ZXnet

I got this machine on the 13th of June 2015 along with a Compaq-branded DEC Rack two HSZ70 storage subsystems and a mountain of StorageWorks disk bricks. About a year later got a pair of AlphaServer 4100s from the same place. It currently contains a PBXGK ELSA GLoria Synergy graphics card, KZPBA-CX QLogic ISP1040B SCSI card, a DE500 10/100 NIC, and a KZPCM dual SCSI and Ethernet card, a few disks and a DDS tape drive.

As it's my fastest Alpha and only EV6 machine, doesn't have any one particular purpose. Instead, it has a selection of operating systems installed:

• Windows NT Workstation 4.0
• Windows 2000 RC2
• Windows build 2210 (64bit)
• Debian Lenny (boot dkd200, or for a non-SMP kernel, boot dkd200 -flags 4)

Below is the configuration of the machine as it currently is - the configuration as received can be found here:

>>>show config
                        AlphaServer DS20 500 MHz

SRM Console:    V7.2-1
PALcode:        OpenVMS PALcode V1.98-79, Tru64 UNIX PALcode V1.92-74

Processors
CPU 0           Alpha EV6 pass 2.3 500 MHz      SROM Revision: V1.82
                Bcache size: 4 MB

CPU 1           Alpha EV6 pass 2.3 500 MHz      SROM Revision: V1.82
                Bcache size: 4 MB

Core Logic
Cchip           DECchip 21272-CA Rev 2.1
Dchip           DECchip 21272-DA Rev 2.0
Pchip 0         DECchip 21272-EA Rev 2.2
Pchip 1         DECchip 21272-EA Rev 2.2

TIG             Rev 4.14
Arbiter         Rev 2.10 (0x1)

MEMORY

Array #       Size     Base Addr
-------    ----------  ---------
   0         512 MB    000000000
   1         512 MB    020000000
   2         512 MB    040000000

Total Bad Pages = 0
Total Good Memory = 1536 MBytes


PCI Hose 00
     Bus 00  Slot 05/0: Cypress 82C693
                                                         Bridge to Bus 1, ISA
     Bus 00  Slot 05/1: Cypress 82C693 IDE
                                   dqa.0.0.105.0
     Bus 00  Slot 05/2: Cypress 82C693 IDE
                                   dqb.0.1.205.0
     Bus 00  Slot 05/3: Cypress 82C693 USB
                                   usba0.0.0.305.0
     Bus 00  Slot 07: ELSA GLoria Synergy
                                   vga0.0.0.7.0
     Bus 00  Slot 08: QLogic ISP10x0
                                   pkd0.7.0.8.0          SCSI Bus ID 7
                                   dkd0.0.0.8.0           COMPAQ BD018122C9
                                   dkd100.1.0.8.0         COMPAQ BD018122C9
                                   dkd200.2.0.8.0         COMPAQ BD018122C9
                                   dkd300.3.0.8.0         COMPAQ BD018122C9
     Bus 00  Slot 09: DE500-BA Network Controller
                                   ewb0.0.0.9.0          08-00-2B-C3-A6-92

PCI Hose 01
     Bus 00  Slot 07: DECchip 21152-AA
                                                         Bridge to Bus 2, PCI
     Bus 00  Slot 08: NCR 53C895A
                                   pkc0.7.0.8.1          SCSI Bus ID 7
     Bus 02  Slot 00: NCR 53C875
                                   pka0.7.0.2000.1       SCSI Bus ID 7
                                   dka100.1.0.2000.1      RRD46
     Bus 02  Slot 01: NCR 53C875
                                   pkb0.7.0.2001.1       SCSI Bus ID 7
     Bus 02  Slot 02: DE500-AA Network Controller
                                   ewa0.0.0.2002.1       00-06-2B-00-AD-DB


ISA
Slot    Device  Name            Type         Enabled  BaseAddr  IRQ     DMA
0
        0       MOUSE           Embedded        Yes     60      12

        1       KBD             Embedded        Yes     60      1

        2       COM1            Embedded        Yes     3f8     4

        3       COM2            Embedded        Yes     2f8     3

        4       LPT1            Embedded        Yes     3bc     7

        5       FLOPPY          Embedded        Yes     3f0     6       2
            

For a long time I didn't do much with it as it had no graphics card and was always a bit temperamental. It always powered up first try, but if I turned it off it wouldn't turn on again for a few hours. The Remote Management Console was still there, but the command to power the machine on had no effect. As of 2026-01-01 I still have no idea what the problem was, but I've been running the machine a bunch lately on only one of its two power supplies, and it seems to be working fine so.... problem with the second PSU?

The other challenge was that the test command would eventually dump a bunch of "Uncorrectable Double Bit Error on CPU 0" to the console suggesting trouble with one or more of the 16 DIMMs installed in the machine. Unfortunately the errors don't tell you which DIMMs. And without fixing this it wasn't really possible to reliably run anything on it.

Resolving this issue involved removing DIMMs one bank at a time (each bank consisting of four DIMMs) until the memexer 3 command stopped reporting errors. It wasn't until I'd pulled everything from banks 3, 2 and 1 before the memory tests stopped reporting errors suggesting that at a minimum there was one bad DIMM in bank 1. From there I pulled the top DIMM from bank 0, and then cycled all four DIMMs that were previously in bank 1 through that slot to identify which one was bad. I then re-introduced the DIMMs that were previously in banks 2 and 3 one bank at a time running memory tests in between to ensure the stuff that was in those banks was OK. In the end it was just one DIMM in bank 1 that was bad, and the machine is happily running on 1.5GB of RAM now.

Lastly, I stole a PBXGK ELSA GLoria Synergy from the AlphaServer 4100 that lacks RAM and put it in this machine allowing it to have a graphical console.