>Number:         4815
>Category:       kern
>Synopsis:       AHC driver can't make ARCHIVE VIPER 150 stream.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jan 13 06:05:02 1998
>Last-Modified:
>Originator:     Ignatios Souvatzis
>Organization:
computer science department, university of Bonn, Germany
>Release:        Release branch as of early January 1998
>Environment:
	
System: NetBSD cosinus.cs.uni-bonn.de 1.3_ALPHA NetBSD 1.3_ALPHA (COSINUS) #1: Sat Jan 10 01:49:13 CET 1998 ignatios@cosinus.cs.uni-bonn.de:/usr/local/obj/kernel/COSINUS i386


>Description:
When writing to an Archive Viper 150, using a DC6150 tape (density code 16),
from a Pentium 166 MMX + Adaptec 2940, the tape doesn't stream. Instead it
moves about 3 seconds forth, and 1 or 2 backwards.

The data rate needed for streaming is about 100 kbytes/s sustained.

Note that:
- the tape does stream when reading.
- the same tape drive (yes, i carried my home one to work to make sure)
and the same tape in it do stream, if driven by NetBSD/Amiga on DraCo
(68060/50MHz, ncr53c710).

>How-To-Repeat:
cosinus# dmesg | grep st1
st1 at scsibus0 targ 5 lun 0: <ARCHIVE, VIPER 150  21247, -005> SCSI1 1/sequential removable
st1: rogue, density code 0x0, 512-byte blocks, write-enabled
cosinus# mknod /dev/nrst1h c 14 21
cosinus# dd if=/dev/zero of=/dev/nrst1h bs=32k count=100
100+0 records in
100+0 records out
3276800 bytes transferred in 140 secs (23405 bytes/sec)
cosinus# mt -f /dev/nrst1h rewind
cosinus# dd if=/dev/nrst1h of=/dev/null bs=32k
100+0 records in
100+0 records out
3276800 bytes transferred in 34 secs (96376 bytes/sec)


>Fix:
	not known.
>Audit-Trail:
>Unformatted: