In article <1992Aug26.125143.17176@murdoch.acc.Virginia.EDU> fh8n@uvacs.cs.Virginia.EDU (Frank Houston) writes:
quoted text
>Hello linux hackers
>
>I have just finished installing the SLS distribution of linux 
>over the weekend. Congratulation to linus and the authors 
>of sls. You guys give hackers a good name. The points is 
>SLS is now 15 disk and growing to morw than 20. Time to 
>go CDROM. On that subject DAK sells a CDROM with controller
>for 9. I alspo received a compuadd catalog on Aug 20
>that has a Cdrom and card for 9. So the price isn't 
>as steep. I know that there is a SCSI cdrom driver in development
>, but they seem a lot more expensive. 
>       
>       0 for the Adaptec board supported.
>       0 for the cheapest scsi cdrom.
>
>How about the linus community agree upon one of the minimaly 
>priced cdrom unix about and create drivers it. This would
>create a defacto common linux cdrom drive.
>

        I feel that I should warn everyone that DAK is in Chapter 11.
For those of you overseas, this means that they have filed for protection
from their creditors because they are unable to pay all of their bills, 
and Chapter 11 means that they want some breathing room so that they can
(hopefully) get things reorganized and get their cash flow situation
under control.  The upshot is that it may take a long time for you to
get any merchandise, and if they really go belly-up, you may never get
your merchandise.  It would be wise to pay by credit card if you purchase
anything from them.

        The CDROM code that exists for linux now can be neatly divided
into two parts.  One part is the SCSI code to read the drive, and the second
part is the filesystem.  The filesystem itself should work with any block
device, and in principle one could have the iso9660 filesystem on a hard disk
or a floppy disk.  The only device specific code in the filesystem is
something to check and see if the disc has been changed, and this currently
tests for major==11.  The filesystem itself calls a function in the SCSI CDROM
code to actually determine if the disc has been changed or not.

        The upshot is that all you would need to do is come up with a device
driver for whatever type of interface is being used.  The problem is that you
need to know how to program the interface, so if it is proprietary you might as
well forget it.  Also, I would want to make sure that a secondary
device/interface is actually becoming a standard before it would make sense to
try and support it.  If each of these really cheap drives all use a different
interface, I would suggest spending the extra money for a SCSI drive.

        Some people have guessed that some of the cheap CDROM drives out there
are actually on an IDE bus (this guess is based upon the connector), but
I have not heard anything definite.  I do not know if a IDE(?) CDROM can
use the same controller as the hard disk.

-Eric