Re: Disassembling an FST...

[dempson@actrix.gen.nz (David Empson)]

Bill Scheffler <schefflr@news.msus.edu> wrote:

> Tai (tai@urd.spidernet.to) wrote:
> : While pretending to be roadkill on the InfoBahn,
> : <devnull@dobbs.eng.sun.com> scrawled:
> : >My feeling is that HFS should replace ProDOS-FS and there should be
> : >DOS-FS for compatability.  However, only a few people have
> : >superdrives, so that is less important to me (esp. since I can use
> : >localtalk to pass files back and forth).
> 
> :     Personally, I would have no problems booting off a prodos partition,
> : and having the rest of my apps, data, etc, whatnot all residing on one
> : HFS+ partition.
> :     Booting off a prodos partition is not really that horrible, is it?
> 
>       Not only that, but it'll probably be the fastests file system the
> Apple IIgs will have.

I don't think so.  A similar _simple_ file system with a larger logical
block size should be faster, because the data will be transferred in
larger clumps with less processing overhead to locate the clumps.

> Just look at how slow HFS and MS-DOS are...

HFS is slow on the IIgs because it uses rather complex data structures
(as far as the IIgs is concerned), and all the fields in the directories
and other data structures need to be swapped on the IIgs (HFS is
big-endian, the IIgs is little-endian).  Its lack of speed might also be
due to code in the FST not being optimized as well as the ProDOS FST.

MS-DOS: pass.  Don't use it enough (on the IIgs) to be able to comment.

> HFS is nice because of the bigger drive sizes and the longer filenames.
> It's a tradeoff I guess.  I still believe HFS+ is overkill for the GS...

I can't believe anyone suggested HFS+ seriously.  It would be major
overkill.

>       Too bad we just couldn't get the MS-DOS.FST finished (with write)
> and maybe find a way to speed up the HFS one a little bit.  I'd be content
> with that.

I wouldn't be content, but both would be a good start.

I want a considerably faster file system, that is simple enough so that
I can understand it while browsing through it with a block-level editor
(rules out HFS), which is a good fit for the capabilities of GS/OS
(rules out MS-DOS), and which can be booted from (rules out HFS without
widespread firmware patches, which is a horrible concept).  I don't care
about portability to other platforms.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand