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Update resources for older Mac OS

The purpose of this page is two-fold: to list the extensions needed for running my Macintosh software under System 7, and to provide useful information about what upgrades can be made to System 7 and Mac OS 8.1 to improve their functionality in line with Mac OS 8.5.

The official system requirements of my software under “classic” Mac OS is Mac OS 8.1. However, it can also be run under earlier versions of Mac OS with the appropriate system extensions installed.

Upgrade matrix

The following table shows what upgrades can be made to various versions of Apple System Software/Mac OS. Items marked with "(Required)" are required for running my software.

Mac OS version
Component System 7.5.5 System 7.6.1 Mac OS 8.1
Appearance Manager 1.0.3 (Required) Recommended Recommended Included
Navigation Services 1.0.1 Not available Not available Recommended for Power Macintosh
Open Transport 1.1.2 Recommended Recommended Part of 8.0
Internet Config 2.0.2 Recommended Recommended Recommended
CFM-68k 4.0 (Required) Required Included Included
PowerPC Interrupt Extension Required for Power Macintosh N/A N/A
Finder Heap Fix (Required) Required Recommended for pre-Power Mac

A note on PowerPC: In the context of Macintosh, “PowerPC” – often written “PPC” – refers to Macintosh computers running Motorola or IBM PowerPC processor chips (Power Performance Computing). The PowerPC computers are all Macs from the 1994 Power Macintosh onwards, the clones, some Performas and any older Mac with a PowerPC upgrade card, but not including the new Intel-based Macs. The majority of the older PowerPC Macs said “PowerPC” on the front of the case, but this has not been the case since the iMac. The original PowerBooks were not PowerPC machines despite the name! Those, like all older Macintoshes, ran processors from the Motorola 68000 range, and are known as “68k” machines for short.

Component notes

Appearance Manager

Appearance Manager provides an updated look and feel for the computer’s interface, including a standard set of new interface widgets (controls such as check boxes and tabs). To keep the System 7 look with Appearance Manager installed, uncheck the “System-wide Platinum appearance” option in the Appearance control panel.

Required: Selection through radio buttons in my applications will not be possible unless Appearance Manager is installed; otherwise, all radio buttons are permanently selected and unusable.

Download Appearance Manager 1.0.3 (StuffIt, 480 kB)

Navigation Services

Navigation Services provides completely overhauled Open and Save dialog boxes for supporting applications on Power Macintoshes:

TraditionalNav. Services

Navigation Services runs on PowerPC (Power Macintosh) machines only. See further information on Navigation Services or download Navigation Services 1.0.1 from Apple as part of the CarbonLib 1.0.4 package (Navigation Services requires CarbonLib); localised versions of CarbonLib/Navigation Services are also available.

Open Transport

System 7 will also benefit from installing Open Transport 1.1.2, Apple’s newer networking technology (for access to the Internet and AppleTalk networks and so forth).

Download Open Transport 1.1.2 from Apple (68k users only need to download the first two image files – part 1 of 4 and part 2 of 4). Mount both images using Disk Copy 6.3.3 before starting the installer. Localised versions of Open Transport are also available.

Internet Config

Internet Config provides a system-wide database of Internet settings for all your Internet software to utilise. For example, it stores your default Web and e-mail clients (and all your other protocol mappings), and file extension and MIME type mappings for downloads so that a Web browser knows what to do with files after downloading them (type and creator code to assign, with which application to open the file, and so on). As of Mac OS 8.5, Apple incuded Internet Config with the operating system and provided their own Internet control panel; users of older versions of Mac OS can install Internet Config to obtain the same features.

Internet Config ships with a Location Manager module to allow you to switch Internet configuration with Location Manager, a Control Strip module to let you switch configuration using the Control Strip, and an extension – ICeTEe – that lets you command-click URLs to launch them in applications such as SimpleText.

Download Internet Config 2.0.2 or visit the Internet Config site.


CFM-68k facilitates executing 68k Code Fragment Manager applications on 68k machines. The Code Fragment Manager can be considered in a sense to be the system in Mac OS which runs Power Mac applications. It is also possible to package up pre-Power Mac (68k) software as Code Fragment Manager programs.

Required: REALbasic software compiled for 68k is Code Fragment Manager software. Mac OS prior to 7.6 did not include the Code Fragment Manager; therefore, to use any of my software on pre-Power Mac machines under System 7.5, you will need to install the Code Fragment Manager.

Download CFM-68k 4.0 from Apple.

PowerPC Interrupt Extension

According to Apple, the PowerPC Interrupt Extension “… may improve reliability and performance on Power Macintosh computers, PowerPC-based Performa computers, Mac OS-compatible computers, and on desktop computers upgraded with a PowerPC upgrade card. This extension requires System 7.5.5.” This extension is of no relevance to PowerBook owners.

Download PowerPC Interrupt Extension from Apple; further information on the extension is also available from Apple.

Finder Heap Fix

Due to a bug in System 7.5.5, it is necessary to apply the Finder Heap Fix on all machines to increase the Finder’s heap size (the amount of memory allocated to the Finder, which cannot be set through Get Info). It is also good practice to increase the Finder’s heap size on all 68k machines regardless of the system software version to allow it more memory. Increasing the Finder’s heap size improves overall Finder stability, getting rid of frequent out-of-memory errors in the Finder (in 7.5.5) and some system freezes. The maximum heap size is 1024 kilobytes (1 megabyte). Don’t forget to reboot immediately afterwards.

Required: 68k software compiled by REALbasic above a certain size seems to crash on 68k machines, so although Finder Heap Fix is not required, you may find it necessary to install and use it to prevent 68k versions of my software from crashing.

Download Finder Heap Fix (StuffIt, 2 kB); view the Heap Fix read me.

Thanks goes to Pierre Cardinal for the basis of this page and much of the information that it contains.