Macintosh SE Hard Drive Systems: HD SC Setup Version 1.3

A problem was discovered when HD SC Setup Version 1.3 was used to
initialize a hard disk inside certain Macintosh SE computers. This
recalibration problem may have, in rare cases, caused a loss of data. The
article below provides more information.

This article has been archived and is no longer updated by Apple.
The Macintosh SE production units which MAY experience this problem have
serial numbers beginning with:

F722, or

The fix for this is to use Version 1.4 or higher of HD SC Setup.

Production units with serial numbers F724 and up didn't have this problem
and could be initialized with either version 1.3 or 1.4 of HD SC Setup.

HD SC Set Up 1.4 was shipped with production units starting in early July
of 1987.

Customers should upgrade to HD SC Set Up 1.4 or higher (and discard
version 1.3) to ensure compatibility with all hardware configurations. Any
Macintosh SE that has been initialized with version 1.3 should be updated
using version 1.4 to avoid loss of data in the future. If a Macintosh SE
hard disk system is serviced, the hard disk must either be updated or
re-initialized with HD SC Setup 1.4.

Version 1.1 may continue to be used -- with Rodime drives only -- but
due to its lack of versatility, its use is not encouraged.


The Macintosh SE originally contained:
- SCSI hard drives made by Rodime
- HD SC Setup version 1.1.

When MiniScribe became a second source of drives, HD SC Setup version 1.3
was required, because version 1.1 would not recognize or initialize
MiniScribe drives.

Version 1.3 was designed to be used with both Rodime and MiniScribe
drives. Unfortunately, version 1.3 exposed a bug in the Rodime drive
controller. Version 1.3 turned on Rodime's head recalibration feature,
which activated every 20 minutes and took 5 seconds. If the Macintosh SE
user attempted to save data onto the hard disk during that time, the drive
controller chip interrupted the recalibration. However, the recalibration
wasn't terminated properly, and scrambled data was written to the sector
over which the drive head resided. The user would notice a problem at some
later date, when attempting to access the file containing the scrambled

HD SC Setup version 1.4 or higher works properly on both Rodime and
MiniScribe drives.

Published Date: Feb 18, 2012