As with the control panels section, below and in the previous two chapters are descriptions of nearly every Apple Extension ever released. If you're curious what the different extensions do, here's your source. If you're interested in whether or not you need various INITs, use the descriptions below to decide whether or not you want/need them. Most are from Apple; however a few are things that are so universal that I included them here (for some non-Apple extensions, check out the "Third-Party Extensions" chapter).
窶｢ PB 1400 PMU Updater: It comes pre-installed on many 1400s; if you later do a "clean" install of 7.6 or 7.5.3, you will need to reinstall this extension.
窶｢ PC Card Extension (v2.5): allows newer PowerBooks to use expansion cards that adhere to the PC Standard.
窶｢ PC Card Modem Extension (v2.0.7): allows newer PowerBooks to use modem expansion cards that adhere to the PC Standard
窶｢ PC Clipboard Translator: on Macs with a DOS Compatibility Card, allows cross-platform Clipboard capability (for example, to "copy" text on the PC side, then "paste" it on the Mac side).
窶｢ PC Net Exchange (v1.0.1): works with the PC Exchange control panel to help Mac users share DOS/Windows files over an AppleTalk network with users of the AppleShare Client for Windows software. If PC Net Exchange is installed on a Mac client system, you can "map" files on the Mac to Mac OS documents in the same way that PC Exchange lets you map PC files on locally attached PC disks. Any mapping that you've previously defined is automatically implemented. If PC Net Exchange is installed on a server, files that users have copied or saved to that server by using AppleShare Client for Windows appear as "PC" (text) files, and you can map these files to Mac OS application document types with the PC Exchange control panel. If PC Exchange is not installed, such files appear on the server as "PC" (text) files, but you cannot map these files to Mac OS document types.
窶｢ PCI Network Legacy Layer & PCI Network Legacy Loader: there is an update available for 6360/6400/5400 series systems which fixes SCSI problems and provides additional Ethernet support. The "6360/64xx/54xx Update" installs these two extensions to the Extensions folder. If you are using the optional Ethernet CS II card for Ethernet capability, these files provide Open Transport support for the MacIPX and Local Area Transport (LAT) network protocols. (The update is available from Apple's support sites.)
窶｢ Power Format Patch Extension: fixed some problems with floppy disks on Macs with a 180 MHz or faster processor. Rolled into the System under System 7.5.5 Update.
窶｢ PowerBook 1400 ATA Flash Extension: used only on the PowerBook 1400, this extension fixes a bug in the 1400's ATA driver. If this extension is not installed and you insert a properly formatted/initialized ATA PCMCIA "Flash Card" (memory card for the PC slot), the PowerBook may incorrectly show a message that the card is not readable and will ask you if you would like to initialize it.
窶｢ PowerBook 1400 Floppy Update (v1.0.2): corrects problems that could occur with DOS/Windows-formatted floppy disks on PowerBook 1400c/133 models running System 7.5.3.
窶｢ PowerBook 1400 PMU Updater (v1.0.1): used only on the PowerBook 1400 and System 7.6 and below. Fixes bugs under System 7.6 and earlier where the contrast and brightness controls do not work properly (actually, backwards). It comes pre-installed on many 1400s; if you later do a "clean" install of 7.6 or 7.5.3, you will need to reinstall this extension.
窶｢ PowerBook 3400: provides support for System 7.6 on the PowerBook 3400. This file must be present for the 3400 to function with System 7.6. It is no longer needed under System 7.6.1, and the support code has been incorporated into the System file.
窶｢ PowerBook 3400 Ethernet (v1.0): provides Ethernet support for the PowerBook 3400. NOTE that the file below (PowerBook Ethernet (PCI)) seems to provide the same support.
窶｢ PowerBook 3400 Modem (v1.0): provides support for the PowerBook 3400 internal modem.
窶｢ PowerBook Ethernet (PCI) (v1.1): used by the PowerBook 3400 for Ethernet support via the built-in PCI-based Ethernet/Modem port.
窶｢ PowerBook Monitors Extension (v7.5): provides added functionality for external monitors connected to a PowerBook. Contains the monitor information strings that show the resolution and scan rate for the attached monitor, as well as the PowerBook video card information string. Also provides the option of adjusting the gamma setting on color PowerBooks.
