non-SCSI disks on a SCSI disk interface (was Re: Space, the next frontier)

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Thu May 27 08:01:52 1999

> > The 2190 is 1224*15. However the number of cylinders can be increased (it
> > was controller limit not the drive) the limit, I think is closer to
> > 4096*16*18*512 or roughly over 600mb. The problem is that RLL with the
>
> Do you mean that Maxtor used only about the first third of the available
> platter for data? That seems like a bit of a waste. I do recall - years
> back - discussion about how the XT1085 could be extended, but not by a
> factor of three!
No, No No...

The maxtor 2190 is 1224 Cylinders by 15 heads and whatever formatting for
the number of sectors.

the command structure for most MFM and RLL controllers only used
1024 of the possible 4096 (10 of the available 12 bits). It's an artifact
of the controller designs.

Physically you can go for up to 16 heads and 4096 cylinders in the st506
interface spec'd drives. The problem was that more cylinders do not
enhance speed. It's better to pack more on a given cylinder as you can
access that data faster than moving heads across a lot of tracks.

Please everyone prune of the unwated portions of the message. If I can do
it using pine across a sluggish telnet link during the day No one has an
excuse.

Allison
Received on Thu May 27 1999 - 08:01:52 BST