Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: Writing a Custom FST
Message-ID: <34578@apple.Apple.COM>
Date: 8 Sep 89 00:18:04 GMT
References: <8909071802.AA25320@trout.nosc.mil>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 35

In article <8909071802.AA25320@trout.nosc.mil> mdavis@pro-sol.cts.com (Morgan Davis) writes:
>Can Apple provide developers with detailed documentation for designing custom
>FSTs for GS/OS?  [...]

(Warning: Strange approach angle.)

Device drivers are a long-standing and fairly traditional concept.  Their
implementation in GS/OS is stable, so that any properly-written device
driver will continue to work with future versions of the System Software.
Device drivers interact with the system in permanently-defined ways (the
implementation can be *extended*, but it can't ever change radically).

File System Translators aren't quite like that.  With each System Software
revision, changes may be required to any or all of the existing File System
Translators, and other parts of the system may need to be revised to deal
with a file system which previosly had no FST.

Since defining for all time how FSTs work could limit the choices in designing
any future versions of GS/OS, the policy on FSTs is that Apple writes them all.

> [...] Also, can an SCSI drive be
>partitioned into multiple areas that are governed by more than one FST?  (In
>other words, could you have a ProDOS, CP/M, Mac HFS, and similar FST-based
>partitions on a single drive?)

Yes, I believe you can, given appropriate FSTs.
-- 

 --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
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