Big MCA Questions answered. . .

There seem to be three big MCA questions every PS/2er must answer:

• When it boots, I get this key symbol?
  Machine has power-on password set. This is disabled on different PS/2's in different ways - so I'm going to to the quick-'n'-dirty thing and send you to
  Peter Wendt's Microchannel Enthusiasts' Page.
  This is an excellent site. Need an ADF? Need to run a M-ACPA under Win95? go there.

• Where do I find Reference diskettes?
  
• Try this mirror for the refdisks
  
• The old ftp at IBM at ftp://ftp.pc.ibm.com/pub/pccbbs/refdisks/ is still there, but takes a twist.

• Why MCA?
  • Because, a system with data integrity as its first goal means something.
  • Because they're built to last.
  • Because I don't have resource conflicts.
  • Because Newer is not necessarily Better.

8570 Types

• 8570-E61 long board(planar): 16Mhz Bus. FRU 93F7309.
• 8570-E61, -081, -061 short planar: 16Mhz Bus. FRU 41G3984.
• 8570-061, -081, -121, -161 long planar: 20Mhz Bus. FRU 96F7308.
• 8570-061, -081, -121, -161 short planar: 20Mhz Bus. FRU 41G3985.
  This is the machine type that I have & on which this is based.
• 8570-AXX: 25 Mhz Bus. FRU 92F0580. 80386 processor board FRU 15F7659.
• 8570-BXX: 25 Mhz Bus. FRU 41G3979. 80486 processor board FRU 92F0103.

The reference diskette you will want to use for these machines will be the RF7080.EXE self-extracting file unless you happen to have a 70-486, in that case check out Louis Ohland's 70-486 page.

These machines should all be easy to cope with provided you give them 72-pin, gold-tinned parity SIMMs at least 85ns fast for all but AXX and BXX; those two will need faster refresh 80ns SIMMs. The FRUs to use would be 92F0104 (85ns) and 92F103(80ns). . . or you can do 'British Museum' approach and simply try a SIMM out and see how the machine responds - either with an error, or the 'Automatically Reconfigure (y/n)?' dialog. The virtue of the trial-and-error method is that no brain cells whatsoever get hurt, but it might involve repeatedly opening & closing the machine's case - and increasing the risk of an inadvertent static discharge to your system.

The AXX & BXX critters are constructed differently, they will allow you to put as much as 8MB on the planar in two 4MB SIMMs, all others have a maximum motherboard limit of 6MB divided into 3 2MB SIMMs. The maximum amount of memory any 8570 system will talk to is 16MB unless you do some creative finagling (See Louis Ohland's page IBM Memory Expansion & BOPT103.EXE). This is due to the DMA (direct MEMORY access, get it?) controller only having 24 address lines - which gives you 16MB worth of individual addresses. Now while we can all stand around and criticize IBM for this shortsightedness, it might be helpful to remember the prices for SIMMs in about 1989 and what software demanded of a system then. You can still have a very nice system (multitasking, GUI-enhanced, TCP/IP-able) in 16MB or less if you pick the right software for it.

The machine has been run at least once beyond IBM's recommended operating temperature range. The fact that it has forgiven me speaks very well of the system's reliability. IBM's recommended range: 60 deg F - 90 deg F (15.5 deg C. - 32.2 deg C.) I got a mysterious TRAP E (page fault error) Wall thermometer said 110 deg F (42.3 deg C.) Add 20 deg to figure out what the core chip temps were. . . about 130 (54.5 deg C.) Ouch. We haven't done this again.

What's gone wrong: Well, nothing really that you wouldn't expect from a 10-year old computer that probably hasn't always gotten the best of care. I've so far only replaced the power supply (no beepy-beepy), and the Drive riser card (when the system failed to acknowledge that disk C: existed). Am on monitor number 3, keyboard number 2, battery number 2. These minor maintenaince issues aside- the machine has provided faultless performance. Anybody know what the MTBF for a 8570 is?