View source for Engineering:BBC Master

{{Short description|Microcomputer}}
{{Infobox information appliance
| name = BBC Master Series
| title = 
| aka = 
| logo = 
| image = Acorn BBC Master Series.jpg
| caption = Acorn BBC Master 128
| developer = 
| manufacturer = 
| family = 
| type = [[8-bit|8-bit]] [[Microcomputer]]
| generation = 
| releasedate = Early {{Start date and age|1986}}
| lifespan = 
| price = 
| discontinued = {{End date|1994}}
| unitssold = 
| unitsshipped = 
| media = 
| os = [[Software:Acorn MOS|Acorn MOS]], optional [[Software:DOS Plus|DOS Plus]]
| power = 
| soc = 
| cpu = MOS Technology 65SC12, optional second processor [[Engineering:Intel 80186|Intel 80186]] or 65C102 depending on model
| memory = 128&nbsp;[[Kilobyte|KB]]–512&nbsp;KB
| storage = 
| memory card = 
| display = 
| graphics = [[Engineering:Motorola 6845|Motorola 6845]], [[Engineering:Mullard SAA5050|Mullard SAA5050]]
| sound = [[Engineering:Texas Instruments SN76489|Texas Instruments SN76489]]
| input = 
| controllers = 
| camera = 
| touchpad = 
| connectivity = 
| platform = 
| service = 
| dimensions = 
| weight = 
| topgame = 
| compatibility = 
| predecessor = [[Engineering:BBC Micro|BBC Micro Model B]]
| successor = [[Engineering:Acorn Archimedes|Acorn Archimedes]]
| related = 
| website = <!--{{URL|example.org}}-->
}}
The '''BBC Master''' is a home computer released by [[Company:Acorn Computers|Acorn Computers]] in early 1986.<ref name="acornuser198602">{{ cite news | url=https://archive.org/details/AcornUser043-Feb86/page/n8/mode/1up | title=Master: the new BBC | work=Acorn User | date=February 1986 | access-date=25 October 2020 | pages=7 }}</ref> It was designed and built for the British Broadcasting Corporation (BBC) and was the successor to the [[Engineering:BBC Micro|BBC Micro Model B]]. The Master 128 remained in production until 1993.<ref name="acorn_sn72">{{ cite press release | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/SN/Acorn_SalesNews72.pdf | title=Sales News Issue 72 | publisher=Acorn Computers Limited | last1=Bottomley | first1=Tracy | date=19 April 1993 | access-date=10 October 2020 }}</ref><ref name="acornuser199306_master128">{{ cite news | url=https://archive.org/details/AcornUser131-Jun93/page/n8/mode/1up | title=Acorn Kills off BBC Master 128 | work=Acorn User | date=June 1993 | access-date=15 June 2021 | pages=7 }}</ref>

== Design ==

The Master series featured several improvements over earlier BBC Micro models. Rather than the MOS Technology 6502 [[Central processing unit|microprocessor]] used by the [[Engineering:BBC Micro|Model B]], Master series models used the slightly improved 65C12.<ref name="acorn_APP83">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP83_TheMasterSeries.pdf | title=The Master Series | publisher=Acorn Computers Limited | date=1986 | access-date=10 October 2020 | pages=2 }}</ref> Fabricated using [[Engineering:CMOS|CMOS]] technology, the 65C12 used less power than the 6502 and offered somewhat better performance, reportedly "almost as fast" as the original 3&nbsp;MHz 6502 second processor for the BBC Micro.<ref name="yourcomputer198603_master128">{{ cite magazine | url=https://archive.org/details/Your_Computer_Magazine_Issue_V603/page/66/mode/2up | title=The master 128 | magazine=Your Computer | date=March 1986 | access-date=13 June 2023 | pages=66–67 }}</ref> The systems had {{val|128|ul=KB}} of dynamic RAM as standard, alleviating the shortage of available RAM which had previously discouraged use of the display modes offering the highest quality graphics on earlier models. Of the total 128&nbsp;KB of RAM, 64&nbsp;KB was provided as standard RAM, being used for applications, screen memory and system workspace. Another 64&nbsp;KB was provided in the form of four 16&nbsp;KB bank-switched pages of sideways RAM.<ref name="master_sm">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_MasterSM.pdf | title=British Broadcasting Corporation Master Series Microcomputer Service Manual | publisher=Acorn Computers Limited | date=April 1986 | access-date=10 October 2020 | issue=1 | pages=15–18 }}</ref>

Of the 64&nbsp;KB standard RAM, the lower region of 32&nbsp;KB was employed in a fashion familiar from earlier models, providing workspace for languages, applications and the system, also hosting screen memory for many programs, particularly games. While the 65C12 ensured software compatibility with the Model B, it perpetuated the architectural limitations of the earlier models, with a 16-bit address bus providing direct access to only 64&nbsp;KB of memory at a time, thus necessitating the use of paging mechanisms to make additional RAM available. Access to the upper 32&nbsp;KB region of standard RAM was provided by one such mechanism to take over some of the demands made on the lower memory region by the system.<ref name="acornuser198603_master"/> It was divided into three separate regions, each with a codename, following Acorn's architectural traditions:<ref name="master_sm"/>

{| class="wikitable"
! Codename !! Size !! Physical address range !! Logical address range !! Description
|-
| LYNNE || 20&nbsp;KB || {{mono|0xB000–0xFFFF}} || {{mono|0x3000–0x7FFF}} || Shadow RAM (freeing conventional screen memory for use)
|-
| HAZEL || 8&nbsp;KB || {{mono|0x9000–0xAFFF}} || {{mono|0xC000–0xDFFF}} || Paged ROM workspace (filing system workspace)
|-
| ANDY || 4&nbsp;KB || {{mono|0x8000–0x8FFF}} || {{mono|0x8000–0x8FFF}} || System workspace (function key, graphics system and character definitions)<ref name="acornuser198603_master"/>
|}

20&nbsp;KB of this upper region could be assigned as [[Shadow RAM (Acorn)|shadow RAM]] to host the screen memory, freeing up the conventional screen memory region for applications. The remaining 12&nbsp;KB was available to the system for workspace, freeing up memory that would normally be claimed by ROMs such as filing systems. The cumulative effect of enabling shadow RAM and using the upper memory for workspace made almost 29&nbsp;KB available for normal programs and was said to "transform the machine" from its predecessors.<ref name="acornuser198603_master">{{ cite magazine | url=https://archive.org/details/AcornUser044-Mar86/page/n74/mode/1up | title=Master Work | magazine=Acorn User | last1=Smith | first1=Bruce | date=March 1986 | access-date=26 May 2023 | pages=73–77 }}</ref>

Use of the 64&nbsp;KB of sideways RAM favoured the installation of ROM images into each of the 16&nbsp;KB banks, with Acorn having announced a "ROM licencing scheme" to authorise the use of the company's ROM-based software in RAM. However, a version of BASIC known as BAS128, previously released for the BBC Model B+ 128, was provided on disk and was able to use the full 64&nbsp;KB of sideways RAM as workspace, thus expanding the memory available to BASIC considerably. Other Acorn languages did not support this arrangement, however.<ref name="acornuser198603_master"/>

Although the extra instructions of the 65C12 permitted slightly greater code density, the [[Operating system|OS]] and BBC BASIC ROMs, still limited by the memory architecture to 16&nbsp;KB each, were augmented by additional ROMs. In total, the updated OS, known as MOS 3.2 occupied 35&nbsp;KB and incorporated features previously introduced in the Graphics Extension ROM for the BBC Micro, along with additional commands and system calls plus a variety of enhancements. The improved version of BBC Basic was named Basic 4, fixing bugs in the earlier Basic 2 and introducing enhancements and new functionality such as a {{kbd|TIME$}} variable yielding the current date and time in a concise but human-readable format. The inclusion of a real-time clock to keep the date and time was a notable built-in feature of the Master 128 and derived models, together with 50 bytes of battery-backed CMOS RAM to retain details of the machine's configuration while powered off.<ref name="acornuser198603_master"/>

To hold the expanded OS and BASIC, the Master 128 was fitted with a ROM device having a capacity of one megabit, or 128&nbsp;KB. Alongside the OS and BASIC, a text editor suitable for writing programs was included, DFS and ADFS provided filing system support to access files stored on disk, the View and ViewSheet applications respectively offered word processing and spreadsheet functionality. A terminal emulator was also included to support serial communications over the machine's RS423 port or the optional internal modem.<ref name="acornuser198603_master"/>

The Master series largely carried forward many of the core architectural features of the earlier BBC Micro models. The sound chip used in earlier models was retained, but the dedicated speech interface was omitted, with a "plug-in speech cartridge" anticipated by one reviewer for the Master 128. Although chips such as the 6522 VIA and 6845 CRTC were retained in the Master series, much of the discrete logic of earlier models was consolidated into CMOS [[Gate array|gate array]] chips to perform tasks such as handling the keyboard, input/output and some display functions. This left an impression of the inside of the Master 128 being "another world" compared to the original BBC Micro, featuring fewer but larger chips.<ref name="acornuser198603_master"/>

In terms of expansion ports, the Master 128 retained all of the standard interfaces of the BBC Micro. One notable addition to the Master 128 was that of an internal modem socket permitting the installation of a modem without occupying the machine's RS423 serial port. An Econet interface could also be fitted internally at a relatively low cost of £49 including VAT. However, the main addition to the Master 128's expansion capabilities was the inclusion of an internal connector for second processor expansions employing Acorn's Tube interface. The first of such internally connected second processors, known as co-processors, was the Turbo co-processor featuring a 4&nbsp;MHz 65C102 and 64&nbsp;KB of RAM,<ref name="acornuser198603_master"/> later followed by the Master 512 upgrade board featuring a 10&nbsp;MHz 80186 and 512&nbsp;KB of RAM.<ref name="APP110"/>

Outwardly, the Master series models added a numeric keypad alongside the familiar keyboard, and the Master 128 and its variants incorporated two cartridge slots behind the keypad, these employing sockets that provided a superset of the [[Engineering:Acorn Electron|Acorn Electron]] [[Engineering:Acorn Electron#Acorn Plus 1|Plus 1]] cartridge interface capabilities, supporting the use of physically compatible Electron cartridges,<ref name="acorn_an37">{{ cite tech report | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/AN/037.pdf | title=Functional Differences Between Master 128 and BBC Models B and B+ | publisher=Acorn Computers Limited | date=3 August 1992 | access-date=31 March 2021 | pages=8 | last1=Bell | first1=D. J. }}</ref> but also supporting enhanced electrical characteristics for some of the cartridge connector pins.<ref name="acorn_an35">{{ cite tech report | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/AN/035.pdf | title=BBC Master 128 Cartridge Interface | publisher=Acorn Computers Limited | date=3 August 1992 | access-date=31 March 2021 | last1=Bell | first1=D. J. }}</ref>

Although the Master series 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 ''[[Software:Elite (video game)|Elite]]'') included enhanced features which took advantage of the extra memory.

=== ROM upgrade ===

An upgrade to the Master 128 operating system ROM was released by Acorn in early 1990, providing bug fixes and some performance and functionality enhancements, with the filing systems benefiting in particular. View, Viewsheet and Edit applications all saw various levels of enhancement. One notable feature was the introduction of "relocatable" language (or application) ROM support, permitting appropriately written ROM-based software to automatically take advantage of a second processor, if fitted. Priced at around £45, it was noted that since the copyright message in the ROM was dated 1988 and the manual dated October 1989, such an upgrade might have been more widely adopted by users (and the relocatable ROM feature adopted by software producers) had it been released earlier, with the Master Compact ROM having already benefited from some of the featured improvements, such as direct entry of "foreign characters" or "top-bit-set characters" from the keyboard.<ref name="acornuser199003_master">{{ cite news | url=https://archive.org/details/AcornUser092-Mar90/page/n133/mode/2up | title=Return of the Master | work=Acorn User | date=March 1990 | access-date=7 May 2021 | last1=Atherton | first1=David | pages=132–133 }}</ref>

=== Battery charging hazard ===

Acorn issued a safety warning for the Master 128 and ET models in 1986 regarding the battery installed in the machine. This battery was in a circuit that would charge the battery "contrary to the recommendations of the battery manufacturer".<ref name="acornuser198609_battery">{{ cite magazine | url=https://archive.org/details/AcornUser050-Sep86/page/n143/mode/1up | title=If you purchased a Master 128 or ET between January-May 1986 please read on. | magazine=Acorn User | date=September 1986 | access-date=26 January 2024 | pages=142 }}</ref> Due to the risk of combustion with this particular lithium battery arrangement, Acorn introduced a remedy involving its replacement with a different solution using three alkaline batteries fitted next to the power supply.<ref name="acornuser198705_battery">{{ cite magazine | url=https://archive.org/details/AcornUser058-May87/page/n8/mode/1up | title=Repeated Master fire warnings | magazine=Acorn User | date=May 1987 | access-date=26 January 2024 | pages=7 }}</ref>

== Models ==
[[File:VCF 2010 Domesday tray open.jpg|upright=0.9|right|thumb|The BBC Master as part of a BBC Domesday System ]]

The Master series consisted of several different models, all of which apart from the Master Compact were variants of the same basic design.<ref name="acornuser198602a">{{ cite news | url=https://archive.org/details/AcornUser043-Feb86/page/n12/mode/1up | title=Plug-in boards boost power | work=Acorn User | date=February 1986 | access-date=25 October 2020 | pages=11 }}</ref>

=== Master 128 ===
This was the "foundation of the new BBC range" when launched.<ref name="acornuser198602a" /> The 128 in the name referred to its 128&nbsp;KB of RAM, though it also featured 128&nbsp;KB [[Read-only memory|ROM]]. A disc interface was fitted, but the drives themselves were not included in the base product, these being offered by third parties and by Acorn as an official expansion.<ref name="acorn_app94">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP94_MasterDiscDriveUnit.pdf | title=Disc Drive Unit | publisher=Acorn Computers Limited | date=1986 | access-date=30 January 2021 }}</ref> The machine was introduced at a price of £499.<ref name="APP87"/>

=== Master Turbo ===
This was a Master 128 with 4&nbsp;MHz 65C102 coprocessor card (which could be either bought with the machine or added to an existing Master 128). This upgrade cost £125 when introduced.<ref name="APP87"/>

=== Master AIV ===
[[File:Acorn 8-bit microcomputers (cropped) BBC Master AIV.jpg|thumb|BBC Master AIV]]
The Master AIV (Advanced Interactive Videodisc) was essentially a Master Turbo model with a [[Engineering:SCSI|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 [[Engineering:Videodisc|videodisc]]s, monitor and [[Trackball|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 color model|RGB]] and [[Composite video]], plus an [[Engineering:Econet|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 [[Read-only memory|ROM]] also contained much less software than that of the Master 128. This reduced configuration allowed the machine to be priced somewhat cheaper than the Master 128, being introduced at £399.<ref name="APP87"/>

=== Master 512 ===
This system boasted a coprocessor card with a 10&nbsp;MHz [[Engineering:Intel 80186|Intel 80186]] and 512&nbsp;KB memory. It also had the ability to run [[Software:DOS Plus|DOS Plus]] and the [[Software:Graphics Environment Manager|GEM]] graphical user interface.<ref name="acorn_APP83" /> The coprocessor card was introduced at £499 as an upgrade to the Master 128, but its price was subsequently reduced to £399.<ref name="APP87">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP87_RetailPriceListJuly86.pdf | title=Acorn Computers Limited Retail Price List July 1986 | publisher=Acorn Computers Limited | date=July 1986 | access-date=25 October 2020 | pages=1 }}</ref>

The competitiveness of the Master 512 was constrained by its compatibility with various DOS applications, with this being limited by "protection and direct use of IBM hardware" by some applications.<ref name="acornuser198609" /> The additional memory requirements of DOS Plus, when compared to those of [[Software:IBM PC DOS|PC DOS]], and the requirements of the GEM desktop caused potential problems when running some applications, although memory expansions existed to mitigate such problems. System call compatibility was only assured for MS-DOS and PC DOS 2.1, but other DOS versions were not supported, and undocumented system call usage ("fairly rare, but does include some Microsoft packages") could cause applications to run incorrectly. Software written for later GEM versions would also not necessarily run correctly.<ref name="acorn_an049">{{ cite tech report | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/AN/049.pdf | title=Master 512:  Applications Compatibility and Software List | publisher=Acorn Computers Limited | date=5 August 1992 | access-date=31 March 2021 }}</ref>

A product by Shibumi Software called Problem Solver aimed to address various compatibility issues related to the increased speed of the coprocessor relative to a traditional IBM PC, display and keyboard differences (also supporting the BBC Model B keyboard for users of that machine with the co-processor attached), the behaviour of "memory resident packages" such as Sidekick, and the behaviour of particular applications. The product reportedly allowed well-known programs such as Ashton Tate's [[DBase#dBase III|dBase III]] and Borland's [[Software:Turbo C|Turbo C]] and Turbo Prolog to work on the coprocessor.<ref name="acornuser198905_shibumi">{{ cite news | url=https://archive.org/details/AcornUser082-May89/page/n130/mode/1up | title=DOS Solutions | work=Acorn User | date=May 1989 | access-date=4 May 2021 | last1=Futcher | first1=Dave | pages=129–130 }}</ref>

To remedy compatibility issues caused by a lack of memory, one company, Essential Software, provided an upgrade service augmenting the fitted RAM of the Master 512 upgrade with four 1&nbsp;megabit devices providing 512&nbsp;KB to yield a total of 1&nbsp;MB of RAM. Priced at £99, and also compatible with Problem Solver, the upgrade overcame the elevated memory requirements of DOS Plus relative to MS-DOS and also allowed the system to meet the requirement of some applications to have 640&nbsp;KB of memory available. Consequently, GEM 3, [[Software:Ventura Publisher|Ventura Publisher]], [[Software:WordPerfect|WordPerfect]] 5.0 and [[DBase#dBase IV|dBase IV]] were all reported as being compatible.<ref name="acornuser199009_essential">{{ cite news | url=https://archive.org/details/AcornUser098-Sep90/page/n124/mode/1up | title=Building up the Beeb | work=Acorn User | date=September 1990 | access-date=8 May 2021 | last1=Futcher | first1=Dave | pages=123 }}</ref> The company also produced a selection of utilities for the Master 512,<ref name="acornuser199101_essential">{{ cite news | url=https://archive.org/details/AcornUser102-Jan91/page/n133/mode/2up | title=Easy PC | work=Acorn User | date=January 1991 | access-date=11 May 2021 | last1=Futcher | first1=Dave | pages=132–133 }}</ref> including the Co-Processor Filing System (CPFS) which allowed the 512&nbsp;KB of coprocessor memory to be used as a RAM disc by the computer when operating in its "native" BBC Micro mode.<ref name="acornuser199107_cpfs">{{ cite news | url=https://archive.org/details/AcornUser108-Jul91/page/n118/mode/1up | title=Filing a Suit | work=Acorn User | date=July 1991 | access-date=3 June 2021 | last1=Futcher | first1=Dave | pages=117 }}</ref>

Along with compatibility issues, the pricing of the Master 512 upgrade also inhibited its competitiveness. The estimated price of an IBM PC clone of £500–800 compared "very favourably with the £900 needed for a complete Master 512", this being the Master 512 upgrade together with the base system, monitor and disk drives, considering that the clone would also include a monitor and drives in the price.<ref name="acornuser198609">{{ cite news | url=https://archive.org/details/AcornUser050-Sep86/page/n154/mode/1up | title=Master meets IBM – or does it? | work=Acorn User | date=September 1986 | access-date=25 October 2020 | last1=Smith | first1=Bruce | pages=153–155 }}</ref> The price was further reduced to £199 plus VAT in early 1987,<ref name="acornuser198701">{{ cite news | url=https://archive.org/details/AcornUser054-Jan87/page/n8/mode/1up | title=M512 U-turn | work=Acorn User | date=January 1987 | access-date=25 October 2020 | pages=7 }}</ref> with GEM Desk Top, GEM Write and GEM Paint being provided free with the upgrade,<ref name="APP110">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP110_OpenUptotheWorldofMSDOS.pdf | title=Open up to the world of MS-DOS | publisher=Acorn Computers Limited | access-date=7 February 2021 |via=Chris's Acorns}}</ref> and a "final price cut to £99" was reported in 1989, effectively exhausting the remaining stocks.<ref name="acornuser198905_shibumi" /> Although largely abandoned by Acorn as the company shifted its emphasis to the [[Engineering:Acorn Archimedes|Archimedes]] range, one commentator considered it "one of the most exciting products Acorn has ever developed".<ref name="acornuser199101_essential" />

=== 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&nbsp;MHz 32016 coprocessor with 32081 floating point processor and 512&nbsp;KB of RAM, running the PANOS operating system.<ref name="acorn_APP83" /> This was similar to the previous external 32016 Second Processor. Ultimately, Acorn dropped the Scientific due to unspecified technical problems with the co-processor, also indicating that 512&nbsp;KB of RAM appeared to be insufficient for the target audience, whose applications tended to need 1&nbsp;MB of RAM,<ref name="acornuser198611">{{cite news |url=https://archive.org/details/AcornUser052-Nov86/page/n8/mode/1up |work=Acorn User |title=Acorn drops Scientific |date=November 1986 |access-date=5 September 2020 |pages=7}}</ref> this already being provided by the upgraded 32016 Second Processor product known as the Cambridge Co-Processor.<ref name="acorn_ccp_userguide">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Sci/AcornScientific_CambridgeCoProUG.pdf | title=Cambridge Co-Processor User Guide | publisher=Acorn Computers Limited | date=July 1985 | issue=1 | pages=5 }}</ref>

=== Master Compact ===
[[File:BBC Master Compact (Amazing Radio modified).jpg|thumb|upright=0.9|BBC Master Compact{{snd}} both the keyboard (front) and under-monitor unit (rear) can be seen.]]
[[File:BBB MC GUI 2.jpg|thumb|right|upright=0.9|The Master Compact [[Graphical user interface|GUI]]]]<!-- FAIR USE of BBB_MC_GUI_2.jpg: see image description page at :Image:BBB MC GUI 2.jpg for rationale -->

This model is, as the name indicates, a compact version of the Master 128 (ostensibly known as the "Baby B" during development<ref name="acorn_do58">{{ cite tech report | url=http://www.4corn.co.uk/archive/do/registers/50to99/58.txt | title=PRODUCTS NUMBER 58 BABY B | publisher=Acorn Computers Limited }}</ref>) with some expansion functionality removed and other expansion options added, and with different bundled software. Unlike previously released Acorn microcomputers, it was sold by Acorn as a complete system bundled with disk drive and monitor (and the first high-volume system from Acorn to do so,<ref name="abcomputing198610">{{ cite news | url=https://archive.org/details/AB_Computing_1986-10_OCR/page/n11/mode/2up | title=Master Compact | work=A&B Computing | date=October 1986 | access-date=5 November 2020 | last1=Taylor | first1=Gordon | pages=12–17 }}</ref>{{rp|pages=13|quote=This is the first high-volume Acorn machine of which this could be said (the Master 128 having been in transition, not having a disc drive included as standard).}} preceded by the unreleased Acorn Business Computer, the low-volume Acorn Cambridge Workstation, and the PC-compatible [[Engineering:Olivetti M19|Olivetti M19]] system rebadged as the Acorn M19<ref name="acorn_app086">{{ cite book | url=http://www.4corn.co.uk/archive/docs/AMPAPP/150/APP086%20(1st%20ed)%20-%20Acorn%20Personal%20Computer%20M19%20(1986)-opt.pdf | title=Acorn Personal Computer M19 | publisher=Acorn Computers Limited | date=July 1986 | access-date=11 July 2021 | issue=1 }}</ref>), aiming to provide a "one plug" solution that had, at the time of release, been successfully popularised by manufacturers such as Amstrad.<ref name="acornuser198611p102">{{ cite news | url=https://archive.org/details/AcornUser052-Nov86/page/n102/mode/1up | title=Master Compact Great and Small | work=Acorn User | date=November 1986 | access-date=28 October 2020 | last1=Atherton | first1=David | pages=101–103 }}</ref> Indeed, one reviewer gave credit to Amstrad for having engineered the delivery of "an innovative, cheap machine for education" – the Compact – through robust competition with Acorn in the sector.<ref name="nzbits198611">{{ cite news | url=https://archive.org/details/nzbitsandbytes-5-03/page/n37/mode/2up | title=Will the real BBC Master please stand up? | work=Bits & Bytes | date=November 1986 | access-date=25 March 2021 | last1=Forer | first1=Pip | pages=38–41 }}</ref>

Although the Compact has a "three box" arrangement, the main functionality of the system is actually provided in the keyboard unit, much like the Master 128, but rather reduced in size in comparison to the Master 128 and Model B, being styled on the Acorn Communicator.<ref name="abcomputing198610" />{{rp|pages=13|quote=The casing is based on that of the Acorn Communicator — a smart desktop computer-plus-telephone being developed by Chris Curry — one of Acorn’s founders.}}<ref name="acornuser198611p102" />{{rp|pages=101|q=The keyboard is almost identical to the Master 128, in a case styled on the Acorn Communicator, measuring 426 x 219 x 75&nbsp;mm, about half way between the width of a model B and a Master, and about two-thirds the depth of a model B.}} The unit under the monitor housed a {{frac|3|1|2}}-inch [[Floppy disk|floppy disk]] drive and the system power supply.<ref name="acornuser198610a">{{cite news |url=https://archive.org/details/AcornUser051-Oct86/page/n16/mode/1up |work=Acorn User |title=Taking the lid off the Master Compact |date=October 1986 |access-date=5 September 2020 |pages=15, 17–18}}</ref> Both monitors supplied with the Compact were Philips models: a "green screen"<ref name="abcomputing198610" /> monochrome monitor for high-resolution applications connected using "an Electron-style phono socket", whereas the colour monitor provided a 0.42mm dot pitch "generally billed as high resolution" and offered the traditional RGB monitor connector used by previous Acorn machines.<ref name="acornuser198611p102"/> However, the colour monitor also provided a [[Engineering:SCART|SCART]] connector, anticipating "future applications" employing more colours and even "overlaying video pictures".<ref name="abcomputing198610" /> The Master Compact was also sold as a "TV system" bundling a PAL television adapter that was also sold separately.<ref name="acorn_APP87">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Brochures/Acorn_APP87_RetailPriceListSep87.pdf | title=Acorn Computers Limited Retail Price List September 1987 | publisher=Acorn Computers Limited | date=September 1987 | access-date=21 May 2023 | pages=1 }}</ref>

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 [[Engineering:D-subminiature|9-pin D type]] with its function configured in software. A Centronics printer interface was also provided. The 1&nbsp;MHz bus and [[Engineering:Analogue electronics|analogue]] port were not provided on the Compact. Additionally, no internal sockets were provided for adding a co-processor or 2nd processor.<ref name="acornuser198610c">{{cite news |url=https://archive.org/details/AcornUser051-Oct86/page/n11/mode/2up |work=Acorn User |title=Acorn packs Master into £399 Compact |date=October 1986 |access-date=5 September 2020 |pages=10, 11}}</ref> However, the machine did include a 50-way expansion edge connector on the right side of the keyboard, that was similar to cartridge socket #3 on a Master 128.<ref name="acornuser198610a" />{{rp|pages=15,17|quote=A 50-way expansion connector protrudes from the right-hand side of the keyboard case. The edge connector is similar in terms of pin order and signals to cartridge socket 3 on a Master 128.}}

