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From: dillon@CORY.BERKELEY.EDU (Matt Dillon)
Newsgroups: net.micro.amiga
Subject: Re: Memory && Disks && Flicker
Message-ID: <8610270427.AA06543@cory.Berkeley.EDU>
Date: Sun, 26-Oct-86 23:27:58 EST
Article-I.D.: cory.8610270427.AA06543
Posted: Sun Oct 26 23:27:58 1986
Date-Received: Mon, 27-Oct-86 05:42:02 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: University of California at Berkeley
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>Some questions and observations about having 512K of memory to work with:

	My system is 512K also.

>-   the ram disk handler is great; however, if you try to copy too much into
>    memory, you will get a guru. No warning beforehand. Why not?
>
>-   Matt Dillon's shell is great; if you try to copy too much into memory,
>    you get a warning, "Volume is full". However I have had this happen
>    when mem said there was ~170K free and I was moving around 10K files.
>    PS Matt, where did ps go?

	My shell has nothing to do with the RAM: drive.. must be something
else.  I didn't put a PS in because I thought it was too costly to make
resident.  I'm glad you like my shell though.  (it also sounds like you
are using a 1.1 system).


>-   Editors are not great. Ed and Emacs both hold their breath & turn blue 
>    when a lot is in memory. In the case of emacs, it told me it could not
>    allocate 80 more bytes (this is with 100K+ free, according to mem).
>    Fine, sez I. I remove several K worth of .o files and such (with
>    emacs still running), but it still can't find those 80 bytes. At this
>    very moment, ed (not in memory) refuses to work with a file that is...
>    lemme see...1997 bytes long. Hang on a sec again...mem tells me I
>    have 85968 bytes left. Since boot up, I've done nothing but copy some
>    (big) files into ram:, 1 assign, invoke vt100, and the failed ed, so I
>    can't see how fragmentation could be that big a problem.

	The problem is fragmentation.. ED tries to allocate huge chunks of
memory and can fail even when you have 200K free!!!! (this has happened
to me!).  Hacker types like most developers become unconciously adept to
doing things in the right order to avoid it.  The real solution, however,
lies in the software... they shouldn't expect to be able to allocate 100K
contiguous memory.

					-Matt