Subject: Re: Floppy driver
To: None <>
From: Ty Sarna <>
List: amiga-dev
Date: 03/01/1994 03:28:34
In article <> (Mike Schwartz) writes:
> Consider the case where you do:
> tar cvfp /dev/floppy /somedir
> Tar is going to create a raw archive on the floppy, which is what you want.
> However, take that floppy and stick it in your drive while ADOS is running
> and you get dos requesters saying "not a dos disk" and the likes.  Now,
> let's say you have made such a disk and you think it's a bad/unformatted
> floppy when running ados - you probably will format it and use it.  And
> you've possibly wiped out a floppy you didn't want to.

...which is in keeping with The Unix Way of allowing users to shoot
themselves in the foot, and OK as far as I'm concerned.

> When we are talking about skipping sectors, we are talking about making it
> possible for you to make that tar floppy.  Then when you stick it in the
> drive with ADOS running, you get a valid dos disk.  You'll even get an icon
> on  your
> workbench.  And by doing the bam as 0xffff, if you do ADOS info command,
> the disk will show up as 100% full.

But then the disk will only read on NetBSD/amiga... I prefer
interoperability over having the system protect me from shooting myself
in the foot. It's my foot, after all, and I should be allowed to shoot
it if I want to :-)

> It seems that if you want to use tar, as I gave in my first example, we
> should have a /dev/fd<something> that does the track/sector skipping.  In
> your text,
> you wrote about having 1760 raw sectors to read/write to.  In the case you
> use tar, you really want 1760-3 raw sectors...

I don't :-). Besides, then we have to problem of having two incompatible
Amiga floppy formats. Also consider the main uses the floppy driver will

- reading/writing AmigaDOS disks with adosfs. Don't want skipping for this.

- reading/writing MS-DOS disks with msdosfs. Don't want skipping for this.

- backing up using tar/cpio, msdos format for interchange. Don't want skipping.

- backing up with tar/cpio, amiga format for space. Could use skipping,
  but you probably want to squeeze every last block out of the disk.
  If we're going to introduce an incompatible format for this one, how
  about making it do that 900-and-something K format that DiskSpace (?)
  uses? This is the case where it would be useful...

Ty Sarna                 "As you know, Joel, children have always looked        up to cowboys as role models. And vice versa."