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Overview of Apple's direction with older Macintoshes

A view of the usability of older Macintoshes on the MIT campus.

Mac OS System Software

The latest version of MacOS, version 7.5.5, will be the last to support Macintoshes without 32-bit clean ROMs1. These are predominantly older machines and are the Plus, SE, SE HDFD, Classic, Portable, PowerBook 100, Mac II, Mac IIx, Mac IIcx, SE/30 and LC2. Although most third party software will not require the newer MacOS system versions for some time, it is a statement of direction from Apple with regard to their active development for these older machines. In dropping new development for this set of machines, Apple will be able to roll out more changes to the MacOS which they have planned for some time.

Impact on IS efforts: This probably will not be felt heavily for at least another year. As stated above, most software that works with these older machines will continue to do so, that is the developers probably will not cut off development for some time. However, this point may happen sooner if these newer versions of the MacOS become very popular. There is a strong chance of this in fact happening as the improvements Apple is planning are greater than in previous system upgrades. One additional hitch in this equation is if we are able to obtain a MacOS site license for the MIT community, our users will probably upgrade much more rapidly than they are doing now. Of the machines on the list, the ones that we probably need to worry about are the Mac II(x/cx)'s, SE/30 and LC. Although we do not have a very good list of how many of these machines are still active on campus, they still probably represent a noticeable number of machines.

CFM-68K and SAP

The security portion of SAP requires the Code Fragment Manager in order to access the GSS shared library. Although CFM is built into all Power Macintoshes, for the older 68K machines it is an optional install. Even then, CFM-68K has a few requirements, 68020 or better processor, System 7.1 or higher and 32-bit addressing turned on. This means that the older 68000 based Macs like the Plus and SE will never be able to run SAP here and that those Mac II's and others from the list may not be able to run SAP securely.

Open Transport

The new networking architecture has similar requirements to CFM-68K except that it needs a 68030 or higher processor. Open Transport becomes important to us in areas such as Tether where the next version of the PPP client that we will be distributing will require OT. Tether software will still be provided for older machines but no active development is being done for that version. This is a similar situation software wise to Techmail-S in that we do not control the connection software used.

Summary

This information is being provided more as a heads up rather than a crisis point. The question for us at or within IS now is how much this should affect our future development plans and how should we let the customers know that some critical products, in house and third party, may not work on their machines. Examples of the first point might include work with Cyberdog, Apple's Internet suite based on OpenDoc and thus requires CFM-68K. Apple is helping somewhat on the second point through their publicity about future versions of MacOS. While solutions are still available for most of these older machines, active development for them is beginning to cease and we need to decide how much effort needs to be spent on bringing them along with our projects.

Note 1: 32-bit dirty and 32-bit clean refer to the old style of memory address usage where the high byte of a memory access was often used to carry extra information not related to the memory address. This is known as 24-bit addressing or 32-bit dirty. 32-bit clean programs do not do this. The Mac IIci was the first Mac with 32-bit clean ROMs. Apple never released a permanent fix for the effected machines.

Note 2: This refers to the original LC and not the LC II, LC III or LC 475.

Guide to the Age and State of older Macs

Machines where development is drying up and hard to support (all 68000 processors)

Machines where supporting, in the development sense, is getting harder. Some technologies work while others do not. (Mostly 68020 and 32-bit dirty ROM machines)
[These machines have not been determined to work with SAP. From a paper requirements standpoint, they would need a piece of software, Mode32 from Connectix, before working. However it has not been determined if Mode32, CFM-68K Runtime Enabler and SAP are compatible.]

Machines that are starting to be considered the baseline for active development but performance might be considered minimal (the majority of 68030 machines)
[These machines will technically function with SAP although performance will be poor.]

Machines where development and performance is still active and reasonable (68040 and PowerPC processors)

Although 68040 based Macintoshes (Centris, Quadra, etc.) may still have some life left in them, it is encouraged that you plan your upgrades to PowerPC based Macintoshes soon. Some third party companies have stated already that future development will be for PowerPC Macs only. The most notable of these are Microsoft starting with MS Office for Macintosh 97. Some technologies from Apple, such as QuickDraw 3D and Game Sprockets, are also PowerPC only.

Questions or comments? Send mail to macdev@mit.edu
Last updated on $Date: 2003/11/18 21:58:16 $
Last modified by $Author: smcguire $