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From: michael@stb.UUCP (Michael)
Newsgroups: comp.sys.tandy
Subject: Re: DOS WARS (Re: Ldos vs. NeWDOS)
Message-ID: <9@stb.UUCP>
Date: Sun, 13-Sep-87 17:26:52 EDT
Article-I.D.: stb.9
Posted: Sun Sep 13 17:26:52 1987
Date-Received: Tue, 15-Sep-87 06:35:20 EDT
References: <52@nancy.UUCP> <18@umn-d-ub.D.UMN.EDU>
Reply-To: michael@stb.UUCP (Michael)
Organization: STB BBS, LA, CA, USA, 90402, (213) 459-7231
Lines: 20

>In article <1123@bsu-cs.UUCP> dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:
>% I used TRSDOS and later LDOS back when I used a TRS-80.  Both have a
>% serious design flaw.  They both want programs to load at a specific
>% address.  Worse, the original TRSDOS had all the system calls at
>% absolute addresses that had to be hard-coded into every program.  This
>% is bad software design at its worst.

Not quite: the address of a JUMP VECTOR is hardwired.

From 4400H to about 44A0H is a table of jump vectors and rst calls. There
are dozens of these defined, but only about 10 documented. These are the
only ones you are supposed to use, and the only ones radio shack will
use in our own programs, or at least thats what the trsdos 2.1 documentation
said. (BTW, they did use other calls. Made porting binary from model 1/3
pretty hard (from the 3 to the 1).

You want bad design? Quick--what does the call at 4409H do. 
-- 
: Michael Gersten		seismo!scgvaxd!stb!michael
: Copy protection? Just say "Off site backup"