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The ZX Spectrum () is an
8-bit In computer architecture, 8-bit Integer (computer science), integers or other Data (computing), data units are those that are 8 bits wide (1 octet (computing), octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) arc ...
home computer that was developed by
Sinclair Research Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge. It was originally incorporated in 1973 as Westminster Mail Order Ltd, renamed Sinclair Instrument Ltd, then Science of Cambridge Ltd, the ...
. It was released in the United Kingdom on 23 April 1982, and became Britain's best-selling
microcomputer A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PC ...
. Referred to during development as the ''ZX81 Colour'' and ''ZX82'', it was launched as the ''ZX Spectrum'' to highlight the machine's colour display, which differed from the black and white display of its predecessor, the
ZX81 The ZX81 is a home computer that was produced by Sinclair Research and manufactured in Dundee, Scotland, by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and designed to be a low-cos ...
. The Spectrum was released as six different models, ranging from the entry level with 16  KB RAM released in 1982 to the ZX Spectrum +3 with 128 KB RAM and built in
floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...
drive in 1987; altogether they sold over 5 million units worldwide (not counting unofficial clones). The Spectrum was among the first home computers in the United Kingdom aimed at a mainstream audience, and it thus had similar significance to the
Commodore 64 The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...
in the US and the
Thomson MO5 The Thomson MO5 is a home computer introduced in France in June 1984 to compete against systems such as the ZX Spectrum and Commodore 64. It had a release price of 2390 FF. At the same time, Thomson also released the up-market Thomson TO7/7 ...
in France. The introduction of the ZX Spectrum led to a boom in companies producing software and hardware for the machine, the effects of which are still seen. Some credit it as the machine which launched the British information technology industry. Licensing deals and clones followed, earning
Clive Sinclair Sir Clive Marles Sinclair (30 July 1940 – 16 September 2021) was an English entrepreneur and inventor, best known for being a pioneer in the computing industry, and also as the founder of several companies that developed consumer electronics ...
a knighthood for services to British industry. The Commodore 64,
Dragon 32 The Dragon 32 and Dragon 64 are home computers that were built in the 1980s. The Dragons are very similar to the TRS-80 Color Computer, and were produced for the European market by Dragon Data, Ltd., initially in Swansea, Wales before mov ...
,
Oric-1 Oric was the name used by UK-based Tangerine Computer Systems for a series of 6502-based home computers sold in the 1980s, primarily in Europe. With the success of the ZX Spectrum from Sinclair Research, Tangerine's backers suggested a hom ...
,
Oric Atmos Oric was the name used by UK-based Tangerine Computer Systems for a series of 6502-based home computers sold in the 1980s, primarily in Europe. With the success of the ZX Spectrum from Sinclair Research, Tangerine's backers suggested a hom ...
,
BBC Micro The British Broadcasting Corporation Microcomputer System, or BBC Micro, is a series of microcomputers and associated peripherals designed and built by Acorn Computers in the 1980s for the BBC Computer Literacy Project. Designed with an emphas ...
and later the
Amstrad CPC The Amstrad CPC (short for ''Colour Personal Computer'') is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the Sin ...
range were rivals to the Spectrum in the UK market during the early 1980s. The machine was officially discontinued in 1992.


Hardware

ZX Spectrum 48K motherboard (Issue 3B: 1983, heat sink removed) The Spectrum is based on a
Zilog Z80 The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples wer ...
, a CPU running at 3.5 
MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
(or
NEC is a Japanese multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It provides IT and network soluti ...
D780C-1 clone). The original model has 16 KB (16×1024
byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...
s) of
ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...
and either 16 KB or 48 KB of
RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...
. Hardware design was by
Richard Altwasser Richard Francis Altwasser is a British engineer and inventor, responsible for the hardware design of the ZX Spectrum. Biography Altwasser graduated at Trinity College, Cambridge, with a degree in engineering in June 1978. He was hired by Si ...
of Sinclair Research, and the outward appearance was designed by Sinclair's industrial designer
Rick Dickinson Rick Dickinson (c. 1957 – 24 April 2018) was a British industrial designer who developed pioneering computer designs in the 1980s. Notable examples of his design work include the ZX81 case and touch-sensitive keyboard and the ZX Spectrum's ...
. Video output is through an
RF modulator An RF modulator (or radio frequency modulator) is an electronic device whose input is a baseband signal which is used to modulate a radio frequency source. RF modulators are used to convert signals from devices such as media players, VCRs a ...
and was designed for use with contemporary television sets, for a simple colour graphic display. Text can be displayed using 32 columns × 24 rows of characters from the
ZX Spectrum character set The ZX Spectrum character set is the variant of ASCII used in the ZX Spectrum family computers. It is based on ASCII-1967 but the characters ^, ` and DEL are replaced with ↑, £ and ©. It also differs in its use of the C0 control codes other ...
or from a set provided within an application, from a palette of 15 shades: seven colours at two levels of brightness each, plus black. The
image resolution Image resolution is the detail an image holds. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies how ...
is 256×192 with the same colour limitations. To conserve memory, colour is stored separate from the pixel
bitmap In computing, a bitmap is a mapping from some domain (for example, a range of integers) to bits. It is also called a bit array A bit array (also known as bitmask, bit map, bit set, bit string, or bit vector) is an array data structure that c ...
in a low resolution, 32×24 grid overlay, corresponding to the character cells. In practice, this means that all pixels of an 8x8 character block share one foreground colour and one background colour. Altwasser received a patent for this design. An "attribute" consists of a foreground and a background colour, a brightness level (normal or bright) and a flashing "flag" which, when set, causes the two colours to swap at regular intervals. This scheme leads to what was dubbed ''colour clash'' or ''
attribute clash Attribute may refer to: * Attribute (philosophy), an extrinsic property of an object * Attribute (research), a characteristic of an object * Grammatical modifier, in natural languages * Attribute (computing), a specification that defines a proper ...
'', where a desired colour of a specific pixel could not necessarily be selected. This became a distinctive feature of the Spectrum, meaning programs, particularly games, had to be designed around this limitation. Other machines available around the same time, for example the
Amstrad CPC The Amstrad CPC (short for ''Colour Personal Computer'') is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the Sin ...
or the
Commodore 64 The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness ...
, did not suffer from this limitation. The Commodore 64 used colour attributes in a similar way, but a special multicolour mode and hardware sprites were used to avoid attribute clash. Sound output is through a beeper on the machine itself, capable of producing one channel with 10 octaves.
Software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...
was later available that could play two channel sound. The machine includes an
expansion bus In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus slo ...
edge connector An edge connector is the portion of a printed circuit board (PCB) consisting of traces leading to the edge of the board that are intended to plug into a matching socket. The edge connector is a money-saving device because it only requires a sing ...
and 3.5 mm audio in/out ports for the connection of a
cassette recorder A cassette deck is a type of tape machine for playing and recording audio cassettes that does not have a built-in power amplifier or speakers, and serves primarily as a transport. It can be a part of an automotive entertainment system, a part of ...
for loading and saving programs and data. The "ear" port has a higher output than the "mic" and is recommended for headphones, with "mic" for attaching to other audio devices as line in. The machine was manufactured in
Dundee Dundee (; sco, Dundee; gd, Dùn Dè or ) is Scotland's fourth-largest city and the 51st-most-populous built-up area in the United Kingdom. The mid-year population estimate for 2016 was , giving Dundee a population density of 2,478/km2 or ...
, Scotland, in the now closed Timex factory.


