NeXT MO disks

From: Mark <>
Date: Mon Mar 5 18:47:39 2001


Replying to a couple of messages here...

On Wed, 28 Feb 2001 Jerome Fine wrote:
>> I took a look at the Pinnacle drive today and it is a
>> Pinnacle Micro Sierra Optical Hard Drive with a 1.3gig capacity on
>> 5-1/4" removable media. Supposedly it is a double-sided cartridge
>> capable of holding 650Mb per side. It appears to be a standard SCSI
>> drive, but unfortunately I do not have any of the disks for it.
> As far as I know (or at least this is what I have always been told), the
> MO drives which can use the larger capacity (NOT larger in physical
> dimensions) media are also backward compatible with the lower
> capacity media for both read and write at least downward one step.

Yes, the only exception I know of being the Pinnacle Micro Vertex 2.6GB drive.

Here's a summary of drive compatibility. 1x means 600 & 650MB, 2x means
1.2/1.3GB, 4x means 2.3/2.6GB, 8x means 4.1/4.8/5.2GB and 14x means 8.6/9.1GB.

Basically any Maxoptix drive can read and write to all previous generations of
media, plus Maxoptix-specific 1GB disks (possibly read-only) and maybe
1.7/2.0GB disks.

2x drives (SMO-F521, SMO-F531) can read and write 1x and 2x media.
All 4x, 8x and 14x drives can read all previous capacities.
Most 4x drives (SMO-F541, SMO-F544) can write to 2x and 4x media. They cannot
write to 1x. However, there is a model which *can* write to 1x media, the
Most 8x drives (SMO-F551) can write to 4x and 8x media. There are models which
can write to 2x (SMO-F551/DD) and 1x & 2x (SMO-F551/SD).
The 14x drive (SMO-F561) can write to 4x, 8x, and 14x media.
Pinnacle Micro
The 2x Sierra drive can read and write to 1x and 2x media.
The 4x Vertex drive can only read and write to 4x media. The reason for this
is that Vertex drives were Apex drives which did not meet the spec for 4.6GB
The 4.6GB Apex drive can read and write 4.2/4.6GB and 4x media. It is not
compatible with 1x or 2x media.
> There are now 5 GByte media and these drives can still read the
> 650 MByte original media for 5 1/4" drives, but are not able to
> write to the original media.
(One version of the Sony 5.2GB drive can write to all older media, as can all
Maxoptix 5.2GB drives.)
Sony recently introduced 9.1GB drives and media, see
There are actually full technical and SCSI spec manuals for the new SMO-F561
drive on the Sony web site, which makes a very welcome change.
The SMO-F561 supports an "emulation mode", whereby 9.1GB disks (whose physical
sector size is 4K) appear to have 512-byte or 1024-byte sectors. So even
computers that require 512-byte sectors can use the higher capacity disks. Of
course write performance will be relatively poor when using emulated sectors.
> NOTE:  The marketing hype produced by the drive manufactures
> always stated (from what I can remember) that an MO drive had
> a capacity equal the the capacity of the media rather than what the
> drive could read on just one side of the media before it was flipped.
Yes, though as far as marketing disks (as opposed to drives) is concerned that
is usual. It's similar to audio cassettes (C60, C90). At least it's better
than the stupid "assuming 2x compression" capacity figures quoted for tape
On Wed, 28 Feb 2001 Jeff Hellige wrote:
> Has me thinking about trying to put the Pinnacle to good use, if it is
> functional.  It would be easy enough to use it with my Mac's, but I wonder
> how hard it would be to get it working with the NeXT.
The drive should appear as a direct access removable device on the SCSI bus.
There may be a jumper to make it appear non-removable, if the NeXT does not
like removable media.
The NeXT native filesystem probably needs 512-byte sectors, so try using it
with a 600MB or 1.2GB disk first. Using, say, tar to write directly to
the drive may work with 650MB or 1.3GB disks.
If removable media support is poor or non-existent on the NeXT, boot up with a
disk in the drive. Then treat it like a hard disk, use the normal
partitioning and formatting tools. Maybe you will be able to eject the disk
after unmounting any partitions, then remount the partitions after inserting
another disk.
>     I'm not sure about the ZIP disks, but somewhat related and 
> on-topic is a drive I used to have for the Atari ST.  It was made by 
> Supra and was basically a 10meg 5-1/4" floppy.  The head tracking was 
Talking of wierd floppies... I saw an ad from 1983 for a drive which used a
magazine of six 1.2MB 5.25" floppies. Does anyone know which company made
-- Mark
Received on Mon Mar 05 2001 - 18:47:39 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:34:02 BST