RE: Hard drive on the EPP

["John H. Kim" <jokim@mit.edu>]

In message Tue, 25 Oct 94 02:12:50 -0500,
  ychou@uxa.cso.uiuc.edu (Sean Chou)  writes:

>> You're missing the point.  If you have a hard disk drive with a
>> reasonably fast throughput you are an order of magnitude faster than
>> the bandwidth of the parallel port on the ThinkPad.

> I understand the concept of thoroughput.  I guess I'm wondering
> whether or not that's the real issue here.  I don't know how often
> you are using contiguous files that are large enough to notice a big
> difference in thoroughput.

Did my message not get out?  The 5-10MB/sec specification being waved around
for many new drives is the burst transfer rate - i.e. moving data from the
built-in cache to the computer.  The vast majority of disks can only read
data off the platter at 500k/s - 1MB/s.  If your drive is rated at 10MB/sec
and it has a 256k cache, the maximum time penalty for using EPP is waiting
0.25 seconds instead of .025 seconds.  In typical use, you'll barely notice
the difference.

All this changes if you hook up multiple SCSI devices to the same EPP.
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John H. Kim        | "Mike Espy simply forgot he was no longer a Congressman."
jokim@mit.edu      | -anonymous, on the Secretary of Agriculture's resignation
jokim@uni.uiuc.edu | due to conflict of interest charges for accepting gifts.
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