Path: utzoo!attcan!uunet!husc6!bbn!mit-eddie!bu-cs!purdue!umd5!mimsy!oddjob!ncar!ames!necntc!drilex!dricej
From: dricej@drilex.UUCP (Craig Jackson)
Newsgroups: comp.software-eng
Subject: Re: Paradigms for source control
Message-ID: <570@drilex.UUCP>
Date: 21 May 88 01:00:13 GMT
References: <5291@cup.portal.com>
Reply-To: dricej@drilex.UUCP (Craig Jackson)
Organization: Data Resources/McGraw-Hill, Lexington, MA
Lines: 34

This is a discussion that is near and dear to my heart.  While the *CS
programs have many advantages, there are a few things which I sorely
miss from 'mainframe' source code control systems, (of which MODIFY/UPDATE
is one).

The biggest thing that I miss in the Unix world is the ability to easily
have independent development on a common body of source by two sets
of programmers in two locations.  The most common case of this is
a vendor sending out source updates, and a local site making patches.
In the Unix world, each time AT&T comes out with a release, all of the
System V vendors need to re-do their port.  Now Unix is portable, but it
isn't so portable that unnecessary ports are to be desired.  In a 
system such as M/U, there is a unique identifier attached to each line
of the source file.  Two modsets can affect different regions of the file
with no change whatsoever.

In the unix world, diff -c & patch attempt to provide the same utility.
However, if there isn't enough common context, things fall apart.  Also,
diff -c only comes from Berkeley; you're left to the net to pick up
diffc if you're on a USG system.  'patch' only comes from the net in
the first place.

You may denigrate the need for 'line numbers' or 'line identifiers' in
systems such as M/U.  Yes, they are extra baggage.  Yes, they do go
along with such things as fixed-length source lines and source listings.
Yes, they do imply occasional resequencing.  However, by uniquely
identifying each line, it's possible to unabiguously talk about precise
regions of code.  I only wish I could give each token in the source file
a unique identifier, but it isn't really feasible.

-- 
Craig Jackson
UUCP: {harvard!axiom,linus!axiom,ll-xn}!drilex!dricej
BIX:  cjackson