Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!mit-eddie!media-lab!lacsap
From: lacsap@media-lab.MEDIA.MIT.EDU (Pascal Chesnais)
Newsgroups: comp.sys.next
Subject: Re: Ejecting the floppy
Summary: use dump to back onto multiple floppies
Message-ID: <4970@media-lab.MEDIA.MIT.EDU>
Date: 21 Jan 91 21:55:46 GMT
References: <10365@pasteur.Berkeley.EDU>
Distribution: usa
Organization: MIT Media Lab, Cambridge, MA
Lines: 40

In article <10365@pasteur.Berkeley.EDU>, carlton@cs.berkeley.edu (Mike Carlton) writes:
> Can anyone tell me how to eject a floppy disk under software control?
> And how to tell when a new one has been inserted?  
> 
> Why do I want to do this?  Well, I'd like to write a 'split' like
> program to write files larger than the size of a floppy to a series
> of disks (e.g. a compressed tar file of my home directory :-).  
> 
The first thing you may want to consider is that the floppy driver deals
with floppy volumes and not floppy drives.  That is to say I can do:
/etc/mount /dev/fd0a /mnt_a
it will ask me to put the diskette in for volume 0
/etc/mount /dev/fd1a /mnt_b
it will eject the volume 0 diskette and then it will ask me for volume 1

then when I refer to /mnt_a/foo it will automatically eject volume 1
and ask me for the volume 0 diskette.

So for your application I would split the big compresses tar file into
files that would fit onto a diskette.  You will want to have the
diskettes initialized as a UNIX filesystem.   The I would mount the
filesystems I am interested in, copy the split file onto the right volume
and then cleanly unmount and eject each of the volumes.

now the thing you will have to remember is that you want to cleanly umount
the floppy before using the disk command to eject the disk... the safest
way to remove a floppy from the machine is to first try to drag the
floppy into the recycler in the browser.

If you want to backup a whole filesystem you probably want to use the
dump(8) command, which you can tell how much a floppy can hold.

The documentation is online,  Librarian is your friend.  Maybe someone
will write an application to do this for people.

pasc
-- 
Pascal Chesnais, Research Specialist, Electronic Publishing Group
Media Laboratory, E15-348, 20 Ames Street, Cambridge, Ma, 02139 (617) 253-0311
email: lacsap@plethora.media.mit.edu (NeXT)