窶｢ PowerBook VM Tuner or PowerBook VM Tuner for OS 7.6 (v1.0): used only on PowerBook 1400 computers. Enhances system stability on PowerBook 1400 models when running memory intensive applications with virtual memory enabled and eliminates a problem with moving the cursor during heavy memory use while virtual memory is turned on. Comes pre-installed on many 1400's; if you later do a "clean" install of 7.6 or 7.5.3, you will need to reinstall this extension. Eliminated under System 7.6.1.
窶｢ PowerBook ZoomedVideo (v1.0): when using appropriate hardware, provides support for "zoomed" video on the PowerBook 3400.
窶｢ PowerCD Extension: driver for the Apple PowerCD portable external CD-ROM drive.
窶｢ PowerMac Debugger: part of Apple's E.T.O. compiler tools. Used by developers to debug remotely from another Mac. If you have this extension installed and try to use the GeoPort modem, you will get an error that the GeoPort/serial port is already in use.
窶｢ PowerPC Finder Update: part of System 7.5.0. Provides Finder support for native PPC code. Also prevents the PowerMac's name from being clipped in the "About This Macintosh" dialog box. Under System 7.5 Update 1.0, the name was changed to Finder Update. Under System 7.5.3, both files were incorporated into the Finder itself and are no longer necessary.
窶｢ PowerPC Interrupt Extension (v1.0): if you have a PowerPC desktop system and System 7.5.5, you may have experienced your computer freezing for several seconds before returning to normal operation, or completely freezing and requiring a restart. This extension fixes one source of this problem. It is intended for users who have installed the System 7.5.5 Update on a desktop Power Macintosh, PowerPC-based Performa, PowerPC Mac OS-compatible, or on any desktop computer with a PowerPC upgrade card. It is unnecessary on PowerPC PowerBooks. Note: some people have reported extension conflicts with this file. A number of people seem to have more problems after installing it! One suggested solution is to make the PowerPC Interrupt Extension load last (by changing its name, or by using a third-party startup file manager). If you do have more problems and can't find a solution, you should probably just remove it. This file is no longer necessary under System 7.6 and later, as it has been incorporated into the System file.
窶｢ PowerPC Monitors Extension (v7.5): needed for use of the AV14, AV15 and AV17 monitors; superseded by Display Enabler 2.0 and later. Also needed by PM 6100AV/ 7100AV/ 8100AV models to enable video-out (such as to an RGB monitor) in the Monitors control panel.
窶｢ Print Monitor (v7.1.2): if you are not using Desktop Printing (see the "Desktop Printer Extension" entry in this Extensions section), this application (it's not really an extension) allows you to monitor and control your print jobs.
窶｢ Printer Descriptions [NA]: this folder in the extensions folder contains printer descriptions for almost every Apple laser printer. It's mainly a waste of space; trash all the descriptions but the ones you use, or might use in the future (how many of us are using a LaserWriter I?)
窶｢ Printer Selector (v2.0.1): under LaserWriter 8.4 and above, adds a menu of configured printers to your menu bar for quick printer switching.
窶｢ Printer Share (v1.1.3) & Printer Share GX (v1.1.1): Allows your Mac to be used as a print server (i.e. another computer on the network can send a document to your computer and then your computer sends it to the printer; this frees up the processor on their computer--not useful for most people). Also allows you to share non-networkable printers (such as the StyleWriters) over a network. You must install Printer Share onto both the server and the client.
窶｢ Processor Info Extension: on 5200, 5300 and 6200 series Macs, fixes a bug where the computer would report the incorrect bus and processor speeds.
窶｢ ProDOS File System: allowed pre-7.5 Macs to recognize ProDOS/Apple IIe disks. Incorporated into PC Exchange 2.0.2 and later, and is incompatible with System 7.5.x.
窶｢ Quadra AV Monitors Extension (v7.5): same as above, only for Quadra AV- and Centris AV-series computers, so it includes the AV video display options.
窶｢ Quadra Monitors Extension (v7.5): allows the Monitors control panel on Quadra- and Centris-series computers to reflect the capabilities of the built-in video. Provides information on the resolution and scan rate for an attached monitor. If you remove this extension, the monitor will work fine; however, the extra "options" such as gamma control will be inoperable.
窶｢ QuickDraw GX (v1.1.5): enables the QuickDraw GX printing system. Note that if this extension is installed, you must have GX-compatible printer drivers. If you have this extension installed, non-GX drivers will not even show up in the Chooser. If you are experiencing this problem, put the QuickDraw GX file in the "Extensions (Disabled)" folder, or in the trash, and restart your computer. The Chooser should then show all of your normal printer drivers.