Various third-party suppliers restored some of the removed expansion functionality via the expansion connector, such as support for Electron and Master 128 cartridges<ref name="acornuser199005">{{ cite news | url=https://archive.org/details/AcornUser094-May90/page/n10/mode/1up | title=Compact Adaptor | work=Acorn User | date=May 1990 | access-date=1 November 2020 | pages=9 }}</ref> and the provision of various BBC Micro expansion connectors.<ref name="abcomputing198710">{{ cite news | url=https://archive.org/details/AB_Computing_1987-10_OCR/page/n8/mode/1up | title=Compact Companion | work=A&B Computing | date=October 1987 | access-date=4 November 2020 | pages=9 | quote=Once fitted, the Compact Companion offers a User Port, an Analogue (Joystick) Port, a 2&nbsp;MHz bus and an Acorn 1770 DFS. The connections are all standard Master 128 type connectors and the DFS may be configured to be the disc interface selected on turning on the machine. }}</ref> Some suppliers instead chose to adapt existing peripherals to the built-in ports of the machine. For example, Morley Electronics employed the mouse/joystick port to attach their teletext adapter to the Compact.<ref name="abcomputing198906_compact">{{ cite magazine | title=Compact Corner | magazine=A&B Computing | last1=John | first1=Kenneth | date=June 1989 | pages=19–20 }}</ref> Such adaptations were facilitated by the availability of the User Port signals via pins provided by the joystick port, together with three signals (PB5, PB6 and PB7) provided by the general expansion connector.<ref name="acorn_master_compact_sm">{{ cite book | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_MasterCompact_SM.pdf | title=British Broadcasting Corporation Master Series Compact Computer Service Manual | publisher=Acorn Computers Limited | date=October 1986 | access-date=27 May 2023 | issue=1 | pages=22–23 }}</ref>

Acorn reportedly designed the Compact to appeal to home users and to primary education, with the single-plug power connection regarded as more convenient for setting up a machine that might be moved around in a school, and the choice of {{frac|3|1|2}}-inch discs using the ADFS format was regarded as conducive to "handling many small files" and "distinguishing between different topics or users on the same disc". Amongst the bundled software, Acorn's adoption of Logotron's Logo implementation was seen as particularly welcome.<ref name="abcomputing198701_compact">{{ cite magazine | title=Compaction Required? | magazine=A&B Computing | last1=Owen | first1=Ann | date=January 1987 | pages=100 }}</ref> In an effort to increase sales of the Compact to education, Acorn reduced the price of the machine in late 1987, bundling the Mertec Compact Companion interface with it to provide the BBC range's traditional expansion connectors, pricing it at £344 including VAT without monitor.<ref name="acornuser198711_compact">{{ cite magazine | url=https://archive.org/details/AcornUser064-Nov87/page/n166/mode/1up | title=Compact sales revive after price cut | magazine=Acorn User | date=November 1987 | access-date=30 June 2022 | pages=165 }}</ref>

Unlike the other models in the series which provided a battery-backed clock and memory for configuration settings, the Compact utilised EEPROM storage for its configuration with support for only a limited number of writes, making the EEPROMs "a consumable, like a battery" requiring "replacement at intervals".<ref name="acorn_csnews3">{{ cite news | url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/CSN/Acorn_CSNews3.pdf | title=EEPROM | work=Acorn Customer Service News | issue=3 | date=June 1989 | pages=1 }}</ref> Hence, it had no built-in real-time clock facility, although the time could be fetched via [[Engineering:Econet|Econet]] where available, being applied to ADFS file timestamps.<ref name="acorn_y2kunrat">{{ cite tech report | url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20Docs/MISC/Y2KUNRAT.TXT | title=Current and Historical Acorn Kit and Y2K: State of the Universe and Testing Strategy | publisher=Acorn Computers Limited | last1=Walker | first1=Dave }}</ref> As a result of this, the <code>*TIME</code> and <code>TIME$</code> commands returned dummy values. Only the ADFS Version 2 filing system was supplied as standard, running via a Western Digital 1772 chip (a faster version of the widely used 1770), though it is possible to load a 1770 DFS ROM into sideways RAM, or to insert a ROM or EPROM containing it.

The keyboard on the Compact was the first to move away from using the traditional "sprung-key" keyswitch design used by the rest of the BBC Micro family. Instead, it used a rubber-plastic moulding membrane. An input method was provided to permit the input of "foreign characters" or "top-bit-set characters" – character codes in the range from 128 to 255 – from the keyboard.

The chip-count was also reduced vs. the rest of the Master range, via the use of 4x custom gate array chips.

The version of BASIC on the Compact included re-coded mathematical routines, said to provide a 30% speed increase over the version included in the rest of the Master series. This version of BASIC was called Basic4(1986),<ref name="acornuser198610a" /> aka 'BASIC41'. This was later replaced with version 'BASIC42' in 1987.<ref>[http://mdfs.net/Software/BBCBasic/Versions BBC Basic versions].</ref> This later BASIC ROM included the updated message (vs previous BBC BASIC ROMs):

{{blockquote|<samp>Roger Wilson & R.A. Sack</samp>|<ref>L Fox, L Hayes and DF Mayers, 'The Double Eigenvalue Problem'; and RA Sack, 'Variational solutions of Lamé equations', Department of Mathematics, University of Salford. 1971-2, latter Department of Theoretical Physics, University of Liverpool.</ref>}}

The Compact included Acorn's first publicly available [[Graphical user interface|GUI]]. Little commercial software, beyond that included on the Welcome disk, was ever made available for the system, despite the claim by Acorn at the time that over 100 titles would be "set for distribution on 3.5in disc format for the Compact launch".<ref name="acornuser198610d">{{ cite news | url=https://archive.org/details/AcornUser051-Oct86/page/n12/mode/1up | title=Discs tie-in with launch | work=Acorn User | date=October 1986 | access-date=1 November 2020 | pages=11 }}</ref> The most avid supporter of the Master Compact appeared to be [[Company:Superior Software|Superior Software]], who produced and specifically labelled their games as Master Compact compatible. Software for the Compact was comparatively expensive (typically £20 for a game) due to the increased costs of adopting, and publishing on, the {{frac|3|1|2}}-inch disk format, alongside the established {{frac|5|1|4}}-inch disk format for the Master and earlier [[Engineering:BBC Micro|BBC Micro]].<ref name="acornuser198611p102"/>

The machines were built by [[Company:Rank Xerox|Rank Xerox]] in Hertfordshire.<ref name="acornuser198610c" /> Ultimately, the Compact was discontinued in 1989 with "over eighty thousand Compacts and Olivetti's Prodest version" having been sold, with Acorn shifting its focus to the Master 128 as "its core 8-bit machine".<ref name="acornuser198909">{{ cite news | url=https://archive.org/details/AcornUser085-Aug89/page/n10/mode/1up | title=New BBC home service | work=Acorn User | date=September 1989 | access-date=1 November 2020 | pages=7 }}</ref>

==== Olivetti Prodest PC 128 S ====
[[Company:Olivetti|Olivetti]] were named as being interested in releasing a version of the Master Compact in Italy under the Olivetti Prodest brand,<ref name="acornuser198610b">{{cite news |url=https://archive.org/details/AcornUser051-Oct86/page/n8/mode/1up | work=Acorn User | title=Acorn gives birth to Master Compact |date=October 1986 |access-date=5 September 2020 |pages=7}}</ref> subsequently announcing the model as the {{nowrap|PC 128 S}} aimed at the home and small business markets.<ref name="acornuser198611b">{{cite news |url=https://archive.org/details/AcornUser052-Nov86/page/n8/mode/1up |title=Italian Compact set for success |work=Acorn User | date=November 1986 |access-date=5 September 2020 |pages=7}}</ref> Unlike the Compact, the {{nowrap|PC 128 S}} was bundled with a mouse, the Nidd Valley Digimouse.<ref name="acornuser198702_digimouse">{{ cite magazine | url=https://archive.org/details/AcornUser055-Feb87/page/n102/mode/1up | title=Jump for Joy | magazine=Acorn User | date=February 1987 | access-date=17 June 2022 | last1=Atherton | first1=David | pages=101–102 }}</ref>{{rp|pages=102|quote=The Digimouse has been chosen by Olivetti to bundle in with its PC128S}}

In the UK the Digimouse was sold with Clares' Artroom, an illustration package, later being made available to purchase on its own.<ref name="acornuser198702_artroom">{{cite magazine | url=https://archive.org/details/AcornUser055-Feb87/page/n146/mode/1up | title=Articulation | magazine=Acorn User | date=February 1987 | access-date=17 June 2022 | last1=Baldwin | first1=Jonathan | pages=145–147 }}</ref> Clares' Artroom was localised for the PC 128 S and sold under the name Project.<ref name="pc128s_project">{{cite book | url=https://archive.org/details/project_olivetti | title=Project | publisher=Olivetti Prodest S.p.A. | date=1987 | access-date=17 June 2022 }}</ref>

