted to go home with >>>>>>> his floppies kept safe (the train was electric).-a We told him to >>>>>>> try wrapping in aluminum kitchen foil, or perhaps in a cookie tin >>>>>>> box.-a I don't remember what he did exactly, but it worked.
rCLFaraday cagerCY.
-a-a-a In a perfect conductor, inside the material itself (such as the >>>>> -a-a-a cage walls), the electric field E is zero because free charges >>>>> -a-a-a move to cancel any applied electric field.
-a-a-a Faraday's law then implies that within the conductor, the
-a-a-a magnetic field B cannot be changing with time.
-a-a-a Changing magnetic fields induce currents (eddy currents).-a These >>>>> -a-a-a induced currents generate opposing magnetic fields that cancel >>>>> -a-a-a the time-varying components inside the conductor, effectively >>>>> -a-a-a shielding against changing magnetic fields.
-a-a-a But this does not imply zero magnetic field inside the
-a-a-a conductor's hollow interior (the cage's interior space).-a Static >>>>> -a-a-a fields do not induce currents because there is no changing
-a-a-a magnetic flux within the conductor to generate an electromotive >>>>> -a-a-a force.-a Consequently, these magnetic fields penetrate the cage >>>>> -a-a-a interior unaffected.
-a-a-a Also, real materials might not be perfect conductors.-a And it >>>>> -a-a-a seems that, in practice, a Faraday cage can possibly protect to >>>>> -a-a-a some extend against fast changing magnetic fields, but less
-a-a-a against slowly changing magnetic fields.
-a-a It would take a fairly extreme static/slow-changing
-a-a field to erase floppies. You can do it - I just did
-a-a a couple weeks ago - using a neo magnet at point blank
-a-a range - but fields from train motors, I just don't
-a-a see it. High-frequency mag fields are more dangerous
-a-a but even THEN would need to be pretty strong.
The drop off of magnetic field intensity by distance can be
**approximated** as 1/(d^3) (inverse cube drop).-a So yes, the field
from the train motors would need to be extremely strong, or the OP's
floppies would have had to be very close to the motors, for the
electric train motors to have any impact on the floppies.
Well, some trains have motors on every carriage. Then also there was
the thought that the overhead cable carried large currents and perhaps
produced large fields.
It was just the fear that something might happen to the floppies, and
what should we do to prevent hypothetical damage. We had no
experience, and there was no internet to ask other people.
-a-a My guess is that we're hearing an "urban legend"
-a-a here.
Yes.-a There are a lot of those that go around.-a And since the "foil
wrap" did nothing, but the floppies were undamaged (and the person did
not do an A-B test with some wrapped, some unwrapped) they delude
themselves into belieiving the foil wrap actually did something.
I don't remember if we used just foil, or a tin box, or both. Also, I
don't remember if there was another floppy outside. I might ask the
other chap if you people are that interested.
-a SOME precautions are logical, esp when the level
-a of danger is unclear.
-a However train motors/feeds ... sorry, just can't
-a see it. The fields would be much too small. The
-a train body also acts as protection.
-a The field needed to erase a floppy ... it'd also
-a fatally magnetize mechanical watches and such and
-a erase audio tapes. Remember when music came on
-a cassette tapes, you paid $$$ for those.
-a The neo mag I used to 'clear' a mis-sectored floppy
-a is, at point-blank range, EXTREME. You don't want to
-a get your finger between two of those. Before the
-a tariffs you could buy 6x4x2-inch neo mags polarized
-a across the z axis. Don't know HOW you'd get those
-a off anything they stuck to. They all came with
-a warning messages. If your hand was in the way
-a it'd be literally pulped. I have a stack of 25x12mm
-a discs - indeed it's two stacks of 6 to 8. I keep
-a them separated by attracting each other thru a
-a 3/4" shelf board.
-a So, floppies/tapes/hdds erasing ... I'm still going
-a to put it down as an old "urban legend".
-a High freqs, 400hz and a bit above, are best for
-a erasing magnetic media. The reversing field does
-a not have time to solidify a new bias in the
-a media. The best scheme is to start with a large
-a field and then taper. For "destruction" 50/60hz
-a will do ok.
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
On 10/7/25 04:56, Pancho wrote:utility/safety.
On 10/5/25 09:51, Richard Kettlewell wrote:-a Look ... you're kind of treading the line between
Pancho <Pancho.Jones@protonmail.com> writes:
I've never trusted the idea as /home/user being for user controlled
data, distinct from the installed system. This folder standardly
contains user preferences/config for the OS and installed
applications.
It does, but it also explicitly intended for the userrCOs own data.
Yes, I understand that. I'm questioning if it is best to follow that
intention, or to instead create my own data area.
-a "home system" and biz SERVER.
-a Servers really do need to be set up differently> -a for max
-a So, "best" is "mission-centric".
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
I'm questioning if it is best to follow that intention, or to instead
create my own data area.
On Tue, 7 Oct 2025 09:56:08 +0100
Pancho <Pancho.Jones@protonmail.com> wrote:
I'm questioning if it is best to follow that intention, or to instead
create my own data area.
Personally, I've long been in the habit of making a separate partition
for large-scale local storage (do have a home fileserver, but that only
gets you anywhere when you're on the home network.) /home is fine for
config files, one-off working documents, and unsorted downloads, but it quickly gets cluttered if I store *everything* there. Having a separate partition with a (vaguely) well-organized directory structure for media/ documents/larger-scale project files makes it a lot easier to find
stuff later, without having to resort to some kind of indexing/search utility.
On Tue, 7 Oct 2025 09:56:08 +0100
Pancho <Pancho.Jones@protonmail.com> wrote:
I'm questioning if it is best to follow that intention, or to instead
create my own data area.
Personally, I've long been in the habit of making a separate partition
for large-scale local storage (do have a home fileserver, but that only
gets you anywhere when you're on the home network.) /home is fine for
config files, one-off working documents, and unsorted downloads, but it quickly gets cluttered if I store *everything* there. Having a separate partition with a (vaguely) well-organized directory structure for media/ documents/larger-scale project files makes it a lot easier to find
stuff later, without having to resort to some kind of indexing/search utility.
Having a separate partition with a (vaguely) well-organized
directory structure ...
I create a separate data partition. After install I move my
Documents, Downloads, Music, and Videos directories to the data
partion and then create symlinks to those directories from within
$HOME.
