Summary: Accessing DOS CD-ROM/Can't mount a CD-ROM

From: SILL D E (
Date: Fri May 10 1991 - 14:52:17 CDT

I recently asked:
>A user has a CD-ROM intended for use under DOS, i.e., it has a DOS
>front-end for accessing the data on the disk.
>How can this data be accessed on SPARCstation with a Sun CD-ROM drive
>and DOS Windows? Can the Sun CD-ROM be accessed from within DOS
>Windows? Is it as simple as mounting the CD-ROM to /cdrom, defining a
>DOS disk that points to /cdrom, and running the front-end?

The short answer is yes, this will probably work.

And shortly followed with:
>I'm now getting the following error when I try to mount a DOS CD-ROM:
>trn# mount -rt hsfs /dev/sr0 /cdrom
>mount_hsfs: /dev/sr0 on /cdrom: No such device or address
>mount: giving up on:
> /cdrom
>The kernel has HSFS configured in, sr0 is recognized at boot time,
>there's a /dev/sr0, and we can even play audio CD's.
>The question is: does the error above indicate that the DOS CD-ROM is
>in the wrong format? Or is something else screwed up?
>[SunOS 4.1 on a SPARCstation 1+]

The problem here was that the user had neglected to insert the disc
into the drive. (I was doing this remotely over the phone and rlogin,
and under severe time pressure.)

Here are the suggestions I received. Thanks to all who replied.

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From: stern@sunne.East.Sun.COM (Hal Stern - Consultant)
Date: Wed, 8 May 91 13:03:32 EDT

why not use the PCFS filesystem (under sunos 4.1)?

        mount -t pcfs /dev/sr0 /cdrom

and go with it. if it's formatted like a dos disk, then
this should work OK

[Note: pcfs doesn't come with 4.1, only 4.1.1. -DS]


From: oconnor! (Mike Raffety)
Date: Wed, 8 May 91 13:08:00 CDT

Turn to pages 89-90 of the SunOS 4.1 Release Manual, where you'll
find exactly your questions answered. Thanks.


From: stern@sunne.East.Sun.COM (Hal Stern - Consultant)
Date: Wed, 8 May 91 15:33:02 EDT

do you have /usr/etc/ in root's path?
if you have /usr/etc/mount_pcfs, it's there (maybe it is 4.1.1,....)

if so, then you can get the DOSVFS consulting special for
something like $300 for 4.1 and earlier.


From: tessi!joey@nosun.West.Sun.COM (Joe Pruett)
Date: Wed, 8 May 91 12:33:06 PDT

what you suggest (mount cd under unix, then point dos drive at it) should
work. i would be quite interested in hearing if it really does work (perhaps
the rest of list would like to hear also).

[It works, but we've had some trouble getting the DOS app to run under
DOS Windows. It's some kind of configuration problem. -DS]


From: sundev!ronin!kevin@Sun.COM (Kevin Sheehan {Consulting Poster Child})
Date: Wed, 8 May 1991 14:06:47 PDT

You may be able to do it either way - getting at it with the DOS front end
depends on how the DOS front end goes looking for a CDROM drive.

If the CDROM is HiSierra (ISO9660) format (and the vast majority are) then
you should be able to mount it straightaway, and point the DOS disk at that.
As in "this should work, take a shot at it"

Depending on the format of the data, you may want to see if the applicable
Sun application exists...


From: (Dennis McCormick)
Date: 9 May 91 08:49 EDT

Great Question about CD ROMs for DOS!
Please post any news you receive (good or bad) on the state of play. I would
be particularly interested in anything on UNIX-based access to DOS CD ROMs
(esp those on which non-proprietary data storage is used).

[The discs we have were produced by NOAA (National Oceanic and
Atmospheric Administration), hence, don't do anything tricky. -DS]


From: Tom Leach <>
Date: Wed, 8 May 91 11:51:24 PDT

Just as an off the wall suggestion, make sure that you have /usr/etc and /etc
in your path.


From: sundev!ronin!kevin@Sun.COM (Kevin Sheehan {Consulting Poster Child})
Date: Wed, 8 May 1991 14:10:59 PDT

I seem to remember the command line syntax changing, although I unfortunately
do not have man pages loaded at the moment to see what the difference is.

The error you get back for "wrong format" is different. At least it was
different when I owned the code.


From: (Joe Garbarino)
Date: Wed, 8 May 91 17:26:39 EDT

Hi. Don't have an answer, but I had the same results after trying to
mount a CD-ROM written in PC format. After I put a CD back in that I
know I've mounted before, I still couldn't mount the drive. Looks
like it might require a reboot...


From: (Bill Selig - SysAdmin)
Date: Wed, 8 May 91 16:31:21 CDT

I would guess the wrong format, since part of the mounting is to
connect the file system on the device into the unix filesystem.


From: Sam Horrocks <sam@john-bigboote.ICS.UCI.EDU>
Date: Wed, 08 May 91 18:21:45 -0700

The only other thing you can try is mounting it as a straight unix
filesystem with:

    mount -r /dev/sr0 /cdrom

Some of the Sun CDROM's have to be mounted that way.


From: (V{{r{nen Kari)
Date: Thu, 9 May 91 10:03:14 +0300

A stupid question: did you create the /cdrom diretory? :-)

[How ironic that the actual problem was even more stupid. -DS]


From: "Bill Eshleman" <>
Date: Thu, 9 May 91 09:26:35 -0400

Is the target set right?


From: alison@c255.ucsf.EDU (ABoeckmann)
Date: Thu, 9 May 91 08:21:09 PDT

I have run into the same error message here when I try to run the
Demo Disc-1.0 that came with my new CD Rom drive. Sometimes mount
works, sometimes it doesn't, with the same messages as you report.
If you get any interesting answers, please post to the net or send
to me directly. Thanks!


From: Claus Assmann <>
Date: 8 May 91 18:51 +0200

Have you tried another CD (with the correct format) ?

If you get the problems even with a 'correct' CD, maybe this helps:

We have encountered this problem with our drive too:
Sun support told me to switch the device off and on again, and try
the mount command two times (if the first fails, with only a minimun
of time between the tries).
After this simple solution our drive works most of the time quit well
(sometimes you have to repeat the procedure).


Date: Fri, 10 May 91 8:18 BST

Have you checked the obvious? Do you have a directory called 'cdrom'
at root level on which to mount the CD?


Date: Thu, 9 May 91 08:44 +1200

I had the same problem a little while ago. Below is the summary I posted to
sun-managers. In my case I never did find out why it wouldn't work it just
started working after a reboot. There's lots of things you can check out.

[duplicates deleted]

does /dev/sr0 have the right device numbers?  my system has 18
for the block and 58 for the character device (/dev/rsr0).
Do the major numbers in the /dev/sr* files match the expected values
from the kernel config file (/usr/sys/sun/conf.c)?  This could cause
you to not be able to access the device when the kernel says it's
It looks as if the machine has lost track of the device altogether (SCSI bus

What I found that works, and sometimes only after several attempts, was to turn off the CD drive, turning it on again, and when the green light on the drive comes on, give the mount command again.

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