Transfer rate/Bandwidth

[manishkumar.sharma]

[Ed's Note: This is the first article that is being crossposted to the new
newsgroup comp.periphs.scsi from comp.sys.sun. Any hardware questions that
deal with SCSI will now be automagically crossposted to this group during
this trial period. If things work out well, this scheme will be continued.
For comp.sys.sun readers, this change does not affect you really except
that your SCSI articles will be read by more people who might have
a good knowledge of SCSI concepts, for comp.periphs.scsi readers, I would
ask that if you summarize many responses that stemmed from a comp.sys.sun
article, that you would also crosspost that summary to comp.sys.sun.
Anyway, enough bandwidth wasted. Readers of either group may feel free
to send any comments to me directly at RGREENEB at RICEVM1.RICE.EDU
-Bob Greene (comp.sys.sun Moderator)]]

What is the difference between disk transfer rate and bandwidth?  For
instance, the IPI disk drives on the Sparc 490 have a transfer rate of
3mb/sec. What is the bandwidth? How are they related?

I understand transfer rate as the block(s) of data that are moved from
memory/cache to disk per unit time. Where does bandwidth come in here?
What is its value on the Sparc 490?  The Sparc that we have has a ISP-80
disk controller and a SCSI host adapter. Where do they fit in for
bandwidth?  Thanks.

-Manish Sharma
 (ucbvax,att,ulysses)!holin!mks