28 Feb
2001
28 Feb
'01
11:25 a.m.
Hi,
This message replies to several in the thread about NeXT MO disks.
On Mon, 26 Feb 2001 Jerome Fine wrote:
The sector layout is stamped into the disk at the factory; it is not possible
to change. That's why there are two variants, e.g. 600MB and 650MB for first-
generation drives. 600MB disks have 512-byte sectors, and 650MB disks have
1024-byte sectors. The extra capacity of 650MB disks is because less space is
wasted on sector headers. Without special driver software, some computers only
work with media with 512-byte sectors, which is why the lower-capacity disks
exist.
(On a kind-of-related note: I understand the sector layout or servo tracks of
e.g. Zip disks are written at the factory. Does that mean if you degauss a
Zip disk it is then useless, and cannot be reformatted?)
That's not really true any more. Well, since 1991 anyway.
Before the original ISO standard was finalised, there were some problems with
interchanging disks between drives from different companies. This was
around 1989-1990. I believe most manufacturers updated the firmware of their
drives to solve the problems.
The major standard 5.25" MO capacities are:
600/650MB "1x", ISO 10089 Format A
1.2/1.3GB "2x", ISO 13549
2.3/2.6GB "4x", ISO 14517
4.1/4.8/5.2GB "8x", ISO 15286
8.6/9.1GB "14x", new, no standard published yet
Newer drives can usually read all, and write to some or all previous
standards.
Currently 5.25" MO drives are manufactured by Maxoptix and Sony (HP and IBM
drives are manufactured by Sony). They are completely compatible; a Maxoptix
drive can read disks written in a Sony drive etc.
In the past, drives have also been made by at least Ricoh, MOST, NEC, Nikon,
Sharp, Pinnacle Micro, IBM, HP. Disks written on any of those should be
readable on modern drives.
There are some other less common capacities; Hitachi made a drive which used
1.7GB/2GB disks, Pinnacle Micro's Apex drive could use 4.2/4.6GB disks, and
Maxoptix made drives which could use 900MB/1GB disks. All those types of disk
are still available new incidentally, and current Maxoptix drives can read
and write the 900MB/1GB disks.
There are a few uncommon types which you will rarely come across:
- Pioneer make MO drives which are mainly used in medical imaging
applications; apparently some CT scanners use Pioneer drives. Drive and
media prices for these are quite high, as Pioneer are the only source.
There are three types of rewritable MO media for Pioneer drives: 654MB (ISO
10089 Format B), 1.7GB and 2.2GB.
- ... and of course the Canon 500MB disks.
On Tue, 27 Feb 2001 Jeff Hellige wrote:
The Sierra is a very nice drive, at least going from the specs; I haven't used
one. Perhaps the fastest 1.3GB MO drive: spins at 4500rpm, average seek time
19ms, 4MB cache memory.
You can use any 1x (600MB, 650MB) or 2x (1.2GB, 1.3GB) MO disks with it. These
can often be found on eBay for a couple of dollars each. 1.2 or 1.3GB disks
will give faster data transfer than 600 or 650MB ones.
-- Mark
A question
about MO disks and the Canon MO drive installed in some NeXT
cube computers.
I know NeXT MO disks are single-sided, commonly quoted as having a capacity
of 256MB.
I have some rather old MO disks as well, but they are made by Sony and are
for a 5 1/4" Magneto Optical Disk drive - an S501. They are very close to
290 MBytes on each side and are formatted for 512 bytes per sector. I don't know anything about the NeXT hardware, but
if the shoe fits, ....
The Canon/NeXT disks are not the same as the ISO standard 600/650MB disks
which the Sony drive uses. They may be the same physical shape, but that is
all.
A page on the Sony web site indicates that NeXT drives can use 600/650MB
disks. I'm almost certain that is wrong. (The URL of the page is
http://www.sel.sony.com/SEL/rmeg/data/cg/table1mo.html - scroll down to the
Canon section.)
...
Since 250 MBytes per side is close, they might be the same as the ones I
have. Mine are 5 1/4" disks and formatted at 512 bytes per sector and hold
about 295 MBytes on each side for a total of about 590 Mbytes per disk. In addition, a friend of mine has a large number of
these disks which he no
longer wants. For a nominal charge plus shipping and handling, I am sure
that they can be made available. The shipping alone (these weigh about 1/2
lb. EACH) will likely be more than the disks, so I do think it is a good
deal. On eBay, they often try to get the suckers to pay over $ US 5.00 a
disk just to start, although sometimes they start at a more reasonable $ US
2.00 each. I am in Toronto, so the shipping may be more than you want to
pay!
