Re: SCSI-1 vs. SCSI-2 -- what's the difference?

[Gregory Ross Thompson <gregt+@CMU.EDU>]

beta@gnh-cathouse.cts.com (Scott Sidley) writes:
> however besides the greater number of STANDARD connectors (I do like the
> HI-DENSITY 50 pin connectors, but they are a pain to interface to other
> non-HI-DENSITY connectors) SCSI-2 also offers FAST SCSI-2 (3 Meg async 10 Meg
> sync) , WIDE SCSI-2 (either 16 or 32 bit interface vs the 8 bit of normal),
> and of course FAST WIDE SCSI-2 (10 Meg Sync (3M async) and 16 or 32 bit
> interface)  These drives are only a few hundred $$$ more than SCSI-1 drive but
> offer up to 8 times the performance.

  I'd just like to point out that even though the bus can support
3-10Mbps, most drives can only send data at around 1-2Mbps.  So it
doesn't really matter that the bus is tons faster.  The only speedup
you will find is that data is sent from the drive's buffer (if it
caches a significant amount of data) to the controller on the other
side of the bus faster.  Since the GS's bus only runs at 1Mbps, it
doesn't matter at all that SCSI-2 is faster than SCSI-1.  On a system
with a faster bus, there will be slight speedups, but then again, modern
OS's should be smart enough to cache and schedule disk seeks to the
point that the disk's buffer doesn't make much of a difference.

		-Greg
		 InterNet: gregt+@cmu.edu
		       or: gt0t+@andrew.cmu.edu
		 BITNet  : R746GT0T@CMCCVB
		 AOL     : GRThompson