Certainly, but keeping it separate allows for some fine-tuning (e.g.Having a separate partition with a (vaguely) well-organized
directory structure ...
You can have the latter without the former. Remember, *nix systems
maintain a single directory hierarchy, regardless of how the storage
may actually be partitioned into separate volumes.
On 08/10/2025 13:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:That may well be true
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
On 10/8/25 06:55, c186282 wrote:
On 10/7/25 04:56, Pancho wrote:
On 10/5/25 09:51, Richard Kettlewell wrote:-a-a Look ... you're kind of treading the line between
Pancho <Pancho.Jones@protonmail.com> writes:
I've never trusted the idea as /home/user being for user controlled
data, distinct from the installed system. This folder standardly
contains user preferences/config for the OS and installed
applications.
It does, but it also explicitly intended for the userrCOs own data.
Yes, I understand that. I'm questioning if it is best to follow that
intention, or to instead create my own data area.
-a-a "home system" and biz SERVER.
-a -a Servers really do need to be set up differently>-a -a for max utility/safety.
-a-a So, "best" is "mission-centric".
I don't know what you mean? I used servers at work and, they were
similar to my workstation, not public facing.
Nowadays, I think a biz SERVER is more likely to be a service, a docker container (swarm) running a webserver or something. The security
concerns are different to those of Linux user accounts.
I'm basically whinging that OS/Desktop designers have hosed my personal
play area, MS Windows does it too.
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
On 2025-10-08 14:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
You can buy wallets that claim to be shielded. For NFC.
On 08/10/2025 13:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:That may well be true
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
On Tue, 7 Oct 2025 09:56:08 +0100
Pancho <Pancho.Jones@protonmail.com> wrote:
I'm questioning if it is best to follow that intention, or to instead
create my own data area.
Personally, I've long been in the habit of making a separate partition
for large-scale local storage (do have a home fileserver, but that only
gets you anywhere when you're on the home network.) /home is fine for
config files, one-off working documents, and unsorted downloads, but it quickly gets cluttered if I store *everything* there. Having a separate partition with a (vaguely) well-organized directory structure for media/ documents/larger-scale project files makes it a lot easier to find
stuff later, without having to resort to some kind of indexing/search utility.
On Wed, 8 Oct 2025 09:02:09 -0700, John Ames wrote:
Having a separate partition with a (vaguely) well-organized
directory structure ...
You can have the latter without the former. Remember, *nix systems
maintain a single directory hierarchy, regardless of how the storage
may actually be partitioned into separate volumes.
On 2025-10-08, The Natural Philosopher <tnp@invalid.invalid> wrote:
On 08/10/2025 13:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:That may well be true
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
Did the test.
My second-to-most-recent emplyer had NFC/RFID badge cards that
each employee was required to scan at the lobby when entering a
facility. For the test of one of the metal-lined sleeves, I
asked the "guard" at the desk for permission to test the sleeve
by doing an experiment to see whether the ID badge card could be
read while inside the sleeve. The "guard" said he would watch
his monitor while I attempted to scan the sleeved badge card. He
said his system could not see that the badge card existed while
it was in the sleeve. Outside the sleeve, the badge card worked
perfectly.
Based on that test, it appears that sleeve was sufficient to
sheild at least the type of NFC/RFID used in that badge card.
You can buy wallets that claim to be shielded. For NFC.
I create a separate data partition. After install I move my Documents, Downloads, Music,
and Videos directories to the data partion and then create symlinks to
those directories
from within $HOME.
For backup, I rsync the data directory, /home, /etc, and portions of
/var to a usb stick. I rotate
multiple 128GB usb sticks for the backup.
Regards, Dave Hodgins
On Wed, 8 Oct 2025 21:13:01 -0000 (UTC)
Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:
Having a separate partition with a (vaguely) well-organized
directory structure ...
You can have the latter without the former. Remember, *nix systems
maintain a single directory hierarchy, regardless of how the storage
may actually be partitioned into separate volumes.
Certainly, but keeping it separate allows for some fine-tuning (e.g.
picking a larger inode size for a partition where small files will be
the exception rather than the rule.)
On 2025-10-08, The Natural Philosopher <tnp@invalid.invalid> wrote:
On 08/10/2025 13:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:That may well be true
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
Did the test.
My second-to-most-recent emplyer had NFC/RFID badge cards that
each employee was required to scan at the lobby when entering a
facility. For the test of one of the metal-lined sleeves, I
asked the "guard" at the desk for permission to test the sleeve
by doing an experiment to see whether the ID badge card could be
read while inside the sleeve. The "guard" said he would watch
his monitor while I attempted to scan the sleeved badge card. He
said his system could not see that the badge card existed while
it was in the sleeve. Outside the sleeve, the badge card worked
perfectly.
Based on that test, it appears that sleeve was sufficient to
sheild at least the type of NFC/RFID used in that badge card.
On 08/10/2025 22:29, John Ames wrote:
On Wed, 8 Oct 2025 21:13:01 -0000 (UTC)Crikey, how long has THAT been an issue.
Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:
Having a separate partition with a (vaguely) well-organized
directory structure ...
You can have the latter without the former. Remember, *nix systems
maintain a single directory hierarchy, regardless of how the storage
may actually be partitioned into separate volumes.
Certainly, but keeping it separate allows for some fine-tuning (e.g.
picking a larger inode size for a partition where small files will be
the exception rather than the rule.)
Like the time you had to define how many TCP/IP buffers or virtual
ttys you had... Suddenly there was enough memory and disk space to
not give a shit
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent >>invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those RFID cards
today, and they're thinking about wrapping them in aluminum foil to
make it harder to scan them.
Certainly, but keeping it separate allows for some fine-tuning (e.g. picking a larger inode size for a partition where small files willCrikey, how long has THAT been an issue. Like the time you had to
be the exception rather than the rule.)
define how many TCP/IP buffers or virtual ttys you had... Suddenly
there was enough memory and disk space to not give a shit
Stefan Ram <ram@zedat.fu-berlin.de> wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent >>>invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those RFID cards
today, and they're thinking about wrapping them in aluminum foil to
make it harder to scan them.
Given that RFID is electromagnetic (radio) comms, and very low power,
an aluminum foil wrap (creating an ungrounded Faraday cage) just might attenuate the signal enough to prevent a "read" from happening.
On 2025-10-09, Rich wrote:
Stefan Ram <ram@zedat.fu-berlin.de> wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent >>>>invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those RFID cards
today, and they're thinking about wrapping them in aluminum foil to
make it harder to scan them.
Given that RFID is electromagnetic (radio) comms, and very low power,
an aluminum foil wrap (creating an ungrounded Faraday cage) just might
attenuate the signal enough to prevent a "read" from happening.
Doesn't it need a non-conductive layer too? What is the state of the art
for cheap shielding of contactless smartcards?
Carlos E.R. wrote:
You can buy wallets that claim to be shielded. For NFC.
Nowadays I only use my phone to pay which does not proceed with the
payment until I authorize it with my fingerprint.
On 10/8/25 08:14, Carlos E.R. wrote:
On 2025-10-08 14:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
You can buy wallets that claim to be shielded. For NFC.
-a Mag HDDs generally come wrapped in heavily
-a metal coated plastic. I saved those wrappers.
-a One large piece in the outside fold of the
-a wallet, and a secondary pouch for the little
-a space where the cards reside.
-a Maybe not necessary, but can't hurt.
Carlos E.R. wrote:
You can buy wallets that claim to be shielded. For NFC.
Nowadays I only use my phone to pay which does not proceed with the
payment until I authorize it with my fingerprint.
On Thu, 9 Oct 2025 12:37:30 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:
Certainly, but keeping it separate allows for some fine-tuning (e.g.Crikey, how long has THAT been an issue. Like the time you had to
picking a larger inode size for a partition where small files will
be the exception rather than the rule.)
define how many TCP/IP buffers or virtual ttys you had... Suddenly
there was enough memory and disk space to not give a shit
Everybody can feel free to make their own judgements - but in my own experience, "more than enough disk space" always manages to grind its
way down to "not as much space as I thought" eventually. Parkinson's
Law is an insidious force...
On 2025-10-09 08:44, c186282 wrote:
On 10/8/25 08:14, Carlos E.R. wrote:
On 2025-10-08 14:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
You can buy wallets that claim to be shielded. For NFC.
-a-a Mag HDDs generally come wrapped in heavily
-a-a metal coated plastic. I saved those wrappers.
-a-a One large piece in the outside fold of the
-a-a wallet, and a secondary pouch for the little
-a-a space where the cards reside.
-a-a Maybe not necessary, but can't hurt.
I sometimes put a bit of aluminum foil there, but it doesn't last a
month. Your idea seems better.
On 2025-10-09 12:50, Joerg Walther wrote:
Carlos E.R. wrote:
You can buy wallets that claim to be shielded. For NFC.
Nowadays I only use my phone to pay which does not proceed with the
payment until I authorize it with my fingerprint.
Yes, but sometimes it fails.
Also, at least in my case, my bank tell us to use google pay, so they
track us.
On 09/10/2025 04:09, Robert Riches wrote:
On 2025-10-08, The Natural Philosopher <tnp@invalid.invalid> wrote:Good. My time designing radios inside tin boxes was not wasted then! Irrelevant factoid. Back when I was involved in professional RF design, there was a rule of thumb, which more or less said 'you will never get a design stable unless it has less gain that 20 dB per inch of separation between stages'. It was surprisingly accurate. But then we started
On 08/10/2025 13:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:That may well be true
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
Did the test.
My second-to-most-recent emplyer had NFC/RFID badge cards that
each employee was required to scan at the lobby when entering a
facility. For the test of one of the metal-lined sleeves, I
asked the "guard" at the desk for permission to test the sleeve
by doing an experiment to see whether the ID badge card could be
read while inside the sleeve. The "guard" said he would watch
his monitor while I attempted to scan the sleeved badge card. He
said his system could not see that the badge card existed while
it was in the sleeve. Outside the sleeve, the badge card worked
perfectly.
Based on that test, it appears that sleeve was sufficient to
sheild at least the type of NFC/RFID used in that badge card.
needing to pack all this stuff into small guided missiles, and as the
parts got smaller so did the permissible separation. Then we started building little tin walls round each stage and got it even smaller...and when ICs game along they were so small that the radiation coupling
between input and output was soi low that they could cram 60dB into a
single chip.
Tinfoil blocks RF. Juts come to my house which uses foil backed
plasterboard everywhere. we ordered some for the bathrooms and over
ordered so we used it everywhere.
Cant get a wifi signal from one room to another at all.
On 2025-10-09, The Natural Philosopher <tnp@invalid.invalid> wrote:
On 09/10/2025 04:09, Robert Riches wrote:
On 2025-10-08, The Natural Philosopher <tnp@invalid.invalid> wrote:Good. My time designing radios inside tin boxes was not wasted then!
On 08/10/2025 13:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:That may well be true
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those
RFID cards today, and they're thinking about wrapping
them in aluminum foil to make it harder to scan them.
Did the test.
My second-to-most-recent emplyer had NFC/RFID badge cards that
each employee was required to scan at the lobby when entering a
facility. For the test of one of the metal-lined sleeves, I
asked the "guard" at the desk for permission to test the sleeve
by doing an experiment to see whether the ID badge card could be
read while inside the sleeve. The "guard" said he would watch
his monitor while I attempted to scan the sleeved badge card. He
said his system could not see that the badge card existed while
it was in the sleeve. Outside the sleeve, the badge card worked
perfectly.
Based on that test, it appears that sleeve was sufficient to
sheild at least the type of NFC/RFID used in that badge card.
Irrelevant factoid. Back when I was involved in professional RF design,
there was a rule of thumb, which more or less said 'you will never get a
design stable unless it has less gain that 20 dB per inch of separation
between stages'. It was surprisingly accurate. But then we started
needing to pack all this stuff into small guided missiles, and as the
parts got smaller so did the permissible separation. Then we started
building little tin walls round each stage and got it even smaller...and
when ICs game along they were so small that the radiation coupling
between input and output was soi low that they could cram 60dB into a
single chip.
Tinfoil blocks RF. Juts come to my house which uses foil backed
plasterboard everywhere. we ordered some for the bathrooms and over
ordered so we used it everywhere.
Cant get a wifi signal from one room to another at all.
On a house, aluminum siding also attenuates (US bands) AM (and I
think FM) broadcast radio. A couple of decades ago, I lived in a
house with aluminum siding. Enough signal got through to listen,
but the SNR was not as good as it would have been without the
aluminum.
On a little different angle of RF oddities, in a house without
aluminum siding but possibly with foil-backed fiberglass
insulation in the exterior walls, my Casio G-Shock watch (near
Portland, Oregon, USA) had great difficulty receiving the 60kHz
signal from WWVB. Even outdoors, reception was not very
reliable. However, ever since getting Comcast Xfinity internet
over coax, indoor reception is fairly close to flawless. Most
nights, it sets at 12:03am, which is the best possible case. My
hunch is the above-ground (pun not intended) TV distribution
system and the coax from the utility pole to the house act as a
passive antenna booster for the watch.
On 10/9/25 06:50, Joerg Walther wrote:
Carlos E.R. wrote:
You can buy wallets that claim to be shielded. For NFC.
Nowadays I only use my phone to pay which does not proceed with the
payment until I authorize it with my fingerprint.
You gave Russia your fingerprint ???
On 2025-10-10, c186282 <c186282@nnada.net> wrote:
On 10/9/25 06:50, Joerg Walther wrote:
Carlos E.R. wrote:
You can buy wallets that claim to be shielded. For NFC.
Nowadays I only use my phone to pay which does not proceed with the
payment until I authorize it with my fingerprint.
You gave Russia your fingerprint ???
No, just Google.
On 08/10/2025 17:02, John Ames wrote:
Well I have a local /home for config data, but all my *real* data is on
a /home/me on my Linux NAS
Along with partitions for music and videos. Which I don't actually
routinely back up
In extremis I CAN access my NAS remotely. Like if I am visiting family
on another continent, but I forget how. Some ssh port in a weird place I think.
The media server is readonly globally accessible though. via https/password--
Handy when stuck in hospital. Full of e-books, music and old Westerns etc.
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 08/10/2025 22:29, John Ames wrote:
On Wed, 8 Oct 2025 21:13:01 -0000 (UTC)Crikey, how long has THAT been an issue.
Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:
Having a separate partition with a (vaguely) well-organized
directory structure ...
You can have the latter without the former. Remember, *nix systems
maintain a single directory hierarchy, regardless of how the storage
may actually be partitioned into separate volumes.
Certainly, but keeping it separate allows for some fine-tuning (e.g.
picking a larger inode size for a partition where small files will be
the exception rather than the rule.)
It /effectively/ ceased being an issue somewhere around about the
latter ext3 or early ext4 filesystem days. Except for *very* unsusal
usage patterns (i.e., Usenet NNTP spools stored as files directly in
the filesystem) it is no longer something anyone thinks about anymore.
Yes, there's a "limit", but much like with "64-bit memory space" the
limit is so large it is all but near impossible to actually hit it
anymore.
A quick check here with 'df -i' shows all but one mounted filesystem in
the single digit percentage usage of inodes. The one 'worst' case (a
4T disk for media encoding/transcoding and other misc usages) is only consuming 17% of its max inodes.
Stefan Ram <ram@zedat.fu-berlin.de> wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those RFID cards
today, and they're thinking about wrapping them in aluminum foil to
make it harder to scan them.
Given that RFID is electromagnetic (radio) comms, and very low power,
an aluminum foil wrap (creating an ungrounded Faraday cage) just might attenuate the signal enough to prevent a "read" from happening.
On 2025-10-09, Rich wrote:Not really no.
Stefan Ram <ram@zedat.fu-berlin.de> wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
Some people around here are walking around with those RFID cards
today, and they're thinking about wrapping them in aluminum foil to
make it harder to scan them.
Given that RFID is electromagnetic (radio) comms, and very low power,
an aluminum foil wrap (creating an ungrounded Faraday cage) just might
attenuate the signal enough to prevent a "read" from happening.
Doesn't it need a non-conductive layer too?
What is the state of the art
for cheap shielding of contactless smartcards?
On 10/9/25 12:00, John Ames wrote:
On Thu, 9 Oct 2025 12:37:30 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:
Certainly, but keeping it separate allows for some fine-tuning (e.g.Crikey, how long has THAT been an issue. Like the time you had to
picking a larger inode size for a partition where small files will
be the exception rather than the rule.)
define how many TCP/IP buffers or virtual ttys you had... Suddenly
there was enough memory and disk space to not give a shit
Everybody can feel free to make their own judgements - but in my own
experience, "more than enough disk space" always manages to grind its
way down to "not as much space as I thought" eventually. Parkinson's
Law is an insidious force...
-a Yep, there's NEVER "enough" space-a :-)
-a Kind of like building a bigger closet, it too
-a will be packed to overflowing within a year.
-a A lot of people work with 8+ K 120fps video now,
-a that'll fill drive and memory up really quick.
On 10/9/25 15:10, Carlos E.R. wrote:
On 2025-10-09 08:44, c186282 wrote:
On 10/8/25 08:14, Carlos E.R. wrote:
On 2025-10-08 14:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
You can buy wallets that claim to be shielded. For NFC.
-a-a Mag HDDs generally come wrapped in heavily
-a-a metal coated plastic. I saved those wrappers.
-a-a One large piece in the outside fold of the
-a-a wallet, and a secondary pouch for the little
-a-a space where the cards reside.
-a-a Maybe not necessary, but can't hurt.
I sometimes put a bit of aluminum foil there, but it doesn't last a
month. Your idea seems better.
-a Actual foil falls apart pretty quick.
-a Western Digital always wrapped its primo drives
-a in heavily-metalized plastic, it can take a
-a crease, unlike the semi-transparent crap used
-a for most devices these days. It also doesn't
-a fall apart in a wallet.
-a You could maybe make a fake version of that ...
-a thin polyester film, some spray glue and foil
-a stuck to both sides.
On 2025-10-10, c186282 <c186282@nnada.net> wrote:
On 10/9/25 06:50, Joerg Walther wrote:
Carlos E.R. wrote:
You can buy wallets that claim to be shielded. For NFC.
Nowadays I only use my phone to pay which does not proceed with the
payment until I authorize it with my fingerprint.
You gave Russia your fingerprint ???
No, just Google.
On 2025-10-08 18:35, The Natural Philosopher wrote:
On 08/10/2025 17:02, John Ames wrote:
Well I have a local /home for config data, but all my *real* data is
on a /home/me on my Linux NAS
Along with partitions for music and videos. Which I don't actually
routinely back up
In extremis I CAN access my NAS remotely. Like if I am visiting family
on another continent, but I forget how. Some ssh port in a weird place
I think.
On a Linux NAS:
sshfs username@remote.system:/ ~/fusermount/
mounts the remote filesystem at local directory ~/fusermount/, over a
plain ssh connection. Doesn't need anything extra on the server, just
the sshd daemon in working order.
