Zx Spectrum

HardwareEurope) were the DISCiPLE and +D systems
ZX Spectrum 48K motherboard (Issue 3B  1983,released by Miles Gordon Technology in 1987 and
heat sink removed)1988 respectively. Both systems had the ability to
The Spectrum is based on a Zilog Z80A CPUstore memory images onto disk snapshots could
running at 3.5 MHz (or NEC D780C-1 clone). Thelater be used to restore the Spectrum to its
original model Spectrum has 16 KB (161024exact previous state. They were also both
bytes) of ROM and either 16 KB or 48 KB ofcompatible with the Microdrive command syntax,
RAM. Hardware design was by Richard Altwasserwhich made porting existing software much
of Sinclair Research, and the machine's outwardsimpler.
appearance was designed by Sinclair's industrialDuring the mid-1980s, Telemap Group Ltd
designer Rick Dickinson.launched a fee-based service allowing users to
Video output is through an RF modulator and wasconnect their ZX Spectrums via a Prism Micro
designed for use with contemporary portableProducts VTX5000 modem to a viewdata service
television sets, for a simple colour graphic display.known as Micronet 800, hosted by Prestel. This
Text can be displayed using 32 columnsservice pre-dated the web, but offered many of
24 rows of characters from the ZX Spectrumthe services now considered commonplace.
character set or from a set provided within anSoftware
application, from a palette of 15 shades: sevenA screenshot from Rebelstar, a well-known
colours at two levels of brightness each, plusSpectrum game
black. The image resolution is 256192 with theMain article: ZX Spectrum software
same colour limitations. To conserve memory,The Spectrum enjoys a vibrant, dedicated
colour is stored separate from the pixel bitmap infan-base. Since it was cheap and simple to learn
a low resolution, 3224 grid overlay, correspondingto use and program, the Spectrum was the
to the character cells. Altwasser received astarting point for many programmers. The
patent for this design.hardware limitations of the Spectrum imposed a
An "attribute" consists of a foreground and aspecial level of creativity on game designers, and
background colour, a brightness level (normal orso many Spectrum games are very creative and
bright) and a flashing "flag" which, when set,playable even by today's standards. The early
causes the two colours to swap at regularSpectrum models' great success as a games
intervals. Unfortunately, this scheme leads to whatplatform came in spite of its lack of built-in
was dubbed colour clash or attribute clash withjoystick ports, primitive sound generation, and
some bizarre effects in the animated graphics ofcolour support that was optimised for text display.
arcade style games. This problem became aThe Spectrum family enjoys a very large
distinctive feature of the Spectrum and an in-jokesoftware library of more than 20,000 titles which
among Spectrum users, as well as a point ofis still increasing. While most of these are games,
derision by advocates of other systems. Otherthe library is very diverse, including programming
machines available around the same time, forlanguage implementations, databases (eg VU-File),
example the Amstrad CPC, did not suffer fromword processors (eg Tasword II), spreadsheets
this limitation. The Commodore 64 used colour(eg VU-Calc), drawing and painting tools (eg OCP
attributes in a similar way, but a special multicolourArt Studio), and even 3D-modelling (e.g. VU-3D) as
mode, hardware sprites and scrolling were usedwell as astronomy and astrology programs and
to avoid attribute clash.archaeology software.
Sound output is through a beeper on the machineDistribution
itself. This is capable of producing one channel withMost Spectrum software was originally distributed
10 octaves. The machine also includes anon audio cassette tapes. The Spectrum was
expansion bus edge connector and audio in/outintended to work with a normal domestic
ports for the connection of a cassette recordercassette recorder, and despite differences in
for loading and saving programs and data.audio reproduction fidelity, the software loading
The machine's Sinclair BASIC interpreter is storedprocess was quite reliable, if somewhat slow (by
in ROM (along with fundamental system-routines)today's standards).
and was written by Steve Vickers on contractAlthough the ZX Microdrive was initially greeted
from Nine Tiles Ltd. The Spectrum's chicletwith good reviews, it never took off as a
keyboard (on top of a membrane, similar todistribution method due to worries about the
calculator keys) is marked with BASIC keywords,quality of the cartridges and piracy. Hence the
so that, for example, pressing "G" when inmain use became to complement tape releases,
programming mode would insert the BASICusually utilities and niche products like the Tasword
command GO TO.word processing software and Trans Express, (a
Modelstape to microdrive copying utility). No games are
Pre-production designsknown to be exclusively released on Microdrive.
