Gaming on the Apple II and useful hardware is mostly straightforward. In this post I intend to identify hardware upgrades and their usefulness to Apple II games. We start with the original Apple II of 1977 :
Paddles and Joystick - Apple II and II+ machines included a pair of paddle controllers. They are black in color and each has a pushbutton and a knob. The cable is plugged into the 16-pin Game I/O socket on the motherboard. Apple did not release a joystick until the Apple IIe and //c machines. Apple II Joysticks operated like a pair of paddles, but usually supported two buttons. Rival machines from Commodore and Atari only supported one button on their controllers. Apple IIe and //c did not come with paddle controllers when bought from Apple, one had to purchase the Apple II Hand Controllers.
RAM - The Apple II and Apple II+ can support up to 48KB on the motherboard. The Apple II has three rows of RAM sockets and can support 4KB or 16KB in each row. Except on the last Apple II+ machines, there were configuration blocks which the user would use to inform the system whether he had 4KB or 16KB in each bank. While some commercial games could work with 16KB or 32KB, most required 48KB.
Revision 1 and later Motherboards - Adds the blue and orange colors to the High Resolution Graphics (HGR) mode. Absolutely essential for games, thousands of which use the HGR mode. Without this functionality, only purple and green colors are displayed in HGR mode. Also useful in eliminating color fringing in text modes on color monitors, making it easier to load and save onto cassettes and turning the system on. Usually not an issue, since Apple IIs with revision 0 motherboards command the highest prices and most people probably would want to keep those in pristine condition. With some user modifications, the revision 0 boards can have the features of a revision 1 board.
Disk II - Another essential upgrade, cassette tapes were seen as too slow and unreliable for most commercial software after it was released. Most Apple II games come on 5.25" floppy disks. The Disk II Interface Card is needed to connect the drives to the system, and each card can support up to two drives. I know of no game that supports more than two disk drives. The card is installed into one of the expansion slots in the Apple II, and eventually slot #6 was settled upon as the de facto standard installation slot.
When the Disk II was first released in 1978, it had two 4-bit PROMs on the card that supported 13 sectors per track (256 bytes per sector) on each of the 35 tracks of a single sided drive. The earliest public releases of the Disk Operating System, DOS, only supported 13 sector disks. This encompasses DOS 3.1, 3.2 and 3.21. Apple later found that using 16 sectors was within the tolerance of the drives, and updated the PROMs in the Disk II Controller Card and released DOS 3.3 to support 16 sector disks. DOS 3.3 had three releases, the first in 1980 and two bugfix releases in 1983, and the vast majority of games were released on 16-sector disks. Some early games were intended for 13-sector disks, but most have been converted to 16-sector.
Games will often require DOS 3.3 to format blank disks for save games. ProDOS will not work for these games. Some really early versions of Sierra's Mystery House and other early text adventures may require DOS 3.2 13-sector formatted disks for saves. Later versions of these games include a utility to format the disk for the appropriate geometry needed for the game.
The Apple II+ is an Apple II with Applesoft BASIC ROMs instead of Integer BASIC ROMs. Many games and programs require Applesoft in ROM. I cannot think of any that cannot get by by having Integer BASIC loaded into the RAM of the Language Card.
Language Card - The Language Card was released with the Apple PASCAL system and added 16KB of bankswitched memory to the Apple II or II+. It was installed in slot 0, which was specially made for RAM or ROM upgrades. Many, many games require 64KB, especially after the Apple IIe was released.
When DOS is booted, it loads a copy of the BASIC version not found in the ROM. So when DOS is booted on an Apple II, Applesoft BASIC is loaded into RAM. Conversely, when DOS is booted on an Apple II+ or IIe, Integer BASIC is loaded into RAM. The version of BASIC currently in use can be selected with a simple command. This way, older programs written for Integer BASIC can still be run on newer Apple II+ and IIe machines.
Apple released a Firmware Card that was inserted into slot 0 and contained the ROMs not found on the system board. The ROM used could be changed with the flip of a switch. However, this did not allow for the Language Card to be used, since both used slot 0. The Language Card is more flexible and adds that extra crucial 16KB.
Mockingboard - In the early 1980s, Sweet Micro Systems released a sound card for the Apple II/II+ in four varieties: the Sound I, Speech I, Sound/Speech and Sound II. The Sound I came with one AY-3-8910 three voice programmable sound synthesizer, the Speech I came with one Vortrax SC-01 speech synthesizer chip, the Sound/Speech come with one AY-3-8910 and one SC-01 chip, and the Sound II came with two AY-3-8910 chips. Many games assume that the board would be located in slot 4 of an Apple II, II+, IIe or IIgs.
Eventually, Sweet Micro Systems refreshed their line and released the Mockingboard A, B, C and D. The Mockingboard A has two pin reduced AY-3-8913 chips and two sockets for SSI-263 speech chips. The Mockingboard B was a SSI-263 speech chip. The Mockingboard C included two AY-3-8913s and one SSI-263. There was a Mockingboard M that had identical capabilities to the C that was bundled with the Bank Street Music Writer. The Mockingboard D was an external unit that connected to the Apple //c's serial port. The Mockingboard D is utterly incompatible with games.
Games typically only supported one AY chip. Ultima IV supported two AY chips and Ultima V three AY chips, requiring two Mockingboard Sound II, A, C or M. A few games like Crypt of Medea and Crime Wave supported the speech chip.
Applied Engineering released the Phasor sound card, which could emulate a two AY chip Mockingboard. It had four AY-3-8913 chips, one SSI-263 speech chip and a socket for a second speech chip. Ultima V could take full advantage of it.
