Ref: 13420008
Title: Changing Tape Drives in a Server
Date: 4/9/90

Copyright 3Com Corporation, 1991.  All rights reserved.

When exchanging an existing tape unit from a server with another
unit, if the exchange is not an exact swap, there are several
steps required to ensure that the server will boot properly with
the new tape unit.

Tandberg and Archive tape drives cannot be directly interchanged.
The screws that hold Tandberg drives in the server bracket are
metric; Archive screws are not.  The SCSI cable from the system
SAE board on Tandberg drives is too short for Archive drives.
Also, pin 1 of the Archive SCSI cable is on the opposite side to
pin 1 of the Tandberg cable.  The most current software driver,
which supports both the Tandberg and Archive tape units, is
REQUIRED for the Archive drive.


Using the Correct Tape Drive Driver

The most common problem occurs when a Tandberg tape drive is
exchanged with an Archive unit on a 3Server386 server.  After the
server is booted, the tape drive cannot be accessed and the error
usually indicates that the drive is not attached or that the
drive cannot read from or write to the tape.

To diagnose the problem, verify that the driver is the correct
version for the tape drive.  (See "Correct Versions of Drivers
for Tape Drives" in this section.)

When you know you have the correct driver, run TAPETEST (on the
3+Backup #2 disk) under a console connection and execute steps A,
B and C to make sure that the tape drive functions properly.
(TAPETEST is also included with the TAPE.SYS and TDRIVE.SYS
drivers in the Ask3Com Forum.)


Checking the Jumper Connections

If the correct driver is loaded and the tape drive still does not
function properly, verify that the tape drive is jumpered for the
correct SCSI address (0 for a 3Server386 or 3Server/500 and 7 for
a 3Server3).

For a drive installed in a 3Server386 or 3Server/500 server,
remove the terminating resistors and install the Parity jumper.
For a drive installed in a 3Server3, remove the Parity jumper and
keep the terminating resistors.


Changing the Cable for a Tandberg-to-Archive Replacement

1.  Flip the SCSI cable (P/N 3612-00) 180 degrees.

    Pin 1 on the Archive drive is reversed from Pin 1 on the
    Tandberg drive.  If the SCSI cable has double-sided tape that
    keeps it folded, carefully pull it apart to accommodate the
    location of pin 1 on the Archive drive.  Arrange the SCSI
    cable as necessary to avoid any damage.  Be sure to keep
    cables from interfering with the drive or the server
    enclosure.

    If you do not wish to bend the cable to accommodate the
    Archive drive, order P/N 3612-01 to replace the existing
    cable.

2.  Make a console connection and run Tapetest from the 3+Backup
    #2 Version 1.3.2 4560-02 disk, either TTST3.COM or
    TTST386.EXE, dated 9/88 or later.

3.  When you run Tapetest, choose option A to select your tape
    vendor.

4.  Choose Initialize.  Initializing the server causes it to
    recognize the correct drive vendor.

5.  Reboot the server in normal mode.  Wait five minutes before
    running a backup.