On Tue, 8 Feb 2000, NetBSD Bob wrote:

> Hey, I can't resist biting on this thread.....cuz, I still use a little
> dos box now and then, for things unixy, like troff, TeX, ftp, telnet, tar
> vi, and that kind of thing...... a dos box should not feel inferior nor
> have an inferiority complex, if it has the right set of tools aboard.....

 Note I am a developer and not a plain user so my point of view is
obviously biased.  I've been writing various programs for DOS for a few
years and it was a nightmare. 

 I agree DOS was a reasonable OS for an 8086 with its 20-bit address
space.  But it was the major mistake to use DOS as is on an 80286 in it's
legacy real mode, having most of the CPU's address space inaccessible. 
Even worse, the mistake was continued when Intel released its IA32 family
of CPUs...  Of course, from the commercial point of view of the vendor of
DOS as long as the product used to sell well, there was no reason to dump
it.  And it looks like it's profitable till today -- changing the name of
the product in 1995 did not stop it being DOS 7.0: try to switch off
himem.sys, the "driver" to access memory beyond the real mode limit of 1
MB, and see it fail miserably...

 Due to DOS legacy:

- IBM had to wire the FPU incorrectly in 80286 (which was then repeated
for 80386) because its exception number collided with the video BIOS
service,

- IBM had to made the address space fragmented (instead of only mapping
BIOS areas at the top of physical memory which must be done anyway and
having the first megabyte of memory being plain RAM),

- Intel had to include various hacks into new processors just to support
DOS (what comes to my mind at least: the NE bit of the cr0 register and
associated circuitry to "fix" the problem with FPUs being wired
incorrectly in PC machines),

- Intel had to complicate APIC chips unnecessarily to make sure they will
fit well into DOS environment,

- etc., etc... 

 From the user's point of view, DOS is of course as good as its tools are
and thanks to the DJGPP effort, many of the tools are just the same code
as Unices have.  But I'm sure you wouldn't like to see what the DJGPP's
DOS extender does to switch between the legacy DOS mode and its normal
32-bit mode to perform system calls...

> The real McCoy, *nix, feels much better, but, sometimes a proper dos box
> is worth its weight in gold as a microworkstationtryingtobeunixy.

 Until you wish to program for it...

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +