Path: utzoo!mnetor!uunet!husc6!bbn!rochester!ur-tut!ur-valhalla!micropen!dave
From: dave@micropen (David F. Carlson)
Newsgroups: comp.unix.microport
Subject: Re: Info needed: UNIX for 286/386 machines (really malloc)
Message-ID: <427@micropen>
Date: 9 Mar 88 22:55:04 GMT
References: <4213@sigi.Colorado.EDU> <863@athos.rutgers.edu> <141@bdt.UUCP> <717@actnyc.UUCP>
Organization: Micropen Dirent Writing Systems, Pittsford, NY
Lines: 38
Summary: malloc is really tough

In article <717@actnyc.UUCP>, jhs@actnyc.UUCP (John Spicer) writes:
> In article <412@elric.UUCP>, root@elric.UUCP (root) writes:
> > the -lmalloc (a faster malloc, according to the man page) i just use the
> When I have tried the -lmalloc version on Microport SYSV/AT 286 it dumps core.
> I tried using the standard version and it is SLOW.  I finally ended rewriting
> malloc so I could get a version that works, and works quickly.
> 
> I hope Microport provides a decent version of malloc some day.
> 
> John Spicer
> InterACT Corporation
> uunet!actnyc!jhs


Microport has real problems with malloc on the 286 because the way
AT&T malloc works is not applicable to 286 processor.  The absurd
segmentation scheme forces Microport to do very bad things with 
respect to allocation.  Read sbk(2) man page.  The jist of it is
that although real malloc will look at all previously allocated
space for new malloc calls, Microport's malloc only looks at the space
in the current sbk segment!  Thus, processes grow without bound because
once a new segment is allocated, all the previously allocated memory
in the other segments (and potentially free'ed) is not available to 
be reallocated.  This is why the 386 product is 1000% more usable for
real computing that the 286 product.

Microport's malloc(3X) DOES NOT WORK on the 286.  It just don't.
I thought briefly about writing a good 286 malloc, but then the
nightmare ended and I bought a 386.

I have had 0.0 bad experiences with malloc(3) with Microport 386
and I heartily recommend it.

-- 
David F. Carlson, Micropen, Inc.
...!{ames|harvard|rutgers|topaz|...}!rochester!ur-valhalla!micropen!dave

"The faster I go, the behinder I get." --Lewis Carroll