Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!iuvax!pur-ee!uiucdcs!uiucdcsp!gillies From: gillies@uiucdcsp.UUCP Newsgroups: comp.sys.mac Subject: Re: support for older machines Message-ID: <76000056@uiucdcsp> Date: Sun, 29-Nov-87 19:46:00 EST Article-I.D.: uiucdcsp.76000056 Posted: Sun Nov 29 19:46:00 1987 Date-Received: Wed, 2-Dec-87 04:07:38 EST References: <4161@utai.UUCP> Lines: 26 Nf-ID: #R:utai.UUCP:4161:uiucdcsp:76000056:000:1328 Nf-From: uiucdcsp.cs.uiuc.edu!gillies Nov 29 18:46:00 1987 From a technical standpoint, I cannot see how Apple could AVOID withdrawing support for some of the older machines. It is nearly impossible to support so many machines in so many configurations. Assumine you plan ahead, I would estimate that if a new release takes N units of work, then a new release for two versions of the underlying O/S + Hardware probably takes N^2 work. If there are three versions of the O/S, it's N^3 work. If Apple were to support all previous versions, you would never see anything new from Apple. One of the problems is testing. If you support 10 major pieces of application software (and Apple maintains more), then you must test 10 packages when you release a new system/finder. If you support 2 system/finders, you must test 20 times. 3 system/finders, 30 tests. And bug track very extremely complex. Another problem is version control and forked development. If each piece of software must be slightly different for each system/finder, then you have programmers knifing themselves because they cannot keep track of what goes with what and which bug was in which release of system x.y.z. Not to mention the hassles in trying to write conversion code (say, from MacWrite 9.8 to MacWrite 10.0 files). Don Gillies {ihnp4!uiucdcs!gillies} U of Illinois {gillies@p.cs.uiuc.edu}