窶｢ Record Button: provides support for the "record" button on the Apple Adjustable Keyboard. Now incorporated into the AV and PowerMac series' ROMs.
窶｢ Scanner: driver used by all "Apple-compatible" scanners (basically, all Apple scanners and any third-party scanners which were designed to use the Apple driver).
窶｢ Scripting Additions: actually a folder within the Extensions folder. The additions contained in the folder enhance the language of the AppleScript system by adding special features such as the time of day, day of the week, or date. When installed, AppleScript behaves as if these additions are part of the standard language. These items are only required when using a script that incorporates them.
窶｢ SCSI Manager 4.3 / SCSI Manager 4.3.1: the new SCSI Manager (4.3.x) system added several new features (such as SCSI 2 compliance, concurrent asynchronous I/O, and disconnect and reconnect) to the Mac's SCSI architecture. There is a lot of conflicting information out there about these extensions. Even Apple's own Tech Info Library gives contradictory explanations. The following is the best summary I can offer (and it is admittedly confusing): Version 4.3 is part of the ROMs on all Power Macintosh and Quadra AV computers, and is installed as a separate extension by the System 7.5 CD, even on these machines which already have it in ROM. It is incorporated into the System under System 7.5.3 and later. So anyone running System 7.5.3 or later should not have any version of this extension installed. The new (4.3/4.3.1) SCSI system is supposedly supported on all PowerPC and 68040 Macs, except for the 630 series and 68040 PowerBooks (including Duos). If your computer doesn't require this extension, you should probably delete it. (In yet another source of confusion, one Apple article claims that having the extension installed when not needed can cause serious problems, while another said that it would not do any harm. This is clearly a situation where too many people at Apple are trying to explain something that none of them knows enough about!) The remaining info is only for people not running System 7.5.3 or later: Non-QuadraAV 68040 Macintosh computers require the SCSI Manager 4.3 extension under System 7.5, or the SCSI Manager extension under System 7.5.1. The SCSI Manager 4.3.1 extension from System 7.5 Update 1.0 contains software fixes needed only on 68040-based Macintosh computers and the PowerPC Upgrade Card. Even though Apple claims that the new SCSI system is not supported on 630-series and PowerBooks, they also say that version 4.3.1 of the extension is needed on 630 machines, the PowerBook 150, and the Quadra AV models to fix possible data corruption problems. It is also supposedly used on those computers to fix a potential crash problem with some (unspecified) external hard drives.
窶｢ SCSI Update: included with the AppleShare IP 5.0 beta. Supposedly updates the SCSI Manager to allow asynchronous access on machines that don't already support it, such as 680x0 machines and early PowerMacs. The new SCSI Manager is required for products such as the Advanced Driver Toolkit from Dantz for accessing Digital Linear Tapes from within Retrospect.
窶｢ SerialDMA 2.0.2 [17.5/?]: first, a note on the DMA chip: a computer's processor supervises the transfer of data between memory and connected devices (such as a hard drive). This takes time away from other processor functions. PowerMacs and the AV Macs, as well as some newer PowerBooks, have what are called direct memory access (DMA) chips, which handle some or all of this data transfer processing, allowing it to pass directly from connected devices to RAM. Note that in order to use this DMA, the connected device must use a driver which was written to support DMA transfers. SerialDMA v2.0 was originally a rewrite of the serial drivers that shipped with the first AV Macs (the Centris 660AV and Quadra 840AV) and were later carried over to Apple's first line of Power Macs (6100, 7100, 8100) and their derivative models. Version 2.0.2 of SerialDMA patched some remaining bugs and added support for Apple's newer PCI Power Macs. In addition to offering greater reliability, better performance, higher baud rates, and a number of bug fixes, version 2.0.2 offered significant performance improvements on 68040-based AV Macintoshes, as well as fixes for printing problems with StyleWriters on PCI Power Macs. Under System 7.5.2, SerialDMA (both versions) had known problems on PCI Macs with the Serial Port Arbitrator extension that is included with AppleTalk Remote Access (ARA) and with the Port Juggler extension. However, Serial DMA has been incorporated into the System since System 7.5.3, and these incompatibilities have reportedly been resolved.
窶｢ Shared Library Manager (v2.0.1) [NA]: supports loading, unloading, and sharing of object-oriented code, including all "shared library" files. Provides support for Open Transport. This extension is needed on both 680x0 Macs (for universal support) and on PowerMacs (for emulation support). Note that if one does a clean install of System 7.5.5, and then afterwards fresh-installs Microsoft Word 5.1a, the Microsoft installer removes the latest version of SLM and replaces it with an older version (1.1).