In addition to the localisation of the system itself,<ref name="pc128s_system">{{cite book | url=https://archive.org/details/olivettiprodest128s | title=Guida all'uso del systema PC 128 S | publisher=Olivetti Prodest S.p.A. | date=September 1986 | access-date=17 June 2022 }}</ref> various applications were localised for the PC128S including View,<ref name="pc128s_view">{{cite book | url=https://archive.org/details/view_olivetti | title=View – Il word processor per il PC 128 S | publisher=Olivetti Prodest S.p.A. | date=1986 | access-date=17 June 2022 }}</ref> ViewSheet,<ref name="pc128s_viewsheet">{{cite book | url=https://archive.org/details/view-sheet | title=ViewSheet - Lo spreadsheet per il PC 128 S | publisher=Olivetti Prodest S.p.A. | date=1986 | access-date=17 June 2022 }}</ref> ViewPlot,<ref name="pc128s_viewplot">{{cite book | url=https://archive.org/details/view-plot | title=ViewPlot - Per il PC 128 S - Guida all'uso | publisher=Olivetti Prodest S.p.A. | date=1986 | access-date=17 June 2022 }}</ref> and ViewIndex,<ref name="pc128s_viewindex">{{cite book | url=https://archive.org/details/view-index | title=ViewIndex - Per il PC 128 S - Guida all'uso | publisher=Olivetti Prodest S.p.A. | date=1986 | access-date=17 June 2022 }}</ref> along with a number of games including ''Aviator'',<ref name="pc128s_aviator">{{cite book | url=https://archive.org/details/aviator_olivetti | title=Aviator | publisher=Olivetti Prodest S.p.A. | date=1987 | access-date=17 June 2022 }}</ref> ''Revs'',<ref name="pc128s_revs">{{cite book | url=https://archive.org/details/revs_olivetti | title=Revs | publisher=Olivetti Prodest S.p.A. | date=1987 | access-date=17 June 2022 }}</ref> ''XOR'',<ref name="pc128s_xor">{{cite book | url=https://archive.org/details/xor-la-sfida-finale-al-labirinto | title=XOR – La sfida finale al labirinto | publisher=Olivetti Prodest S.p.A. | date=1987 | access-date=17 June 2022 }}</ref> and ''Doctor Who and the Mines of Terror''.<ref name="pc128s_drwho">{{cite book | url=https://archive.org/details/doctor-who-e-le-miniere-del-terrore | title=Doctor Who e le miniere del terrore | publisher=Olivetti Prodest S.p.A. | date=1987 | access-date=17 June 2022 }}</ref> Pricing for the {{nowrap|PC 128 S}} started at 995,000 lire for a system with monochrome monitor or 1,295,000 lire with a colour monitor (equivalent to €{{Format price|{{#expr:({{Inflation|IT|995000|1987|r=-2}} / {{FixedEuroRate|ITL}}) round 0}}}} and €{{Format price|{{#expr:({{Inflation|IT|1295000|1987|r=-2}} / {{FixedEuroRate|ITL}}) round 0}}}} respectively in {{inflation/year|IT}}, adjusted for inflation).<ref name="pc128s_prices">{{ cite book | url=https://archive.org/details/pc128s-listino | title=Olivetti Prodest PC 128 S - Prezzi al pubblico | publisher=Olivetti Prodest S.p.A. | date=1 September 1986 | access-date=17 June 2022 }}</ref>

==Specifications==
[[Image:romboard fan.jpg|thumb|Internal image of a Master 128 showing Vine Micro Romboard4 fitted, meaning the cartridge slots can no longer be used{{snd}} a non-standard cooling fan has also been added by the owner.]]

{{unordered list
|2 [[Megahertz|MHz]] [[Company:Rockwell International|Rockwell]] R65SC12 processor<ref>{{Cite web |title=BBC Master Acorn Computer |url=https://www.old-computers.com/museum/computer.asp?st=1&c=850 |access-date=2023-05-25 |website=old-computers.com}}</ref>

|128 KB [[Read-only memory|ROM]] in the Master 128, Master Turbo, and Master 512. Comprising a 16&nbsp;KB MOS (Machine Operating System), always accessible, and seven 16&nbsp;KB [[Sideways address space|sideways]] ROMs, any one of which could be paged into memory at a time:{{unordered list
|16 KB Terminal emulator and MOS extras (such as the cassette filing system) in paged ROM 15
|16 KB Acornsoft View (word processor) in paged ROM 14
|16 KB [[Advanced Disc Filing System]] in paged ROM 13
|16 KB BBC BASIC in paged ROM 12
|16 KB Acorn Screen Editor AKA Edit (text/BBC BASIC editor) in paged ROM 11
|16 KB [[Software:ViewSheet|ViewSheet]] (spreadsheet) in paged ROM 10
|16 KB [[Disc Filing System]] and Sideways RAM utilities in paged ROM 9}}

|64 KB [[Read-only memory|ROM]] in the Master ET. Comprising a 16&nbsp;KB MOS (Machine Operating System), always accessible, and three 16&nbsp;KB [[Sideways address space|sideways]] ROMs, any one of which could be paged into memory at a time:{{unordered list
|16 KB MOS extras (such as the cassette filing system and Sideways RAM utilities) in paged ROM 15
|16 KB [[Engineering:Econet|Advanced Network Filing System]] in paged ROM 14
|16 KB BBC BASIC in paged ROM 13}}

|128 KB RAM, comprising:{{unordered list
|32 KB main user program/data storage
|20 KB "[[Shadow RAM (Acorn)|shadow]]" video memory (paged over main user RAM)
|12 KB OS workspace (paged over ROM)
|64 KB workspace accessible to user machine code applications (divided into up to four 16&nbsp;KB regions to act like volatile paged ROMs)}}

|Full-travel [[Computer keyboard|keyboard]] with a top row of ten red-orange function keys&nbsp;ƒ0–ƒ9 and AT-style numeric keypad. The {{key|BREAK}} reset key could be physically disabled by rotating a small plastic [[Engineering:Cam (mechanism)|cam]], particularly useful in educational environments

|Highly configurable graphics display based on the [[Engineering:Motorola 6845|Motorola 6845]]. Unlike on the original [[Engineering:BBC Micro|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:{{unordered list
|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 color model|RGB]] colours (black, red, green, yellow, blue, magenta, cyan, white) and the same colours in a flashing state;
|<!-- Deleted image removed: [[Image:MODE 6 Master Series.png|thumb|right|Screen mode 6 with a blue background, showing the filler lines]] -->Modes 3 and 6 were special software (framebuffer) text modes. To save RAM, the count of lines was reduced from 32 to 25. As this would reduce the height of the frame, filler rows were created between each line of text when the frame was output, where no pixels were read from the framebuffer. This creates characteristic black lines between the rows of text when a different background colour is set, and a blank gap at the bottom of the display with the left-over pixels. The screen mode is otherwise held in memory as a regular graphics mode.
|Mode 7's Teletext capability was provided by a [[Engineering:Mullard SAA5050|Mullard SAA5050]] Teletext chip.}}
{{wikitable| class="wikitable" style="text-align:center;"
|-
!rowspan{{=}}"2" |Graphics<br />mode
!colspan{{=}}"2" |Resolution (X×Y)
!rowspan{{=}}"2" |Hardware<br />colours
!colspan{{=}}"2" |Video RAM
!rowspan{{=}}"2" |Type
|-
! Char cells
! Pixels
! used<br />(KB)
! map
|-
| 0
| 80 × 32
| 640 × 256
| style{{=}}"text-align:right;" |2
| style{{=}}"text-align:right;" |20
| 0x3000–0x7FFF
| style{{=}}"text-align:left;" |Graphics
|-
| 1
| 40 × 32
| 320 × 256
| style{{=}}"text-align:right;" |4
| style{{=}}"text-align:right;" |20
| 0x3000–0x7FFF
| style{{=}}"text-align:left;" |Graphics
|-
| 2
| 20 × 32
| 160 × 256
| style{{=}}"text-align:right;" |8
| style{{=}}"text-align:right;" |20
| 0x3000–0x7FFF
| style{{=}}"text-align:left;" |Graphics
|-
| 3
| 80 × 25
| 640 × 200
| style{{=}}"text-align:right;" |2
| style{{=}}"text-align:right;" |16
| 0x4000–0x7FFF
| style{{=}}"text-align:left;" |Text
|-
| 4
| 40 × 32
| 320 × 256
| style{{=}}"text-align:right;" |2
| style{{=}}"text-align:right;" |10
| 0x5800–0x7FFF
| style{{=}}"text-align:left;" |Graphics
|-
| 5
| 20 × 32
| 160 × 256
| style{{=}}"text-align:right;" |4
| style{{=}}"text-align:right;" |10
| 0x5800–0x7FFF
| style{{=}}"text-align:left;" |Graphics
|-
| 6
| 40 × 25
| 320 × 200
| style{{=}}"text-align:right;" |2
| style{{=}}"text-align:right;" |8
| 0x6000–0x7FFF
| style{{=}}"text-align:left;" |Text
|-
| 7 (Teletext)
| 40 × 25
| 480 × 500<ref>[http://www-uxsup.csx.cam.ac.uk/~bjh21/BBCdata/SAA5050.pdf Reference Data Sheet:SAA5050 Series] {{Webarchive|url=https://web.archive.org/web/20160303193433/http://www-uxsup.csx.cam.ac.uk/~bjh21/BBCdata/SAA5050.pdf |date=3 March 2016 }}, ''Teletext Character Generator'', July 1982, Mullard.</ref>
| style{{=}}"text-align:right;" |8
| style{{=}}"text-align:right;" |1
| 0x7C00–0x7FFF
| style{{=}}"text-align:left;" |Text
}}

