Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!decwrl!sun-barr!rutgers!sunybcs!ugkamins
From: ugkamins@sunybcs.uucp (John Kaminski)
Newsgroups: comp.sys.amiga
Subject: Re: Apple System 7.0 [ and some 1.4 suggestions ]
Message-ID: <5847@cs.Buffalo.EDU>
Date: 13 May 89 05:11:21 GMT
References: <17148@usc.edu> <24279@agate.BERKELEY.EDU> <18268@cup.portal.com> <17183@usc.edu> <21814@srcsip.UUCP>
Sender: nobody@cs.Buffalo.EDU
Reply-To: ugkamins@sunybcs.UUCP (John Kaminski)
Organization: SUNY/Buffalo Computer Science
Lines: 73

In article <21814@srcsip.UUCP> mnkonar@gorby.UUCP (Murat N. Konar) writes:
=>What advantages does 'true multi-tasking' (by which I assume you mean
=>pre-emptive multi-tasking) have over Apple's co-operative multi-tasking?  Co-
=>operative multi-tasking has significant user interface advantges over the
=>pre-emptive kind.  
=>
=>I for one would rather not have my application pre-empted by a background process
=>in the middle of say a menu selection.  Any one who has used TOPS while a large
=>file transfer is in progress can attest to the fact that having the interface
=>slow down is a real drag.  (TOPS for those who may not know, is an AppleTalk
=>fileserver system that runs in the 'background')
=>
=>Anyone who has used Suntools on the Sun's can attest to the horrible things that
=>can happen when your're trying to get a menu up but the processor is too busy servicing
=>some other process.
=>
=>Sure, pre-emptive multi-tasking makes it easier for the programmer who would rather
=>not worry about whether he's in the background or whatever, but it's the user's
=>view that matters most.  That's what the Mac's all about.
=>Murat N. Konar        Honeywell Systems & Research Center, Camden, MN
=>mnkonar@SRC.honeywell.com (internet) {umn-cs,ems,bthpyd}!srcsip!mnkonar(UUCP)

Things may tend to seem to go slowly, but at least EVERYTHING is getting DONE.
I would MUCH rather get SOME timeslice sometime REGULARLY, rather than relying
on some other process "handing me" the processor.  One blemish of the Amiga is
that it provides Enable(), Disable(), Permit(), and Forbid().  Any process
utilizing these falls into the same class as Multifinder.  R U listening,
CATS guys?  Provide access functions to the programs that do this, to do
what those programs do, which is generally access to system structures any-
way.

Another blemish on the Amiga system, performance-wise, is general disk access
by more than one process.  Thrashing is most evident.  That is just the
result of poor disk controlling software design.  Anyone doing "concurrent"
disk accesses on an Amiga floppy knows well that something along the lines
of disk request buffering coupled with the a periodic application of a seek
optimization algorithm (elevator for example) would be "to die for."

I say "general access" because I tried both sequential and concurrent disk
formats, and on our totally preemtive Amiga, it was faster formatting two
floppies rather than just format-swap-format.  This works like a charm
on a fresh box of 10 floppies.  I thought from what I heard from the drives
in terms of head step rate that the system was slowed, but in an actual
timing of two formats versus format-swap-format, the "concurrent" formats
turned out to be faster by a few seconds (15?). I know it isn't very scientific,
but it WAS faster.  (BTW, I was using a shell with uparrow to recall an entire
command line, so the speed of typing uparrow enter enter should be relatively
constant.  Also, the format program was in the RAMdisk.)

Also to the CATS people: how about making the standard DiskCopy do a verify
pass, just like Format?  Since the formatting is virtually all in software, a
DiskCopy is roughly the same speed as Format on an unformatted disk.  The
ONLY reason that I always Format FIRST is to check for bad spots on the disk.
If DiskCopy had a verify read pass, this wouldn't be necessary.

I'm an Amiga user (as in as stated in the quoted article), and that's my
view.  So there.


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We can only contemplate the facts as we are able to perceive them.
Do we get what we deserve, or deserve what we get?
"I've seen yellow stripes in the middle of the road before, kids, but
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