8595 / 9595 XP Planar

"XP" - Expandable Processor

85, 95, and 3511 Common Devices (Installing drives, memory etc.)
Opening and closing the case
Operator Panel Information

95 XP Planar
Board Revisions and P/Ns
System Firmware
95A Ports
95A Operator Panel
J4 Remote Power-ON Request
SIMM Connector Versions
Supported MCA Features
Planar Limitations?

95 XP 486 Planar FRU P/N 33F5717, different P/Ns

A1-4 72-pin SIMM socket Bank A (J22-25)
B1-4 72-pin SIMM socket Bank B (J18-21)
BH1 Battery (CR2032)
DU1 PAL? or empty (?)
DU2 Pads for IC
F1 Keyboard Fuse
J1,2,5,6,9,11 32-bit MCA slot
J3 Op Panel Connector
J4 Remote Power-ON Request
J7 40-pin Floppy Connector (1 key)
J8 32-bit MCA slot w/ BVE
J10 32-bit MCA slot w/ AVE
J12/13 Processor Complex slot
J14 DB25 Serial Port
J15 Power Supply Connector
J16 Password override
J17 Parallel Port
J26 Mouse Port
J27 Keyboard Port
J28 Side Cover Fan Connector
TP1 Reset input test point?
TP29 Battery+ test point
U1 LM386 Audio op-amp (PC Speaker)
U7 24.0000 MHz osc (FDC)
U12 82077AA Floppy controller
U18 33F5499 (part of the FDC circuit)
U21 1x9 solder pads (?)
U24 20.0000 MHz osc (planar I/O bus?)
U25 14.3181 MHz osc (adapters, 85F0464?)
U26 85F0464 ASIC (int/KB/mouse)
U27 64F0942 ASIC (UART/parallel)
U30 Dallas DS1210 NVRAM controller
U32 Dallas DS1285 RTC/CMOS
U33 22.1184 MHz osc (UART)
U55 PAL or empty (?)
U56-58 SPARE
Y1 32.768 KHz xtal (RTC)

DU1 and U55 are present on some boards but unpopulated on other - see below. Purpose currently unknown.

U22 8Kx8 SRAM (NVRAM) SRM2264LC-12 (alt) or Sony CXK5864BP-12L

Board Revisions and P/Ns

All 1S1P boards use the same FRU P/N - 33F5717. There are however multiple different board revisions, from different sources, with different P/Ns:

  • 91F7441 (no U55 pads, w/ DU1, early, Greenock)
  • 84F8309 (w/ U55, w/ DU1)
  • 04G3888? (w/o U55, w/o DU1)
  • 04G3863 (w/o U55, w/o DU1)
  • 92F1480?

Early 1S1P planars (P/N 91F7441) have a slightly different layout and lack provision for U55-58. Three DIP resistor networks between slots 1 and 2 are also missing. Additionally, these boards come with quite a few bodge wires (8 total - 4 near the I/O ports, 1 next to U26, 1 near Slot 1/RN2, and 2 at the underside of Slot 2).

System Firmware (POST & BIOS)

Firmware stored on the Processor Complex.

8595 / 9595 Ports

COM DB25 serial port capable of 345K
LPT is standard parallel port

The parallel port is NOT ExpressPrint capable.

8595 / 9595 Operator Panel

On the earliest 8595s, the power button has no shutter and is surrounded by a raised lip. On later models, the power button is covered with a shutter.

More information about the operator panel can be found HERE.

J4 Remote Power-ON Request

The J4 header can be used to turn the system on and off from an external source (i.e. a modem card). This can be achieved by connecting pin 2 to ground (either of the remaining pins). It will only work if the hidden switch SW1 on the Op Panel has been pressed to enable the Remote Power-ON feature.

2-Remote Power-ON Request

Pin 2 is directly connected to pin 29 of the nearby Op Panel connector (J3).

SIMM Connector Versions (Grey or Green)

8MB ECC SIMMs from IBM (Option P/N 92G7208, FRU P/N 92F0098) may not fit properly in the SIMM connectors of some systems.

The following system types and models are potentially affected:
   8595 - all models
   9595 - model 0LF (see note below)

Early production 8595 system boards have gray plastic SIMM connectors which physically interfere with the installation of the referenced 8 MB ECC SIMM.

Later production system boards used a green SIMM connector, which is compatible with the larger SIMMs. Many earlier systems, which have been serviced in the past 18 months, could have the later production system board (green SIMM connectors) already installed.

All system boards with green memory SIMM connectors, regardless of model number or processor upgrade are not affected.

Note: 9595 model 0LF is the only model of 9595 to use the 8595 system board, FRU P/N 92F0270, (identified by a single serial and a single parallel port).

Supported MCA Features

Source: PS/2 Models 95 XP 486, 90 XP 486, 55LS and P75 486 Fundamentals (page 36 physical)

All of the 32-bit Micro Channel slots on the IBM PS/2 Model 90 XP 486 and Model 95 XP 486 systems are full 32-bit implementations of the Micro Channel Architecture. In addition to the basic Micro Channel features the IBM PS/2 Model 90 XP 486 and Model 95 XP 486 systems support the following enhancements to the Micro Channel architecture that were announced in November 1989:

  • Data parity - This is supported on the Micro Channel for peer-to-peer transfers between supporting adapters.
  • Address parity - This is supported on the Micro Channel for peer-to-peer transfers between supporting adapters.
  • Streaming data procedure - This is supported up to 80 MBps using a 64 bit data path and a 100 ns cycle. It is supported on the Micro Channel for peer-to-peer transfers between supporting adapters.

These three new Micro Channel features are implemented on the planar boards of the Model 90 XP 486 and Model 95 XP 486 systems.

Planar Limitations?

Important: The information below is known to be inaccurate. It's retained here solely for historical context. Please refer to the editor's note for corrections.

From Peter (source):
   The 8595 planar is "stage 3" and does not support the "stage 4" "synchrostream mode", which is turned off then. It supports the normal 64-bits burst mode with up to 40 MB/s. So a Type 4 platform will be significantly slower in an old 8595-type planar than in a Server 95A planar (the one with the two serial and two parallel ports). The planar controller on the "single-LPT" planars does not return the proper values on trying to start up the SynchroStream - therefore it is not used. The only advantage left over is the faster CPU and higher calculation data throughput - and the ability to run Pentium software (if required). The overall performance is of course higher compared with e.g. the DX-50 platform - but it does not even come close to the values achieved with the same processor card in the 9595A "double LPT"-planar. At least not in a cumulative / weighted application which includes combined calculation and I/O traffic loads.

Ed. There is no such thing as a "synchrostream mode". The SynchroStream Controller on the T4 complex supports 40 MB/s data streaming - but the same is true for the T3 complex that was shipped exclusively with the 1S1P planar. Also, the 64-bit streaming mode has a theoretical bandwidth of 80 MB/s instead of 40 MB/s and it's certainly not a "normal" transfer mode in the PS/2 world - it's only used by a very few late development cards. Further, according to the Tech. Ref. (see MCA Features above) the bus on all Model 90/95 planars should be compatible with streaming transfers up 80 MB/s - at least between the adapters, as no 90/95 processor complex ever supported the 80 MB/s mode. The bus on the 2S2P planar might actually support the 50 ns 160 MB/s streaming (as mentioned in the INF Reference), but to our knowledge no PS/2 adapters or complexes ever implemented this mode. So, to sum things up, there should be no performance difference between the two Model 95 planars (aside from the faster parallel port on the 2S2P board).

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Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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