Subject: Getting Tape to Stream
To: None <amiga@NetBSD.ORG>
From: Darren Steven <>
List: amiga
Date: 12/07/1995 17:14:24

I have just obtained temporary access to an Archive Viper 150 SCSI tape
unit. I am having trouble getting it to work efficiently under NetBSD (1.0)
and AmigaDOS.

The unit does not support reselection (or diconnect/reconnect???), that is,
when the access to the Tape occurs, the SCSI bus is locked out until it
finishes. When I backup from the SCSI disk to the tape, I get a lot of
start/stop action and the throughput is poor. My best alternative at the
minute is to make each write to the tape a large one to minimise stop/rewinds.

Under AmigaDOS, I can get good performance (constant tape motion) from IDE
disk to SCSI tape (no contention) using BTN handler.

Does any one know how to optimise the i/o characteristics for small buffered
tapes such as this. Where are the bits I can tweak under NetBSD.

System is:
GVP4008 SCSI, Quantum 850M, Panasonic CD ROM., 1M RAM
120M IDE
NetBSD 1.0/AmigaDOS 3.1


Darren Steven

Australian Maritime College
Information Technology Services Department
Newnham Campus
Launceston, Tasmania, Australia

Phone (003) 35 4842