Super Serial Card - One of the most popular expansion cards for the Apple II, II+ and IIe is the Super Serial Card. This was typically used to connect to printers like the Apple ImageWriter II and Modems like the Hayes Smartmodem line. They typically go into slots 1 & 2. A few games supported printer output, like Wasteland, which could use a serial or parallel printer.
Apple IIe - This is an Apple II+ with a Language Card built in, far fewer chips integrated on the motherboard and added DE-9 port for game controllers. The official Apple II Joystick and Hand Controllers plug into this port, which is much easier than plugging older joysticks into the Game I/O socket. The Apple II Joystick could operate in self-centering or free-form mode by a switch for each axis on the base of the joystick.
The Apple IIe has a newer keyboard with a much more IBM-like layout. Gone is the REPT key, its function is contained in the ROM. Added keys include Up and Down cursor keys, Open and Closed Apple keys (corresponding to joystick buttons 0 and 1) and a Caps Lock key. The Apple IIe has true lowercase support and fully functional shift keys. Initially, BASIC commands could not be entered in lowercase. The IIe machines also have a socket to connect the Apple IIe Numeric Keypad, except for the Platinum, which has most of the previously-separate keypad built-in. The Numeric Keypad, whether attached or detached, functions as duplicate keys, they do not report their own scancodes.
The Apple IIe has an AUX slot for memory expansion. This could house the 1K 80-Column Memory Expansion Card, which allowed 80-column text. Later releases of Infocom text adventures supported 80-column text. Wizardry does not intentionally support 80-column text, but will display its text in an 80-column mode with each character separated by a space if there is an 80-column card in the system. The other option was the 64KB Extended 80-Column Memory Card, which added 64KB of Bankswitched Memory and the 80-Column Text Mode.
Revision B Motherboard - Changes in this motherboard allowed Apple IIe machines to use Double High Resolution Graphics Mode with an Extended 80-Column Memory Card. While an Apple IIe Revision A Motherboard could use the extra 64KB, it could not display DHGR graphics. A user modification exists to fix the Revision A boards.
Third party boards like the Applied Engineering RAM Works exist to expand the Apple IIe to well beyond the extra 64KB of the Extended 80-Column Memory Card, but it relies on an extension of the bankswitching memory scheme and it is unknown whether any game ever used more than 128KB of RAM. There is also an Apple-branded Apple II Memory Expansion that fit in one of the seven slots of an Apple II=//e can could provided more memory, but the memory addressing is utterly incompatible with the addressing of the 80-Column Memory Card, which is what games used.
Apple //c - The Apple //c was a portable version of the IIe with 128KB and contains the equivalent of two Super Serial Cards, a Disk II Interface. Its DE-9 port also supports a one-button mouse. One floppy drive is built-in, a second external drive can be added. First versions of this system did not allow RAM to be expanded beyond 128KB, later versions did. It supports DHGR graphics.
Apple Mouse - The mouse was supported in approximately fifteen or so games, so it is not a major peripheral. Balance of Power was one such game. The Apple IIe required a Mouse Interface Card to be installed, while the Apple //c's mouse connected to its joystick port. The IIe can use standard Macintosh mice from the time period, but the //c requires its own mice. However, its de facto slot is slot 4, which is where many games expect to find the Mocking Board.
ProDOS - This is Apple's successor operating system to DOS 3.3, and it came with the Apple //c. Several later games have obvious ProDOS derived boot loaders, and they often load far more quickly than older games based of DOS 3.3. Unless a game informs you it needs ProDOS, stick with DOS 3.3 as needed. Several games will require the user to format save game disks, but they will insist on the DOS 3.3 format.
Apple //e Enhanced & Platinum - This exchanged the original 6502 for the slightly more advanced 65C02 and new character and firmware ROMs. I have never seen any box state that the game requires an enhanced Apple //e, only that it requires an Apple IIe with 128KB of RAM. This would suggest that no game uses the extra features of the Enhanced model. Except for some minor backward compatibility issues regarding games that used illegal opcodes of the 6502 (the original Ultima's space battles are an example), the Enhanced //e is just as good as the IIe with a numeric keypad.
Apple //c+ and Accelerator cards - The Apple //c+ is an Apple II running at 4 MHz. Many accelerators for the II-//e run at 3.58MHz. While rare, these accelerators can really help with games that use double high resolution graphics like Rampage or King's Quest. However, most games assume that the Apple will be running at 1.02MHz and time everything by that speed. Moreover, transfers from and to the 5.25" floppy drives will occur at the 1.02MHz speed.
Upgrades Not Useful for Gaming :
Apple II/II+ 80-Column Cards - Games would simply not support 80-column text prior to Apple standardizing it with the IIe. Earlier cards had no particular standard, but the Videx Vidterm was a popular choice. Games also do not like lowercase characters until the Apple IIe became popular, so there is no immediate need for a shift-key modification or a character ROM replacement.
Microsoft Z-80 Softcard - This card enabled Apple II users to run the CP/M operating system. CP/M games are generally text-based and platform agnostic.
Apple IIe Video Upgrade Cards - No game is known to use one.
3.5" Floppy Drive - The Unidisk 3.5" drive required its own special controller because the Apple IIe could not quite keep up with the drive. The 3.5" drives on the Apple //c+ provides the same functionality. Very, very few games were released on the 3.5" disk format, and all have more common 5.25" versions.
Modem - Only two games I know of, The American Challenge: A Sailing Simulation and Battle Chess, support modem play, and the latter game is too slow to be enjoyable on an unaccelerated Apple II.
This blog entry does not cover the Apple //gs, which deserves its own discussion.