Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!cory.Berkeley.EDU!koster
From: koster@cory.Berkeley.EDU (David Ashley)
Newsgroups: comp.sys.amiga.tech
Subject: Possibilities for speeding/expanding standard floppies
Message-ID: <5565@pasteur.Berkeley.EDU>
Date: 10 Sep 88 06:24:52 GMT
Sender: news@pasteur.Berkeley.EDU
Reply-To: koster@cory.Berkeley.EDU (David Ashley)
Organization: University of California, Berkeley
Lines: 33

I was just going through an old issue of Amazing Computing, and I re-read
an article called "Fun with the Amiga disk controller." It is a fine article,
(it has a mistake: the minterm values are wrong) and it suggests a way
of getting 18 percent more than the 880K on a normal 3.5 inch disk.

It would mean storing data on the disk in a completely incompatable fashion.
The existing handlers for DFn: would have to somehow be replaced with new
handlers, which would do their own disk read/writes rather than going through
trackdisk.

Maybe they can be turned off with an action_inhibit. Anyway, 18 percent is a
worthy increase, and at the same time, improvements could be incorporated. I
have seen IBM PC's, with their measly 8088, do very fast disk directories.
The directories must be stored in a fixed place, so that all the children can
be accessed at once. The Amiga, on the other hand, stores file headers as
linked lists so that to get a directory will require reads over the whole
disk.

Also better error checking could be used. The Amiga will throw away an
entire track, 11 independent sectors, if any of the checksums in any
of the sectors is bad. Don't let anyone fool you; this was a short-cut. The
people that made the Amiga just didn't want to spend time trying to recover
from disk errors, and they were in a hurry, so they ended up with a piece of
shit method: too bad if you get an error.....

What is FFS? Does it do this kind of thing? Store files in a different
manner? Would it be profitable to work on this kind of project? Is 18
percent increase in storage, faster directories, more reliable storage, and
incompatability with the existing system worth enough?

I know I won't get any answers to this, but I felt like posting anyway.

David Ashley
koster@cory.berkeley.edu (Soon to be turned off)