From: mea@sparta.com (Mike Anderson)
Newsgroups: comp.os.vxworks
Subject: re:  SCSI floppy disk/tape drives under vxWorks
Date: 28 Jul 92 14:08:33 GMT
Organization: Lawrence Berkeley Laboratory, Berkeley CA
NNTP-Posting-Host: 128.3.112.16
Originator: daemon@vxw.ee.lbl.gov

Greetings!

> Sender: kevinr@ceco.ceco.com
> 
> 
> I am looking for both good and bad experiences with any SCSI 3.5" floopy
> drives and any SCSI 1/4" cartridge tape drives anyone out there has
> used succesfully/unsuccesfully under vxWorks 5.0.2.  We are running
> MV147s and have not purchased any drive hardware yet, so we are open
> to just about anything.  If anyone has any drive specific driver code
> that they are willing to share it would be much appreciated.  I will
> summarize the results if there is much interest.

I have been working with the Teac SCSI 3.5" floppy disk drive
(FD-535HF) and have successfully formatted in MSDOS 1.44MB format and
have Heurikon 68Ks (V30XE, V3D) booting VxWorks from floppy and then
booting other VxWorks targets from the just booted machine using FTP.
I use these when I teach file systems and SCSI devices in my
intermediate real-time programming course.  There are a lot of
other gotchas (as my students quickly discover) when you boot up
from a local file system because the initialization of VxWorks and
all of the daemons (err... tasks :-) is considerably different from
booting up from a network and trying to get the symbol table loaded
from floppy takes a little finessing.

The tricky part with these devices is to get the controller (i.e., the
floppy drive controller not the Heurikon) set up for various formats
(the drive supports over 19 different formats).  1.44MB is easy, just
send the SCSI mode header, but the 720KB is quite a bit more involved
because of roughly 25 additional parameters you have to send to the
drive.  The floppy drives I use only work in asynchronous SCSI mode which is
just fine for your purposes because I believe that the MVME147s can't
speak synchronous SCSI anyway.

Sorry, I haven't played much with SCSI tape except at task level with
and Archive Viper (150MB QIC).  You pretty much have to keep track
of how much you've written and where you are on the tape yourself.  You
might look at the Exabyte code that's been posted here before for
clues as to how to deal with tape.  However, from what I understand,
don't expect stellar performace from the 147 SCSI.  It's supposed
to be dog slow.

Good luck,


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Newsgroups: comp.os.vxworks