> On Fri, 1 Aug 1997, S.J. Borrill wrote:
> 
> > Has anyone got any experience of CD writers under RISC BSD (or even RISC
> > OS at a push)? Are there any particular ones recommended or any caveats in
> > their use?
> 
> You cannot do it under RiscBSD running on a RiscPC due to the speed of the
> drivers unless you have a writer with a build in HD.

Lets quantify this.
Say one use a phillips CDwriter, with 1MB cache, and 300KB writing speed,
and have an old SCSI I card, writing 1MB/s.

To fail, RiscBSD would have to stop sending data to the CDwriter for
at least 3 seconds. This is a large latency. I have worked with old
16MHz 68020 Unix machines that had latencies at least an order of
magnitude less than this.

The writing itself, would require the moving of 300KB of data to the
SCSI card. This is very little of the DEBI-bus bandwith of a RiscPC.

The SCSI card would only have to work at 1/3 of its capacity,
which gives very large room for overhead.


So, why is RiscBSD so bad at handling this?


Kim0