Shipping may not be that expensive. A while ago I bought 50 5.25" MO disks,
and shipping within the USA by UPS cost $17 (from memory). The "media mail"
USPS rate is comparable to book rate, but for computer media.
Getting an older MO drive and disks is a really cheap way to get reliable
removable storage. The drives are so cheap (usually under $25 for a 650MB
drive, under $50 for 1.3GB) it is practical to get one for each computer.
Used disks cost $1 or $2 each. Way better than using a Zip drive, I think.
On Mon, 26 Feb 2001 Jeff Hellige wrote:
I have some
rather old MO disks as well, but they are made by Sony and are
for a 5 1/4" Magneto Optical Disk drive - an S501. They are very close to
290 MBytes on each side and are formatted for 512 bytes per sector.
If I recall correctly, one of the problems with the MO drives
was that there was little to no standardization of the formats or
disks for the drives. Pinnacle
called their drive the REO-650 and in a dual configuration it
was called an REO-1300. Since I also have an REO-650 and have
looked inside, I can verify that on the early models, this was the actual
hardware. Obviously, both the S501 and the REO-650 use the
identical media.
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. 
28 Feb
28 Feb
7 a.m.
From: Mark <mark_k(a)iname.com>
To: classiccmp(a)classiccmp.org
Date: Thu, 01 Mar 2001 01:25:03 +0000
Subject: Re: NeXT MO disks
Reply-to: classiccmp(a)classiccmp.org
Snip!
- ... and of course the Canon 500MB disks.
Not just that, I have a Kurata w/ 1GB flip rewriteable 5.25" MO.
Actual drive in that thing is made by Panasonic and sold under
Kurata, some of them were used by Corel. Evidence of that
is on the rear panel sticker. Cartridges can be single sided 500MB
or 1GB double sided, 500MB per side, flip it over for other side.
FYI: If you have problem writing/read, split the casing and clean
the media carefully, check (fish-filled) capacitors inside the drive
itself. Mine has both problems and had to correct them.
These panasonic (Double sided: LM-D702W, single sided has no W
suffix) 1GB cartridges is shockingly expensive! Cartridges are still
available new.
Got these used, good cartridges to buy?
That Kurata works under winblows without having driver installed
except for the any type of scsi controllers. Easy to do in winblows
but I wondered if I could support that drive on different OSes and
Macs for example?
Also it's very on-topic since this drive is 10 years old now.
Snip
The Sierra is a very nice drive, at least going from
the specs; I haven't used
one. Perhaps the fastest 1.3GB MO drive: spins at 4500rpm, average seek time
19ms, 4MB cache memory.
Drool! That's what I love to have! Mine is slow and tiny 128K
buffer. :-)
What brand or models that uses this drive to look for that blazing
fast sierra MO rewriteable drive? What about other makers that does
make fast MO rewriteable drives?
What about Fujitsu 640 and
anything else larger than 1GB cartridge per side?
I prefer MO over tape, magnetic media and floppies for backups and
transfer large data. But the compatiablity on Kurata between
winblows and non-winders is big question mark. Anybody to care to
chip in with your experiences?
-- Mark
Cheers,
Wizard
12:19 p.m.
Mark,
thanks for all of the info on the MO disks/drives. It's been
quite a while since I've dealt with them at all, so the info was most
welcome. 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. I've got an Exabyte 8200 8mm tape drive that I used to use for
my archival backups but it seems that most software no longer
supports it's use. It worked great on my Amiga's though.
(On a kind-of-related note: I understand the sector
layout or servo tracks of
e.g. Zip disks are written at the factory. Does that mean if you degauss a
Zip disk it is then useless, and cannot be reformatted?)
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
done with pre-recorded servo tracks that were tracked with a laser of
some sort. Otherwise the disks themselves were pretty normal
looking. I believe it plugged directly to the ST's DMA port and it
was about the size of the Atari SH-204 hard disk. It's been quite a
while since I've even seen one of these mentioned and unfortunately,
I no longer have mine. It was produced around 1987.
Jeff
--
Collector of Classic Microcomputers and Video Game Systems:
Home of the TRS-80 Model 2000 FAQ File
http://www.geocities.com/siliconvalley/lakes/6757
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