|Four independent sound channels (one noise and three melodic) using the [[Engineering:Texas Instruments SN76489|Texas Instruments SN76489]] [[Engineering:Sound chip|sound chip]]
|Built-in hardware support included:{{unordered list
|pluggable ROMs, directly or via cartridge slots
|floppy disc drives (both [[Disc Filing System|DFS]] and the newer [[Advanced Disc Filing System|ADFS]] supported) with WD1770 disc controller
|tape interface (with motor control), using a variation of the [[Kansas City standard]] data encoding scheme
|parallel printer port ([[Company:Centronics|Centronics]] compatible)
|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 [[Engineering:Joystick|joystick]]s, four digital/contact ports (for buttons) and a special [[Light pen]] input
|proprietary "Tube" interface for internal or external second CPU (in the Master 512 model, an [[Engineering:Intel 80186|80186]] was used; other options included a 3&nbsp;MHz extra 6502, a Zilog Z80 for e.g. CP/M, an [[NS320xx|NS32016]], an [[ARM architecture|ARM1]], and others)
|a 20-pin IDC style "user port" consisting of eight general purpose digital I/O pins (and two special [[Handshake (computing)|handshaking]] ones) mapped directly into the 6522 VIA
|generic expansion through the "1&nbsp;MHz bus", and
|[[Engineering:Econet|Econet]] interface, installed by adding a module board and the ANFS ROM (fitted as standard to the Master ET machine)}}
}}
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 control applications.

==Code page layout (BBC Master microcomputer)==
This character set was used in the BBC Master microcomputer.<ref name="bfnt">{{Citation|title=RISC OS 3.7 User Guide|chapter-url=http://www.riscos.com/support/users/userguide3/book3b/bfnt.html|chapter=BFont characters|date=1997-01-20}}</ref>

