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Apple II GS - What happened to ROM 2 ?

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PostPosted: Thu Feb 24, 2005 1:36 am    Post subject: Apple II GS - What happened to ROM 2 ? Reply with quote

I was surfing for informations about the Apple II GS ROM versions.

I asked myself: I know Hardware ROM #1 and Hardware ROM #3. but what ever happend to Hardware ROM #2 ?
Here is the answer I found at
Information Courtesy of the Apple FAQ, Part II

Released in September 1986, the original GS ROM 00 (which tended to have the Woz signature on the front case, though that is no guarantee) must have one or two chips (the ROM and possibly also the Video graphics controller) upgraded to become a ROM 01 machine and boot/run current software.

The first 50,000 GSs sold had a 'Woz' signature painted on the front of the case; this was known as the 'limited' edition. With so many of these cases, there's almost no added value to the limited edition.

A later revision of the motherboard, known as the ROM 3 had a number of significant changes: more ROM (256K vs 128K) on the motherboard, more (1MB vs 256K) RAM on the motherboard, different capabilities for the internal slots, better support for the disabled, and a cleaner motherboard which can result in quieter sound support.

The extra ROM allows more parts of the system software to be accessed from there, which allows a ROM 3 to boot and run GS/OS and GS/OS programs slightly faster than a ROM 01. (The two have identical toolbox functionality from the programmer's standpoint, however.)

To determine which ROM version you're using, when you power it up, it should say "Apple IIGS" at the top of the text screen for a second or so, and possibly some text at the bottom, which states either ROM 01 or ROM 3. If it does not say either, you have a ROM 00, the original version. You must upgrade a ROM 00 to a ROM 01 (easy-- swap 2 chips), or a ROM 3 (much harder-- a motherboard swap is required, and you might as well purchase a ROM 3 system outright) it in order to run current system software.

There is no such thing as a ROM 02 or 2. The engineers at Apple called the first revision of the GS's ROM a ROM 00, and the second 01. However, many people were confused by the second revision having a 1 in the name. To get things back in sync, the third revision also has the numeral 3 in the name. The ROM 4 existed in several prototypes, but was killed off before general production.

The current system software works to make a ROM 01 and a ROM 3 two systems appear almost identical to the software, except for the obvious such as the amount of RAM built in. Certain games and other copy protected software that used undocumented entry points on the ROM 01 will not work on the ROM 3.

and mooooore informations at

The case and motherboard used in the Apple IIGS was made smaller than that found in the IIe, both in order to make a smaller "footprint" on a desktop, and also to make it easier to make an upgrade available for IIe owners.

This original motherboard (known as a "ROM 0") was released with all the parts necessary to install it into an Apple IIe (the conversion kit included the motherboard, an optional mouse, and a backplane for the IIe.) They had wanted to make it possible even for Apple II and II Plus owners to upgrade, but in the end it turned out to be just too expensive and difficult to execute. The Apple IIe-to-IIGS upgrade resulted in a computer that looked like a IIe, but contained the motherboard of a IIGS. A new name plate on the cover identified the modified computer as a IIGS, even though in all other respects it looked like a IIe.

At first, they were given 64K of space for the ROM, over four times as much as was available on the original Apple II. Later, they had to go back and ask for 128K of ROM, because of the many things that they needed and wanted to do. Of course, Applesoft had to be present in ROM in order to maintain compatibility with the older Apple II software. Additionally, they also put all of the mouse-handling tools into the ROM (unlike the II, II Plus, and IIe, which had to have the mouse firmware on a card in a peripheral slot).

In September 1987 Apple made an incremental improvement to the IIGS with the release of a new ROM. The ROM 01 revision made a few changes in the original IIGS ROMs and included an improved video controller chip. Bugs in the ROM code were fixed, and a problem with a "pink fringe" effect with certain graphics displays was fixed.

The new ROMs were not compatible with any IIGS System Disks earlier than version 2.0. The new ROM was identified by a message at the bottom of the screen when booting the IIGS that said "ROM Version 01". The original IIGS had no message in this location.Also, where the original motherboard (the ROM "0" board) was designed to be useable for a IIe-to-IIGS conversion, the ROM 01 board did NOT have this capability. None of the internal plugs for attaching Apple IIe-style power or other connectors were provided.

However, if a ROM 01 motherboard was found to be defective and required service, it was replaced with one of the original, convertable motherboards (supplied with the appropriate ROM 01 chips), and the non-convertable boards were then refurbished into convertable ones.

The next change came with the release of the ROM 03 version of the IIGS in August of 1989. This new IIGS computer came standard with 1 meg of RAM on the motherboard, and twice as much ROM (256K versus 128K on the older IIGS). This allowed more of the operating system to be in ROM, rather than having to be loaded from disk when booting. Additionally, fixes were made to known bugs in the ROM 01 firmware. (The latest version of the IIGS system software made patches to ROM 01 to fix those bugs, but these patches still had to be loaded from disk, which slowed startup time. Having the latest new tools and fixed new ones already in ROM made booting the version 03 IIGS a bit quicker).

The new Apple IIGS also had the capability of using both the internal slot firmware as well as using a peripheral card plugged into a slot. The ROM 01 IIGS could, of course, use cards plugged into the slots, but only at the expense of being unable to use the internal firmware for that slot. With so much useful system firmware built-in, a ROM 01 user who wanted, for example, to add a controller card for a hard disk would have to give up either AppleTalk in slot 7 or use of 5.25 disks in slot 6. Almost everything else had to be set in the control panel to the internal firmware.

The ROM 03 IIGS also included enhancements for disabled users. A feature called "sticky keys" made it possible to do multiple keypresses. (To execute an "Option-Control-X" sequence, for example, required pressing three keys at once. This was something that a paralyzed user with a mouth-stick to press keys could not previously do). Also, more things that had required a mouse now had keyboard equivalents (using the keypad).

The new IIGS also had somewhat "cleaner" sound and graphics. However, because the improvements made were minimal compared to the cost of providing upgrades to previous owners, no upgrade program was announced by Apple. In any case, many of the new features could be obtained on older IIGS's by upgrading the memory to at least one megabyte and using GS/OS System Software 5.0.2 or greater.[7]

A feature that was added to the ROM 03 firmware that was entirely fun, instead of functional, was accessed by a specific key-sequence. If the computer was booted with no disk in the drive, a message that said "Check startup device" appeared, with an apple symbol sliding back and forth. At that point, if the user pressed the keys "Ctrl", "Open Apple", "Option", and "N" simultaneously, the digitized voices of the Apple IIGS design team could be heard shouting "Apple II!"

Also, the names of those people would be displayed on the screen. If running GS/OS System 5.0 or greater, the user would have to hold down the "Option" and "Shift" keys, then pull down the "About" menu in the Finder. It would then say "About the System". Using the mouse to click on that title would cause the names to be displayed and the audio message to be heard.

Info about the Apple IIe to IIGS update at

The Apple IIe-to-IIGS Upgrade version is considered the most rare commercially available version of the Apple IIGS. Based on my research, very few Apple IIe owners took advantage of the Upgrade. The Upgrade appeared in the Official Apple Price List the same day as the Apple IIGS introduction in September 1986, with a retail price of $500.00. Customers were able to place orders for the Upgrade on that day, but didn't actually start shipping until around the middle of 1987.

any more questions ?
MacOS aka Oliver
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