Firmware

The machine's
Sinclair BASIC Sinclair BASIC is a dialect of the programming language BASIC used in the 8-bit home computers from Sinclair Research and Timex Sinclair. The Sinclair BASIC interpreter was made by Nine Tiles Networks Ltd. History Sinclair BASIC was orig ...
interpreter is stored in ROM (along with fundamental system-routines) and was written by Steve Vickers on contract from Nine Tiles Ltd. The Spectrum's
chiclet keyboard A chiclet keyboard or island-style keyboard is a computer keyboard with keys that form an array of small, flat rectangular or lozenge-shaped rubber or plastic keys that look like erasers or "Chiclets", a brand of chewing gum manufactured in the s ...
(on top of a membrane, similar to calculator keys) is marked with BASIC keywords. For example, pressing "G" when in programming mode would insert the BASIC command GO TO. The BASIC interpreter was developed from that used on the
ZX81 The ZX81 is a home computer that was produced by Sinclair Research and manufactured in Dundee, Scotland, by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and designed to be a low-cos ...
and a ZX81 BASIC program can be typed into a Spectrum largely unmodified, but Spectrum BASIC included many extra features making it easier to use. The
ZX Spectrum character set The ZX Spectrum character set is the variant of ASCII used in the ZX Spectrum family computers. It is based on ASCII-1967 but the characters ^, ` and DEL are replaced with ↑, £ and ©. It also differs in its use of the C0 control codes other ...
was expanded from that of the ZX81, which did not feature lower-case letters. Spectrum BASIC included extra keywords for the more advanced display and sound, and supported multi-statement lines. The cassette interface was much more advanced, saving and loading around five times faster than the ZX81 (1500 bits per second compared to 307), and unlike the ZX81, the Spectrum could maintain the TV display during tape storage and retrieval operations. As well as being able to save programs, the Spectrum could save the contents of arrays, the contents of the screen memory, and the contents of any defined range of memory addresses.


Sinclair Research models


Pre-production designs

Rick Dickinson came up with a number of designs for the "ZX82" project before the final ZX Spectrum design. A number of the keyboard legends changed during the design phase including ARC becoming CIRCLE, FORE becoming INK and BACK becoming PAPER. The Spectrum reused a number of design elements of the ZX81: The ROM code for things such as
floating point In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can be ...
calculations and expression parsing were very similar (with a few obsolete ZX81 routines left in the Spectrum ROM). The simple keyboard decoding and cassette interfaces were nearly identical (although the latter was now programmed to load/save at a higher speed). The central ULA
integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
was somewhat similar although it implemented the major enhancement over the ZX81: A (fully) hardware based television raster generator (with colour) that indirectly gave the new machine approximately four times as much processing power as the ZX81, simply due to the Z80 now being released from this video generation task. A bug in the ULA as originally designed meant that the keyboard did not always scan correctly, and was rectified by a "dead cockroach" (a small
circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in Electrical engineering, electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a L ...
mounted upside down next to the CPU) for Issue 1 ZX Spectrums.


ZX Spectrum 16K/48K

ZX Spectrum 16K/48K (Dimensions (mm): 233×144×30 (W×H×D) @ ≈552 grams). The original ZX Spectrum is remembered for its rubber
chiclet keyboard A chiclet keyboard or island-style keyboard is a computer keyboard with keys that form an array of small, flat rectangular or lozenge-shaped rubber or plastic keys that look like erasers or "Chiclets", a brand of chewing gum manufactured in the s ...
, diminutive size and distinctive rainbow motif. It was originally released on 23 April 1982 with 16 KB of RAM for or with 48 KB for ; these prices were reduced to and respectively in 1983. Owners of the 16 KB model could purchase an internal 32 KB RAM upgrade, which for early "Issue 1" machines consisted of a
daughterboard In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus slo ...
. Later issue machines required the fitting of 8
dynamic RAM Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxid ...
chips and a few
TTL TTL may refer to: Photography * Through-the-lens metering, a camera feature * Zenit TTL, an SLR film camera named for its TTL metering capability Technology * Time to live, a computer data lifespan-limiting mechanism * Transistor–transistor lo ...
chips. Users could mail their 16K Spectrums to Sinclair to be upgraded to 48 KB versions. Later revisions contained 64 KB of memory but were configured such that only 48 KB were usable. External 32 KB RAM packs that mounted in the rear expansion slot were available from third parties. Both machines had 16 KB of onboard ROM. An "Issue 1" ZX Spectrum can be distinguished from later models by the colour of the keys – light grey for Issue 1, blue-grey for later machines. Although the official service manual states that approximately 26,000 of these original boards were manufactured, subsequent serial number analysis shows that only 16,000 were produced, almost all of which fell in the serial number range 001-000001 to 001-016000. An online tool now exists to allow users to ascertain the likely issue number of their ZX Spectrum by inputting the serial number. The Sinclair models featured audio line in and out, in the form of an "ear" and "mic" socket. An external tape recorder was needed to load the majority of software released, or the
ZX Microdrive ZX Microdrive unit The ZX Microdrive is a magnetic-tape data storage system launched in July 1983 by Sinclair Research for its ZX Spectrum home computer. It was proposed as a faster-loading alternative to the cassette and cheaper than a flo ...
. Either socket could be connected to headphones or an amplifier as an audio output, although this would not disable the internal speaker. The original ZX Spectrum model experienced numerous changes to its motherboard design; mainly to improve manufacturing efficiencies, but also to correct bugs from previous boards. Another issue was with the Spectrum's power supply. In March 1983, Sinclair issued an "URGENT" recall warning for all owners of models bought after 1 January 1983. Plugs with a plain (rather than textured) surface were at risk of causing shock, and were asked to be sent back to Sinclair's office in Broad Lane, Cottenham. It's not known how many power supplies were returned, and how many still exist in the wild. Sales of the Spectrum reached 200,000 in its first nine months rising to 300,000 for the whole of the first year. By August 1983 total sales in the UK and Europe had exceeded 500,000 with the millionth Spectrum manufactured on December 9th.


ZX Spectrum+

ZX Spectrum+ (Dimensions (mm): 319×149×38 (W×H×D)) Planning of the ''ZX Spectrum+'' started in June 1984, and was released on October 15. This 48 KB Spectrum (development code-name ''TB'') introduced a new QL-style case with an injection-moulded keyboard and a reset button that was basically a switch that shorted across the CPU reset capacitor. Electronically, it was identical to the previous 48 KB model. It was possible to change the system boards between the original case and the Spectrum+ case. It retailed for . A
DIY "Do it yourself" ("DIY") is the method of building, modifying, or repairing things by oneself without the direct aid of professionals or certified experts. Academic research has described DIY as behaviors where "individuals use raw and sem ...
conversion-kit for older machines was available. Early on, the machine outsold the rubber-key model 2:1; however, some retailers reported a failure rate of up to 30%, compared with a more usual 5–6% for the older model. In early 1985, the original Spectrum was officially discontinued and the ZX Spectrum+ was reduced in price to .


ZX Spectrum 128

ZX Spectrum 128 In 1985, Sinclair developed the ''ZX Spectrum 128'' (code-named ''Derby'') in conjunction with their Spanish distributor Investrónica (a subsidiary of
El Corte Inglés El Corte Inglés S.A. (), headquartered in Madrid, is the biggest department store group in Europe and ranks third worldwide. Its primary source of sales is from department stores, followed by internet sales. It is a family business, with most s ...
department store group). Investrónica had helped adapt the ZX Spectrum+ to the Spanish market after the Spanish government introduced a special tax on all computers with 64 KB RAM or less, and a law which obliged all computers sold in Spain to support the Spanish alphabet and show messages in Spanish. Ministerio de Industria y Energía (BOE 179 de 27 July 1985)
Real Decreto 1250/1985, de 19 de junio, por el que se establece la sujeción a especificaciones técnicas de los terminales de pantalla con teclado, periféricos para entrada y representación de información en equipo de proceso de datos
. Rango: Real Decreto, Páginas: 23840–23841, Referencia: 1985/15611.
The appearance of the ZX Spectrum 128 was similar to the ZX Spectrum+, with the exception of a large external
heatsink A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, the ...
for the internal 7805
voltage regulator A voltage regulator is a system designed to automatically maintain a constant voltage. A voltage regulator may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism, or electronic components ...
added to the right hand end of the case, replacing the internal
heatsink A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, the ...
in previous versions. This external
heatsink A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, the ...
led to the system's nickname, "The Toast Rack". New features included 128 KB RAM with RAM disc commands 'save !"name"', three-channel audio via the
AY-3-8912 The AY-3-8910 is a 3-voice programmable sound generator (PSG) designed by General Instrument in 1978, initially for use with their 16-bit CP1610 or one of the PIC1650 series of 8-bit microcomputers. The AY-3-8910 and its variants were used i ...
chip,
MIDI MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
compatibility, an
RS-232 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such a ...
serial port, an
RGB The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three addi ...
monitor port, 32 KB of ROM including an improved BASIC editor, and an external keypad. The machine was simultaneously presented for the first time and launched in September 1985 at the SIMO '85 trade show in Spain, with a price of 44,250 pesetas. Because of the large number of unsold Spectrum+ models, Sinclair decided not to start selling in the UK until January 1986 at a price of . No external keypad was available for the UK release, although the ROM routines to use it and the port itself remained. The
Z80 The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were ...
processor used in the Spectrum has a 16-bit address bus, which means only 64 KB of memory can be directly addressed. To facilitate the extra 80 KB of RAM the designers used
bank switching Bank switching is a technique used in computer design to increase the amount of usable memory beyond the amount directly addressable by the processor instructions. It can be used to configure a system differently at different times; for example ...
so the new memory would be available as eight pages of 16 KB at the top of the address space. The same technique was used to page between the new 16 KB editor ROM and the original 16 KB BASIC ROM at the bottom of the address space. The new sound chip and
MIDI MIDI (; Musical Instrument Digital Interface) is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and re ...
out abilities were exposed to the BASIC programming language with the command ''PLAY'' and a new command ''SPECTRUM'' was added to switch the machine into 48K mode, keeping the current BASIC program intact (although there is no command to switch back to 128K mode). To enable BASIC programmers to access the additional memory, a RAM disk was created where files could be stored in the additional 80 KB of RAM. The new commands took the place of two existing user-defined-character spaces causing compatibility problems with certain BASIC programs. The ZX Spectrum 128 had no internal speaker, unlike its predecessors. Sound was produced from the television speaker instead. The Spanish version had the "128K" logo in white; the British one had the same logo in red.


Amstrad models


ZX Spectrum +2

ZX Spectrum +2 The ''ZX Spectrum +2'' was
Amstrad Amstrad was a British electronics company, founded in 1968 by Alan Sugar at the age of 21. The name is a contraction of Alan Michael Sugar Trading. It was first listed on the London Stock Exchange in April 1980. During the late 1980s, Amstrad ...
's first Spectrum, coming shortly after their purchase of the Spectrum range and "Sinclair" brand in 1986. The machine featured an all-new grey case featuring a spring-loaded keyboard, dual joystick ports, and a built-in cassette recorder dubbed the "Datacorder" (like the Amstrad CPC 464), but was in most respects identical to the ZX Spectrum 128. The main menu screen lacked the Spectrum 128's "Tape Test" option, and the ROM was altered to account for a new 1986 Amstrad copyright message. Production costs had been reduced and the retail price dropped to £139–£149. The new keyboard did not include the BASIC keyword markings that were found on earlier Spectrums, except for the keywords ''LOAD'', ''CODE'' and ''RUN'' which were useful for loading software. Instead, the +2 boasted a menu system, almost identical to the ZX Spectrum 128, where one could switch between 48K BASIC programming with the keywords, and 128K BASIC programming in which all words (keywords and otherwise) must be typed out in full (although the keywords are still stored internally as one character each). Despite these changes, the layout remained identical to that of the 128. The ZX Spectrum +2 power supply was a grey version of the ZX Spectrum+ and 128 power supply.


ZX Spectrum +3

ZX Spectrum +3 The ''ZX Spectrum +3'', released in 1987, looked similar to the +2A but featured a built-in 3-inch
floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...
drive (like the Amstrad CPC 6128) instead of the tape drive, and was in a black case. It was launched in 1987, initially retailed for £249 and then later £199 and was the only Spectrum capable of running the
CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initial ...
operating system without additional hardware. The +3 saw the addition of two more 16 KB ROMs. One was home to the second part of the reorganised 128 ROM and the other hosted the +3's disk operating system. This was a modified version of Amstrad's PCWDOS (the disk access code used in
LocoScript LocoScript is a word processing software package created by Locomotive Software and first released with the Amstrad PCW, a personal computer launched in 1985. Early versions of LocoScript were noted for combining a wide range of facilities with ...
), called +3DOS. These two new 16 KB ROMs and the original two 16 KB ROMs were now physically implemented together as two 32 KB chips. To be able to run CP/M, which requires RAM at the bottom of the address space, the bank-switching was further improved, allowing the ROM to be paged out for another 16 KB of RAM. Such core changes brought incompatibilities: * Removal of several lines on the expansion bus edge connector (video, power, and IORQGE); caused many external devices problems; some such as the VTX5000 modem could be used via the "FixIt" device. * Dividing ROMCS into two lines, to disable both ROMs. * Reading a non-existent I/O port no longer returned the last attribute; caused certain games such as ''
Arkanoid is a 1986 block breaker arcade game developed and published by Taito. In North America, it was published by Romstar. Controlling a paddle-like craft known as the Vaus, the player is tasked with clearing a formation of colorful blocks by deflect ...
'' to be unplayable. * Memory timing changes; certain RAM banks were now contended causing high-speed colour-changing effects to fail. * The keypad scanning routines from the ROM were removed. * Move 1 byte address in ROM. Some older 48K and 128K games were incompatible with the machine. The ZX Interface 1 was incompatible due to differences in ROM and expansion connector, making it impossible to connect and use the Microdrive units. Unlike previous models, the ZX Spectrum +3 power supply uses a DIN connector and has "Sinclair +3" written on the case. The same power supply could also be used with the later +2A/B models. Production of the +3 ceased in December 1990, believed to be in response to Amstrad relaunching their CPC range. At the time, it was estimated about 15% of ZX Spectrums sold had been +3 models. Production of the +2B (the only other model then still in production) continued, as it was believed not to be in competition with other computers in Amstrad's product range.


ZX Spectrum +2A

ZX Spectrum +2A The ''ZX Spectrum +2A'' was a new version of the Spectrum +2 using the same circuit board as the Spectrum +3. It was sold from late 1988 and unlike the original grey +2 was housed inside a black case. The Spectrum +2A/+3 motherboard (AMSTRAD part number Z70830) was designed so that it could be assembled with a +2 style "datacorder" connected instead of the
floppy disk controller A floppy-disk controller (FDC) has evolved from a discrete set of components on one or more circuit boards to a special-purpose integrated circuit (IC or "chip") or a component thereof. An FDC directs and controls reading from and writing to ...
.''Spectrum +3 Service Manual''. AMSTRAD. p.18. Amstrad planned to introduce an additional disk interface for the +2A/+2B called the ''AMSTRAD SI-1'',Spital, Ivor. ''Sinclair ZX Spectrum +2A''. AMSTRAD, 1987. p.354. but it never appeared. If an external disk drive was added, the "+2A" displayed on the system menu text would change to "+3". The power supply of the ZX Spectrum +2A used the same
pinout In electronics, a pinout (sometimes written "pin-out") is a cross-reference between the contacts, or ''pins'', of an electrical connector or electronic component, and their functions. "Pinout" now supersedes the term "basing diagram" that was the s ...
as the +3 and has "Sinclair +2" written on the case.


ZX Spectrum +2B and +3B

The ''ZX Spectrum +2B'' and ''ZX Spectrum +3B'' were functionally similar in design to the Spectrum +2A and +3. The main electronic differences were changes to the generation of the audio output signal to resolve problems with
clipping Clipping may refer to: Words * Clipping (morphology), the formation of a new word by shortening it, e.g. "ad" from "advertisement" * Clipping (phonetics), shortening the articulation of a speech sound, usually a vowel * Clipping (publications) ...
. Unlike the +2A and +3, the Spectrum +2B and +3B do not share a common motherboard. The +2B board (AMSTRAD part number Z70833) has no provision for floppy disk controller circuitry and the +3B motherboard (Amstrad part number Z70835) has no provision for connecting an internal tape drive. Production of all Amstrad Spectrum models ended in 1992.


Clones and re-creations


Official clones

Sinclair licensed the Spectrum design to
Timex Corporation Timex Group USA, Inc. (formerly known as Timex Corporation) is an American global watch manufacturing company founded in 1854 as the Waterbury Clock Company in Waterbury, Connecticut. In 1944, the company became insolvent but was reformed into ...
in the United States, that sold several machines under the
Timex Sinclair Timex Sinclair was a joint venture established in December 1982 between the British company Sinclair Research and Timex Corporation in an effort to gain an entry into the rapidly growing early-1980s home computer market in North America. His ...
brand. An enhanced version of the original Spectrum, with better sound, graphics and other modifications was marketed in the US by Timex as the
Timex Sinclair 2068 The Timex Sinclair 2068 (T/S 2068), released in November 1983, was Timex Sinclair's third and last home computer for the United States market. It was also marketed in Canada, Argentina, Portugal and Poland, as Timex Computer 2068 (TC 2068). Hi ...
. Timex's derivatives were largely incompatible with Sinclair systems. Some of the Timex innovations were later adopted by Sinclair Research. A case in point was the abortive ''Pandora'' portable Spectrum, whose ULA had the high resolution video mode pioneered in the T/S 2068. ''Pandora'' had a flat-screen monitor and Microdrives and was intended to be Sinclair's business portable. After
Amstrad Amstrad was a British electronics company, founded in 1968 by Alan Sugar at the age of 21. The name is a contraction of Alan Michael Sugar Trading. It was first listed on the London Stock Exchange in April 1980. During the late 1980s, Amstrad ...
bought the computer business of Sinclair Research, Sir Clive retained the rights to the ''Pandora'' project, and it evolved into the Cambridge Computer Z88, launched in 1987. Starting in 1984, Timex of Portugal developed and produced several Timex branded computers, including the Timex Computer 2048, highly compatible with the Sinclair ZX Spectrum 48K, which was very successful in both Portugal and Poland. An NTSC version was also made, initially intended for a United States release, but it was sold only in Chile, Ecuador and Argentina. Timex of Portugal also made a PAL version of the T/S 2068, called the Timex Computer 2068 (or TC 2068 for short) which had different buffers for both the ULA and the CPU, which significantly increased the compatibility with ZX Spectrum software when compared to the North American model (the T/S 2068). The expansion port was also modified and made to be 100% compatible with the ZX Spectrum's, which bypassed the need for a "Twister Board" expansion that the T/S 2068 needed to make it compatible with ZX Spectrum expansion hardware. It also had the AY sound output routed to the monitor/TV speakers instead of the internal twitter. The software developed for the TC 2068 is completely compatible with the T/S 2068, since the ROMs weren't altered. Timex of Portugal also developed a ZX Spectrum "emulator" on cartridge form that mapped the first 16 KB exactly like the earlier TC 2048 computer did. Several other upgrades were made available, including a BASIC64 cartridge that enabled the TC 2068 to use high resolution (512x192) modes. Despite having an AY-3-8912 sound chip, it's not connected in the same ports as in the ZX Spectrum 128K, rendering the TC 2048 incompatible with the AY sound that the Spectrum 128K games produced. Due to all its advantages compared to the usual T/S 2068, a North American company, Zebra Systems, licensed the Timex TC 2068 and sold it in the United States as the Zebra Silver Avenger. They also sold the FDD 3000 as the Zebra FDD 3000 in a silver case (as opposed to the European black cases) to match their colour scheme. Timex of Portugal was working on a successor to the TC 2068 called the TC 3256, using a Z80A CPU and featuring 256 KB of RAM, which would feature a ZX Spectrum BASIC operating mode and a
CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initial ...
operating mode, but the company pulled the plug on its development as the 8-bit market was no longer profitable by the end of 1989. Only one complete and fully working prototype of the TC 3256 was made. deciBells dB Spectrum+ and PSU In India, Deci Bells Electronics Limited introduced a licensed version of the Spectrum+ in 1988. Dubbed the "dB Spectrum+", it did reasonably well in the Indian market, selling over 50000 units and achieving an 80% market share.


Unofficial clones

Didaktik Gama Numerous unofficial Spectrum clones were produced, especially in the Eastern and Central European countries (e.g. in
USSR The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
(called ),
Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...
, and
Czechoslovakia , rue, Чеськословеньско, , yi, טשעכאסלאוואקיי, , common_name = Czechoslovakia , life_span = 1918–19391945–1992 , p1 = Austria-Hungary , image_p1 ...
) where several models were produced (such as the Tim-S, HC85, HC91, Cobra, Junior, CIP, CIP 3, Jet,
Didaktik Gama The Didaktik was a series of 8-bit home computers based on the clones of Intel 8080 and Zilog Z80 processors produced in former Czechoslovakia. Didaktik Alfa Didaktik Alfa was produced in 1986, as a "more professional" clone of PMD 85. It fe ...
), some featuring
CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initial ...
and a 5.25"/3.5"
floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...
. There were also clones produced in South America (e.g. Microdigital
TK90X The TK90X was the first Brazilian ZX Spectrum clone made in 1985 by Microdigital Electrônica, a company located in São Paulo, Brazil, that had manufactured some ZX81 clones (TK82C, TK83 and TK85) and ZX80 clones (TK80, TK82) before. Technic ...
and
TK95 The TK 95 microcomputer was a 1986 ZX Spectrum clone by Microdigital Eletrônica, a company located at São Paulo, Brazil. It was an evolution of the TK90X introduced the previous year. The case was redesigned (copied from the Commodore Plus/ ...
, made in Brazil and the Czerweny CZ, made in
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
). In the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
, ZX Spectrum clones were assembled by thousands of small start-ups and distributed through poster ads and street stalls. Over 50 such clone models existed. Some of them are still being produced, such as the ''
Pentagon In geometry, a pentagon (from the Greek πέντε ''pente'' meaning ''five'' and γωνία ''gonia'' meaning ''angle'') is any five-sided polygon or 5-gon. The sum of the internal angles in a simple pentagon is 540°. A pentagon may be simpl ...
'' and ''
ATM Turbo ATM (ATM Turbo) is a ZX Spectrum clone, developed in Moscow in 1991, by two firms, MicroArt and ATM. It offers enhanced characteristics, compared to the original Spectrum, such as a , RAM, ROM, AY-8910 (two ones in upgraded models), 8-bit ...
''. In the UK, Spectrum peripheral vendor
Miles Gordon Technology {{unreferenced, date=August 2012 Miles Gordon Technology, known as MGT, was a small British company, initially specialising in high-quality add-ons for the ZX Spectrum home computer. It was founded in June 1986 in Cambridge, England by Alan Miles ...
(MGT) released the
SAM Coupé Sam, SAM or variants may refer to: Places * Sam, Benin * Sam, Boulkiemdé, Burkina Faso * Sam, Bourzanga, Burkina Faso * Sam, Kongoussi, Burkina Faso * Sam, Iran * Sam, Teton County, Idaho, United States, a populated place People and fictional ...
as a potential successor with some Spectrum compatibility. By this point, the
Commodore Amiga Amiga is a family of personal computers introduced by Commodore in 1985. The original model is one of a number of mid-1980s computers with 16- or 32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphi ...
and
Atari ST The Atari ST is a line of personal computers from Atari Corporation and the successor to the Atari 8-bit family. The initial model, the Atari 520ST, had limited release in April–June 1985 and was widely available in July. It was the first pers ...
had taken hold of the market, leaving MGT in eventual receivership.


