Olivetti Prodest PC128S

Pubblicato: giugno 24, 2011 in Acorn, Olivetti

Versione italiana importata da Olivetti del BBC Master Compact, completamente compatibile (o quasi)

From Wikipedia, the free encyclopedia

Type 8-bit Microcomputer
Release date Early 1986
Discontinued 1994
Operating system Acorn MOS, optional DOS Plus
CPU MOS Technology 65SC12, optional Intel 80186 or 65C102 depending on model
Memory 128 kB–512 kB

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. The Master 128 remained in production until 1993.[1]


The Master featured several improvements on its predecessor. The systems had 128 kB RAM as standard, alleviating the shortage of available RAM which had amongst other things discouraged use of the best graphics modes in the original design, and had two cartridge slots mounted above the new numerical keypad. Rather than the MOS Technology 6502 microprocessor used by the Model B it ran on the slightly improved 65SC12:[2] the cost of this CPU compatibility with the Model B was that the address bus was still only 16 bits, meaning that only 64 kB could be directly addressed at any one time and the remaining memory had to be paged in as required. However the 65SC12’s extra instructions allowed a little more to be shoehorned into the OS and BBC BASIC ROMs, limited by the memory architecture to 16 kB each.

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.


The Master was available in several different models.

Master 128

This was the standard issue computer. The 128 in the name referred to its 128 kB of RAM, though it also featured 128 kB ROM.

Master Turbo

This was a Master with 4 MHz 65C102 coprocessor card (which could be either bought with the machine or added to an existing Master 128).

Master AIV

The Master AIV (Advanced Interactive Videodisc) was essentially a Master Turbo model with a SCSI interface and a VFS (Videodisc Filing System) ROM added, and formed the basis of the BBC Domesday System. Although normally supplied as part of a Domesday System, with LaserVision player, Domesday videodiscs, monitor and trackerball included, an upgrade kit was also available to turn a normal BBC Master into a Domesday System.

Master ET

The ET (Econet Terminal) system was designed for use in a network and as such had no interfaces except RGB and Composite video, plus an Econet interface module and ANFS fitted as standard (it was usually an option). It used the same main circuit board as the Master 128, but the components for missing interfaces were simply not fitted (though there was nothing stopping them being added later by someone with appropriate soldering skills). The internal ROM also contained much less software than that of the Master 128.

Master 512

This system boasted a coprocessor card with a 10 MHz Intel 80186 and 512 kB memory. It also had the ability to run DOS+ and the GEM graphical user interface.

Master Scientific

The Master Scientific was announced at the time of the BBC Master’s launch, but was not produced. It was to have an 8 MHz 32016 coprocessor with 32081 floating point processor and 512 kB of RAM, running the PANOS operating system. This was similar to the previous external 32016 Second Processor.

Master Compact

This model separated the keyboard from another unit which could be placed under the monitor. Only the ADFS filing system was supplied as standard, though it is possible to load a 1770 DFS ROM into sideways RAM, or to insert a ROM or EPROM containing it. The Compact also utilised a limited re-burn EEPROM, instead of the battery backed clock plus CMOS memory found in the other models, and hence had no real time clock of its own (the time could be fetched via Econet where available).

The unit under the monitor housed a 3½” 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, and RS-232 hardware not populated on the circuit board as standard. A multifunction mouse and joystick port was provided as a 9 pin D type with its function configured in software.

Software for the Compact became very expensive (typically £20 for a game) due to the much lower demand for the 3½” disk format (5¼” was the de facto standard for the Master and earlier BBC Micro).

The Compact included Acorn’s first public GUI. Little commercial software, beyond that included on the Welcome disk, was ever made available for the system.



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