{|{{chset-table-header1|BBC Master microcomputer character set<ref name="ReadMe">{{Citation|title=L2/19-025: Proposal to add characters from legacy computers and teletext to the UCS|chapter-url=https://www.unicode.org/L2/L2019/19025-terminals-prop.pdf|chapter=ReadMe.txt|date=2019-01-04}}</ref><ref>{{Citation|title=L2/19-025: Proposal to add characters from legacy computers and teletext to the UCS|chapter-url=https://www.unicode.org/L2/L2019/19025-terminals-prop.pdf|chapter=RISCOSB.TXT|date=2019-01-04}}</ref><ref name="bfnt"/>}}
|-
|{{chset-left1|0x}}
|{{chset-ctrl1|U+0000 NULL|[[Null character|NUL]]}}
|{{chset-ctrl1|U+0001 START OF HEADING|SOH}}
|{{chset-ctrl1|U+0002 START OF TEXT|STX}}
|{{chset-ctrl1|U+0003 END OF TEXT|ETX}}
|{{chset-ctrl1|U+0004 END OF TRANSMISSION|EOT}}
|{{chset-ctrl1|U+0005 ENQUIRY|ENQ}}
|{{chset-ctrl1|U+0006 ACKNOWLEDGE|ACK}}
|{{chset-ctrl1|U+0007 BELL|BEL}}
|{{chset-ctrl1|U+0008 BACKSPACE|BS}}
|{{chset-ctrl1|U+0009 CHARACTER TABULATION|HT}}
|{{chset-ctrl1|U+000A LINE FEED (LF)|LF}}
|{{chset-ctrl1|U+000B LINE TABULATION|VT}}
|{{chset-ctrl1|U+000C FORM FEED (FF)|FF}}
|{{chset-ctrl1|U+000D CARRIAGE RETURN (CR)|CR}}
|{{chset-ctrl1|U+000E SHIFT OUT|SO}}
|{{chset-ctrl1|U+000F SHIFT IN|SI}}
|-
|{{chset-left1|1x}}
|{{chset-ctrl1|U+0010 DATA LINK ESCAPE|DLE}}
|{{chset-ctrl1|U+0011 DEVICE CONTROL ONE|DC1}}
|{{chset-ctrl1|U+0012 DEVICE CONTROL TWO|DC2}}
|{{chset-ctrl1|U+0013 DEVICE CONTROL THREE|DC3}}
|{{chset-ctrl1|U+0014 DEVICE CONTROL FOUR|DC4}}
|{{chset-ctrl1|U+0015 NEGATIVE ACKNOWLEDGE|NAK}}
|{{chset-ctrl1|U+0016 SYNCHRONOUS IDLE|SYN}}
|{{chset-ctrl1|U+0017 END OF TRANSMISSION BLOCK|ETB}}
|{{chset-ctrl1|U+0018 CANCEL|CAN}}
|{{chset-ctrl1|U+0019 END OF MEDIUM|EM}}
|{{chset-ctrl1|U+001A SUBSTITUTE|SUB}}
|{{chset-ctrl1|U+001B ESCAPE|[[Escape character|ESC]]}}
|{{chset-ctrl1|U+001C INFORMATION SEPARATOR FOUR|FS}}
|{{chset-ctrl1|U+001D INFORMATION SEPARATOR THREE|GS}}
|{{chset-ctrl1|U+001E INFORMATION SEPARATOR TWO|RS}}
|{{chset-ctrl1|U+001F INFORMATION SEPARATOR ONE|US}}
|-
|{{chset-left1|2x}}
|{{chset-ctrl1|U+0020 SPACE|&nbsp;SP&nbsp;}}
|{{chset-cell1|U+0021 EXCLAMATION MARK|!}}
|{{chset-cell1|U+0022 QUOTATION MARK|"}}
|{{chset-cell1|U+0023 NUMBER SIGN|#}}
|{{chset-cell1|U+0024 DOLLAR SIGN|[[Finance:Dollar sign|$]]}}
|{{chset-cell1|U+0025 PERCENT SIGN|[[Percent sign|%]]}}
|{{chset-cell1|U+0026 AMPERSAND|[[Ampersand|&amp;]]}}
|{{chset-cell1|U+0027 APOSTROPHE|'}}
|{{chset-cell1|U+0028 LEFT PARENTHESIS|(}}
|{{chset-cell1|U+0029 RIGHT PARENTHESIS|)}}
|{{chset-cell1|U+002A ASTERISK|*}}
|{{chset-cell1|U+002B PLUS SIGN|[[Plus and minus signs|+]]}}
|{{chset-cell1|U+002C COMMA|,}}
|{{chset-cell1|U+002D HYPHEN-MINUS|[[Plus and minus signs|-]]}}
|{{chset-cell1|U+002E FULL STOP|.}}
|{{chset-cell1|U+002F SOLIDUS|/}}
|-
|{{chset-left1|3x}}
|{{chset-cell1|U+0030 DIGIT ZERO|[[0 (number)|0]]}}
|{{chset-cell1|U+0031 DIGIT ONE|[[1 (number)|1]]}}
|{{chset-cell1|U+0032 DIGIT TWO|[[2 (number)|2]]}}
|{{chset-cell1|U+0033 DIGIT THREE|[[3 (number)|3]]}}
|{{chset-cell1|U+0034 DIGIT FOUR|[[4 (number)|4]]}}
|{{chset-cell1|U+0035 DIGIT FIVE|[[5 (number)|5]]}}
|{{chset-cell1|U+0036 DIGIT SIX|[[6 (number)|6]]}}
|{{chset-cell1|U+0037 DIGIT SEVEN|[[7 (number)|7]]}}
|{{chset-cell1|U+0038 DIGIT EIGHT|[[8 (number)|8]]}}
|{{chset-cell1|U+0039 DIGIT NINE|[[9 (number)|9]]}}
|{{chset-cell1|U+003A COLON|:}}
|{{chset-cell1|U+003B SEMICOLON|;}}
|{{chset-cell1|U+003C LESS-THAN SIGN|[[Less-than sign|&lt;]]}}
|{{chset-cell1|U+003D EQUALS SIGN|[[Equals sign|=]]}}
|{{chset-cell1|U+003E GREATER-THAN SIGN|[[Greater-than sign|&gt;]]}}
|{{chset-cell1|U+003F QUESTION MARK|?}}
|-
|{{chset-left1|4x}}
|{{chset-cell1|U+0040 COMMERCIAL AT|@}}
|{{chset-cell1|U+0041 LATIN CAPITAL LETTER A|A}}
|{{chset-cell1|U+0042 LATIN CAPITAL LETTER B|B}}
|{{chset-cell1|U+0043 LATIN CAPITAL LETTER C|C}}
|{{chset-cell1|U+0044 LATIN CAPITAL LETTER D|D}}
|{{chset-cell1|U+0045 LATIN CAPITAL LETTER E|E}}
|{{chset-cell1|U+0046 LATIN CAPITAL LETTER F|F}}
|{{chset-cell1|U+0047 LATIN CAPITAL LETTER G|G}}
|{{chset-cell1|U+0048 LATIN CAPITAL LETTER H|[[Company:H|H]]}}
|{{chset-cell1|U+0049 LATIN CAPITAL LETTER I|I}}
|{{chset-cell1|U+004A LATIN CAPITAL LETTER J|J}}
|{{chset-cell1|U+004B LATIN CAPITAL LETTER K|K}}
|{{chset-cell1|U+004C LATIN CAPITAL LETTER L|L}}
|{{chset-cell1|U+004D LATIN CAPITAL LETTER M|M}}
|{{chset-cell1|U+004E LATIN CAPITAL LETTER N|N}}
|{{chset-cell1|U+004F LATIN CAPITAL LETTER O|O}}
|-
|{{chset-left1|5x}}
|{{chset-cell1|U+0050 LATIN CAPITAL LETTER P|P}}
|{{chset-cell1|U+0051 LATIN CAPITAL LETTER Q|[[Software:Q|Q]]}}
|{{chset-cell1|U+0052 LATIN CAPITAL LETTER R|R}}
|{{chset-cell1|U+0053 LATIN CAPITAL LETTER S|S}}
|{{chset-cell1|U+0054 LATIN CAPITAL LETTER T|T}}
|{{chset-cell1|U+0055 LATIN CAPITAL LETTER U|U}}
|{{chset-cell1|U+0056 LATIN CAPITAL LETTER V|V}}
|{{chset-cell1|U+0057 LATIN CAPITAL LETTER W|W}}
|{{chset-cell1|U+0058 LATIN CAPITAL LETTER X|X}}
|{{chset-cell1|U+0059 LATIN CAPITAL LETTER Y|Y}}
|{{chset-cell1|U+005A LATIN CAPITAL LETTER Z|Z}}
|{{chset-cell1|U+005B LEFT SQUARE BRACKET|[}}
|{{chset-cell1|U+005C REVERSE SOLIDUS|\}}
|{{chset-cell1|U+005D RIGHT SQUARE BRACKET|]}}
|{{chset-cell1|U+005E CIRCUMFLEX ACCENT|^}}
|{{chset-cell1|U+005F LOW LINE|[[Underscore|]]}}
|-
|{{chset-left1|6x}}
|{{chset-cell1|U+00A3 POUND SIGN|[[Finance:Pound sign|£]]}}
|{{chset-cell1|U+0061 LATIN SMALL LETTER A|a}}
|{{chset-cell1|U+0062 LATIN SMALL LETTER B|b}}
|{{chset-cell1|U+0063 LATIN SMALL LETTER C|c}}
|{{chset-cell1|U+0064 LATIN SMALL LETTER D|d}}
|{{chset-cell1|U+0065 LATIN SMALL LETTER E|e}}
|{{chset-cell1|U+0066 LATIN SMALL LETTER F|f}}
|{{chset-cell1|U+0067 LATIN SMALL LETTER G|g}}
|{{chset-cell1|U+0068 LATIN SMALL LETTER H|[[Company:H|h]]}}
|{{chset-cell1|U+0069 LATIN SMALL LETTER I|i}}
|{{chset-cell1|U+006A LATIN SMALL LETTER J|j}}
|{{chset-cell1|U+006B LATIN SMALL LETTER K|k}}
|{{chset-cell1|U+006C LATIN SMALL LETTER L|l}}
|{{chset-cell1|U+006D LATIN SMALL LETTER M|m}}
|{{chset-cell1|U+006E LATIN SMALL LETTER N|n}}
|{{chset-cell1|U+006F LATIN SMALL LETTER O|o}}
|-
|{{chset-left1|7x}}
|{{chset-cell1|U+0070 LATIN SMALL LETTER P|p}}
|{{chset-cell1|U+0071 LATIN SMALL LETTER Q|[[Software:Q|q]]}}
|{{chset-cell1|U+0072 LATIN SMALL LETTER R|r}}
|{{chset-cell1|U+0073 LATIN SMALL LETTER S|s}}
|{{chset-cell1|U+0074 LATIN SMALL LETTER T|t}}
|{{chset-cell1|U+0075 LATIN SMALL LETTER U|u}}
|{{chset-cell1|U+0076 LATIN SMALL LETTER V|v}}
|{{chset-cell1|U+0077 LATIN SMALL LETTER W|w}}
|{{chset-cell1|U+0078 LATIN SMALL LETTER X|x}}
|{{chset-cell1|U+0079 LATIN SMALL LETTER Y|y}}
|{{chset-cell1|U+007A LATIN SMALL LETTER Z|z}}
|{{chset-cell1|U+007B LEFT CURLY BRACKET|{}}
|{{chset-cell1|U+00A6 BROKEN BAR|¦}}
|{{chset-cell1|U+007D RIGHT CURLY BRACKET|}}}
|{{chset-cell1|U+007E TILDE|[[Tilde|~]]}}
|{{chset-ctrl1|U+007F <control>|[[Delete character|DEL]]}}
|-
|{{chset-left1|8x}}
|{{chset-cell1|U+00C4 LATIN CAPITAL LETTER A WITH DIAERESIS|Ä}}
|{{chset-cell1|U+00C5 LATIN CAPITAL LETTER A WITH RING ABOVE|Å}}
