BBC Master: Difference between revisions

| name = BBC Master Series

| title =
| aka =

| aka logo =

| image caption = Acorn BBC Master Series.jpg128

| family =

| type = [[8-bit]] [[Microcomputer]]

| generation =

| releasedate = Early {{Start date and age|1986}}

| lifespan =

| price =

| unitssold =

| media =

| os = [[Acorn MOS]], optional [[DOS Plus]]

| power =
| soc =

| storage memory card =

| memorydisplay card= =

| sound input =

| input controllers =

| controllers camera =

| camera touchpad =

| platform =

| service =

| dimensions =

| weight =

| topgame =

| compatibility =

| predecessor = [[BBC Micro|BBC Micro Model B]]

| successor = [[Acorn Archimedes]]

| related =

| website = <!--{{URL|example.org}}-->

== 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 [[BBC Micro|Model B]], itMaster ranseries onmodels used the slightly improved [[WDC 65C02|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 [[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">[http{{ cite magazine | url=https://wwwarchive.8bs.comorg/insides.htm#m128details/Your_Computer_Magazine_Issue_V603/page/66/mode/2up Circuit| boardtitle=The photographs]master appear128 to| indicatemagazine=Your theComputer use| ofdate=March the1986 65SC12| variant.access-date=13 June 2023 | pages=66–67 }}</ref> The costsystems had {{val|128|ul=KB}} of thisdynamic CPURAM compatibilityas standard, withalleviating the Modelshortage Bof wasavailable thatRAM which had previously discouraged use of the addressdisplay busmodes offering the highest quality graphics on earlier models. Of the total 128&nbsp;KB of RAM, 64&nbsp;KB was stillprovided onlyas 16standard bitsRAM, meaningbeing thatused onlyfor 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">{{val cite book |64 url=http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_MasterSM.pdf |u title=KB}}British couldBroadcasting beCorporation directlyMaster addressedSeries atMicrocomputer anyService oneManual time| andpublisher=Acorn theComputers remainingLimited memory| haddate=April to1986 be| pagedaccess-date=10 inOctober as2020 required.| issue=1 | pages=15–18 }}</ref>

! Codename !! PageSize !! Physical address range !! Logical address range !! Description

| LYNNE || 20 KB || {{mono|0x3000–0x7FFF0xB000–0xFFFF}} || CRT{{mono|0x3000–0x7FFF}} frame-switch|| regionShadow RAM (allowsfreeing allconventional screen modesmemory tofor be used without using main memoryuse)

| HAZEL || 8 KB || {{mono|0x9000–0xAFFF}} || {{mono|0xC000–0xDFFF}} || Paged ROM/RAM switchingworkspace (filing system workspace)

| ANDY || 4&nbsp;KB || {{mono|0x8000–0x8FFF}} || ROM/RAM{{mono|0x8000–0x8FFF}} switching|| System workspace (function key, graphics system and character definitions)<ref name="acornuser198603_master"/>

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 [[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 techreporttech 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>

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-£800500–800 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 [[Acorn Archimedes|Archimedes]] range, one commentator considered it "one of the most exciting products Acorn has ever developed".<ref name="acornuser199101_essential" />

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 techreporttech 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]] and low-volume [[Acorn Cambridge Workstation]]), 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]] 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 [[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 [[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 [[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 functionality via this 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> 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.<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>

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.

{{quoteblockquote|<samp>[[Sophie Wilson|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>}}

[[Olivetti]]In werethe namedUK asthe beingDigimouse interestedwas insold releasingwith aClares' versionArtroom, ofan theillustration Masterpackage, Compactlater inbeing [[Italy]]made underavailable theto Olivettipurchase Prodeston brand,its own.<ref name="acornuser198610bacornuser198702_artroom">{{cite newsmagazine | url=https://archive.org/details/AcornUser051AcornUser055-Oct86Feb87/page/n8n146/mode/1up | worktitle=Acorn UserArticulation | titlemagazine=Acorn givesUser birth| to Master Compact |date=OctoberFebruary 19861987 | access-date=517 SeptemberJune 20202022 |pages=7}}</ref> subsequently announcing the model as the {{nowrap|PC 128 S}} aimed at the home and small business markets.<ref namelast1="acornuser198611b">{{cite newsBaldwin |url=https://archive.org/details/AcornUser052-Nov86/page/n8/mode/1up |titlefirst1=Italian Compact set for successJonathan |work=Acorn User | datepages=November145–147 1986 |access-date=5 September 2020 |pages=7}}</ref> UnlikeClares' theArtroom Compact,was localised for the {{nowrap|PC 128 S}} wasand bundledsold with a mouse,under the Niddname Valley DigimouseProject.<ref name="acornuser198702_digimousepc128s_project">{{ cite magazinebook | url=https://archive.org/details/AcornUser055-Feb87/page/n102/mode/1upproject_olivetti | title=Jump for JoyProject | magazinepublisher=AcornOlivetti UserProdest S.p.A. | 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}}

! stylerowspan{{=}}"text-align:center;2" |usedHardware<br />(KB)colours

| style="text-align:center;" |4080 × 32

| style="text-align:center;" |320640 × 256

| style{{=}}"text-align:right;" |42

| style{{=}}"text-align:right;" |20

| style="text-align:center;" |0x3000–0x7FFF

| style{{=}}"text-align:left;" |Graphics

| style="text-align:center;" |2040 × 32

| style="text-align:center;" |160320 × 256

| style{{=}}"text-align:right;" |84

| style{{=}}"text-align:right;" |20

| style="text-align:center;" |0x3000–0x7FFF

| style{{=}}"text-align:left;" |Graphics

| style{{=}}"text-align:right;" |28

| style{{=}}"text-align:right;" |1620

| style{{=}}"text-align:right;" |2

| style{{=}}"text-align:right;" |1016

| style="text-align:center;" |2040 × 32

| style="text-align:center;" |160320 × 256

| style{{=}}"text-align:right;" |42

| style{{=}}"text-align:right;" |10

| style="text-align:center;" |0x5800–0x7FFF

| style{{=}}"text-align:left;" |Graphics

| style{{=}}"text-align:right;" |24

| style{{=}}"text-align:right;" |810

| style="text-align:center;" |40 × 25

| style{{=}}"text-align:right;" |82

| style{{=}}"text-align:right;" |18

|}-