A BBC Master 128 with monitor and disk drives. The cartridge slots can be seen above the numerical keypad and to the right of the speaker grille.

The BBC Master was a home computer released by Acorn Computers in early 1986. It was designed and built for the British Broadcasting Corporation (BBC) and was the successor to the BBC Micro Model B. Download high resolution version (1045x720, 660 KB)A BBC Master microcomputer with monitor and disk drives. ... Download high resolution version (1045x720, 660 KB)A BBC Master microcomputer with monitor and disk drives. ... Nineteen inch (48 cm) CRT computer monitor A computer display, monitor or screen is a computer peripheral device capable of showing characters and/or still or moving images generated by a computer and processed by a graphics card. ... A 3,5 inch diskette, removed from its casing A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ... Acorn Computers Ltd. ... 1986 (MCMLXXXVI) was a common year starting on Wednesday of the Gregorian calendar. ... This article is an overview article about the Crown chartered British Broadcasting Corporation formed in 1927. ... The BBC Micro, affectionately known as the Beeb, was an early home computer. ...

The Master featured several improvements on its predecessor. The systems had 128Kb RAM as standard, alleviating the shortage of available RAM which inter alia discouraged use of the best graphics modes in the original design, and had two cartridge slots mounted above the numerical keypad. Rather than the 6502 microprocessor used by the Model B it ran on the slightly improved 65C102: the cost of this CPU compatibility with the Model B was that the address bus was still only 16 bits, meaning that only 64Kb could be directly addressed at any one time and the remaining memory had to be paged in as required. However the 65C102's extra instructions allowed a little more to be shoehorned into the OS and BBC BASIC ROMs, limited by the memory architecture to 16Kb each. The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. ... CPU redirects here. ... The BBC Micro, affectionately known as the Beeb, was an early home computer. ... WDC 65C02 Microprocessor // Introduction The W65C02S is a low power, cost effective 8-bit microprocessor. ...

Although the Master was intended to be compatible with "legally written" software for the older models, there were some problems running older programs, particularly games. Conversely, although few programs were ever targeted specifically at Master series machines (except the Master 512), many later BBC games (and Master versions of earlier classics such as Elite) included "enhanced" features which took advantage of the extra memory. Elite is a seminal space trading computer game, originally published by Acornsoft in 1984 for the BBC Micro and Acorn Electron computers and subsequently ported to many others. ...

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 RAM, though it also featured 128Kb ROM.

Master Turbo

This was a Master with 4MHz 65C02 second processor card (which could be either bought with the machine or added to an existing Master 128).

Master ET

The ET (Econet Terminal) system was designed for use in a network and as such had no tape or disk interfaces but had the Econet interface fitted as standard (it was usually an option requiring the addition of extra chips). It was based on a Master 128 main board and the components for missing interfaces were simply not fitted (though there was nothing stopping them being added later by someone with appropriate soldering skills). Econet is an abbreviation of Economy Network. ...

Master 512

This system boasted a second processor card with an 8MHz Intel 80186 and 512Kb memory. It also had the ability to run DOS+ and the GEM graphical user interface. An Intel 80186 Microprocessor The 80186 architecture. ... DOS Plus (also known as DOS+) is an operating system written by Digital Research, first released in 1985. ... GEM (Graphical Environment Manager) was a windowing system created by Digital Research, Inc. ...

Master Compact

A Master Compact with power supply and disk drive in a separate unit underneath the display.

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 (though it was possible to load a 1770 DFS ROM into sideways RAM, or to insert a ROM or EPROM containing it). The Master Compact also utilised a limited re-burn EEPROM, instead of the battery backed CMOS memory found in the other models. Download high resolution version (909x969, 172 KB)A BBC Master Compact microcomputer, part of the BBC Master series. ... Download high resolution version (909x969, 172 KB)A BBC Master Compact microcomputer, part of the BBC Master series. ... A 3,5 inch diskette, removed from its casing A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ... Nineteen inch (48 cm) CRT computer monitor A computer display, monitor or screen is a computer peripheral device capable of showing characters and/or still or moving images generated by a computer and processed by a graphics card. ... The Advanced Disc Filing System (ADFS) is a computing file system particular to the Acorn computer range, although the Linux kernel does have support for this format. ... The Disc Filing System (DFS) is a computer filing system developed by Acorn Computers Ltd. ...

