RE: SCSI errors

From: Richard Elwell <rjelwell_at_telemedia.co.uk>
Date: Tue, 10 Aug 1999 12:52:31 +0100

> How does the suggested lower resolution/colour depth affect SCSI
> stability?

The screen is held in the main RAM. Every screen update (at say 60
times a second) involves copying the entire screen RAM across the
buses to the VGA chip. The buses have a limited band width, of
about 64MB/s, so with a 640x480x16colour screen of 150KB it is
taking nearly 9MB/s of that bandwidth just to update the screen.

The SCSI devices are read/written to from the same RAM so all that
data goes through the same bus too.

The less bandwidth taken by the screen the more is available for
everything else. With a Nova or Eclipse attached to a Afterburner the
normal motherboard buses should be almost entirely free from the
screen updates, especially if you switch of the VDI or use a very small
resolution and colour depth, eg. 640x400x2colour (32KB per screen).

I may be slightly inaccurate in some of that but the basic concept is
correct (I hope :-)


Rich.
Received on ti. aug. 10 1999 - 17:50:44 CEST