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Thread: IBM PS/2 Server 195 & 295

  1. #1

    Default IBM PS/2 Server 195 & 295

    Hello all,

    Does anyone have any experience with these? Documentation or software?

    I've visited Louis' page on the 8600.


  2. #2


    I've been hunting around for some more info for years. There used to be a PS/2 website with an image of it. I want to say Peter Wendt's site, but when I looked again it wasn't there. This was the early 2000's.

    IBM PS-2 model 195,295.jpg
    Looking for: OMTI SMS Scientific Micro Systems 8610 or 8627 ESDI ISA drive controller, May also be branded Core HC, Please PM me if you want to part with one.

  3. #3

    Exclamation IBM 8600 (PS/2 Server 195 / 295) slowly emerging from the shadows

    8600 Processor Board (either 486DX33 or 486DX-50)

    8600 Memory Board (128MB ECC-P)

    8600 SCSI Controller Board (IDC) (2x 53C700)

    8600 Remote Maintenance Processor (RMP) Board

    8600 Power (Todd Products MAX-753-0512)

    Work In Progress 295 pix

    Chulofiasco dug up two 8600, one is up, OS/2 is throwing hissy fits.

    You MUST use the 400MB 0661-467 or the 1GB 0663- Exx/Hxx drives. Though I am suspicious that any of the blocky 0661/0663/0664 would do. Air flow is based on that drive shape. It MIGHT be possible to use other IBM OEM drives, it MIGHT be the system programs look for an "IBM" text string in the drive firmware...

    Started to update the page. Am anticipating the arrival of the IP Bus cards, they are so chock full 'o GALs, PALs, and logic that it is quite amazing Parallan could build a superserver with such chips...

    As I was tripping out on brown monster, I was stumped on why Parallan would install 30 pin SIMMs on the PC Server 295 (Parallan Server 290). Here we have a 200MB/s Corollary bus system that in this guise sports two 486DX33 (if not DX50) CPUs, a dual 53C700 SCSI controller (64 bit wide!) on that same IP bus, and yet the Parallan Server 290 was released in 1990-ish.

    For those that know a bit about the 8600, you might be looking for a RISC based SCSI RAID conroller... Bronx cheer! The "RISC based SCSI controller" is the RISC core in the 53C700 (called a "SCRIPTS" controller). So... with one dual SCSI controller card (IDC), you can create a fault tolerant pair, or a simple parallel drive array. BUT to do the uber fault tolerant Orthogonal RAID-5, you will need TWO of the IDCs.

    The Parallan -AND- the ISA bus based 7552 BOTH share the same ECC function providing chip, the 49C460 EDC 32-Bit CMOS Error Detection and Correction Unit. The 7552 uses one 30 pin SIMM to provide ECC to four other 30 pin SIMMs. BUT Parallan used banks of four SIMMs, not one plus four....

    The 7568 MCA based system uses the AMD AM29C660BJC to use one 72 pin SIMM to provide ECC for the other four 72 pin SIMMs. It uses the common 57X4111 so the 29C660 certainly does the ECC stuff internally.

    Think of it like ECC On a SIMM, but without EOS memory...

    I might have figured out the ECC function. Memory was sold in two banks worth of 30 pin SIMMs (32MB increments). Two banks gives you a 64 bit word, plus 8 bits for ECC. Pants on head amazing. Then there are two 32 bit EDC chips chained together to support Error Detection and Correction before the data gets onto the 64 bit Inter Processor bus.

    Parallan used a 386DX-25 support chipset (82311, to be exact) with a multiprocessor 486... Specs mention 16MB max on board. But the 486DX has 32 bit addressing. Not figured that out yet, but there are a number of XYLINX gate arrays....

    Parallan figured out the 195 / 295 using older (cheaper and more developed) chips... Wonder what their margins were...
    Last edited by ardent-blue; October 23rd, 2017 at 01:42 PM.

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    Extracted all floppy image files, the *.ABS for all the IP Bus boards is in the 295 Diagnostics (720K disk image!!!)

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    Cool Messy fun (8600 RMP outline done)

    A bit kaotic, but most of the info is identified. Need to add the datasheets and link them, but L8ter.


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