Also, at least in my case, my bank tell us to use google pay, so they
track us.
On 10/10/2025 08:29, Carlos E.R. wrote:
On 2025-10-08 18:35, The Natural Philosopher wrote:Yeah. That's how it works, with a port specification.
On 08/10/2025 17:02, John Ames wrote:
Well I have a local /home for config data, but all my *real* data is
on a /home/me on my Linux NAS
Along with partitions for music and videos. Which I don't actually
routinely back up
In extremis I CAN access my NAS remotely. Like if I am visiting
family on another continent, but I forget how. Some ssh port in a
weird place I think.
On a Linux NAS:
sshfs username@remote.system:/ ~/fusermount/
mounts the remote filesystem at local directory ~/fusermount/, over a
plain ssh connection. Doesn't need anything extra on the server, just
the sshd daemon in working order.
Its good enough to find and grab files off the user data areas.
When I think that my minimum internet speed is what my maximum LAN speed
was 35 years ago...
Carlos E.R. wrote:
Also, at least in my case, my bank tell us to use google pay, so they
track us.
So you can't use other wallet apps, you are forced to use google pay?
On 10/9/25 15:10, Carlos E.R. wrote:
On 2025-10-09 08:44, c186282 wrote:
On 10/8/25 08:14, Carlos E.R. wrote:
On 2025-10-08 14:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention. We simply did not know. We invented the urban legends.
-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
You can buy wallets that claim to be shielded. For NFC.
-a-a Mag HDDs generally come wrapped in heavily
-a-a metal coated plastic. I saved those wrappers.
-a-a One large piece in the outside fold of the
-a-a wallet, and a secondary pouch for the little
-a-a space where the cards reside.
-a-a Maybe not necessary, but can't hurt.
I sometimes put a bit of aluminum foil there, but it doesn't last a
month. Your idea seems better.
-a Actual foil falls apart pretty quick.
-a Western Digital always wrapped its primo drives
-a in heavily-metalized plastic, it can take a
-a crease, unlike the semi-transparent crap used
-a for most devices these days. It also doesn't
-a fall apart in a wallet.
-a You could maybe make a fake version of that ...
-a thin polyester film, some spray glue and foil
-a stuck to both sides.
On 2025-10-10 10:58, The Natural Philosopher wrote:
Yeah. That's how it works, with a port specification.
I don't have to specify ports. If I use a non standard port, I configure that in the client .ssh/config:
Host host.dyndns
-a-a-a-a-a-a-a Port 5000
Its good enough to find and grab files off the user data areas.
When I think that my minimum internet speed is what my maximum LAN
speed was 35 years ago...
Heh, but maybe not everywhere.
On 10/10/2025 12:45, Carlos E.R. wrote:
On 2025-10-10 10:58, The Natural Philosopher wrote:
...where anyone who steals the laptop in a foreign land can find it.Yeah. That's how it works, with a port specification.
I don't have to specify ports. If I use a non standard port, I
configure that in the client .ssh/config:
Host host.dyndns
-a-a-a-a-a-a-a-a Port 5000
Its good enough to find and grab files off the user data areas.
When I think that my minimum internet speed is what my maximum LAN
speed was 35 years ago...
Heh, but maybe not everywhere.
Everywhere except the USA. And possibly Spain
On 2025-10-10 15:02, The Natural Philosopher wrote:
On 10/10/2025 12:45, Carlos E.R. wrote:
...where anyone who steals the laptop in a foreign land can find it.
Host host.dyndns
-a-a-a-a-a-a-a-a Port 5000
It is fully encrypted.
Anybody that steals a laptop can find the ssh command in the bash
history, too. Hopefully not the password to the remote system.
On 2025-10-09 17:07, Rich wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 08/10/2025 22:29, John Ames wrote:
On Wed, 8 Oct 2025 21:13:01 -0000 (UTC)Crikey, how long has THAT been an issue.
Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:
Having a separate partition with a (vaguely) well-organized
directory structure ...
You can have the latter without the former. Remember, *nix systems
maintain a single directory hierarchy, regardless of how the storage >>>>> may actually be partitioned into separate volumes.
Certainly, but keeping it separate allows for some fine-tuning (e.g.
picking a larger inode size for a partition where small files will be
the exception rather than the rule.)
It /effectively/ ceased being an issue somewhere around about the
latter ext3 or early ext4 filesystem days.-a Except for *very* unsusal
usage patterns (i.e., Usenet NNTP spools stored as files directly in
the filesystem) it is no longer something anyone thinks about anymore.
Yes, there's a "limit", but much like with "64-bit memory space" the
limit is so large it is all but near impossible to actually hit it
anymore.
A quick check here with 'df -i' shows all but one mounted filesystem in
the single digit percentage usage of inodes.-a The one 'worst' case (a
4T disk for media encoding/transcoding and other misc usages) is only
consuming 17% of its max inodes.
Telcontar:~ # df -i Filesystem-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a Inodes-a-a IUsed-a-a-a-a-a IFree IUse%
Mounted on
/dev/nvme0n1p5-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 9830400 2135223-a-a-a 7695177-a-a 22% /
...
/dev/sdc9-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 16777216 1632362-a-a 15144854-a-a 10% /
data/WasReiserfs-a-a-a-a-a-a-a (holds the news spool)
...
/dev/sdb10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 15295056-a 943965-a-a 14351091-a-a-a 7% /
data/storage_b
/dev/sdc10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 2621440-a 131132-a-a-a 2490308-a-a-a 6% /usr/
local
...
On 09/10/2025 16:16, Rich wrote:
Stefan Ram <ram@zedat.fu-berlin.de> wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent
invention.-a We simply did not know.-a We invented the urban legends.
-a-a Some people around here are walking around with those RFID cards
-a-a today, and they're thinking about wrapping them in aluminum foil to >>> -a-a make it harder to scan them.
Given that RFID is electromagnetic (radio) comms, and very low power,
an aluminum foil wrap (creating an ungrounded Faraday cage) just might
attenuate the signal enough to prevent a "read" from happening.
On consideration, it's more than might just. It's 'will, definitely.'
Unlike magnetic shielding RF shielding does not rely on mass or
thickness since HF currents circulate in the surface.
And aluminium is a very good conductor.
On 10/10/2025 02:24, c186282 wrote:
On 10/9/25 12:00, John Ames wrote:Actually I seem to have arrived at a limit for 'personal' use.