Recreations

In 2013, an
FPGA A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware de ...
-based redesign of the original ZX Spectrum known as the ZX Uno, was formally announced. All of its hardware, firmware and software are open source, released as
Creative Commons license A Creative Commons (CC) license is one of several public copyright licenses that enable the free distribution of an otherwise copyrighted "work".A "work" is any creative material made by a person. A painting, a graphic, a book, a song/lyrics ...
Share-alike. The use of a
Spartan Sparta (Doric Greek: Σπάρτα, ''Spártā''; Attic Greek: Σπάρτη, ''Spártē'') was a prominent city-state in Laconia, in ancient Greece. In antiquity, the city-state was known as Lacedaemon (, ), while the name Sparta referred t ...
FPGA allows the system to not only re-implement the ZX Spectrum, but many other 8 bit computers and games consoles The device can also run modern open FPGA machines such as the Chloe 280SE. The Uno was successfully
crowdfunded Crowdfunding is the practice of funding a project or venture by raising money from a large number of people, typically via the internet. Crowdfunding is a form of crowdsourcing and alternative finance. In 2015, over was raised worldwide by crow ...
in 2016 and the first boards went on sale during the same year. In January 2014,
Elite Systems Elite Systems is a British video game developer and publisher established in 1984 as Richard Wilcox Software. It is known for producing home computer conversions of popular arcade games. Elite also published compilations of games on the Hit-Pak ...
, who produced a successful range of software for the original ZX Spectrum in the 1980s, announced plans for a Spectrum-themed
bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limi ...
keyboard that would attach to mobile devices. The company used a crowdfunding campaign to fund the ''Recreated ZX Spectrum'', which would be compatible with games the company had already released on
iTunes iTunes () is a software program that acts as a media player, media library, mobile device management utility, and the client app for the iTunes Store. Developed by Apple Inc., it is used to purchase, play, download, and organize digital mul ...
and
Google Play Google Play, also known as the Google Play Store and formerly the Android Market, is a digital distribution service operated and developed by Google. It serves as the official app store for certified devices running on the Android (operating sys ...
. Elite Systems took down its Spectrum Collection application the following month, due to complaints from authors of the original 1980's game software that they had not been paid for the content. ''Wired'' described the finished device, which was styled as an original Spectrum 48k keyboard, as "absolutely gorgeous" but said it was ultimately more of an expensive novelty than an actual Spectrum. In July 2019, ''Eurogamer'' reported that many of the orders had yet to be delivered due to a dispute between Elite Systems and their manufacturer, Eurotech. Later in 2014, the Sinclair
ZX Spectrum Vega The ZX Spectrum Vega is a modern redesign of the ZX Spectrum in the form of a miniaturized TV game, that comes preloaded with several games from the platform, created with the involvement of Sir Clive Sinclair. Hardware The Vega mimics the lo ...
retro video game console was announced by Retro Computers Ltd and crowdfunded on Indiegogo with the backing of Clive Sinclair. The Vega, released in 2015, took the form of a
handheld TV game A handheld TV game or plug and play game is an integrated home video game console and game controller, usually battery powered, which connects directly to a television. The game software is built directly into the unit, which is typically designe ...
but the lack of a full keyboard led to criticism from reviewers due to the large number of text adventures supplied with the device. Most reviewers branded the device cheap and uncomfortable to use The follow-up, the
ZX Spectrum Vega+ The ZX Spectrum Vega+ is a handheld game console based on the ZX Spectrum and designed by Rick Dickinson as a follow-up to the ZX Spectrum Vega handheld TV game which was released in 2015. Only a small number of Vega+ machines were released, bef ...
was designed as a
handheld game console A handheld game console, or simply handheld console, is a small, portable self-contained video game console with a built-in screen, game controls and speakers. Handheld game consoles are smaller than home video game consoles and contain the cons ...
. Despite reaching its crowdfunding target in March 2016, the company failed to fulfil the majority of orders. On 30 July 2018, ''Eurogamer'' reported that one backer had received a ZX Vega+ console and quoted them as being "quite disappointed" that "the few supplied sample games don't work" and that the "build quality's not the greatest". Reviewing the Vega+, ''
The Register ''The Register'' is a British technology news website co-founded in 1994 by Mike Magee, John Lettice and Ross Alderson. The online newspaper's masthead sublogo is "''Biting the hand that feeds IT''." Their primary focus is information tec ...
'' criticised numerous aspects and features of the machine, including its design and build quality and summed up by saying that the "entire feel is plasticky and inconsequential". Retro Computers Ltd was wound up on 1 February 2019. The
ZX Spectrum Next ZX Spectrum Next is an 8-bit home computer, initially released in 2017, which is compatible with software and hardware for the 1982 ZX Spectrum. It also has enhanced capabilities. It is intended to appeal to retrocomputing enthusiasts and to " ...
(not to be confused with the older, two-processor ZX Next) is an expanded and updated version of the ZX Spectrum computer implemented with FPGA technology funded by a
Kickstarter Kickstarter is an American public benefit corporation based in Brooklyn, New York, that maintains a global crowdfunding platform focused on creativity. The company's stated mission is to "help bring creative projects to life". As of July 2021, ...
campaign in April 2017, with the board-only computer delivered to backers later that year. The finished machine, including a case designed by
Rick Dickinson Rick Dickinson (c. 1957 – 24 April 2018) was a British industrial designer who developed pioneering computer designs in the 1980s. Notable examples of his design work include the ZX81 case and touch-sensitive keyboard and the ZX Spectrum's ...
who died during the development of the project, was released to backers in February 2020. ''MagPi'' called it "a lovely piece of kit", noting that it is "well-designed and well-built: authentic to the original, and with technology that nods to the past while remaining functional and relevant in the modern age". PC Pro magazine called the Next "undeniably impressive" while noting that the printed manual lacked an index, and that some features are "not quite ready". A further Kickstarter for an improved revision of the hardware was funded in August 2020.


