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From: chukran@austin.iinus1.ibm.com
Newsgroups: comp.os.coherent
Subject: floppy writing very slow
Message-ID: <6877@awdprime.UUCP>
Date: 22 Apr 91 13:29:22 GMT
Sender: news@awdprime.UUCP
Reply-To: chukran@austin.iinus1.ibm.com
Organization: IBM Advanced Workstation Division
Lines: 15

Can anyone confirm that writing floppys are very inefficient and
that there might be a workaround or fix?

I observe that reading a 3.5" floppy using dd takes 50s using a block size
of 1 track (18*512) from device /dev/rfva0, which is as I would
expect.  However writing the
same device takes 610s using the same block size.  I varied the
device as rfva0 and fva0, and varied the block size from 512,
3*512, 9*512, and 18*512, and still get the same real time measure.
Its as if the device driver is writing to the device one block at a time.
dd if=/tmp/floppyimage ibs=9216 obs=9216 of=/dev/rfva0

Kind of makes making floppy backups tedious.

Rudy Chukran