IBM PS/2 Model 8580-
	041	071	111	121	321	A21	A31
Microprocessor	Intel 80386 DX 32bit
Clock speed	16Mhz		20Mhz			25Mhz
Display	VGA, 320x200 @ 256 colours, 640x480 @ 16 colours
BUS type	MICRO CHANNEL ARCHITECTURE (MCA)
16 bit slots	5 slots					4 slots
32 bit slots	3 slots					4 slots
RAM	1Mb		2Mb			4Mb
RAM Type	DRAM 80ns parity checked (2 sockets)
ROM	128Kb
L1 Cache	0Kb					64Kb
Power Supply	225W					242W
HDD Capacity	44Mb	70Mb	115Mb	120Mb	120Mb	320Mb
HDD Access time	40ms	30ms	28ms	23ms	23ms	12.5ms
HDD Interface	ST-506	ESDI		SCSI
FDD	1.44Mb FDD
PORTS	PS/2 keyboard, PS/2 mouse, serial, parallel, VGA
Keyboard	101 key enhanced
Weight	23.6 Kg (52 lbs) (8580-041)
Height	597mm
Width	166mm
Depth	483mm
Drive Bays	4 3.5" half-height (2 accessable), 1 5.25" full height (or 2 3.5" HH)

Other Model 80's not listed
081, 161, 311, A16, M81, M16
Mxx - same as Axx but with 20Mhz CPU

I have a Model 8580-111 with the following

HARDWARE:
IBM 16Mb RAM - 6Mb on system board, two expansion cards one with 8Mb and the other with 2Mb.
IBM XGA-2 Display Adapter - 1Mb Video memory.
IBM Dual Async Adapter - Two serial ports (three including the one on the system board)
3Com 3C529 Ethernet Adapter - 10Base-T, RJ45 Connector.
Intel EtherExpress 16 - 10Base-T, RJ45 Connector.
IBM SCSI Controller
- DEC RZ26L 1.0 GB
1.44Mb PC FDD - for information on how to do this look below
 

PS/2 BOX
I am running Slackware 7 on it at the moment with Kernel 2.2.13
It is used as a router box for my internal network, it is running the following services:
FTP, HTTP, TELNET, SMTP, POP3.

Just shows what you can do with these old beasts!

Uptime since i got a cable modem is only 5 days on 14th May 2000
Thats when i upgraded from 115MB ESDI to 1GB SCSI
and to Kernel 2.2.13
 

OTHER PS/2 PARTS
I also have the following which are not being used at present. But will be when I get more PS/2's going.
(I like bringing these old things back to life)

IBM ESDI Adapter
- IBM 115Mb ESDI HDD - Original 5.25" Full height - now thats what I call a hard drive!
Arco IDE Adapter
Alliance Technology TapeDrive Adapater
3Com 3C523 - 10Base-T
HP Scanjet Adapter - Can also use as additional printer port
IBM PS/2 Model 8580-111 - dead FDD's
And a heap of cards i have not checked yet!
 
 

The Problem
The probelm was and is PS/2 Model 80 FDD's, the general problem is that they are very noisy, slow and collect a lot of dust.
But they are not the main problems. The main problem (in my experience) is that they die. Quite often in fact.

And when they die, well you have to buy another one. But the replacement is probably as old as the one that died and will die soon
to. So what can we do?

The Solution
The solution is to hook up a normal PC FDD to your PS/2. But this can present some problems of its own as we talk about later.
It may seem that the PS/2 FDD interface is completely different from the PC FDD interface. But don't be fooled by the large connector on the PS/2. From pin 1 to pin 34 all pinouts are almost identical, and the extra 6 pins on the PS/2 are for the power.

The Pinouts
I have included the pinouts of both interfaces. The PS/2 pinout came from the PS/2 FAQ and corrected by Peter Wendt, and the PC pinout came from an electronics store referece sheet.

