Server - 'DDD' RAID - Drives (addr.-bit 8)



 

Server - 'DDD' RAID - Drives (addr.-bit 8)

 

For machine type 8641 Server 500 see > RAID Recovery Procedure Not Effective

Prevention of Multiple Defunct SCSI Drives PC Servers 320/520/720

Some PC Server systems may experience multiple fixed disks appearing as Defunct (DDD) after only one drive had an actual failure. This symptom is related to PC Servers 8640 (with Hot-Swap Bay Assemblies installed), 8641 and 8642 that have any of the following fixed disks installed:

The following eligible HD-drives are SILVER 

Engineering Changes Announcement 003 (ECA003) provides for the installation of a Pin Converter (Interposer) on these SCSI drives. This ECA, which expires 30-Apr-1997, may be installed at any time on eligible systems, there is no fix-on-fail requirement.

NOTE:

When a PCI RAID Adapter FRU P/N 06H5078 is installed, and sometimes one ore more RAID HD-drives will have a DD status, then an address cable, with not connected bit-8 (floating), will solve the problem. (The above displayed Interposer will simply not connect address bit-8 to the Hard-Disk-Drive. Do not use the Interposer if you have a need to set the HI/LO-jumper on backplane to HI, because addr.-bit 8 will never go active (minus)).

                  (Resistor IC-7 on Backplane)
                           + 5Vdc
                              o
                     1Kohm    |
                  +--/\/\/\---+  6   5   4   3   2   1   HDD Backplane
   Jumper  HI  o--+--------------°---°---°---°---°---°     connector
               o-------+         |   |   |   |   |   ~   (addr.-Bit-8)
           LO  o       |         |   |   |   |   |   ~
         (N.C.)      Signal      |   |   |   |   |   |
                     ground      v   v   v   v   v   v
                                   to RAID HD-drives
                           (~ = OPEN, when interposer is used)


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