Forwarding note from: Fletcher Christian <fletch2@ibm.net> 12/08/96  8:03pm EST  

** Reply to note from Andreas Brusinsky <brusinsk@ibdr.inf.tu-dresden.de> 12/09/96  3:55pm +0100 
 
 
> If I put the QUANTUM PD425S back into the HP disk box and 
> plug an external terminator resistor into the open interface 
> there are still scsi device errors. 
>  
> Can this be? 
>  
> The other hp disks(HP2212A) have beside their normal scsi interface  
> another 10-pin connector that is used inside the hp-box. Is this one 
> responsible for correct scsi termination? 
 
 
Andreas, 
        Have you considered SCSI parity? 
 
 
                          Fletch 
 
 
     ProDrive 425/425iS 
 
     --------------------------------------------------------- 
 
          [o]Jumper Definitions 
          [o]Drawing 
 
     ------------------------------------------- 
     ------------------------------------------- 
                   Jumper  Setting   Description 
 
                  EP       OFF     Parity 
                                   disabled 
                           ON      Parity enabled 
 
                  WS       OFF     Wait Spin 
                                   disabled 
 
                           ON      Wait Spin 
                                   enabled 
 
                  SS       OFF     Self Seek 
                                   disabled 
                           ON      Self enabled 
                  A0, A1, 
                  A2       -       SCSI ID 
                              Table 1 
 
                   A2     A1    A0      SCSI ID 
                  OFF   OFF   OFF    0 
                  OFF   OFF   ON     1 
                  OFF   ON    OFF    2 
                  OFF   ON    ON     3 
                  ON    OFF   OFF    4 
                  ON    OFF   ON     5 
                  ON    ON    OFF    6 
                  ON    ON    ON     7 
                              Table 2 
 
     --------------------------------------------------------- 
     Termination Resistors 
 
     One of the requirements of the SCSI bus is that it be 
     properly terminated. If more than one SCSI device is 
     connected to the host, the last device on each end of 
     the bus must be terminated. The ProDrive disk drive 
     utilizes three (3) Terminating Resistor packs, when 
     installed these resistors enable termination on the SCSI 
     bus. With the Terminating Resistor packs removed, bus 
     termination is disabled. 
 
     At the factory, Quantum configures the ProDrive 
     425/425iS hard disk drive with termination enabled; that 
     is, all three resistor packs are installed. To disable 
     termination, remove the Terminating Resistor packs. 
 
     Enable Parity (EP) Jumper 
 
     The Enable Parity (EP) jumper is used to set the Parity 
     option on the drive. With parity checking enabled (EP 
     installed), the drive performs parity checking. With 
     parity checking disabled (EP removed), the drive 
     continues to generate parity information, but does not 
     perform parity checking. 
 
     At the factory, Quantum configures the ProDrive 
     425/425iS hard disk drive with the EP jumper in place. 
 
     SCSI-Bus Device Identification (A0 - A2) Jumpers 
 
     Used in combination, the jumper settings across pins A2, 
     A1 and A0 determine the ProDrive 425/425iS hard disk 
     drive's SCSI-bus device I.D. By default, Quantum 
     configures the drive with a SCSI ID of 6; that is, with 
     jumpers installed across the pins labeled A2 and A1, and 
     no jumpers installed across pins labeled A0. 
 
     To assign a different SCSI ID, change the jumper 
     settings as shown in Table 2. 
 
     Wait Spin (WS) Jumper 
 
     With the Wait/Spin (WS) jumper disabled, at power on or 
     reset, the drive motor starts to spin automatically, and 
     the drive prepares itself to perform read or write 
     operations without the need for a start command. At a 
     power on or reset, with the Wait/Spin jumper enabled, 
     the host must send a START/STOP UNIT command to activate 
     the drive motor for read or write operations. In 
     addition, with the W/S jumper enabled, the drive 
     performs power sequencing to prevent an overload of the 
     host's power supply due to simultaneous, peak start-up 
     current demands from multiple devices. 
 
     At the factory, Quantum configures the ProDrive 
     425/425iS hard disk drive with the Wait/Spin jumper 
     disabled; that is, without a jumper installed across the 
     pins labeled WS. To enable Wait/Spin, install a jumper 
     across the pins labeled WS. 
 
     Self Seek (SS) Jumper 
 
     The Self Seek (SS) jumper is used to place the drive in 
     a test mode at start up. This will inhibit the drive 
     from normal operation and is for factory use only. 
 
     At the factory, Quantum configures the ProDrive 
     425/425iS hard disk drive with no jumper in place. 
 
 
 
Fletch 
 
 
>  
> 	Thanks Brusi