From Newsgroup: comp.sys.ibm.ps2.hardware
Summary for the impatient reader: it works
The Server 320/520 PCI/MCA has a bad reputation. The motherboard is
considered prone to failure and unreliable, especially when PCI and MCA network cards are installed simultaneously.
On the other hand,
- it has two Pentium 133MHz CPUs
- six 32-bit MCA slots
- it boots from CD-ROM
Last but not least, this Server 520 is sitting right next to me. So it's simply there, waiting for tasks.
The plan is to first install a Linux kernel 2.4.31 with Slackware 10.2
from 2007 and then kernel 2.6.37.6 with Slackware 13.37 from 2011.
Unfortunately, to my knowledge, there is no Linux driver for the
installed IBM PCI DAC960 RAID adapter. Therefore, I removed the RAID
adapter and connected a 36GB Hitachi LVD SCSI drive, along with the SCSI CD-ROM drive, to the Adaptec AIC-7870 SCSI host adapter integrated into
the motherboard.
The maximum storage capacity of the boot drive on this system is 8.38GB.
Using HDAT2 (
https://www.hdat2.com/), I was able to adjust the capacity reported by the drive accordingly.
The drive misleads the BIOS during boot. The BIOS accepts this misrepresentation as long as the Linux kernel, kernel modules, GNU
operating system, and swap partition remain below the 8.38GB limit. This allows the system to boot Slackware from the hard drive. Once the kernel
has taken control of the hardware and the operating system is loaded, Slackware can access the remaining storage space.
Neither Slackware release natively supports the 520's hardware (SMP,
PCI, MCA, AIC-7870). A first step is the adaptec.s kernel from Slackware
10.2. It supports a 486 CPU, the PCI bus, the AIC-7870, and a maximum of
64MB of RAM from the Server 520. The system is incredibly slow, but it's possible to install Slackware 10.2.
A good hardware test is to build a new, compatible kernel. The new
kernel should support the Server 520's hardware as much as possible:
- the installed RAM using Alfred Arnold's kernel hack
- Pentium Classic SMP
- PCI
- AIC-7870
- MCA
- ISA
The first build took overnight. The third build is currently running at
531.66 BogoMIPS. An unusually high value for a Pentium Classic (
https://tldp.org/HOWTO/BogoMips/bogo-list.html).
Something is wrong with the AIC-7870. The kernel reports "PCI: Cannot
allocate resource region 0 of device 00:0c.0". The command `lspci -v` indicates that the I/O ports at 1400 have a problem. The PCI data
throughput is OK, but on the SCSI bus it's only 6 MB/s.
Here is the output from hdparm:
# hdparm -T /dev/sda
/dev/sda:
Timing cached reads: 84 MB in 2.04 seconds = 41.18 MB/sec
# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 18 MB in 3.00 seconds = 6.00 MB/sec
Here is the output of the PCI devices:
# lspci -v
00:00.0 Host bridge: Intel Corporation 82434LX/NX [Mercury/Neptune]
Processor to PCI bridge (rev 11)
Flags: bus master, slow devsel, latency 32
00:04.0 Ethernet controller: 3Com Corporation 3c900 10Mbps Combo [Boomerang]
Flags: bus master, medium devsel, latency 24, IRQ 15
I/O ports at 9000 [size=64]
Expansion ROM at <unassigned> [disabled] [size=64K]
00:06.0 ISA bridge: IBM Fire Coral (rev 01)
Flags: slow devsel
I/O ports at 0500 [size=8]
00:08.0 MicroChannel bridge: IBM GXT1000 Graphics Adapter (rev 01)
Flags: bus master, slow devsel, latency 0
I/O ports at 0508 [size=8]
I/O ports at 0510 [size=8]
I/O ports at 1000 [size=512]
00:0a.0 VGA compatible controller: Cirrus Logic GD 5430/40 [Alpine] (rev
4c) (prog-if 00 [VGA])
Flags: fast devsel
Memory at 38000000 (32-bit, prefetchable) [size=16M]
Expansion ROM at <unassigned> [disabled] [size=16M]
00:0c.0 SCSI storage controller: Adaptec AHA-294x / AIC-7870 (rev 03)
Flags: bus master, medium devsel, latency 64, IRQ 11
I/O ports at 1400 [disabled] [size=256]
Memory at 30000000 (32-bit, non-prefetchable) [size=4K]
Expansion ROM at <unassigned> [disabled] [size=64K]
So the MicroChannel Bridge of the motherboard is the PCI to MCA ASIC of
the IBM GXT1000 Graphics Adapter. (
https://cdn11.bigcommerce.com/s-017c0/images/stencil/1280x1280/products/14173/62533/IBM-93H2399-Graphics-1__17516.1603219407.JPG?c=2)
Finally, here are the devices supported by the 520 kernel:
# lsmod
Device DMA IRQ I/O Ports ------------------------------------------------
00:04.0 9000-903f
aic7xxx 11
arbitration 0090-0090
card 0091-0091
cascade 4 2
dma 0080-008f
dma1 0000-001f
dma2 00c0-00df
eth0 15
fpu 00f0-00ff
keyboard 1 0060-006f
Mouse 12
parport0 03bc-03be
PCI 0500-0507 0508-050f 0510-0517 0cf8-0cff
1000-11ff 1400-14ff 9000-903f
pic1 0020-003f
pic2 00a0-00bf
POS 0096-0097 0100-0107
rtc 8 0070-007f
serial 02f8-02ff 03f8-03ff
system 0092-0092 0094-0094
timer 0
timer0 0040-0043
timer1 0050-0053
vga+ 03c0-03df
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