Rick Dickinson came up with a number of designsDespite the popularity of the DISCiPLE and +D
called the ZX82 before the finalised ZX Spectrum.systems, most software released for them took
A number of the keyboard legends changedthe form of utility software. The ZX Spectrum
during the design phase including ARC becoming+3 enjoyed much more success when it came to
CIRCLE, FORE becoming INK and BACK becomingcommercial software releases on floppy disk.
PAPER.More than 700 titles were released on 3-inch disk
Sinclair Research modelsfrom 1987 to 1997.
ZX Spectrum 16K/48KSoftware was also distributed through print media;
ZX Spectrum 16K/48K (Dimensions (mm):magazines and books. The reader would type the
233x144x30 (WxHxD) @ ~552 grams).Sinclair BASIC program listing into the computer
The original ZX Spectrum is remembered for itsby hand, run it, and could save it to tape for later
rubber keyboard, diminutive size and distinctiveuse. The software distributed in this way was in
rainbow motif. It was originally released in 1982general simpler and slower than its assembly
with 16 KB of RAM for 125 Sterling or with 48language counterparts. Magazines also printed long
KB for 175; these prices were later reduced tolists of checksummed hexadecimal digits with
99 and 129 respectively. Owners of the 16 KBmachine code games or tools.
model could purchase an internal 32 KB RAMAnother software distribution method was to
upgrade, which for early "Issue 1" machinesbroadcast the audio stream from the cassette on
consisted of a daughterboard. Later issueanother medium and have users record it onto an
machines required the fitting of 8 dynamic RAMaudio cassette themselves. In radio or television
chips and a few TTL chips. Users could mail theirshows in many European countries, the host
16K Spectrums to Sinclair to be upgraded to 48would describe a program, instruct the audience
KB versions. To reduce the price, the 32 KBto connect a cassette tape recorder to the radio
extension used eight faulty 64 kilobit chips withor TV and then broadcast the program over the
only one half of their capacity working and/orairwaves in audio format. Some magazines
available. External 32 KB RAM packs that mounteddistributed 7" 33 rpm flexidisc records, a variant
in the rear expansion slot were also available fromof regular vinyl records which could be played on
third parties. Both machines had 16 KB of onboarda standard record player. These disks were
ROM.known as floppy ROMs.
About 60,000 "Issue 1" ZX Spectrums wereCopying and backup software
manufactured; they can be distinguished fromMany copierstilities to copy programs from audio
later models by the colour of the keys (light greytape to another tape, microdrive tapes, and later
for Issue 1, blue-grey for later models).on diskettesere available for the Spectrum. As a
ZX Spectrum+response to this, publishers introduced copy
ZX Spectrum+ (Dimensions (mm): 319x149x38protection measures to their software, including
(WxHxD))different loading schemes. Other methods for
Planning of the ZX Spectrum+ started in Junecopy prevention were also used including asking
1984, and the machine was released in Octoberfor a particular word from the documentation
the same year. This 48 KB Spectrumincluded with the gameften a novella like in Silicon
(development code-name TB) introduced a newDreams trilogyr another physical device distributed
QL-style case with an injection-moulded keyboardwith the software.g. Lenslok as used in Elite.
and a reset button. Electronically, it was identicalSpecial hardware, such as Romantic Robot's
to the previous 48 KB model. It retailed forMultiface, was able to dump a copy of the ZX
179.95. A DIY conversion-kit for older machinesSpectrum RAM to disk/tape at the press of a
was also available. Early on, the machine outsoldbutton, entirely circumventing the copy protection
the rubber-key model 2:1; however, somesystems.
retailers reported a failure rate of up to 30%,Most Spectrum software has, in recent years,
compared with a more usual 5-6%.been converted to current media and is available
ZX Spectrum 128for download. One popular program for converting
ZX Spectrum 128Spectrum files from tape is Taper; it allows
Sinclair developed the ZX Spectrum 128connecting a cassette tape player to the line in
(code-named Derby) in conjunction with theirport of a sound card, orhrough a simple
Spanish distributor Investrnica. Investrnica hadhome-built deviceo the parallel port of a PC. Once
helped adapt the ZX Spectrum+ to the Spanishin files on a host machine, the software can be
market after the Spanish government introducedexecuted on one of many emulators, on virtually
a special tax on all computers with 64 KB RAMany platform available today.