Peripherals

Several peripherals were marketed by Sinclair: the
ZX Printer The Sinclair ZX Printer is a spark printer which was produced by Sinclair Research for its ZX81 home computer. It was launched in 1981, with a recommended retail price of £49.95. The ZX Printer used special wide black paper which was supplie ...
was already on the market, as the ZX Spectrum expansion
bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...
was partially
backwards-compatible Backward compatibility (sometimes known as backwards compatibility) is a property of an operating system, product, or technology that allows for interoperability with an older legacy system, or with input designed for such a system, especially in ...
with that of the ZX81. The
ZX Interface 1 ZX may refer to: Arts and entertainment * Kamen Rider ZX (pronounced "Zed-Cross"), the tenth fictional superhero in the "Kamen Rider" franchise * ''Mega Man ZX'', a video game for the Nintendo DS * '' ZX Tunes'', remastered soundtracks of the "M ...
add-on module included 8 KB of ROM, an
RS-232 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such a ...
serial port, a proprietary LAN interface (called ZX Net), and an interface for the connection of up to eight
ZX Microdrive ZX Microdrive unit The ZX Microdrive is a magnetic-tape data storage system launched in July 1983 by Sinclair Research for its ZX Spectrum home computer. It was proposed as a faster-loading alternative to the cassette and cheaper than a flo ...
s – somewhat unreliable but speedy tape-loop cartridge storage devices released in July 1983. These were used in a revised version on the
Sinclair QL The Sinclair QL (for ''Quantum Leap'') is a personal computer launched by Sinclair Research in 1984, as an upper-end counterpart to the ZX Spectrum. The QL was aimed at the serious home user and professional and executive users markets from small ...
, whose storage format was electrically compatible but logically incompatible with the Spectrum's. Sinclair also released the ZX Interface 2 which added two joystick ports and a
ROM cartridge A ROM cartridge, usually referred to in context simply as a cartridge, cart, or card, is a replaceable part designed to be connected to a consumer electronics device such as a home computer, video game console or, to a lesser extent, electroni ...
port. left, The Kempston_interface,_a_third-party_add-on_widely_used_for_ Kempston_interface,_a_third-party_add-on_widely_used_for_joysticks">joystick.html"_;"title="Kempston_interface,_a_third-party_add-on_widely_used_for_joystick">Kempston_interface,_a_third-party_add-on_widely_used_for_joysticks There_were_a_plethora_of_third-party_hardware_addons._The_better_known_of_these_included_the_Kempston_Interface.html" ;"title="joysticks.html" ;"title="joystick.html" ;"title="Kempston interface, a third-party add-on widely used for joystick">Kempston interface, a third-party add-on widely used for joysticks">joystick.html" ;"title="Kempston interface, a third-party add-on widely used for joystick">Kempston interface, a third-party add-on widely used for joysticks There were a plethora of third-party hardware addons. The better known of these included the Kempston Interface">Kempston joystick interface, the Morex Peripherals Centronics/RS-232 interface, the Currah Microspeech unit (speech synthesis), Videoface Digitiser, RAM pack, the Cheetah Marketing SpecDrum, a drum machine, and the
Multiface The Multiface was a hardware peripheral released by Romantic Robot for several 1980s home computers. The primary function of the device was to dump the computer's memory to external storage. Pressing a red button on the Multiface activated it. ...
, a snapshot and disassembly tool from Romantic Robot. Keyboards were especially popular in view of the original's notorious "dead flesh" feel. There were disk drive interfaces, such as the Abbeydale Designers/ Watford Electronics SPDOS, Abbeydale Designers/
Kempston Kempston is a town and civil parish in the Borough of Bedford, Bedfordshire, England. It had a population of 19,330 in the 2011 census. Kempston is part of Bedford's built-up area and is situated directly south-west of Bedford proper. The River ...
KDOS and Opus Discovery. The SPDOS and KDOS interfaces were the first to come bundled with office productivity software (
Tasword ''Tasword'' was a word processor for the ZX Spectrum developed by Tasman Software. The first version was released in 1982 and spawned two major revisions in addition to several add-ons and, later, tailored versions for the +2 and +3 Spectrum mode ...
Word Processor, Masterfile database and
Omnicalc Microsphere was a British software company formed in Muswell Hill, north London in 1982 by husband and wife team David and Helen Reidy, best known for several popular computer games in the mid 1980s. Company history The company was formed in Nov ...
spreadsheet). This bundle, together with OCP's Stock Control, Finance and Payroll systems, introduced small businesses to a streamlined, computerised operation. The most popular floppy disk systems (except in East Europe) were the
DISCiPLE A disciple is a follower and student of a mentor, teacher, or other figure. It can refer to: Religion * Disciple (Christianity), a student of Jesus Christ * Twelve Apostles of Jesus, sometimes called the Twelve Disciples * Seventy disciples in t ...
and +D systems released by
Miles Gordon Technology {{unreferenced, date=August 2012 Miles Gordon Technology, known as MGT, was a small British company, initially specialising in high-quality add-ons for the ZX Spectrum home computer. It was founded in June 1986 in Cambridge, England by Alan Miles ...
in 1987 and 1988 respectively. Both systems had the ability to store memory images onto disk ''snapshots'' could later be used to restore the Spectrum to its exact previous state. They were both compatible with the Microdrive command syntax, which made porting existing software much simpler. During the mid-1980s, Telemap Group Ltd launched a fee-based service allowing users to connect their ZX Spectrums via a Prism Micro Products VTX5000
modem A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by Modulation#Digital modulati ...
to a
viewdata Viewdata is a Videotex implementation. It is a type of information retrieval service in which a subscriber can access a remote database via a common carrier channel, request data and receive requested data on a video display over a separate c ...
service known as
Micronet 800 Micronet 800 was an information provider (IP) on Prestel, aimed at the 1980s personal computer market. It was an online magazine that gave subscribers computer related news, reviews, general subject articles and downloadable telesoftware. User ...
, hosted by
Prestel Prestel (abbrev. from press telephone), the brand name for the UK Post Office Telecommunications's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979. It achieved a maximu ...
, which provided news and information about microcomputers. The service allowed a form of
instant messaging Instant messaging (IM) technology is a type of online chat allowing real-time text transmission over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and trigge ...
and
online shopping Online shopping is a form of electronic commerce which allows consumers to directly buy goods or services from a seller over the Internet using a web browser or a mobile app. Consumers find a product of interest by visiting the website of the r ...
.


Software

While games comprised the majority of commercial ZX Spectrum software, there were also
programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...
implementations,
database In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases sp ...
s (e.g. VU-File),
word processor A word processor (WP) is a device or computer program that provides for input, editing, formatting, and output of text, often with some additional features. Word processor (electronic device), Early word processors were stand-alone devices ded ...
s (e.g.
Tasword ''Tasword'' was a word processor for the ZX Spectrum developed by Tasman Software. The first version was released in 1982 and spawned two major revisions in addition to several add-ons and, later, tailored versions for the +2 and +3 Spectrum mode ...
 II),
spreadsheet A spreadsheet is a computer application for computation, organization, analysis and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in cel ...
s (e.g. VU-Calc), drawing and painting tools (e.g.
OCP Art Studio OCP Art Studio or Art Studio was a popular bitmap graphics editor released in 1985, created by Oxford Computer Publishing and written by James Hutchby (original ZX Spectrum version). It featured a GUI with windows, icons, pull-down menus, pointin ...
), and even 3D-modelling (e.g. VU-3D) and
archaeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...
software. The early Spectrum models' great success as a games platform came in spite of its lack of built-in joystick ports, primitive sound generation, and colour support that was optimised for text display: the hardware limitations of the platform required a particular level of creativity from
video game designer Video game design is the process of designing the content and rules of video games in the pre-production stage and designing the gameplay, environment, storyline and characters in the production stage. Some common video game design subdiscipline ...
s. From August 1982, the ZX Spectrum came bundled with a software starter pack in the form of a cassette tape entitled Horizons: Software Starter Pack, which included 8 programs: Thro' the Wall (a Breakout clone), Bubblesort, Evolution (an ecosystem of foxes and rabbits), Life (an implementation of
Conway's Game of Life The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is a zero-player game, meaning that its evolution is determined by its initial state, requiring no further ...
), Draw (a basic object-based drawing utility), Monte Carlo (a simulation of the rolling of two dice), Character Generator (for editing user defined graphics), Beating of Waves (plots the sum of two sine waves). According to the 90th issue of the British gaming magazine GamesMaster, the ten best games released were (in descending order) Head Over Heels,
Jet Set Willy ''Jet Set Willy'' is a platform video game originally written by Matthew Smith for the ZX Spectrum home computer. It was published in 1984 by Software Projects and ported to most home computers of the time. The game is a sequel to ''Manic ...
,
Skool Daze ''Skool Daze'' is a computer game released by Microsphere in 1984 for the ZX Spectrum and Commodore 64 home computers. It was written by David Reidy, with graphics designed by Keith Warrington. The game was commercially and critically successfu ...
,
Renegade Renegade or The Renegade may refer to: Aircraft *Lake Renegade, an American amphibious aircraft design *Murphy Renegade, a Canadian ultralight biplane design *Southern Aeronautical Renegade, an American racing aircraft design Games *'' Comman ...
,
R-Type is a horizontally scrolling shooter arcade video game developed and released by Irem in 1987 and the first game in the ''R-Type'' series. The player controls a star ship, the R-9 "Arrowhead", in its efforts to destroy the Bydo, a powerful a ...
,
Knight Lore ''Knight Lore'' is a 1984 action-adventure game developed and published by Ultimate Play the Game, and written by company founders Chris and Tim Stamper. The game is known for its use of isometric graphics, which it further popularized in vid ...
, Dizzy,
The Hobbit ''The Hobbit, or There and Back Again'' is a children's fantasy novel by English author J. R. R. Tolkien. It was published in 1937 to wide critical acclaim, being nominated for the Carnegie Medal and awarded a prize from the '' ...
,
The Way of the Exploding Fist ''The Way of the Exploding Fist'' is a 1985 fighting game based on Japanese martial arts developed by Beam Software, by a team consisting of Gregg Barnett, Bruce Bayley, Neil Brennan and David Johnston. Originally developed on the Commodore 64 ...
, and
Match Day II ''Match Day II'' is a football sports game part of the Match Day series released for the Amstrad CPC, Amstrad PCW, ZX Spectrum, MSX and Commodore 64 platforms. It was created in 1987 by Jon Ritman with graphics by Bernie Drummond and music an ...
. The last full price, commercial game to be released for the Spectrum was Alternative Software's ''Dalek Attack'', which was released in July 1993. A homebrew community continues into the present day, with several games being released commercially from new software houses such as Cronosoft.