On Thu, 9 Oct 2025 12:37:30 +0100
The Natural Philosopher <tnp@invalid.invalid> wrote:
Certainly, but keeping it separate allows for some fine-tuning (e.g. >>>>> picking a larger inode size for a partition where small files willCrikey, how long has THAT been an issue. Like the time you had to
be the exception rather than the rule.)
define how many TCP/IP buffers or virtual ttys you had... Suddenly
there was enough memory and disk space to not give a shit
Everybody can feel free to make their own judgements - but in my own
experience, "more than enough disk space" always manages to grind its
way down to "not as much space as I thought" eventually. Parkinson's
Law is an insidious force...
-a-a Yep, there's NEVER "enough" space-a :-)
Running with a couple of terabytes for media and 24GB or RAM I simply
have now 'more than enough'
-a-a Kind of like building a bigger closet, it tooThen throw those old clothes that no longer fit away. Accept you will
-a-a will be packed to overflowing within a year.
never have a 30" waist ever again..
-a-a A lot of people work with 8+ K 120fps video now,
-a-a that'll fill drive and memory up really quick.
On 10/10/2025 02:36, c186282 wrote:
On 10/9/25 15:10, Carlos E.R. wrote:Copper foil with glue backing is available for EMF shielding., Very
On 2025-10-09 08:44, c186282 wrote:
On 10/8/25 08:14, Carlos E.R. wrote:
On 2025-10-08 14:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent >>>>>>> invention. We simply did not know. We invented the urban legends. >>>>>>-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
You can buy wallets that claim to be shielded. For NFC.
-a-a Mag HDDs generally come wrapped in heavily
-a-a metal coated plastic. I saved those wrappers.
-a-a One large piece in the outside fold of the
-a-a wallet, and a secondary pouch for the little
-a-a space where the cards reside.
-a-a Maybe not necessary, but can't hurt.
I sometimes put a bit of aluminum foil there, but it doesn't last a
month. Your idea seems better.
-a-a Actual foil falls apart pretty quick.
-a-a Western Digital always wrapped its primo drives
-a-a in heavily-metalized plastic, it can take a
-a-a crease, unlike the semi-transparent crap used
-a-a for most devices these days. It also doesn't
-a-a fall apart in a wallet.
-a-a You could maybe make a fake version of that ...
-a-a thin polyester film, some spray glue and foil
-a-a stuck to both sides.
useful for electric guitars. As is conductive paint
Yes, I can see that foil alone is mechanically weak, and probably needs
a plastic substrate for strength
On 10/10/2025 07:51, Charlie Gibbs wrote:
On 2025-10-10, c186282 <c186282@nnada.net> wrote:Is there a difference these days?
On 10/9/25 06:50, Joerg Walther wrote:
Carlos E.R. wrote:
You can buy wallets that claim to be shielded. For NFC.
Nowadays I only use my phone to pay which does not proceed with the
payment until I authorize it with my fingerprint.
-a-a-a You gave Russia your fingerprint ???
No, just Google.
On 2025-10-10 03:36, c186282 wrote:
On 10/9/25 15:10, Carlos E.R. wrote:
On 2025-10-09 08:44, c186282 wrote:
On 10/8/25 08:14, Carlos E.R. wrote:
On 2025-10-08 14:10, Stefan Ram wrote:
"Carlos E.R." <robin_listas@es.invalid> wrote or quoted:
There was no urban legend in those years, floppies were a recent >>>>>>> invention. We simply did not know. We invented the urban legends. >>>>>>-a-a Some people around here are walking around with those
-a-a RFID cards today, and they're thinking about wrapping
-a-a them in aluminum foil to make it harder to scan them.
You can buy wallets that claim to be shielded. For NFC.
-a-a Mag HDDs generally come wrapped in heavily
-a-a metal coated plastic. I saved those wrappers.
-a-a One large piece in the outside fold of the
-a-a wallet, and a secondary pouch for the little
-a-a space where the cards reside.
-a-a Maybe not necessary, but can't hurt.
I sometimes put a bit of aluminum foil there, but it doesn't last a
month. Your idea seems better.
-a-a Actual foil falls apart pretty quick.
-a-a Western Digital always wrapped its primo drives
-a-a in heavily-metalized plastic, it can take a
-a-a crease, unlike the semi-transparent crap used
-a-a for most devices these days. It also doesn't
-a-a fall apart in a wallet.
-a-a You could maybe make a fake version of that ...
-a-a thin polyester film, some spray glue and foil
-a-a stuck to both sides.
Hum!-a Long ago I made roller reflective curtains with aluminum foil
stuck to self-adhesive plastic rolls made to line kitchen drawers.
Aironfix, I think was the name. Yes, they still sell it.
On 2025-10-10 11:19, Joerg Walther wrote:
Carlos E.R. wrote:
Also, at least in my case, my bank tell us to use google pay, so they
track us.
So you can't use other wallet apps, you are forced to use google pay?
And how does it talk to my bank, if my bank doesn't support them?
On 10/10/2025 12:45, Carlos E.R. wrote:
On 2025-10-10 10:58, The Natural Philosopher wrote:
...where anyone who steals the laptop in a foreign land can find it.Yeah. That's how it works, with a port specification.
I don't have to specify ports. If I use a non standard port, I
configure that in the client .ssh/config:
Host host.dyndns
-a-a-a-a-a-a-a-a Port 5000
Its good enough to find and grab files off the user data areas.
When I think that my minimum internet speed is what my maximum LAN
speed was 35 years ago...
Heh, but maybe not everywhere.
Everywhere except the USA. And possibly Spain
On 10/10/25 07:51, Carlos E.R. wrote:
On 2025-10-10 11:19, Joerg Walther wrote:
Carlos E.R. wrote:
Also, at least in my case, my bank tell us to use google pay, so they
track us.
So you can't use other wallet apps, you are forced to use google pay?
And how does it talk to my bank, if my bank doesn't support them?
-a Different bank dude ....
On 10/10/25 07:49, Carlos E.R. wrote:
On 2025-10-10 03:36, c186282 wrote:
On 10/9/25 15:10, Carlos E.R. wrote:
-a-a You could maybe make a fake version of that ...
-a-a thin polyester film, some spray glue and foil
-a-a stuck to both sides.
Hum!-a Long ago I made roller reflective curtains with aluminum foil
stuck to self-adhesive plastic rolls made to line kitchen drawers.
Aironfix, I think was the name. Yes, they still sell it.
-a My brother had a big roll of (thinly) metalized
-a film ... for his weed garden-a :-)
-a But the stuff WD uses for its HDDs is far better
-a for the purpose.
-a Best guess, very thin mylar film, a can of spray
-a carpet adhesive, a roller squeegie, and some
-a household aluminum foil.
-a Argue about the 'need', but if it's EASY to RF
-a shield then Why Not ?
On 10/10/25 03:45, Carlos E.R. wrote:
On 2025-10-09 17:07, Rich wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 08/10/2025 22:29, John Ames wrote:
On Wed, 8 Oct 2025 21:13:01 -0000 (UTC)
Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:
A quick check here with 'df -i' shows all but one mounted filesystem in
the single digit percentage usage of inodes.-a The one 'worst' case (a
4T disk for media encoding/transcoding and other misc usages) is only
consuming 17% of its max inodes.
Telcontar:~ # df -i
Filesystem-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a Inodes-a-a IUsed-a-a-a-a-a IFree IUse%
Mounted on
/dev/nvme0n1p5-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 9830400 2135223-a-a-a 7695177-a-a 22% /
...
/dev/sdc9-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 16777216 1632362-a-a 15144854-a-a 10% /
data/WasReiserfs-a-a-a-a-a-a-a (holds the news spool)
...
/dev/sdb10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 15295056-a 943965-a-a 14351091-a-a-a 7% /
data/storage_b
/dev/sdc10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 2621440-a 131132-a-a-a 2490308-a-a-a 6% /
usr/ local
...
-a We tend to think about inodes less and less these
-a days as both CPUs got more powerful and disks got
-a much larger and faster.
-a However sometimes you DO need to think about them,
-a especially for certain environments, usually servers.
-a Are you going to be storing a few BIG files or a
-a zillion TINY files ? Adjustments to block sizes
-a and inode params may be advised.
Don't remember ... does Win have a /dev/null
equiv device ? SEEMS like those employees
did a cut/paste to one of them somehow :-)
I'd like to know the inode percent per directory in a
partition. Chatgpt suggests
du --inodes -d 1
On 2025-10-11, Carlos E.R. wrote:
I'd like to know the inode percent per directory in a
partition. Chatgpt suggests
du --inodes -d 1
Is there some implementation of the du utility that provides a
percentage with that invocation?
(I guess an actually intelligent AI would have attempted to precisely
clarify what "percent per directory" is expected to mean before
suggesting any code or command?)
This recursively counts all files and directories inside each folder rCo i.e. inode usage.
This shows inode usage (number of files/directories) like `du` shows disk usage.
On 2025-10-11 08:30, c186282 wrote:
On 10/10/25 07:51, Carlos E.R. wrote:
On 2025-10-10 11:19, Joerg Walther wrote:
Carlos E.R. wrote:
Also, at least in my case, my bank tell us to use google pay, so they >>>>> track us.
So you can't use other wallet apps, you are forced to use google pay?
And how does it talk to my bank, if my bank doesn't support them?
-a-a Different bank dude ....
Ha ha. Not viable.
On 2025-10-11 06:57, c186282 wrote:
On 10/10/25 03:45, Carlos E.R. wrote:
On 2025-10-09 17:07, Rich wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 08/10/2025 22:29, John Ames wrote:
On Wed, 8 Oct 2025 21:13:01 -0000 (UTC)
Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:
...
A quick check here with 'df -i' shows all but one mounted filesystem in >>>> the single digit percentage usage of inodes.-a The one 'worst' case (a >>>> 4T disk for media encoding/transcoding and other misc usages) is only
consuming 17% of its max inodes.
Telcontar:~ # df -i
Filesystem-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a Inodes-a-a IUsed-a-a-a-a-a IFree IUse%
Mounted on
/dev/nvme0n1p5-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 9830400 2135223-a-a-a 7695177-a-a 22% /
...
/dev/sdc9-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 16777216 1632362-a-a 15144854-a-a 10% /
data/WasReiserfs-a-a-a-a-a-a-a (holds the news spool)
...
/dev/sdb10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 15295056-a 943965-a-a 14351091-a-a-a 7% /
data/storage_b
/dev/sdc10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 2621440-a 131132-a-a-a 2490308-a-a-a 6% /
usr/ local
...
-a-a We tend to think about inodes less and less these
-a-a days as both CPUs got more powerful and disks got
-a-a much larger and faster.
-a-a However sometimes you DO need to think about them,
-a-a especially for certain environments, usually servers.
-a-a Are you going to be storing a few BIG files or a
-a-a zillion TINY files ? Adjustments to block sizes
-a-a and inode params may be advised.
Well, you can see that my root filesystem has a high percent of used
inodes, more than the /data/WasReiserfs which holds the news spool and
is customized for many small files.
I'd like to know the inode percent per directory in a partition. Chatgpt suggests
du --inodes -d 1
On 2025-10-11, c186282 <c186282@nnada.net> wrote:
Don't remember ... does Win have a /dev/null
equiv device ? SEEMS like those employees
did a cut/paste to one of them somehow :-)
Nah, they just accidentally drop the icon while moving
across the screen toward the icon where they intended
to drop it. One little slip while trying to keep constant
pressure on that mouse button and >poof<. And then it's
time to start searching the entire file system.
I don't do drag-and-drop anymore. It's too dangerous.
On 2025-10-11, Carlos E.R. wrote:
I'd like to know the inode percent per directory in a
partition. Chatgpt suggests
du --inodes -d 1
Is there some implementation of the du utility that provides a
percentage with that invocation?
(I guess an actually intelligent AI would have attempted to precisely
clarify what "percent per directory" is expected to mean before
suggesting any code or command?)
On 10/11/25 08:32, Carlos E.R. wrote:
On 2025-10-11 08:30, c186282 wrote:
On 10/10/25 07:51, Carlos E.R. wrote:
On 2025-10-10 11:19, Joerg Walther wrote:
Carlos E.R. wrote:And how does it talk to my bank, if my bank doesn't support them?
Also, at least in my case, my bank tell us to use google pay, so they >>>>>> track us.
So you can't use other wallet apps, you are forced to use google pay? >>>>
-a-a Different bank dude ....
Ha ha. Not viable.
-a Why not ? People jump banks all the time.