or less which did not support the Spanish alphabetThe largest on-line archive of ZX Spectrum
(such as ) and show messages in Spanish.software is World of Spectrum, with more than
New features included 128 KB RAM,18,000 titles. The legality of this practice is still in
three-channel audio via the AY-3-8912 chip, MIDIquestion and a number of copyright holders have
compatibility, an RS-232 serial port, an RGBexplicitly objected to the posting of their
monitor port, 32 KB of ROM including ansoftware, with which some Spectrum
improved BASIC editor, and an external keypad.abandonware sites have usually complied.
The machine was simultaneously presented forNotable developers
the first time and launched in September 1985 atA number of current leading games developers
the SIMO '85 trade show in Spain, with a price ofand development companies began their careers
44,250 pesetas. Because of the large number ofon the ZX Spectrum, including David Perry of
unsold Spectrum+ models, Sinclair decided not toShiny Entertainment, and Tim and Chris Stamper
start selling in the UK until January 1986 at a price(founders of Ultimate Play The Game, now
of 179.95. No external keypad was available forknown as Rare, maker of many famous titles for
the UK release, although the ROM routines to useNintendo and Microsoft game consoles). Other
it and the port itself, which was hastily renamedprominent games developers include Julian Gollop
"AUX", remained.(Chaos, Rebelstar, X-COM series), Matthew Smith
The Z80 processor used in the Spectrum has a(Manic Miner, Jet Set Willy), Jon Ritman (Match
16-bit address bus, which means only 64 KB ofDay, Head Over Heels), The Oliver Twins (the
memory can be directly addressed. To facilitateDizzy series), Clive Townsend (Saboteur), Pete
the extra 80 KB of RAM the designers usedCooke (Tau Ceti), Mike Singleton (The Lords of
bank switching so that the new memory wouldMidnight,War In Middle Earth), and Alan Cox.
be available as eight pages of 16 KB at the topAlthough the Spectrum's audio hardware was not
of the address space. The same technique wasas capable as that of the Commodore 64,
also used to page between the new 16 KB editorcomputer musicians David Whittaker and Tim
ROM and the original 16 KB BASIC ROM at theFollin produced notable multi-channel music for the
bottom of the address space.machine.
The new sound chip and MIDI out abilities wereJeff Minter ported some of his Commodore
exposed to the BASIC programming languageVIC-20 games for the ZX Spectrum.
with the command PLAY and a new commandCommunity
SPECTRUM was added to switch the machine intoThe ZX Spectrum enjoyed a very strong
48K mode, keeping the current BASIC programcommunity early on. Several dedicated magazines
intact (although there is no way to switch back towere released including Sinclair User (1982), Your
128K mode). To enable BASIC programmers toSinclair (1983) and CRASH (1984). Early on they
access the additional memory, a RAM disk waswere very technically oriented with type-in
created where files could be stored in theprograms and machine code tutorials. Later on
additional 80 KB of RAM. The new commandsthey became almost completely game-oriented.
took the place of two existingSeveral general contemporary computer
user-defined-character spaces causing compatibilitymagazines covered the ZX Spectrum in more or
problems with some BASIC programs.less detail. They included Computer Gamer,
The Spanish version had the "128K" logo in whiteComputer and Video Games, Computing Today,
while the English one had the same logo in red.Popular Computing Weekly, Your Computer and
Amstrad modelsThe Games Machine.
ZX Spectrum +2The Spectrum is affectionately known as the
ZX Spectrum +2Speccy by elements of its fan following.
The ZX Spectrum +2 was Amstrad's firstMore than 80 electronic magazines existed,
Spectrum, coming shortly after their purchase ofmostly in Russian. Most notable of them were
the Spectrum range and "Sinclair" brand in 1986.AlchNews (UK), ZX-Format (Russia), and
The machine featured an all-new grey caseSpectrofon (Russia).
featuring a spring-loaded keyboard, dual joystickSee also
ports, and a built-in cassette recorder dubbed theSAM Coup A Similar system, often considered a
"Datacorder" (like the Amstrad CPC 464), butclone of the ZX Spectrum.
was in most respects identical to the ZXZX Spectrum graphic modes
Spectrum 128. The main menu screen lacked theList of ZX Spectrum games
Spectrum 128's "Tape Test" option, and the ROMList of ZX Spectrum clones
was altered to account for a new 1986 AmstradHistory of computing hardware (1960s-present)
copyright message. These changes resulted inReferences
minor incompatibility problems with software that^ a b c "How the Spectrum began a revolution".
