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From: norton@manta.NOSC.MIL (LT Scott A. Norton, USN=)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Peter, can you explain to the Amigoids (was: NeXT software size
Summary: Smaller could be slower, but is often faster.
Message-ID: <1970@manta.NOSC.MIL>
Date: 9 May 91 03:16:08 GMT
References: <*05Gx0x&1@cs.psu.edu> <11877@uwm.edu> <sutela.673606047@polaris>
Organization: Space & Naval Warfare Systems Command
Lines: 44

Jon Bentley, in his book _Programming Pearls_, has a paragraph
that adds some perspective to the Big Code thread here.

  If you're like several people I know, your first thought on reading
  the title of this column is "How old-fashoned!"  In the bad old days
  of computing, so the story goes, programmers were constrained by small
  macines, but those days are long gone.  The new philosophy is
  "a megabyte here, a megabyte there, pretty soon you're talking 
  about real memory."  And there is truth in that view -- many
  programmers use big machines and rarely have to worry about squeezing
  space from their programs.

  But every now and then, thinking hard about compact programs can
  be profitable.  Sometimes the thought gives new insight that makes
  the program simpler.  Reducing space often has desirable side-effects on
  run time:  smaller programs are faster to load, and less data to
  manipulate usually means less time to manipulate it.  Even with
  cheap memories, space can be critical.  Many microprocessors have
  64-kilobyte address spaces, and sloppy use of virtual memory
  on a large machine can lead to disterously slow thrashing.

In the context of this discussion, certainly it takes longer to
load 2MB of code than 512KB, but displaying animation frames
can be done quicker if they are stored uncompressed in memory.

I would dismiss the "size of Hello World" issue as irrelavant:
code size there is strongly dependant on the up-front cost of
operating system support.  My world-record short Hello World
program displays the message in 3-D rotating chrome letters,
and its only 150 bytes long.  It does use the hello.world.library
though :^)  Before I get flamed on this statement, think
about the spectrum from OS ROM to loadable shared libraries to
linked libraries to your own code.  Also factor in the OS's
overhead for buffers, Process Control Blocks, stack space,
and other RAM costs.

I recently got a new appreciation for the word "slow" -- my
office computer at my new job is an original PC-XT, with a
genuine full height, 10MB hard drive.  It also gives
me a perspective on small programs.

----
LT Scott A. Norton, USN
JTIDS Ship Integration Officer