The BBC Master was a home computer released by Acorn Computers in 1985. It was designed and built for the British Broadcasting Corporation (BBC) and was the succesor to the BBC Micro Model B.

The Master featured several improvements on its predecessor. The systems had 128Kb as standard, supported better graphics modes and had two cartridge slots mounted above the numerical keypad. It ran on the slightly improved 65C02 microprocessor rather than the 6502 used by the Model B. Although the Master had a certain degree of compatibility with the older models, there were still some problems running older programs.

Models

The Master was available in several different models.

Master 128

This was the standard issue computer. The 128 in the name referred to its 128Kb of memory.

Master Turbo

This was a Master with a second processor.

Master ET

The ET (Econet Terminal) system was designed for use in a network and as such had no tape or disk interfaces. The specific protocol involved was Acorn's Econet, standing for Economy Network.

with no tape or disk interfaces)

Master 512

This system boasted 512Kb memory and a second processor. It also had the ability to run [[DOS+]] and the GEM graphical user interface.

Master Compact

This model separated the keyboard from another unit which could be placed under the monitor. Only the ADFS file system could be used, preventing backward compatibility with DFS disks.

The unit under the monitor housed a 3.5 inch floppy disk drive and the system power supply. The remainder of the system was housed in the same unit as the keyboard, much like a conventional Master 128. The cartridge and cassette ports were removed as a space saving measure. The loss of the latter was a move Acorn later came to regret. Software for the Compact became very expensive (typically £20 for a game) due to the small user base.