The Franklin Ace 500 is the last of the Franklin line of computers. The first few computer that Franklin produced were illegal clones of the AppleII but after a lawsuit that Franklin lost the company decided to produce legal clones.

The Ace 500 is a clone of the Apple IIc. It is very similar to the IIc with the notable addition of a separate numerical island to the built-in keyboard. The power supply unit is external, and on the right side of the machine there is a 143K built in floppy disk drive. The use of an external power supply is interesting, as the machine does have space inside for an internal PSU. It seems that the power requirements were such that a larger PSU was needed that did not fit within the case.

The Franklin Ace 500 came standard with 256K of RAM, but there was room for another 256K making the machine capable of supporting 512K Ram. The motherboard had a battery-backup for the clock and the calendar.

Functionally, Franklin DOS 2 mirrored Apple DOS at the command level. Users could issue familiar commands like LOAD, SAVE, RUN, or CATALOG exactly as they would on an Apple II running DOS 3.3. The file system also adopted the same 35-track, 16-sector disk layout, which meant disks created on one system could generally be read or written on the other. From the standpoint of a typical BASIC programmer, Franklin DOS 2 appeared to work seamlessly alongside AppleSoft BASIC in ROM.

However, Franklin DOS 2 was not an exact clone under the hood. Certain programs that relied on the internal structure of Apple DOS could fail when run under Franklin’s variant. This limited its usefulness once software libraries began to take advantage of Apple DOS internals for copy protection or direct disk access. The incompatibility issues, although subtle, meant that Franklin’s operating system could not achieve universal acceptance among Apple II software publishers or users.

As a result, Franklin DOS 2 quickly faded into the background. Most ACE owners simply replaced it with Apple DOS 3.3, which was the true standard in the Apple II world, and later with ProDOS once that became widespread. Franklin’s experiment with its own DOS illustrates both the company’s early attempt to skirt Apple’s intellectual property and the reality that in the microcomputer market of the early 1980s, software compatibility mattered more than proprietary differentiation.

The 6502 is an 8-bit MicroProcessor designed by MOS Technology. The team was led by Chuck Peddle and had also worked on the Motorola 6800. The 6502 is a simplified, but faster and cheaper design than the 6800.

The 6502 was introduced in 1975 and was the cheapest microprocessor on the market. Together with the Zilog Z80, the 6502 helped start the home computer revolution of the 1980s. The 6502 was used in a wide range of devices: the Atari 2600, the 8-bit Atari home computers, the Apple II, the Nintendo Entertainment System, the Commodore 64, the BBC Micro and many others. All used the 6502 or a variation of it.

The 6502 is a 1MHz design, while the 6502A is designed for 2MHz. The 6502A is 100% compatible with the original 6502.

Commodore soon bought MOS Technology, but conitnued to sell the microprocessor to competitors and licensed the design to other manufacturers.