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From: marc@dumbcat.sf.ca.us (Marco S Hyman)
Newsgroups: comp.lang.c++
Subject: Re: Zortech C++ Version 2.1
Summary: Where the extra memory goes
Message-ID: <185@dumbcat.sf.ca.us>
Date: 30 Jun 90 04:48:36 GMT
References: <25252@unix.cis.pitt.edu>
Organization: MH Software, Hayward, Ca.
Lines: 30

In article <25252@unix.cis.pitt.edu> rozin@unix.cis.pitt.edu (R Rozin) writes:
    
    I just received an upgrade order form from Zortech, for version 2.1. 
    Two of the advertised new features which seem unclear to me are:
    
        1. Virtual code manager, which is supposed to let you write programs
           up to 4 megabytes in size in real mode.
    
        2. Rational systems Dos extender, which is supposed to let you write
           proprams which access memory beyond 640k.
    
    If you have 1., why would you need 2.?

The issues are orthogonal.

1. allows you to write big programs.  Like most (all?) virtual memory systems
that which can't fit in memory resides on disk.  Your still limited to the
640K of memory that the PC (_NOT DOS_)* limits you to, in that only 640K
(less system overhead) can be resident at any given time.  Swapping from
disk can be S L O W !

2. allows you to use the memory above the 640K PC limit.  I assume it
requires a 286 or 386, but could be wrong.  Having more memory means less
swapping (or swapping from memory to memory) which makes your big program
run faster.

// marc
-- 
// marc@dumbcat.sf.ca.us
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