Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!hacgate!ashtate!dbase!awd
From: awd@dbase.A-T.COM (Alastair Dallas)
Newsgroups: comp.databases
Subject: dBASE IV and extended memory
Keywords: dBASE IV
Message-ID: <1991Apr24.163132.10805@dbase.A-T.COM>
Date: 24 Apr 91 16:31:32 GMT
Organization: Ashton-Tate, Inc.
Lines: 36

I've been asked privately about dBASE IV and extended memory, and if I'm
going to reply it must be posted to the net because I (not anyone else,
just me) have so far failed to spend the necessary time to make email
replies work.

dBASE IV 1.0 was supposed to take advantage of extended memory, but a 
matter of weeks before it was to ship we discovered a killer bug in
the interaction with a popular DOS extender.  We couldn't quickly 
figure out a way to detect this particular extender and avoid stepping
on it, so we disabled extended memory support.  I feel responsible about
this because I gave a speech the month before that and specifically said
that we would support it.

dBASE IV 1.1 does support both extended and expanded memory by virtue
of a third-party disk cache program called HyperDisk.  dBASE is loaded
by a driver which first loads the cache program and then loads dBASE.
We chose HyperDisk because of the wide range of other products that it
cooperates nicely with, and because it offers a significant performance
boost.  A general cache seems to be superior to adding code to the
dBASE product to detect and use secondary memory, but we're still
testing alternatives.

Anyway, the answer to Mr. Grossman's question is that 1.0 does not
take advantage of extended memory.  You can upgrade from 1.0 to 1.1
by calling (800) 2-ASHTON, and I would highly recommend it, obviously.
1.0 is not the bug-riddled product you read about, but 1.1 fixes 
hundreds of little things that you may never run into and it also
uses less memory thanks to an innovative overlay manager.  And it
uses expanded/extended memory.

/alastair/

-- 
|Disclaimer: I am speaking for myself, not as a spokesman for Ashton-Tate,
|which does not monitor my outbursts here.  I reserve all rights to my
|opinions in terms of commercial endorsements.