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CODE and RUN which were useful for loadinggood, old 'speccy'". Computer Museum. Retrieved
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with the keywords, and 128k BASICSpectrum: 25 today". Register Hardware. Situation
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the case reads "ZX Spectrum +2", the +2A/B is^ EP patent 0107687, "Display for a computer",
easily distinguishable from the original +2 as thegranted 1988-07-06 , assigned to Sinclair Research
case was restored to the standard SpectrumLtd 
black.^ Vickers, Steven (1982). "Basic programming
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featured a built-in 3-inch floppy disk drive (like theSinclair. Retrieved 2006-08-21. 
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version of Amstrad's AMSDOS, called +3DOS.^ Phillips, Max (November 1986). "ZX Spectrum
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CP/M, which requires RAM at the bottom of theRetrieved 2008-01-05. 
address space, the bank-switching was further^ South, Phil (July 1987). "It's here... the Spectrum
improved, allowing the ROM to be paged out for+3". Your Sinclair (17): 2223. Retrieved
another 16 KB of RAM.2008-08-05. 
Such core changes brought incompatibilities:^ Amstrad (November 1987). "The new Sinclair
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such as the VTX5000 modem could be used viaSuperspectrum". comp.sys.sinclair. (Web link).
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were removedmove 1 byte address in ROMWorld: Spectrum receives its biggest
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accounting for one third of all home computer^ "Hardware World: Clear speech from Currah
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Didaktik MVideoface to Face". CRASH (37): 8687. Retrieved
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Corporation in the United States. An enhancedCRASH (27): 100. Retrieved 2007-08-09. 
version of the Spectrum with better sound,^ Frey, Franco (March 1986). "Tech Niche:
graphics and other modifications was marketed inMultifaceted device". CRASH (36): 86. Retrieved
the USA by Timex as the Timex Sinclair 2068.2008-08-05. 
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Pandora portable Spectrum, whose ULA had theGospel". CRASH (38): 8283. Retrieved
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(e.g. in Romania, several models were producedThe Word Processor". CRASH! (5): 126. Retrieved
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ZX81.^ Foot, Cathy (November 1985). "Microdrive
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connection of up to eight ZX Microdrives ^ Heide, Martijn van der. "Books". World of
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Morex Peripherals Centronics/RS-232 interface,^ Heide, Martijn van der. "World of Spectrum 
the Currah Microspeech unit (speech synthesis),Software  Copyrights and Distribution
Videoface Digitiser, RAM pack, the CheetahPermissions". World of Spectrum. Retrieved
Marketing SpecDrum, a drum machine, and the2008-09-12. 
Multiface, a snapshot and disassembly tool from^ Bezroukov, Nikolai. "Alan Cox: and the Art of
Romantic Robot. Keyboards were especiallyMaking Beta Code Work". Portraits of Open
popular in view of the original's notorious "deadSource Pioneers. Retrieved 2007-01-18. 
flesh" feel.^ Minter, Jeff. "Llamasoft History  Part 8 - The
ZX PrinterDawn of Llamasoft". Retrieved 2007-09-26. 
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ZX Interface 2of the near past.". TV Cream's Top Shelf.
ZX MicrodriveRetrieved 2008-09-10. 
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There were numerous disk drive interfaces,(Ever!)". Your Sinclair (70): 31. October 1991.
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Electronics SPDOS, Abbeydale DesignersExternal links
Kempston KDOS and Opus Discovery. TheWikimedia Commons has media related to: Sinclair
SPDOS and KDOS interfaces were the first toZX Spectrum
come bundled with Office productivity softwareWorld of Spectrum  Fan site officially endorsed
(Tasword Word Processor, Masterfile databaseby Amstrad
and OmniCalc spreadsheet). This bundle, togetherPlanet Sinclair  Spectrum pages
with OCP's Stock Control, Finance and PayrollZX Spectrum at the Open Directory Project
systems, introduced many small businesses to aZXF magazine
streamlined, computerised operation. The mostThe Incomplete Spectrum ROM Assembly and
popular floppy disk systems (except in Eastactual assembly listingcomp.sys.