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. A 3,5 inch diskette, removed from its casing A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ...

The Compact included a copy of Acorn's first public GUI interface. No commercial software or utilities, others than those included on the Welcome disk were ever made available for the system.

The Master Compact GUI

Image File history File links BBB_MC_GUI_2. ... Image File history File links BBB_MC_GUI_2. ...

Notable applications

The BBC Master Turbo was the basic hardware platform required to run the 1986 BBC Domesday Project. Also required were a SCSI interface and videodisc player, both of which were designed specifically for this application. The BBC Domesday Project was a partnership between Acorn Computers Ltd, Philips, Logica and the BBC to mark the 900th anniversary of the original Domesday Book, an 11th century census of England. ... SCSI stands for Small Computer System Interface, and is a standard interface and command set for transferring data between devices on both internal and external computer buses. ... Videodisc (or video disc) is a general term for a laser- or stylus-readable random-access circular disc that contains both audio and video signals recorded in an analog form. ...

Specifications

• 2 MHz Rockwell R65C102 processor
• 128 KB ROM, consisting of 16 KB MOS (Machine Operating System), always accessible, and seven 16 KB ROMs, any one of which could be paged into memory at a time:
  • 16 KB BBC BASIC
  • 16 KB Disk Filing System
  • 16 KB Advanced Disk Filing System
  • 16 KB Acornsoft View (word processor)
  • 16 KB Acornsoft ViewSheet (spreadsheet)
  • 16 KB EDIT (editor)
  • 16 KB MOS extras (such as the cassette filing system)
• 128 KB RAM, comprising:
  • 32 KB main user program/data storage
  • 20 KB video memory (paged over main user RAM)
  • 12 KB OS workspace (paged over main user RAM)
  • 64 KB workspace accessible to user machine code applications (in four 16 KB blocks any one of which could be paged into memory if BBC BASIC and the other paged ROMs were not required)
• Full-travel keyboard with a top row of ten red-orange function keys  f₀ − f₉ and AT-style numeric keypad
• Highly configurable graphics display based on the Motorola 6845. Unlike on the original BBC Micro, separate video RAM was used so that choosing a high-resolution mode did not reduce the amount of available user RAM. (However, user RAM could still be used as the video buffer if required, in order to allow effects such as double buffering.) Eight graphics modes were provided by the system ROM:
  • Modes 0 to 6 could display a choice of colours from a logical palette of sixteen, though only eight physical colours could really be generated by the hardware; the eight RGB colours (black, red, green, yellow, blue, magenta, cyan, white) and said colours in a flashing state;
  • Mode 7's Teletext capability was provided by a Mullard SAA5050 Teletext chip.

• Four independent sound channels (one noise and 3 melodic) using the Texas Instruments SN76489 sound chip
• Built-in hardware support included:
  • pluggable ROMs, directly or via cartridge slots
  • floppy disk drives (both DFS and the newer ADFS supported) with WD1770 disk controller
  • tape interface (with motor control), using a variation of the Kansas City standard data encoding scheme
  • Centronics parallel printer
  • serial communication (using RS-423, a superset of RS-232)
  • display output for TV, RGB or 1v p-p video monitor
  • A 15 pin 'D shaped' port with four analogue inputs (suitable for two joysticks, four digital/contact ports (for buttons) and a special Light pen input, and
  • proprietary "Tube" interface for internal or external second CPU (in the Master 512 model, an 80186 was used; other options included a 3 MHz extra 6502, a Zilog Z80 for e.g. CP/M, an NS32016, an ARM1, and others)
  • a 16 pin IDC style "user port" consisting of 8 general purpose digital I/O pins (and two special ones) mapped directly into the 6502 via, and
  • generic expansion through the "1 MHz bus".

Several of the inputs were directly wired to specific registers in order to allow the hardware to do some of the heavy lifting. For example the light-pen input would directly halt a counter which was started by the start of the vertical sweep of each display refresh, making calculation of where the lightpen was touching the screen little more than a simple divide/remainder operation. Likewise, the motor control relay for the audio cassette tape was controlled by a simple command and could be readily used in numerous applications. MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... Rockwell can refer to: Rockwell International - a defense company in the United States Rockwell Automation - an industrial automation company that descended from Rockwell International Rockwell Collins - a communications and aviation electronics company that also descended from Rockwell International Willard Rockwell - businessman who helped shape and name what became Rockwell International... WDC 65C02 Microprocessor // Introduction The W65C02S is a low power, cost effective 8-bit microprocessor. ... Read-only memory (ROM) is a class of storage media used in computers and other electronic devices. ... BBC BASIC was developed in 1981 as a native programming language for the MOS Technology 6502 based Acorn BBC Micro home/personal computer, mainly by Roger Wilson. ... The Disc Filing System (DFS) is a computer filing system developed by Acorn Computers Ltd. ... The Advanced Disc Filing System (ADFS) is a computing file system particular to the Acorn computer range, although the Linux kernel does have support for this format. ... ViewSheet was a spreadsheet program produced in the 1980s by Acorn Computers for use with their series of microcomputers. ... A four-megabyte RAM card for the VAX 8600 computer (circa 1986). ... A computer keyboard is a peripheral modeled after the typewriter keyboard. ... A 102-key PC US English keyboard layout with the function keys in orange. ... The IBM Personal Computer/AT (IBM 5170), more commonly known as the IBM AT and also sometimes called the PC AT or PC/AT, was IBMs second-generation PC, designed around the Intel 80286 microprocessor running at 6 MHz and released in 1984. ... The Motorola 6845 (commonly MC6845) is a video address generator first introduced by Motorola and used in the CGA and EGA video adapters, Amstrad CPC and BBC Micro. ... The BBC Micro, affectionately known as the Beeb, was an early home computer. ... In computer graphics, double buffering (sometimes called ping-pong buffering) is a technique used to reduce or remove visible artifacts from the drawing process. ... The RGB color model utilizes the additive model in which red, green, and blue light are combined in various ways to create other colors. ... A BBC Ceefax page from the 10th September 1999. ... Mullard Limited was a British manufacturer of electronic components. ... The SN76489 Programmable Sound Generator (PSG) is a TTL compatible four-channel sound chip from Texas Instruments. ... A sound chip is an integrated circuit (i. ... A 3,5 inch diskette, removed from its casing A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ... The Disc Filing System (DFS) is a computer filing system developed by Acorn Computers Ltd. ... The Advanced Disc Filing System (ADFS) is a computing file system particular to the Acorn computer range, although the Linux kernel does have support for this format. ... The WD1770 is the first in a line of floppy disc controllers produced by Western Digital. ... Typical 60-minute Compact Cassette. ... The Kansas City standard (abbreviated KCS) for storage of digital (micro)computer data on an ordinary compact audio cassette is also known as the BYTE standard, from its connection with BYTE magazine, or the Processor Technology CUTS (PT Computer Users Tape Standard). ... Centronics logo 23 June 1986 Centronics logo 1971 Centronics Data Computer Corporation was a pioneering American manufacturer of computer printers, now remembered only for the parallel interface that bears their name. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... For other uses, see Joystick (disambiguation). ... A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with the computers CRT monitor. ... The 80186 is a microprocessor that was developed by Intel circa 1982. ... The MOS Technology 6502 is an 8-bit microprocessor designed by MOS Technology in 1975. ... One of the first Z80 microprocessors manufactured; the date stamp says well before July 1976. ... CP/M (Command Processor for Microcomputers) was an operating system for Intel 8080/85 and Zilog Z80 based microcomputers. ... The 320xx is a series of microprocessors from National Semiconductor (NS, Natsemi). The 320xx processors have a coprocessor interface which allows coprocessors such as FPUs and MMUs to be attached in a chain. ... The ARM architecture (originally the Acorn RISC Machine) is a 32-bit RISC processor architecture that is widely used in a number of embedded designs. ...