Servers with SCSI Adapters and SCSI Tape Drives

A number of different scenarios have recently been found whereby SCSI tape drives in NetWare servers would not operate correctly unless the SCSI adapter was configured with the ‘Synchronous Transfer started by host adapter’ set to No/Off (the default in Yes/On).

If set incorrectly, some of the problems that can be encountered include:-

• Conner Backup Exec (NetWare NLM) hanging when initialising the tape drive.
• Third party SCSI tape drives (such as HP and Wangtek) failing to operate with SBACKUP.
• NetWare deactivating SCSI disks attached to the same SCSI card as the SCSI tape drive when the tape drive is under heavy load. (also see note below)

To disable the ‘Synchronous Transfer started by host adapter’ option, you will need to do one of the following:-

• Adaptec AHA1510 (AT)
  
  When loading AHA1510.DSK in STARTUP.NCF, add the command SYNC=OFF to the line that loads AHA1510.DSK, for example;
  
  load AHA1510 port=340 int=9 sync=off
  
  
• Adaptec AHA1640 (MCA)
  
  Within the Reference/Setup disk configuration screen for the AHA1640 card, scroll down to the ‘Sync Xfer Started by AHA-1640 Yes/No’ option and set it to No.
  
  
• Buslogic BT-646S (MCA)
  
  Within the Reference/Setup disk configuration screen for the BusLogic 32Bit Bus Master MCA-to-SCSI Host Adapter card, scroll down to the ‘Adapter Initiate Sync Negotiation’ option and set it to Off.
  
  Note that this change is also needed if running OS/2 2.1 on a Panther 2 (FT//s or FT//e) server
  
  
• Adaptec AIC7770 (EISA)
  
  Boot the system from the MCS-EISA Configuration Utility disk, then select the following:-
  
  select Configure Computer and press enter
  select Configure Computer - Advanced Method and press enter
  scroll down to Slot 9 - Adaptec AIC-7770 SCSI Host Adapter and press enter
  select BIOS and Device Configuration and press enter
  select Device Configuration and press enter
  select the Channel and SCSI ID for the tape drive, and press enter on the yes field in the ‘Initiate Sync Negotiation’ column. This will change the option to no.
  Press TAB to get to the OK button and then press enter.
  Press Esc and then select the System Exit command.
  Select Save Configuration and Exit and press enter

Additional note for SCSI Systems that have SCSI disks and SCSI Tape Drives sharing the same SCSI Adapter.

If the disk sub-system is likely to be placed under heavy load whilst a tape operation is in progress, and the server is configured with a SCSI tape drive connected to the Primary SCSI controller (i.e. the one with the system Boot Disk connected), it is advisable to reconfigure the server so that the tape drive is moved from the Primary SCSI controller to another

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