On 2025-10-11 06:57, c186282 wrote:
On 10/10/25 03:45, Carlos E.R. wrote:
On 2025-10-09 17:07, Rich wrote:
The Natural Philosopher <tnp@invalid.invalid> wrote:
On 08/10/2025 22:29, John Ames wrote:
On Wed, 8 Oct 2025 21:13:01 -0000 (UTC)
Lawrence DrCOOliveiro <ldo@nz.invalid> wrote:
...
A quick check here with 'df -i' shows all but one mounted filesystem in >>>> the single digit percentage usage of inodes.-a The one 'worst' case (a >>>> 4T disk for media encoding/transcoding and other misc usages) is only
consuming 17% of its max inodes.
Telcontar:~ # df -i
Filesystem-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a Inodes-a-a IUsed-a-a-a-a-a IFree IUse%
Mounted on
/dev/nvme0n1p5-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 9830400 2135223-a-a-a 7695177-a-a 22% /
...
/dev/sdc9-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 16777216 1632362-a-a 15144854-a-a 10% /
data/WasReiserfs-a-a-a-a-a-a-a (holds the news spool)
...
/dev/sdb10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 15295056-a 943965-a-a 14351091-a-a-a 7% /
data/storage_b
/dev/sdc10-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a 2621440-a 131132-a-a-a 2490308-a-a-a 6% /
usr/ local
...
-a-a We tend to think about inodes less and less these
-a-a days as both CPUs got more powerful and disks got
-a-a much larger and faster.
-a-a However sometimes you DO need to think about them,
-a-a especially for certain environments, usually servers.
-a-a Are you going to be storing a few BIG files or a
-a-a zillion TINY files ? Adjustments to block sizes
-a-a and inode params may be advised.
Well, you can see that my root filesystem has a high percent of used
inodes, more than the /data/WasReiserfs which holds the news spool and
is customized for many small files.
I'd like to know the inode percent per directory in a partition. Chatgpt suggests
du --inodes -d 1
On 2025-10-12 00:46, Nuno Silva wrote:
On 2025-10-11, Carlos E.R. wrote:
I'd like to know the inode percent per directory in a
partition. Chatgpt suggests
du --inodes -d 1
Is there some implementation of the du utility that provides a
percentage with that invocation?
I don't know.
(I guess an actually intelligent AI would have attempted to precisely
clarify what "percent per directory" is expected to mean before
suggesting any code or command?)
It suggested more methods, I took the simplest :-)
To check **inode usage per directory** in Linux rCo that is, to see **how many inodes (files/directories)** each subdirectory is using rCo you can
use a combination of tools like `find`, `awk`, and `du`.
Here are the most useful and efficient ways:
---
## rLa **1. Using `find` to count inodes per subdirectory**
This gives you the number of inodes (i.e. files + dirs) in each top-
level subdirectory:
```bash
for dir in *; do
-a [ -d "$dir" ] && echo -n "$dir: " && find "$dir" | wc -l
done
```
This recursively counts all files and directories inside each folder rCo
i.e. inode usage.
---
## rLa **2. Using `find` + `awk` for sorted output**
List inode counts for subdirectories in current dir, sorted by usage:
```bash
find . -xdev -type f -printf '%h\n' | sort | uniq -c | sort -nr
```
* `-xdev`: restricts to current filesystem (avoid crossing mount points)
* `-type f`: only counts files (you can remove this to include dirs too)
* `%h`: prints parent directory (for grouping)
---
## rLa **3. Using `du` (but for inodes) rCo with `--inodes`**
If your version of `du` supports it (on newer GNU coreutils), use:
```bash
du -a --inodes
```
Or for top-level dirs:
```bash
du --inodes -d 1
```
This shows inode usage (number of files/directories) like `du` shows
disk usage.
---
## rLa **4. Get total inode usage of filesystem**
To check **total inodes used/available** on a filesystem (not per directory):
```bash
df -i
```
Sample output:
```
Filesystem-a-a-a-a Inodes-a IUsed-a IFree IUse% Mounted on /dev/sda1-a-a-a-a-a 524288-a 10234 514054-a-a-a 2% /
```
---
## Efoa Pro Tip: WhatrCOs an inode?
Each **file**, **directory**, **symlink**, etc. uses **one inode**. On filesystems like ext4, the number of inodes is fixed at creation time.
You can run out of inodes even if disk space is free rCo especially if you create millions of tiny files (like maildirs, caches, etc.).
---
## rLa Summary
| Goal-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a | Command-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a |-a-a-a-a-a-a-a |
-a-a-a-a-a-a-a-a |-a-a-a-a-a-a-a-a-a-a |
| ---------------------- | ---------------------------- | ------ |
------- | --------- |
| Inode usage per subdir | `find "$dir"-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a | wc -l` |
-a-a-a-a-a-a-a-a |-a-a-a-a-a-a-a-a-a-a |
| Sorted inode usage-a-a-a-a | `find . -xdev -printf '%h\n' | sort-a-a | uniq
-c | sort -nr` |
| Inode-aware du-a-a-a-a-a-a-a-a | `du --inodes -d 1`-a-a-a-a-a-a-a-a-a-a |-a-a-a-a-a-a-a |
-a-a-a-a-a-a-a-a |-a-a-a-a-a-a-a-a-a-a |
| Total inodes used/free | `df -i`-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a-a |-a-a-a-a-a-a-a |
-a-a-a-a-a-a-a-a |-a-a-a-a-a-a-a-a-a-a |
Let me know if you want a script to alert when inode usage gets too high.
--------
The invocation:
find . -xdev -type f -printf '%h\n' | sort | uniq -c | sort -nr | less
found out where the inodes are going to in my root:
-a 76119 ./tmp/imapsync_cache/legolas-e.valinor/cer/telcontar.valinor/ cer/alpine_r_gmx/alpine_r_gmx
-a 62998 ./tmp/imapsync_cache/legolas-e.valinor/cer/telcontar.valinor/ cer/alpine_r_tl/alpine_r_tl
-a 49326 ./tmp/imapsync_cache/legolas.valinor/cer/telcontar.valinor/cer/ alpine_r_gmx/alpine_r_gmx
caches of mail folders, created by "imapsync", seems one zero sized file
per email. /tmp is in root (/).
On 10/11/25 20:42, Carlos E.R. wrote:
On 2025-10-12 00:46, Nuno Silva wrote:
On 2025-10-11, Carlos E.R. wrote:
-a 'df -i" will tell you exactly what you need.