30 Aug
2006
30 Aug
'06
1:10 p.m.
Subject: Re: "File types"
From: Fred Cisin <cisin at xenosoft.com>
Date: Wed, 30 Aug 2006 11:04:03 -0700 (PDT)
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
I did that once to annoy someone only the dollar sign was faked by
adding 80h to it so the terminator was not observed by BDOS-9.
Another time I modded CP/M itself to use null (00h) instead. Then
again I didn't want it to be portable. ;)
Allison
>Some of the CP/M tools used $ as a string
terminator, if I'm remembering
>right...
On Wed, 30 Aug 2006, Chuck Guzis wrote:
Actually, it's BDOS call 9--preserved to this
day in MS-DOS/Windoze. I've
no idea why a printable character was selected as a terminator. Anyone
have any idea of its origin?
IIRC, I saw an interview long ago, (maybe when Gary Kildall was the
co-host with Jim Warren of Computer Chronicles?), in which Gary
APOLOGIZED for that, and said that it had been a temporary kludge,
and hadn't originally been meant to be permanent.
For their first assignment, I have my assembly language students write a
program to display their name AND the price that they paid for the
textbook (to force use of function 2, instead of 9). We then use creating
their own puts() function to get into jumps, conditional jumps, and loops.