PS/2 40pin 1.44Mb FDD pinout for old models (50/60, 55/65, 70/80 and P70/P75)
 

The PS/2 FDD controller is a little different to the PC controllers. The IBM PS/2 FDD is "non media-sensing".
It uses a BIOS routine to blind-read the first sector of a floppy at Sect. 0 / Head 0 / Track 0 and uses the "media descriptor byte"
to set the controller according to the disk format (360 / 720K or 1.44MB).

Normal FDDs do it other way round: the pin 2 is "Density Select" - driven low for 1.44MB by the right-hand switch on the FDD ...
which is not present (or not functional) on the old PS/2 FDDs. This switch sets the controller to the according mode - a reason why
you can format 720K DD floppies to 1.44MB on PS/2 without drilling a hole into the floppy (media hole - right side of the floppy)
and "downformatting" 1.44MBs to 720KB without covering the media hole with some adhesive tape. It is simply not used on the older
PS/2.

But read / write /format of 720KB disks may not be possible because of this ( I have not tested it yet ).

The PS/2 controller is CMOS, so if you have a floppy disk drive that supports CMOS then this should work.
Thanks to Peter for providing this info.
 
 

So what does all this mean?
Well this is good news for people with PS/2 Model 80 FDD's that seem to keep dying.

My Experience
I managed to successfully attach a normal PC Floppy to my Model 80 with no re-wireing!
According to the digram if you plug a PC FDD cable into the right-most portion of the FDD interface
and connect the FDD up to the power supply, the disk drive should funtion with no problems (in my theory).

So I plugged a 34pin connector into the 40pin socket on the system board, matching pin 1 together.
Then I plugged a power connector between the power supply and the FDD. I booted up and the disk
drive light came on when it was suppose to. Good so far.

But when it came to booting the RefDisk or any boot disk it wouldn't work. It just loads IBM BASIC.
No good!!!!

BUT! I started to fiddle with the jumpers on the back of the FDD

I changed the FDD's logic setting by removing the jumper( it was labled TTL/CMOS). I plugged the FDD in, turned the computer on
with the RefDisk in the FDD, and after a while I saw that BIG BLUE screen I have been waiting so long to see.
Harray!!, I couldn't believe that it worked.

It runs very well, not as noisy as the PS/2 FDD's and probably a bit faster too. Those of you who want to run
linux on your Model 80 but can't load the root disk because of the slow FDD, well good news, with a normal
PC FDD there is no problem at all. I installed Linux quit easily.

I hope this helps others that have gone though hell with Model 80 FDD's (Maybe other models as well).

Update:

I have been running my PS/2 Model 80 with the PC FDD for over a year now... and its still running excelent!
 

What to do.
WARNING:
If you try this and blow up the FDD controller on the system
board or your FDD (Very unlikely), don't blame me. I took a risk trying this
out on my PS/2. And if you want to do the same, do it. But
if you are worried about the PS/2 system board don't do it!

What you need:

• IBM PS/2 Model 80 (of course)
• PC FDD (See if you can find one with a jumper that allows you to change the logic family.)
• PC FDD Cable (34pin, with two 34pin IDC Line Sockets)
• Power Cable (4pin 5.25" drive connector to 4pin 3.5" drive connector)

Dont forget to change the logic setting on the FDD!

Mounting it
The way I mounted mine was in the 5.25" accesable bay. I used a 5.25" to 3.5" bay converter (as shown in figure).
I made up two thin wooden blocks so the converter would slide into the HDD support structure.

Here is a diagram of what my PS/2 lookes like with the PC FDD.

The only thing I am missing for this is the cover plate which had a HH 5.25" hole in it, to cover the gaps.
 
 

If you live in Melbourne Australia and want to throw away your PS/2 Model 80, or any PS/2 parts email me and I might
take it off your hands free of charge.. :-)

If you have any questions. Success stories or failures. with Model 80 PC FDD's Please email me.
Kane
kane@kanotech.org