Distribution

Most Spectrum software was originally distributed on
audio cassette tape The Compact Cassette or Musicassette (MC), also commonly called the tape cassette, cassette tape, audio cassette, or simply tape or cassette, is an analog magnetic tape recording format for audio recording and playback. Invented by Lou Otten ...
s. The Spectrum was intended to work with a normal domestic cassette recorder. Although the ZX Microdrive was initially greeted with good reviews, it never took off as a distribution method due to worries about the quality of the cartridges and piracy. Hence the main use became to complement tape releases, usually utilities and niche products like the Tasword
word processing A word is a basic element of language that carries an objective or practical meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consen ...
software and Trans Express, (a tape to microdrive copying utility). No games are known to be exclusively released on Microdrive. Although the Interface 2 proved popular, the high cost of ROM cartridges, and the fact that they were limited to 16K in size, meant that very few titles were released in this format. Software was distributed through print media; magazines and books. The reader would type the BASIC program listing into the computer by hand, run it, and could save it to tape for later use. Software distributed in this way was in general simpler and slower than its
assembly language In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence be ...
counterparts. Magazines printed long lists of
checksum A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify data ...
med
hexadecimal In mathematics and computing, the hexadecimal (also base-16 or simply hex) numeral system is a positional numeral system that represents numbers using a radix (base) of 16. Unlike the decimal system representing numbers using 10 symbols, hexa ...
digits with machine code games or tools. Another software distribution method was to broadcast the audio stream from the cassette on another medium and have users record it onto an audio cassette themselves. In radio or television shows in many European countries, the host would describe a program, instruct the audience to connect a cassette tape recorder to the radio or TV and then broadcast the program over the airwaves in audio format. Some magazines distributed 7" 33 rpm ''
flexidisc The flexi disc (also known as a phonosheet, Sonosheet or Soundsheet, a trademark) is a phonograph record made of a thin, flexible vinyl sheet with a molded-in spiral stylus groove, and is designed to be playable on a normal phonograph turntabl ...
'' records, a variant of regular
vinyl record A phonograph record (also known as a gramophone record, especially in British English), or simply a record, is an analog sound storage medium in the form of a flat disc with an inscribed, modulated spiral groove. The groove usually starts nea ...
s which could be played on a standard record player. These disks were known under various trademarked names including " Floppy ROM", "Flexisoft", and "Discoflex".


Copying and backup

Spectrum software was distributed almost exclusively on audio cassettes Many copiers—utilities to copy programs from audio tape to another tape, microdrive tapes, and later on diskettes—were available for the Spectrum. As a response to this, publishers introduced
copy protection Copy protection, also known as content protection, copy prevention and copy restriction, describes measures to enforce copyright by preventing the reproduction of software, films, music, and other media. Copy protection is most commonly found on ...
measures to their software, including different loading schemes. Other methods for copy prevention were also used including asking for a particular word from the documentation included with the game—often a novella such as the Silicon Dreams trilogy—or another physical device distributed with the software—e.g.
Lenslok Lenslok is a copy protection mechanism found in some computer games and other software on the 8-bit Atari computers, Commodore 64, ZX Spectrum, Sinclair QL, MSX and Amstrad CPC. The first game to use it was '' Elite'' for the ZX Spectrum. Ove ...
as used in
Elite In political and sociological theory, the elite (french: élite, from la, eligere, to select or to sort out) are a small group of powerful people who hold a disproportionate amount of wealth, privilege, political power, or skill in a group. D ...
, or the colour-code chart included with
Jet Set Willy ''Jet Set Willy'' is a platform video game originally written by Matthew Smith for the ZX Spectrum home computer. It was published in 1984 by Software Projects and ported to most home computers of the time. The game is a sequel to ''Manic ...
. Special hardware, such as Romantic Robot's
Multiface The Multiface was a hardware peripheral released by Romantic Robot for several 1980s home computers. The primary function of the device was to dump the computer's memory to external storage. Pressing a red button on the Multiface activated it. ...
, was able to dump a copy of the ZX Spectrum RAM to disk/tape at the press of a button, entirely circumventing the copy protection systems. Most Spectrum software has been converted to current media and is available for download. One popular program for converting Spectrum files from tape is Taper; it allows connecting a cassette tape player to the line in port of a
sound card A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio i ...
, or—through a simple home-built device—to the
parallel port In computing, a parallel port is a type of interface found on early computers (personal and otherwise) for connecting peripherals. The name refers to the way the data is sent; parallel ports send multiple bits of data at once ( parallel ...
of a PC. Once in files on a host machine, the software can be executed on an
emulator In computing, an emulator is Computer hardware, hardware or software that enables one computer system (called the ''host'') to behave like another computer system (called the ''guest''). An emulator typically enables the host system to run so ...
.


Community

The ZX Spectrum enjoyed a very strong community early on. Several commercially published print
magazines A magazine is a periodical publication, generally published on a regular schedule (often weekly or monthly), containing a variety of content. They are generally financed by advertising, purchase price, prepaid subscriptions, or by a combination ...
were dedicated to covering the home computer family and its offshoots including ''
Sinclair User ''Sinclair User'' was a magazine dedicated to the Sinclair Research range of home computers, most specifically the ZX Spectrum (while also occasionally covering arcade games). Initially published by ECC Publications, and later EMAP, it was publi ...
'' (1982), ''
Your Spectrum ''Your Sinclair'', or ''YS'' as it was commonly abbreviated, was a commercially published and printed British computer magazine for the Sinclair range of computers, mainly the ZX Spectrum. It was in circulation between 1984 and 1993. History The ...
'' (1983) – rebranded as ''
Your Sinclair ''Your Sinclair'', or ''YS'' as it was commonly abbreviated, was a commercially published and printed British computer magazine for the Sinclair range of computers, mainly the ZX Spectrum. It was in circulation between 1984 and 1993. History The ...
'' in 1986, and ''
CRASH Crash or CRASH may refer to: Common meanings * Collision, an impact between two or more objects * Crash (computing), a condition where a program ceases to respond * Cardiac arrest, a medical condition in which the heart stops beating * Couch su ...
'' (1984). In the early years, the magazines were focused on programming for the system, and carried many articles containing type-in programs and machine code tutorials. Later on they became almost completely game-oriented, starting many of the writing-styles, trends and tropes found in later video-game publications and reviews. Several other contemporary computer magazines covered the ZX Spectrum as part of their regular coverage of the home computer industry at that time. These included ''
Computer Gamer ''Computer Gamer'' was a video game magazine published in the United Kingdom by Argus Specialist Publications, covering home gaming from April 1985 to June 1987. It was a colourful relaunch of the failing magazine '' Games Computing'', a mor ...
'', ''
Computer and Video Games ''Computer and Video Games'' (also known as ''CVG'', ''Computer & Video Games'', ''C&VG'', ''Computer + Video Games'', or ''C+VG'') was a UK-based video game magazine, published in its original form between 1981 and 2004. Its offshoot website ...
'', '' Computing Today'', ''
Popular Computing Weekly ''Popular Computing Weekly'' was a computer magazine in the UK published from 1982 to 1990. It was sometimes referred to as ''PCW'' (although that abbreviation is more commonly associated with '' Personal Computer World'' magazine). Overview ...
'', '' Your Computer'' and ''
The Games Machine ''The Games Machine'' is a video game magazine that was published from 1987 until 1990 in the United Kingdom by Newsfield, which also published ''CRASH'', ''Zzap!64'', ''Amtix!'' and other magazines. History The magazine ran head to head with ...
''. The Spectrum is affectionately known as the ''Speccy'' by elements of its fan following. More than 80 electronic
magazines A magazine is a periodical publication, generally published on a regular schedule (often weekly or monthly), containing a variety of content. They are generally financed by advertising, purchase price, prepaid subscriptions, or by a combination ...
existed, many in Russian. Most notable of them were ''AlchNews'' (UK), ''Enigma Tape Magazine'' (UK), ''16/48'' (UK), ''ZX-Format'' (Russia), ''Adventurer'' (Russia), ''Microhobby'' (Spain) and ''
Spectrofon ''Spectrofon'' was an electronic magazine for ZX Spectrum produced in Russia by the developer group ''STEP Interactive'' from Moscow. The magazine appeared on a monthly basis, and 23 issues were published in total. The issues were stored on a (usua ...
'' (Russia). These frequently included games, demos, and utilities alongside the magazine content (much like a covertape on a paper magazine).


