Re: 36XX disk drive compatibility & cannibalism

[moon@cambridge.apple.com (David A. Moon)]

> Date: Tue, 18 Jun 1991 13:23-0400
> From: barmar@Think.COM (Barry Margolin)
> L- and G-machines use incompatible disk formatting (maybe someone from
> Symbolics would explain why), so disks aren't interchangeable between
> them.

The disk controllers are built out of different technologies.  The VLSI
disk interface chip used in the "G machine" is not flexible enough to be
programmed to support the disk format used by the original 3600 disk
controller.  The advantages of changing (decreased cost and power
consumption, increased reliability, higher maximum disk bit rate) were
evidently considered worth the media incompatibility.