Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rochester!mcinerny
From: mcinerny@rochester.ARPA (Michael McInerny)
Newsgroups: comp.sys.amiga
Subject: Re: Workbench improvements
Message-ID: <27184@rochester.ARPA>
Date: Tue, 21-Apr-87 07:23:06 EST
Article-I.D.: rocheste.27184
Posted: Tue Apr 21 07:23:06 1987
Date-Received: Wed, 22-Apr-87 02:20:51 EST
References: <8704172157.AA15623@cory.Berkeley.EDU> <3050@sunybcs.UUCP> <6311@amdahl.UUCP>
Reply-To: mcinerny@rochester.UUCP (Michael McInerny)
Followup-To: comp.sys.amiga
Distribution: na
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 27
Keywords: cache disk icon
Summary: Cache It!


[]
One of the two principles of Operating Systems (I'll leave the other to
you) is "Cache It".  One easy way to solve the Icon speed problem is to
chache the .info files.  Ideally, this would be in RAM, but we all know
that RAM is volatile &c., so, what the WorkBench could do is build a 
.Desktop-ish file of ALL the information (maybe just the bitmaps for the
icons?) it needs on a, say, directory by directory basis.  This would
allow the WB to render the icons with only one seek (which is where most
of disk time is spent).  Further, a single file is much more likely to
be cached in a disk buffer than multiple .info files.

But what about the current .info files?  Keep 'em.  The .Desktop file 
is a _cache_ for the .info files--it needs to be treated as such.  That is,
whenever the .info files change (which can be detected through
timestamps or other means), the .Desktop will need to be updated, or at worse,
rebuilt (a la Macintosh).

This "caching" principle can be (and I believe, has been) use(d) for
"normal" CLI directories and lists--again, whenever the directory is
scanned, cache the results in a .directory file.  When a second dir is
requested, if the timestamp on the .dir file is later than the
timestamp of the directory itself, use the .dir file, o.w. rebuild it.

Of course, it would be nice if disk accesses themselves were optimized....

-Michael McInerny