[plt-scheme] Requirements of DrScheme

From: Neil W. Van Dyke (neil at neilvandyke.org)
Date: Tue Sep 24 20:00:56 EDT 2002

MJ Ray <markj at cloaked.freeserve.co.uk> writes at 22:41 24-Sep-2002 GMT:
> Jesus Alexander Aranda <jesarana at eisc.univalle.edu.co> wrote:
> >    -Could you tell me the  exacts system  requirements for good
> >      performance  of DrScheme version 202?
> Do you want good or least?  As far as I can tell, DrScheme needs about 32Mb
> of physical RAM on a Pentium-MMX or more to be "happy", but you can probably
> get away with about 12Mb if you have enough swap.  MzScheme needs about 4Mb
> RAM on anything that can run it.  More if you load things.

I'm not sure how usable DrScheme 202 will be on a GNU/Linux box with
only 32 MB *total* RAM.  I suspect DrScheme would run acceptably if at
least 32 MB RAM were *dedicated* to DrScheme (separate from the RAM
requirement overhead of basic OS services).

Just did a quick test on my P5-166 MMX laptop with 48 MB RAM.  Running a
stripped-down GNU/Linux installation leaves a bit over 24 MB RAM free
for DrScheme (after kernel, X server and lightweight WM, absolute
minimal daemons, and buffers).  At startup, DrScheme 202 "mred" process
RSS was 31 MB.  Opening "collects/net/url-unit.ss" and running (a very
slow) Check Syntax caused the RSS to become 46 MB.  Then, attempting to
scroll the window caused a long lockup for very heavy swapping (perhaps
due to a GC pass), and then there was swapping on each subsequent
incremental scroll of the window.  With this 48 MB RAM configuration,
starting a Web browser to view the PLT manuals would put the system even
further into swap, and cause further painful swapping every time the
user switched between viewing documentation and going to their DrScheme
window to edit and run code.

This is not a criticism of DrScheme for the majority of its student
users -- even the cheapest US discount-store PCs nowadays have 128 MB
RAM, which is enough for doing real work in DrScheme.  Even some
grossly-underfunded schools in developing nations and poor US school
districts receive donated computers that are sufficient for DrScheme.

Students who must rely on 5-year-old PCs with low RAM, however, may have
to use the command-line MzScheme interpreter under Emacs, perhaps in
Linux text console mode rather than under the graphical X Window System.
And the Emacs add-on package Quack ("http://www.neilvandyke.org/quack/")
adds a few conveniences to Emacs for people who cannot run DrScheme.

                                                        Neil W. Van Dyke

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