Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!auspex!yuping
From: yuping@auspex.auspex.com (YuPing Cheng)
Newsgroups: comp.periphs.scsi
Subject: Re: sync scsi tape drives (non 1/2 inch)
Message-ID: <6060@auspex.auspex.com>
Date: 15 Feb 91 17:33:11 GMT
References: <grl.666498133@groucho>
Organization: Auspex Systems, Santa Clara
Lines: 19

In article <grl.666498133@groucho> grl@brb.dmt.csiro.au (Greg Lehmann) writes:
>Does anybody have a DAT or 8mm tape drive that can do synchronous scsi
>transfers. Apparently most 1/2 inch tape drives support it these days.

The difference between synchronous and asynchronous transfer is that using
the former you can get up to 5MB per second, while the latter allows you
to get 1.5 to 3 MB per second depending on you cable length.

But, don't forget your 8mm tape is writing data at 246KB per second, and
your 4mm DAT is writing at 183KB per second.  Hence the data transfer rate
on the SCSI bus only changes the amount of time needed for fill the tape
data buffer.

If you have another disk device is sharing the SCSI bus with the tape
device, the SCSI bus data transfer rate could be important, but not
significantly. Because the tape device empties its buffer at its own
recording data rate.

Yu-Ping Cheng, Auspex Systems Inc., ycheng@auspex.com