MO question

From: Jerome Fine <jhfine_at_idirect.com>
Date: Sat Dec 9 09:21:05 2000

>Mark wrote:

> The first generation of (ISO standard) 5.25" MO drives can work with 600 and
> 650MB media.
>
> 650MB disks have a sector size of 1024 bytes, but some operating systems &
> software only work with 512-byte sectors. If the drive was marketed for use
> with a particular operating system or software package that required 512-byte
> sector media, that would explain the 600 designation on the case. With
> appropriate driver software, Macs can use 1024-byte sector media. If you want
> to use it in conjunction with a modern PC, both 600 and 650MB disks will work
> fine under Windows 9x, no drivers needed.
>
> The SMO-E501 is a first-generation MO drive, albeit not the first first-
> generation drive that Sony made (if that makes any sense). Circa 1992 I think.
>
> Let me know if you would like specs or jumper setting info for the MO drive.

Jerome Fine replies:

As far as I know, the first erasable magneto optical drive made by Sony was
the SMO D501 which REQUIRED an SMO C501 as a separate controller
between the host adapter and the D501 drive. The one big advantage was that
the C501 could manage two D501 drives at the same time. But since many
host adapters could not manage a C501 controller with two D501 drives,
Sony probably realized that the option was not really useful. From what I
remember, it was around 1990 when I sold a C501/D501/D501 configuration
to a company which needed multiple copies of about 1 GByte of off-site storage.
Since the files were in groups of about 300 MBytes, a copy from one drive
to the other was a very simple solution. The total physical size of the storage
was reduced from three large cabinets to a box that could hold 30 5 1/4"
floppies - and that was not one copy but three as opposed to one copy in the
three large cabinets. A total of 3 cartridges were needed and 9 cartridges
held 3 copies. A copy from each side took about an hour (including a
separate verify operation) for each 300 MBytes, so over a lunch hour,
one backup could easily be made each day. Since a complete backup
was rarely required (changes were usually only about once a month
to any of the five 300 MByte sections) more than once a month, that was
a very reasonable way of handling the situation.

The SMO E501 was, as far as I know, the first version which combined the
C501/D501 into a single unit with the controller embedded within the hardware
of the drive. Since it is rare for more than even 4 drives to be connected to
a single host adapter (except these days when a RAID configuration has a
whole bank of a dozen or more SCSI hard drives), the embedded controller
solution seems to work quite well.

Sincerely yours,

Jerome Fine
Received on Sat Dec 09 2000 - 09:21:05 GMT