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BBC Master 512

[Master Computers]     [Computers ]


The Master 512 is a Master 128 with a Master 512 module installed. The Master 512 module had an Intel 80186 CPU, 512KB of memory and runs Digital Research DOS Plus. The Master 512 was comparable to PCs of the time and a lot of PC software could be configured to run on the Master 512, including dBase II, Wordstar 3.3, Supercalc and Turbo Pascal. The Master 512 module cost £399 (inc VAT).

Manuals and documents

 The Acorn documentation for the Master 512 was a bit sparse and was supplemented by Dabs Press titles Master 512 User Guide and Master 512 Technical Guide (see pictures).

Here is the Acorn leaflet Open Up To The World of MS-DOS .

In January 1987 Practical Computing published a review titled "BBC Master 512 & Compact ".

For documents for all Master computers see Master Computers .

Master 512

I bought my Master 512 on ebay in April 2002, and have subsequently bought the Dabs Press titles and other software for the 512. The Master 512 came with the Acorn 2 Button Mouse for use with the GEM GUI
Here are some photographs:

Master 512  

Master 512

Master 512 with a plinth with 2x 5.25" disc drives and an Acorn monitor. The Master 512 boots DOS Plus from disc and is waiting for a disc in drive A.

Master 512 loading DRDOS  

Master 512 loading DR DOS Plus

Master 512 booting Digital Research DOS Plus from drive A. I had to change the monitor from the Microvitec Cub to the Acorn AKF11 because the Cub's resolution was not good enough to photograph there screens clearly.

Master 512 DRDOS loaded

 Master 512 DR DOS Plus loaded

Master 512 with Digital Research DOS+ loaded. The last line on the screen is the A> command prompt. Also on the right of the keyboard is the Acorn 2 button mouse for use with GEM and other GUI environments.

Master 512 GEM loaded  

Master 512 GEM loaded

Master 512 running GEM, mouse to the right. GEM was Digital Research's alternative to Microsoft Windows and was also used in the Atari ST range. Although it worked, I remember having to continually swap discs. I think it was much better suited to use with a Winchester disc.

Master 512 opened  

Master 512 case opened

Master 512 with the case open. The Master 512 (80186 co-processor) module is in the center between the yellow tape round the battery pack and the speaker. The big square chip is the Intel 80186.

Acorn ADC08 80186 Co Processor  

Master 512 Module (Intel 80186 co-processor)

The 80186 co-processor module, the Ferranti TUBE ULA is on the left. The Intel 80186 CPU is the square IC in the center.

Dabs Press Guides

 Dabs Press Guides, the "missing" Manuals

The Dabs Press Master 512 User & Technical Guides provided an excellent pair of reference manuals for the Master 512. Acorn's Master 512 User Guide only covered the GEM environment. Whereas the Dabs Guides also covered the DOS+ environment and the 80186 co-processor in detail.

Acorn Master 512 Guide and DRDOS discs  

Acorn 512 Guide and DR DOS Plus discs

Acorn's Master 512 User Guide and the Digital Research DOS Plus discs.


Serial no.01-AMB15-0143103
Motherboard0243,000 issue 2
CPU clock2MHz
Disc controllerWD1772-PH
Disc Filing SystemADFS 1,50
DFS 2.24
OSOS 3.20
Co-processor board0243,200 Issue 1
Co-processor serial no.01-ADC08-018489
Co-processor CPUIntel 80186
Co-processor CPU clock8MHz
Co-processor memory512KB
Co-processor OSDigital Research DOS Plus with GEM 
MouseAcorn 2 button