Apple external SCSI drives

From: Mark <mark_k_at_iname.com>
Date: Sat Jan 13 13:46:51 2001

Hi,

[Firstly, for some reason I never received classiccmp digest #482. Could
someone be kind enough to email it to me, preferably compressed?]


On Wed, 10 Jan 2001 12:11:35 -0500
> For Pr1me minis, hard drives have to be able to support a sector size
> of 2080 bytes, instead of or in addition to the usual 512-byte sector
> support. With Apple, their *first* hard drive (a non-SCSI unit) had
> things called disk tags that required drives that support a sector
> size of 576 bytes (from memory, probably wrong).
>
> I'm not defending the practice; while I assumed your remark was
> rhetorical, not everyone in the audience may be as well-informed
> as we are.

Sector size is sometimes/usually controllable by the user.

By issuing a format unit command with the appropriate parameters, some drives
can be formatted to (almost) any sector size. The 86MB Fujitsu hard disk that
I bought in 1991 came with a leaflet describing how to do this. The OEM manual
for any given drive should say whether the sector size can be altered.

This could be useful if you want to use a "normal" SCSI drive with some exotic
computer, or vice versa.

If you are not using a lame OS that has trouble with non-512-byte sectors,
"free" disk space may be obtainable by reformatting with larger sector size
such as 1K or 2K. Since there are fewer sector headers etc. with larger
sector
sizes, the disk capacity increases.

On some drives, the manufacturer name that the drive reports can be changed by
issuing the correct SCSI command(s). I have no idea what proportion of drives
support this; it is probably not common (I know Fujitsu 230MB MO drives do).



On a related subject, does anyone have OEM manuals for any old hard disks,
optical drives or any other SCSI devices? These are usually impossible to
obtain from the manufacturer, and can be very useful. In particular, I'd like
to get hold of OEM/SCSI manuals for:
  Chinon CDS-435 CD-ROM
  Fujitsu M2511 MO drive
  Fujitsu M2612ESA hard disk
  Fujitsu M3191F1/F2 scanner
  Ricoh RH5500 50MB removable cartridge drive
  Various Ricoh MO drives
  Seagate ST1480N hard disk


-- Mark
Received on Sat Jan 13 2001 - 13:46:51 GMT