Re: ide-floppy.c vs devfs

From: Paul Bristow (paul@paulbristow.net)
Date: Tue Nov 27 2001 - 12:47:03 EST


Borsenkow Andrej wrote:

>>This is made somewhat more complicated by the fact that ide-floppy
>>
> disks
>
>>can use either the whole disk, with no partition table or, more
>>commonly, partition4. So a user-friendly solution would be to create
>>
> a
>
>>floppy node that pointed to the partition, if it existed, or the whole
>>disk if it didn't. With appropriate code to handle that fact that
>>anyone can partition these disks in any way they like.
>>
>>
>
> Where's the problem? Use .../disc for whole disc or .../part4 for
> "normal" access. (Or /dev/hdc and /dev/hdc4 if you prefer) It is nice if
> partition code can detect it but it is not ide-floppy driver problem.

Just wondering if we should be clever for the users here. Maybe I
should leave that to user-space tools? Or is there anything in devfs
that can take care of this? The nice solution for end-users might be
a /dev/idefloppy that is a symlink to the relevant node in the
/dev/ide... tree.

>>Note this doesn't take account of the nice ATAPI command that sets the
>>disk into "ignore track 0" mode, making a partition 4 look like an
>>entire floppy with 1 less track.
>>
>>
>
> Why complicate things more than needed?

Because you can boot from a zip or ls-120 drive, with the BIOS setting
it to this mode. There are disks out there that are unreadable unless
you ignore track zero, by formatting them in a PC like this.

>>Anyone up to telling me how this is handled in the SCSI layer?
>>
>>
>
> When I boot without media in Jaz drive I get something like "no media
> inserted, assuming 1GB 512B per sector". Actually I modeled my patch
> from this - use some default values reported by drive when no media
> currently exists.

OK. This makes the most sense here. I'm happy to go with this.

I'll dig out your patch - discovered I was on holiday when you
originally submitted it - and code and test something over the next day
or so. Thanks for the help

> -andrej

-- 

Paul

Email: paul@paulbristow.net Web: http://paulbristow.net ICQ: 11965223

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