From: mr2@netcom.com (Jongyoon Lee) Subject: Re: 2 SCSI cards in the same Linux box? Date: Fri, 2 Jul 1993 21:37:57 GMT
Wolfgang Stukenbrock (wgstuken@immd4.informatik.uni-erlangen.de) wrote:
: A good FAST-SCSI controller is able to transfer up to 8 MB/sec average
: over the SCSI bus. This will allow you to put two disk with each up to
: 5 MB/sec transferrate from disk-cache to media on that bus without the
: bus beeing the bottleneck. The "normal"-SCSI controller may transfer
: up to 3 MB/sec (depending of the connection devices) avarage. Better
: SCSI-disk will allow up to 5 MB/sec with a transferrate of to the media
: equal to that. So on "normal"-SCSI one disk will saturate the SCSI-bus.
Not really. Those numbers are the *maximum trasfer rate* they can do.
They rarely reach 2-3 megabytes/sec. Also, the operation of
these resources are bursty. So even if you connect two 5Mb/s disk drives
on a 5Mb/s SCSI channel, it doesn't mean these two drives will fight for
the bus all the time. For the most of tme, the bus will be idle under
a *normal* load. Even when there is traffic, chances are only one device
is transmitting. They will rarely have a conflict.
[stuff deleted]
: --
: Wolfgang Stukenbrock
Jongyoon
--+-----------------------------+-----------------------------------------------+ | Jongyoon Lee | _/_/ _/ _/_/ | | University of California | _/ _/ _/ _/ _/ | | Los Angeles | _/ _/ _/ _/ | | Computer Science | _/ _/ _/_/_/ _/ _/ _/_/_/ | | | _/ _/ _/ _/ _/_/ _/ _/ | | jong@seas.ucla.edu | _/ _/_/ _/ _/ _/ _/ | | mr2@netcom.com | _/_/_/_/ _/_/ _/_/_/_/_/ _/_/_/ _/_/_/ _/ | +-----------------------------+-----------------------------------------------+