Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!van-bc!rsoft!mindlink!a218
From: a218@mindlink.UUCP (Charlie Gibbs)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: 68000 Multitasking
Message-ID: <4158@mindlink.UUCP>
Date: 17 Dec 90 20:41:05 GMT
Organization: MIND LINK! - British Columbia, Canada
Lines: 43

In article <44872@cci632.UUCP> dsg@cci632.UUCP (David Greenberg) writes:

>Hi,

Hi there.  :-)

>        I was wondering if anyone has any idea what could be wrong
>(If anything) with my amiga 2000 (3 meg) 68000.

     Probably nothing.  Read on...

>        I am using JRCOMM to download to ram: and everything works fine
>unless I try to multi-task...It seems like the 68000 isn't fast enough to keep
>up with the download (2400 baud) and do something else at the same time
>(ie. DIR) of course this does't seem correct!.....Any ideas?? I suppose it
>could be a drive problem ....even though I d/l to RAM, When I dir,
>it accesses my HD (Kronos - seagate st296N)........any ideas???

     I've found on my 1000 that a terminal program running at 2400
bps chews up a lot of the processor's time.  I found myself getting
overruns from time to time until I increased the serial port's buffer
size.  Go into Preferences and select "Change Serial."  Check the
"Buffer Size" entry; it's likely at the original value of 512 bytes.
I ran mine up as high as I could (16000) and I no longer have any
problems.

     At 2400 bps, the processor only gets an occasional chance to
service the serial device if something else is running.  It doesn't
take long for it to fall behind 512 bytes and overrun the minimum
buffer that you get by default.  Chances are, though, a 16K buffer
will be far from full when the processor gets a chance to empty it.
I find that the terminal screen spits out chunks of data (a couple
of hundred bytes at a crack) if something else is running; the
processor might fall a few hundred bytes (or even a couple of K)
behind, but it can catch up in a hurry whenever it gets a chance.

     I routinely multitask with 2400-bps downloads; since I
increased my buffer size, I haven't lost a single byte.

Charlie_Gibbs@mindlink.UUCP
"I've seen The Exorcist about a hundred and sixty-seven times,
and it keeps getting funnier every single time I see it!"
        -- Beetlejuice