窶｢ Shared Library Manager PPC (v2.0.1) [NA]: supports loading, unloading, and sharing of native object-oriented code, including all "shared library" files. Provides PowerPC-native support for Open Transport and other libraries. Both this extension and the "Shared Library Manager" (above) are needed for OT and other shared libraries to function properly on a PowerMac, while 680x0 users only need the non-PPC version.
窶｢ Slow SCSI Extension: addresses a potential conflict between PowerBook 5300 series computers (and possibly other models such as the 190 and 1400) and slow SCSI devices (such as single-speed CD-ROM drives, Zip drives, and other PowerBooks attached via SCSI disk mode) where sometimes the PowerBook will crash and/or freeze. Not all PowerBooks will experience this problem and even PowerBooks that do will not necessarily experience it on a consistent basis (even with different units of the same make and model). The reason for this conflict is due to two peculiarities found in these PowerBooks: 1) the internal hard drives are IDE drives, and as such do not provide an "anchor" for the SCSI chain; 2) the PowerBook does not provide steady termination power to the SCSI chain. When these two factors are put together, activity on the SCSI chain can cause power along the chain to fluctuate, and thus intermittent termination; if too much fluctuation occurs, the PowerBook crashes due to SCSI termination problems. This extension actually slows down data transfer rates along the SCSI chain, dampening these fluctuations enough to avoid the problem. NOTE: You should only install this extension if you are experiencing constant freezes or crashes when transferring files with a particular SCSI device, since it will impact performance with ALL SCSI devices by 10 to 50 percent. While the slowdown may not seem significant with an external Zip drive, it will quickly become apparent if you have a 24x CD-ROM drive attached! You can use a startup manager to disable the extension when not needed.
窶｢ Sound Input Amplification: adds the "microphone amplification" option to the Sound control panel, which when active amplifies sound input by +25 dB. Some microphones, such as the Apple PlainTalk microphone, produce a "line-level" signal which does not need amplification to be properly received by your computer's sound hardware. However, other microphones produce a "mic-level" signal which needs to be amplified. If you are using a microphone which produces a mic-level signal, you will need to turn microphone amplification on. NOTE: According to Apple, this extension was designed for PowerMac 7200 computers, and thus can be installed from the "Apple Extras" folder on the hard drive or on the 7200 System CD-ROM.
窶｢ Sound Manager (v3.2.1) [0/96]: PowerMac native. Sound Manager 3.2 was incorporated into the System in System 7.5.3, and included asynchronous sound playback and better Power Mac performance. The newer version 3.2.1, which is a separate extension and is part of the QuickTime 2.5 package, supposedly provides even better low-memory performance and better multi-channel sound via a new sound clock component. However, it includes no new "features." If you disable version 3.2.1, the version (3.2) included in the System will be used instead. NOTE: according to the Mac OS 7.6 Technical Note, Sound Manager 3.2.1 is actually built into the System file under 7.6 and the extension is no longer needed; however, that statement seems to go against all other Apple documentation on version 3.2.1. For the time being, I would recommend keeping this extension until further clarification can be found. It will not cause any harm to have version 3.2.1 installed even if it has been incorporated into the System. NOTE: on a Quadra with a PowerPC card and System Software 7.5.1, you may need to update your System Software to 7.5.3 to use Sound Manager 3.2.x. NOTE: the QuickTime 2.5 installer will only "Easy Install" v3.2.1 if an older version is present, so be sure that you have your older Sound Manager extension present before you install, or else do a "custom" install. NOTE: on PowerBook 500 series computers which have not been upgraded to PowerPC, Sound Manager 3.2.1 prevents sound recording. If you wish to record sounds, you should disable this file and restart. When you have finished recording sounds, you should then re-enable it and restart.
窶｢ Startup Tuner [NA]: part of the System 7.5.3 revision, fixes a problem with the Startup Disk control panel where the Mac may not startup from the selected disk. Only useful on the models for which the Revision is recommended (see Chapter 2). Not necessary under System 7.5.5 and later.
窶｢ Stationary: not really an extension. Part of the QuickDraw GX package, this extension enables the "Stationary" paper type option in the "Page Setup..." window of compatible applications.
窶｢ System 7 Tuner: part of System 7.0, this extension was part of the System Tune-Up disk. It provided better memory management for the initial release of System 7.
