Path: utzoo!utgpu!news-server.csri.toronto.edu!csri.toronto.edu!wayne
Newsgroups: comp.os.minix
From: wayne@csri.toronto.edu (Wayne Hayes)
Subject: Re: PC Minix and 1.44MB floppies
Message-ID: <1990Aug9.004630.25197@jarvis.csri.toronto.edu>
Organization: CSRI, University of Toronto
References: <3851@crash.cts.com>
Date: 9 Aug 90 04:46:30 GMT
Lines: 26

In article <3851@crash.cts.com> cwr@pnet01.cts.com (Will Rose) writes:
>curiously, one blocksize was slower reading onto the hard disk and the
>other was slower reading onto the floppy.  The times were:
> 
>    dd if=/dev/fd1 of=file bs=1k count=1440 takes 15 min.
>    dd if=file of=/dev/fd1 bs=1k count=1440 takes 7 min.
>    dd if=/dev/fd1 of=file count=2880 takes 6 min.
>    dd if=file of=/dev/fd1 count=2880 takes 12 min.
> 
>Are these times typical, and is there any input buffering or whatever that
>could speed things up?

After some experimentation, I found that the larger the buffer size, the
faster it worked.  I started out with bs=10240 (10K), count=144, but hey,
since *all* the floppy sizes are divisible by 30K, I now use

	dd if=df1 of=file bs=30720 count={***}

where {***} = (disk size) / (30720).  This works pretty fast.

-- 
"The number of programs that can be done with the Hubble Space Telescope has
always greatly exceeded the time available for their execution, and this
remains true even with the telescope in its current state." -- HST Science
Working Group and User's Commitee Report, 1990 June 29.
Wayne Hayes	INTERNET: wayne@csri.utoronto.ca	CompuServe: 72401,3525