Date: Sun, 26 Dec 1999 22:20:53 +0800 From: Peter Wemm <peter@netplex.com.au> To: KATO Takenori <kato@ganko.eps.nagoya-u.ac.jp> Cc: FreeBSD-hackers@FreeBSD.org Subject: Re: device name of floppy disk Message-ID: <19991226142053.8A38C1CA0@overcee.netplex.com.au> In-Reply-To: Message from KATO Takenori <kato@ganko.eps.nagoya-u.ac.jp> of "Sat, 25 Dec 1999 23:42:13 %2B0900." <19991225234213C.kato@gneiss.eps.nagoya-u.ac.jp>
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KATO Takenori wrote:
> The MAKEDEV has such lines as:
>
> # ln -f ${name}${unit}.1200 ${name}${unit}96
> # ln -f r${name}${unit}.1200 r${name}${unit}96
> # ln -f ${name}${unit}.1200 ${name}${unit}96ds15
> # ln -f r${name}${unit}.1200 r${name}${unit}96ds15
> # ln -f ${name}${unit}.1200 ${name}${unit}135ds15
> # ln -f r${name}${unit}.1200 r${name}${unit}135ds15
>
> for floppy disk device. I have questions about these lines.
>
> 1. What is meanings of the name? I cannot understand meanings of
> `96', `96ds15' and `135ds15'.
Those are the SCO Unix/Xenix compatable names. SCO (and SYSV/386) uses those
instead of "fdN.1440" etc.
48 = 48 tracks per inch = 5.25" disk,
96 = 96 tracks per inch = 5.25" disk,
135 = 135 tracks per inch = 3.5" disk
<nothing> = single sided
ds = double sided
<nothing> = 9 sectors per track (as used on 360K disks)
15 = 15 sectors per track (as used on 5.25" 1.2M HD disks)
18 = 18 sectors per track (as used on 3.5" 1.44M HD disks
There are some variations on different systems. Sometimes there is "s", "d"
and "q" for single, double and quad speed in the "ds" field.
> 2. Why they are commented out?
Probably because they are not needed for general SCO Unix compatability (SCO
apps generally let you choose the pathnames to the fd devices manually since
there are so many of them) and having all the variations would just make a
mess in /dev.
> 3. Are these entries mandatory for all floppy disk devices? (Should I
> make such lines when I add new mode for floppy disk?)
I wouldn't worry about it, as long as the normal modes are supported.
Cheers,
-Peter
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