Date: Fri, 29 May 1998 19:20:10 +0200 (MET DST) From: Joerg Schilling <schilling@fokus.gmd.de> To: mike@smith.net.au, schilling@fokus.gmd.de Cc: freebsd-current@FreeBSD.ORG Subject: Re: cdrecord trouble on currnet / SCSI ABI test Message-ID: <199805291720.TAA15036@sherwood.gmd.de>
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>> The scg drvier which I wrote in 1986 is based on this interface and
>> itself is the base for my portable SCSI user-level command transport
>> system. It should be faily easy to make a CAM adoption layer for scg.
>It was. The real problems with scg have to do with the lack of visible
>documentation. It is unclear how to do any sort of meaningful error
>handling, or whether this should be managed at a lower level. Again,
>this is an issue I was postponing until I had established that
>everything else was going to behave and the interface had stabilised.
The main problem with this documentation is that a hacker who wants to
contribute code must have thorough knowledge on the SCSI protocol to
understand what to do from reading simply a API doc.
For this reason, I prefer to have some ABI checker software.
The main problem with this checker software is that I must be able to
create certain error situations like:
- drive not selectable
- timeout
- SCSI status code on error
- correct sense data content
- correct sense data length
- return code of scsisend()
- check for working DMA residual count
....
I am tending to do the necessarily tests with CD-ROM drive as most people
seem to have one.
But for timeout tests not every CD-ROM drive is usable because the only
idea I currently have to force a SCSI timeout is to do one very big
SCSi-VERIFY on a disk with > 400MB data on it. This is because not all
timeout implementations catch timeouts fast (< 1 minute).
Jörg
EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
js@cs.tu-berlin.de (uni) If you don't have iso-8859-1
schilling@fokus.gmd.de (work) chars I am J"org Schilling
URL: http://www.fokus.gmd.de/usr/schilling ftp://ftp.fokus.gmd.de/pub/unix
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