• CPU: MOS 6502 1.8 MHz
• RAM: 16 kb [Model A], 32 kb [Model B], 64 kb [Model B+]
• ROM: 32 kb
• Text Modes: 80 x 32/25 (2 colors) / 40 x 32/25 (2 or 4 colors) / 20 x 32 (16 colors) / 40 x 25 (Teletext display)
• Graphics Modes: 640 x 256 (2 colors) / 320 x 256 (4 colors) / 160 x 256 (16 colors)
• Colors: 16 (8 colors + flashing option)
• Sound: 3 channels + 1 noise channel, 7 octaves
• I/O Ports: UHF TV out, BNC video out, RGB video out, RS423, Cassette, Analogue In (DB15), Econet port, TUBE interface, 1MHz BUS, User port, Printer port, Disk-drive connector
• Keyboard: Full-stroke QWERTY keyboard, 64 keys, 10 function keys, arrow keys
• Built In Language: BBC Basic
• Peripherals: Controller card for 1 to 4 5” 1/4 F.D. drives, Floppy disk unit 5” 1/4 250K, Numerical cassette recorder 100K, Second 6502 microprocessor with card

MESS currently supports the following computers:

• bbca [BBC Micro Model A]
• bbcb [BBC Micro Model B]
• bbcbp [BBC Micro Model B+ 64K]
• bbcbp128 [BBC Micro Model B+ 128K]

For each driver, MESS allows to use various devices:

• a “cassette” (cass) device which supports tapes in .wav, .csw and .uef format
• two floppy devices, “floppydisk1” (flop1) and “floppydisk2” (flop2), which support disks in .ssd, .bbc and .img format
• four cartridge devices, “cartridge1” (cart1) to “cartridge4” (cart4), which support cart dumps in .rom format

Also notice that the “printer” (prin) is supported as well.

You can type

*CAT

to list the content of a disk, and then

CHAIN"filename"

to run the filename program.

These systems require full keyboard emulation to work correctly. At startup, full keyboard emulation mode is enabled by default. Whilst in full keyboard emulation mode, some key associated functionality may be disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the “Scroll Lock” key (by default).

Original Keyboard: Full-stroke QWERTY keyboard, 64 keys, 10 function keys, arrow keys

f0   f1   f2   f3   f4   f5   f6   f7   f8   f9  BREAK 


  ESCAPE   1!   2"   3#   4$   5%   6&   7'   8(   9)   0   -=   ^~   \|   Right   Left 


    TAB      Q    W    E    R    T    Y    U    I    O    P    @    [{   £_    Up    Down

 CAPS
 LOCK   CTRL    A    S    D    F    G    H    J    K    L    ;+   :*   ]}   RETURN

 SHIFT
 LOCK    SHIFT     Z    X    C    V    B    N    M    ,<   .>   /?  SHIFT  DELETE  COPY 

                                      SPACEBAR

Notice that at the bottom left corner (to the left of the Spacebar) there are three LEDs: “ Cassette Motor”, “Caps Lock” and “Shift Lock”.

The keys ^~, \|, [{, ]} and £_ can be somewhat confusing because they seem to generate the wrong characters on screen. The problem is that there are two international standards for displayed characters (Teletext and ASCII) and the BBC Microcomputer can display either. MODE 7 generates the Teletext display characters and MODES 0 to 6 show the ASCII characters. In both cases, the computer recognises the key correctly regardless of what is displayed on the screen.

In MESS, emulations starts in MODE 7. To correctly see the characters, type at the BASIC prompt MODE n (n between 0 and 6) and press enter.

The Acorn BBC model A was the successor of the Acorn Atom and its first name was Acorn Proton. It was a very popular computer in the UK and was widely used in schools, but it didn't have great success elsewhere (even though it did have great features, it was too expensive).

The Model A lacked some of the connectors of the Model B/B+ (User port, Tube, …) on the underside.

This computer got its name because in 1980, the BBC decided to start a computer literacy television series. The network realized that, with more powerful and increasingly inexpensive microcomputers, it would soon be possible to create them with enough computing power to offer their owners personal hands-on experience with microcomputers at an affordable price. The BBC considered the NewBrain computer and rejected it. Acorn and Sinclair Research, along with other companies, then submitted designs, and Acorn won. The BBC model B was then used almost universally in British schools from its birth into the 90's.

It was followed in 1982 by the Acorn BBC model B. The Model B had the same features but had 32 KB RAM (expandable to 64K).

The “Tube” was an expansion port which was designed to connect other processors to the BBC (6502, Z80, 68000 or ARM 1 RISC). An interface card was specially designed for the tube. It used another 6502 and a Z80.

One of its most popular peripherals was the “Torch” floppy disk unit, a 5.25” floppy disk drive with a Z80 which allowed the BBC to use CP/M software.

Acorn also made a “cheap” version of the BBC (fewer connectors & video modes) called Acorn Electron.

In 1985, the Acorn BBC Model B+ was released. The Model B+ had new features : 64K of RAM instead of 32 KB and internal circuitry for the Econet and Disk Drive as standard (both available as an upgrade in the models A and B). The later models included disk support as standard, using either an 8271 or a 1770 disk controller.

It was then followed by the BBC Master.

(info from old-computers.com)

• BBC Documentation Project
• The BBC Lives!
• BBC Micro at old-computers.com

• B-EM (Windows, MS-DOS, Mac OS X)
• BeebEm
• model-b