Summary : MO disk 640 MB

From: JOSEPH AAJ Chackompally (
Date: Tue Feb 24 1998 - 05:49:34 CST

Short Answer :
640MB MO disks don't work with Solaris 'out of the box'.
The 128, 230 and 540 MB MO disks should work fine.

Question and the detailed answer follows

Thanks to the following people.

Harry Levinson <>
David S. Foster
Joel Lee <>
Kevin Sheehan {Consulting Poster Child} <>
John Devitofranceschi <>

Question :

Dear Sun Managers

I am not able to do newfs on an MO disk, which is on an MO drive with
SCSI id 2.
I can see the raw devices /dev/rdsk/c0t2d0s0, s1,s2 etc
the other scsi devices on the machine are

Boot disk : scsi id 3
cdrom : scsi id 6

when I tried newfs -Nv /dev/rdsk/c0t2d0s0
I got an error : Invalid disk geometry

The MO disk drive is Fujitsu Dyna MO 640
and the OS version is Solaris 2.5.1

Thanks and Regards

Answer/Suggestion :

The following mail is from John <>

This is the deal:

the 640MB MO disks don't work with Solaris 'out of the box'. They have
2048K block size, which, in order to work with Solaris, requires a special
(non-existent at this time, correct me if I'm wrong) driver. Confirmation
of this came from a very helpful
Fujitsu technical support rep.

The 128, 230 and 540 MB MO disks should work fine. They have
a 512K bock size. I know that the 230 MB disks work because I
tried it and it was fine. The necessary geometry information to format
these disks in Solaris can be found in the master 'fomat.dat'
file that is posted to comp.sys.sun.admin from time to time and it is
also available as a 'faxback' document from Fujitsu (408 428 0456,
doument # 2495). Additional geometry info can be found at Keep in mind that
all of these sources seem to conflict on some point or another so
you may need to experiment, however I have found the master
format.dat to be reasonably useful 'as is'. You just need to change the
'disk-type' from M2512 to M2513.

Anyway, that's all I know right now.

If anyone has any other info, or any way of using a disk with a 2048K
block size with Solaris, I'd be happy to try it out.


And this one from Joel (I haven't tried this) :

I think you need a software tool to manage your MO disk. Try go to for info on the product. (I think you have to use
od_format, before you can use newfs).

-- Joel

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