|{{chset-cell1|U+00C6 LATIN CAPITAL LETTER AE|Æ}}
|{{chset-cell1|U+00C7 LATIN CAPITAL LETTER C WITH CEDILLA|Ç}}
|{{chset-cell1|U+00C9 LATIN CAPITAL LETTER E WITH ACUTE|É}}
|{{chset-cell1|U+00D6 LATIN CAPITAL LETTER O WITH DIAERESIS|Ö}}
|{{chset-cell1|U+00DC LATIN CAPITAL LETTER U WITH DIAERESIS|Ü}}
|{{chset-cell1|U+00A9 COPYRIGHT SIGN|©}}
|{{chset-cell1|U+2190 LEFTWARDS ARROW|[[Arrow (symbol)|←]]}}
|{{chset-cell1|U+2192 RIGHTWARDS ARROW|[[Arrow (symbol)|→]]}}
|{{chset-cell1|U+2193 DOWNWARDS ARROW|[[Arrow (symbol)|↓]]}}
|{{chset-cell1|U+2191 UPWARDS ARROW|[[Arrow (symbol)|↑]]}}
|{{chset-cell1|U+00E0 LATIN SMALL LETTER A WITH GRAVE|à}}
|{{chset-cell1|U+00E8 LATIN SMALL LETTER E WITH GRAVE|è}}
|{{chset-cell1|U+00EB LATIN SMALL LETTER E WITH DIAERESIS|ë}}
|{{chset-cell1|U+00EA LATIN SMALL LETTER E WITH CIRCUMFLEX|ê}}
|-
|{{chset-left1|9x}}
|{{chset-cell1|U+00E4 LATIN SMALL LETTER A WITH DIAERESIS|ä}}
|{{chset-cell1|U+00E5 LATIN SMALL LETTER A WITH RING ABOVE|å}}
|{{chset-cell1|U+00E6 LATIN SMALL LETTER AE|æ}}
|{{chset-cell1|U+00E7 LATIN SMALL LETTER C WITH CEDILLA|ç}}
|{{chset-cell1|U+00E9 LATIN SMALL LETTER E WITH ACUTE|é}}
|{{chset-cell1|U+00F6 LATIN SMALL LETTER O WITH DIAERESIS|ö}}
|{{chset-cell1|U+00FC LATIN SMALL LETTER U WITH DIAERESIS|ü}}
|{{chset-cell1|U+00EC LATIN SMALL LETTER I WITH GRAVE|ì}}
|{{chset-cell1|U+00EE LATIN SMALL LETTER I WITH CIRCUMFLEX|î}}
|{{chset-cell1|U+00F2 LATIN SMALL LETTER O WITH GRAVE|ò}}
|{{chset-cell1|U+00F4 LATIN SMALL LETTER O WITH CIRCUMFLEX|ô}}
|{{chset-cell1|U+00F9 LATIN SMALL LETTER U WITH GRAVE|ù}}
|{{chset-cell1|U+00FB LATIN SMALL LETTER U WITH CIRCUMFLEX|û}}
|{{chset-cell1|U+00FF LATIN SMALL LETTER Y WITH DIAERESIS|ÿ}}
|{{chset-cell1|U+00A4 CURRENCY SIGN|¤}}
|{{chset-cell1|U+00A7 SECTION SIGN|§}}
|-
|{{chset-left1|Ax}}
|{{chset-cell1|U+00B0 DEGREE SIGN|°}}
|{{chset-cell1|U+2577 BOX DRAWINGS LIGHT DOWN|╷}}
|{{chset-cell1|U+2576 BOX DRAWINGS LIGHT RIGHT|╶}}
|{{chset-cell1|U+250C BOX DRAWINGS LIGHT DOWN AND RIGHT|┌}}
|{{chset-cell1|U+2574 BOX DRAWINGS LIGHT LEFT|╴}}
|{{chset-cell1|U+2510 BOX DRAWINGS LIGHT DOWN AND LEFT|┐}}
|{{chset-cell1|U+2500 BOX DRAWINGS LIGHT HORIZONTAL|─}}
|{{chset-cell1|U+252C BOX DRAWINGS LIGHT DOWN AND HORIZONTAL|┬}}
|{{chset-cell1|U+2575 BOX DRAWINGS LIGHT UP|╵}}
|{{chset-cell1|U+2502 BOX DRAWINGS LIGHT VERTICAL|│}}
|{{chset-cell1|U+2514 BOX DRAWINGS LIGHT UP AND RIGHT|└}}
|{{chset-cell1|U+251C BOX DRAWINGS LIGHT VERTICAL AND RIGHT|├}}
|{{chset-cell1|U+2518 BOX DRAWINGS LIGHT UP AND LEFT|┘}}
|{{chset-cell1|U+2524 BOX DRAWINGS LIGHT VERTICAL AND LEFT|┤}}
|{{chset-cell1|U+2534 BOX DRAWINGS LIGHT UP AND HORIZONTAL|┴}}
|{{chset-cell1|U+253C BOX DRAWINGS LIGHT VERTICAL AND HORIZONTAL|┼}}
|-
|{{chset-left1|Bx}}
|{{chset-cell1|U+256D BOX DRAWINGS LIGHT ARC DOWN AND RIGHT|╭}}
|{{chset-cell1|U+256E BOX DRAWINGS LIGHT ARC DOWN AND LEFT|╮}}
|{{chset-cell1|U+2570 BOX DRAWINGS LIGHT ARC UP AND RIGHT|╰}}
|{{chset-cell1|U+256F BOX DRAWINGS LIGHT ARC UP AND LEFT|╯}}
|{{chset-cell1|U+00BF INVERTED QUESTION MARK|¿}}
|{{chset-cell1|U+00A1 INVERTED EXCLAMATION MARK|¡}}
|{{chset-cell1|U+00D1 LATIN CAPITAL LETTER N WITH TILDE|Ñ}}
|{{chset-cell1|U+00F1 LATIN SMALL LETTER N WITH TILDE|ñ}}
|{{chset-cell1|U+2020 DAGGER|†}}
|{{chset-cell1|U+2021 DOUBLE DAGGER|‡}}
|{{chset-cell1|U+02D9 DOT ABOVE|˙}}
|{{chset-cell1|U+0060 GRAVE ACCENT|`}}
|{{chset-cell1|U+00B6 PILCROW SIGN|¶}}
|{{chset-cell1|U+00B7 MIDDLE DOT|·}}
|{{chset-cell1|U+221A SQUARE ROOT|√}}
|{{chset-cell1|U+2592 MEDIUM SHADE|▒}}
|-
|{{chset-left1|Cx}}
|{{chset-cell1|U+00D8 LATIN CAPITAL LETTER O WITH STROKE|Ø}}
|{{chset-cell1|U+0391 GREEK CAPITAL LETTER ALPHA|Α}}
|{{chset-cell1|U+0392 GREEK CAPITAL LETTER BETA|Β}}
|{{chset-cell1|U+0393 GREEK CAPITAL LETTER GAMMA|Γ}}
|{{chset-cell1|U+0394 GREEK CAPITAL LETTER DELTA|Δ}}
|{{chset-cell1|U+0395 GREEK CAPITAL LETTER EPSILON|Ε}}
|{{chset-cell1|U+0396 GREEK CAPITAL LETTER ZETA|Ζ}}
|{{chset-cell1|U+0397 GREEK CAPITAL LETTER ETA|Η}}
|{{chset-cell1|U+0398 GREEK CAPITAL LETTER THETA|Θ}}
|{{chset-cell1|U+0399 GREEK CAPITAL LETTER IOTA|Ι}}
|{{chset-cell1|U+039A GREEK CAPITAL LETTER KAPPA|Κ}}
|{{chset-cell1|U+039B GREEK CAPITAL LETTER LAMDA|Λ}}
|{{chset-cell1|U+039C GREEK CAPITAL LETTER MU|Μ}}
|{{chset-cell1|U+039D GREEK CAPITAL LETTER NU|Ν}}
|{{chset-cell1|U+039E GREEK CAPITAL LETTER XI|Ξ}}
|{{chset-cell1|U+039F GREEK CAPITAL LETTER OMICRON|Ο}}
|-
|{{chset-left1|Dx}}
|{{chset-cell1|U+03A0 GREEK CAPITAL LETTER PI|Π}}
|{{chset-cell1|U+03A1 GREEK CAPITAL LETTER RHO|Ρ}}
|{{chset-cell1|U+03A3 GREEK CAPITAL LETTER SIGMA|Σ}}
|{{chset-cell1|U+03A4 GREEK CAPITAL LETTER TAU|Τ}}
|{{chset-cell1|U+03A5 GREEK CAPITAL LETTER UPSILON|Υ}}
|{{chset-cell1|U+03A6 GREEK CAPITAL LETTER PHI|Φ}}
|{{chset-cell1|U+03A7 GREEK CAPITAL LETTER CHI|Χ}}
|{{chset-cell1|U+03A8 GREEK CAPITAL LETTER PSI|Ψ}}
|{{chset-cell1|U+03A9 GREEK CAPITAL LETTER OMEGA|Ω}}
|{{chset-cell1|U+2207 NABLA|∇}}
|{{chset-cell1|U+00B1 PLUS-MINUS SIGN|±}}
|{{chset-cell1|U+2213 MINUS-OR-PLUS SIGN|∓}}
|{{chset-cell1|U+007C VERTICAL LINE|[[Vertical bar|{{pipe}}]]}}
|{{chset-cell1|U+2016 DOUBLE VERTICAL LINE|‖}}
|{{chset-cell1|U+222A UNION|∪}}
|{{chset-cell1|U+2229 INTERSECTION|∩}}
|-
|{{chset-left1|Ex}}
|{{chset-cell1|U+00F8 LATIN SMALL LETTER O WITH STROKE|ø}}
|{{chset-cell1|U+03B1 GREEK SMALL LETTER ALPHA|α}}
|{{chset-cell1|U+03B2 GREEK SMALL LETTER BETA|β}}
|{{chset-cell1|U+03B3 GREEK SMALL LETTER GAMMA|γ}}
|{{chset-cell1|U+03B4 GREEK SMALL LETTER DELTA|δ}}
|{{chset-cell1|U+03B5 GREEK SMALL LETTER EPSILON|ε}}
|{{chset-cell1|U+03B6 GREEK SMALL LETTER ZETA|ζ}}
|{{chset-cell1|U+03B7 GREEK SMALL LETTER ETA|η}}
|{{chset-cell1|U+03B8 GREEK SMALL LETTER THETA|θ}}
|{{chset-cell1|U+03B9 GREEK SMALL LETTER IOTA|ι}}
|{{chset-cell1|U+03BA GREEK SMALL LETTER KAPPA|κ}}
|{{chset-cell1|U+03BB GREEK SMALL LETTER LAMDA|λ}}
|{{chset-cell1|U+03BC GREEK SMALL LETTER MU|μ}}
|{{chset-cell1|U+03BD GREEK SMALL LETTER NU|ν}}
|{{chset-cell1|U+03BE GREEK SMALL LETTER XI|ξ}}
|{{chset-cell1|U+03BF GREEK SMALL LETTER OMICRON|ο}}
|-
|{{chset-left1|Fx}}
|{{chset-cell1|U+03C0 GREEK SMALL LETTER PI|π}}
|{{chset-cell1|U+03C1 GREEK SMALL LETTER RHO|ρ}}
|{{chset-cell1|U+03C3 GREEK SMALL LETTER SIGMA|σ}}
|{{chset-cell1|U+03C4 GREEK SMALL LETTER TAU|τ}}
|{{chset-cell1|U+03C5 GREEK SMALL LETTER UPSILON|υ}}
|{{chset-cell1|U+03C6 GREEK SMALL LETTER PHI|φ}}
|{{chset-cell1|U+03C7 GREEK SMALL LETTER CHI|χ}}
|{{chset-cell1|U+03C8 GREEK SMALL LETTER PSI|ψ}}
|{{chset-cell1|U+03C9 GREEK SMALL LETTER OMEGA|ω}}
|{{chset-cell1|U+2202 PARTIAL DIFFERENTIAL|[[∂|∂]]}}
|{{chset-cell1|U+2243 ASYMPTOTICALLY EQUAL TO|≃}}
|{{chset-cell1|U+2261 IDENTICAL TO|[[Triple bar|≡]]}}
|{{chset-cell1|U+2264 LESS-THAN OR EQUAL TO|≤}}
|{{chset-cell1|U+2260 NOT EQUAL TO|≠}}
|{{chset-cell1|U+2265 GREATER-THAN OR EQUAL TO|≥}}
|{{chset-cell1|U+2588 FULL BLOCK|█}}
|}

==References==
{{reflist}}

==External links==
* http://bbc.nvg.org/doc/

{{Acorn computers}}
{{BBC Computer Literacy Project}}

[[Category:Home computers]]

{{Sourceattribution|BBC Master}}