The PET 4064, or Model 4064 was a microcomputer made by Commodore Business Machines in 1983. It was sold to schools as a replacement for the older Commodore PET systems. Schools were reluctant to get the Commodore 64, since the smaller design made it easier to steal.

The Internals of the Model 4064 were refurbished Commodore 64 motherboards, hooked up to a monochrome green monitor. The area above the keyboard contained a BASIC 2.0 reference card and Commodore DOS commands. There were difference between the Educator version and the other model 4064s. The Educator had the ability to display shades of green, while the PET 64 and the 4064 could only display monochrome. The CPU used in the 64's was the MOS Technology 6510.

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.