窶｢ Telephone Manager Extension (v3.0): installed by Apple Telecom software, as well as the USR modem software. Allows you to use your modem and computer together as an answering machine. Also allows you to control your phone line via your computer.
窶｢ Text Preview: when using ClarisWorks 4.0, and other compatible applications, shows previews of TEXT files in the preview window of the "open" dialog box. NOTE: The Text Preview extension conflicts with the "file preview" feature when selecting MPEG files in Open/Save dialogs. While this does not affect the ability to view MPEG files, you will not be able to preview them in Open/Save dialogs.
窶｢ Thread Manager (v2.1.5): Thread Manager is an addition to the Macintosh Toolbox that enables "concurrent programming" for real multitasking within an application. Supports cooperative and preemptive threads of execution at the application level, but not at the system level -- sort of the Mac's version of "multi-tasking" (although true multitasking occurs across applications and includes System operations). Version 2.1 of this extension, which is what the Finder and most applications still use, has been incorporated into the System since System 7.5. However, the installer for Apple's QuickTime MPEG Extension installs a newer version of Thread Manager (2.1.5) which is required for QT MPEG support. NOTE: The LaserWriter 8.4.1 installer deletes the newer (v2.1.5) Thread Manager extension; the various Color StyleWriter software installers actually delete it and replace it with the older v2.1! If you are planning to install the LW 8.4.1 or Color StyleWriter software, disable or remove Thread Manager 2.1.5, and then enable or replace it after the installation.
窶｢ TokenTalk Phase 2 (v2.5.7): driver used by the Apple Token Ring card and the Network/AppleTalk control panels.
窶｢ TokenTalk Prep (v2.5.2): provides driver support for TokenTalk Phase II
窶｢ Trackpad Climate Control (v1.1): reduces unexpected pointer movements caused by humidity or moisture on the trackpad. Only works on the PowerBook 190, 1400, and Duo 2300. You should not use this extension if you don't have pointer movement problems, as it could actually make the pointer less responsive.
窶｢ TrueType: needed by System 6.0.7 and all subsequent versions of System 6 to print TrueType fonts, as well as to display them on screen.
窶｢ Video Out Default (PAL) (v11.2): used by the Apple Video Player. On the standard U.S. System, the default video-out for the Apple Video Player is NTSC. Outside of the U.S., the standard video format is PAL; this extension changes the Apple Video Player default to PAL.
窶｢ Video Startup (v1.6) [22/0]: provides support for the Apple Video Player; needed to use the AVP. NOTE: If you disable the "Video Startup" extension on a Performa 6300CD the Volume-Up button on the front of the CPU will not work. The Volume-Down continues to work. NOTE: If you are going to install System 7.5 Update 2.0 (ignore this part if you have OS 7.6), first check the version number of both Video Startup and the Apple Video Player. During the installation, you may get a message that says something like "a newer version is already installed." However, chances are it really isn't, and you do need to install. If you did already have 1.4 installed, leave it. If you have a version prior to 1.4, ignore the installer's warning and install the "older" version. This is a bug in the 7.5 Update 2.0 installer. You should end up with v1.4. If not, you should go back and do a custom install of only the Apple Video Player software. There is a version 1.4.2 which is available from the CoolTalk for MacOS package.
窶｢ Voices: folder which contains voices for use by Speech/ PlainTalk/ Text-to-Speech. NOTE: Apple has made available three "high-quality" versions of the Agnes, Bruce and Victoria voice files. These voices are supposedly more lifelike and more easily understandable. However, they only function with MacinTalk Pro. If you are not running the MacinTalk Pro extension, you cannot use the high quality voices.
窶｢ WindowPicker (v1.1): older "unsupported" utility which provides the ability to bring any open window to the front via a pop-up menu and/or arrow keys. Does not work with System 6.x.
窶｢ WorldScript Power Adapter (v7.5.3): see entry in the "WorldScript" section of the "Groups" chapter.
窶｢ ﾂｰAppleVision (v1.5.3): only used for support of AppleVision displays, such as the 1710AV. Previous versions (1.0.2, 1.0.4) were plagued by compatibility problems. The version number was upped to 1.5.3 for continuity with entire AppleVision 1.5.3 package (see entry under "Groups").
窶｢ ~AudioVision: part of the AudioVision 14" monitor software package. Only needed on pre-7.5 systems.
窶｢ 窶｢ Shutdown Items enabler: provides support for the "Shutdown Items" folder under System 7 Pro. The extra bullet in this item is actually part of the extension's name so that it will load last in the startup process.