Notable developers

A number of notable games developers began their careers on the ZX Spectrum, including David Perry of
Shiny Entertainment Shiny Entertainment, Inc. was an American video game developer based in Laguna Beach, California. Founded in October 1993 by David Perry (game developer), David Perry, Shiny was the creator of video games such as ''Earthworm Jim (video game), E ...
, and
Tim and Chris Stamper Brothers Tim and Chris Stamper are British entrepreneurs who founded the video game companies Ultimate Play the Game and Rare. They first worked together on arcade conversion kits, which were licensed to companies, but later became developer ...
(founders of Rare, formerly
Ultimate Play the Game Ashby Computers and Graphics Limited, trading as Ultimate Play the Game, was a British video game developer and publisher, founded in 1982, by ex-arcade game developers Tim and Chris Stamper. Ultimate released a series of successful games for t ...
, maker of many games for
Nintendo is a Japanese Multinational corporation, multinational video game company headquartered in Kyoto, Japan. It develops video games and video game consoles. Nintendo was founded in 1889 as by craftsman Fusajiro Yamauchi and originally produce ...
and
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...
game consoles). Other prominent games developers include
Julian Gollop Julian Gollop is a British computer game designer and producer specialising in strategy games, who has founded and led Mythos Games, Codo Technologies and Snapshot Games. He is known best as the "man who gave birth to the '' X-COM'' franchise ...
(''
Chaos Chaos or CHAOS may refer to: Arts, entertainment and media Fictional elements * Chaos (''Kinnikuman'') * Chaos (''Sailor Moon'') * Chaos (''Sesame Park'') * Chaos (''Warhammer'') * Chaos, in ''Fabula Nova Crystallis Final Fantasy'' * Cha ...
'', ''
Rebelstar The ''Rebelstar'' games are a series of turn-based tactics video games designed by Julian Gollop. ''Rebelstar Raiders'' was published in 1984 in video gaming, 1984 by Red Shift (publisher), Red Shift for the ZX Spectrum. It was reworked in machin ...
'', ''X-COM'' series), Matthew Smith (''
Manic Miner ''Manic Miner'' is a platform video game originally written for the ZX Spectrum by Matthew Smith and released by Bug-Byte in 1983 (later re-released by Software Projects). It is the first game in the Miner Willy series and among the early titl ...
'', ''
Jet Set Willy ''Jet Set Willy'' is a platform video game originally written by Matthew Smith for the ZX Spectrum home computer. It was published in 1984 by Software Projects and ported to most home computers of the time. The game is a sequel to ''Manic ...
''),
Jon Ritman Jon Ritman is a game designer and programmer notable for his work on 1980s computer games, primarily for the ZX Spectrum and Amstrad CPC home computers. His first experience with a computer was when he was 13, his first computer was a Sinclair ZX ...
('' Match Day'', '' Head Over Heels''), Jonathan "Joffa" Smith ('' Batman: The Caped Crusader'', ''
Mikie ''Mikie'', known as in Japan, is an arcade video game developed and released by Konami in 1984. The object of the game is to guide a student named Mikie around the school locations to collect hearts which make up a letter from his girlfriend whil ...
'', ''
Hyper Sports ''Hyper Sports'', known in Japan as is an Olympic video games, Olympic-themed sports video game released by Konami for Arcade game, arcades in 1984 in video games, 1984. It is the sequel to 1983's ''Track & Field (video game), Track & Field'' and ...
''),
The Oliver Twins Andrew Nicholas Oliver and Philip Edward Oliver, together known as the Oliver Twins, are British twin brothers and video game designers. They began to professionally develop computer games while they were still at school, contributing their fir ...
(the ''Dizzy'' series), Clive Townsend (''
Saboteur Sabotage is a deliberate action aimed at weakening a polity, effort, or organization through subversion, obstruction, disruption, or destruction. One who engages in sabotage is a ''saboteur''. Saboteurs typically try to conceal their identiti ...
''), Sandy White (''
Ant Attack ''Ant Attack'' is a ZX Spectrum computer game by Sandy White, published by Quicksilva in 1983. It was converted to the Commodore 64 in 1984. While ''Zaxxon'' and ''Q*bert'' previously used isometric projection, ''Ant Attack'' added an extra degre ...
''; ''I, of the Mask''), Pete Cooke (''
Tau Ceti Tau Ceti, Latinized from τ Ceti, is a single star in the constellation Cetus that is spectrally similar to the Sun, although it has only about 78% of the Sun's mass. At a distance of just under from the Solar System, it is a relativ ...
''),
Mike Singleton Mike Singleton (21 February 1951 – 10 October 2012) was a British video game designer who wrote various well-regarded titles for the ZX Spectrum during the 1980s. His titles include '' The Lords of Midnight'', ''Doomdark's Revenge'', ' ...
('' The Lords of Midnight'', '' War in Middle Earth''), and Alan Cox. Although the 48K Spectrum's audio hardware was not as capable as chips in other popular 8-bit home computers of the era, computer musicians David Whittaker and Tim Follin produced notable multi-channel music for it.
Jeff Minter Jeff Minter (born 22 April 1962) is an independent English video game designer and programmer who often goes by the name Yak. He is the founder of software house Llamasoft and has created dozens of games during his career, which began in 19 ...
ported some of his
VIC-20 The VIC-20 (known as the VC-20 in Germany and the VIC-1001 in Japan) is an 8-bit home computer that was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PE ...
games to the ZX Spectrum.


Reception

''
BYTE The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...
'' in January 1983 acknowledged the appeal of the Spectrum's low £125 price to British consumers and called it a "promising machine". It criticised the keyboard; "inexpensive or not, the ... layout is impossible to justify ... poorly designed in several respects". The review was sceptical of the computer's appeal to American consumers if sold for —"hardly competitive with comparable low-cost American units"—and expected that Timex would sell it for .


Legacy

On 23 April 2012, a
Google doodle A Google Doodle is a special, temporary alteration of the logo on Google's homepages intended to commemorate holidays, events, achievements, and notable historical figures. The first Google Doodle honored the 1998 edition of the long-running an ...
honoured the 30th anniversary of the Spectrum. As it coincided with
St George's Day Saint George's Day is the feast day of Saint George, celebrated by Christian churches, countries, and cities of which he is the patron saint, including Bulgaria, England, Georgia, Portugal, Romania, Cáceres, Alcoy, Aragon and Catalonia. Sa ...
, the logo was of St George fighting a dragon in the style of a Spectrum loading screen. In December 2018, one of the alternate endings in '' Black Mirror: Bandersnatch'' included the main character playing data tape audio that, when loaded into a ZX Spectrum software emulator, generates a QR code leading to a website with a playable version of the Nohzdyve game featured in the episode. Some programmers have continued to code for the platform by using emulators on PCs. Since 2020, there has been a museum, LOAD ZX Spectrum, dedicated to the ZX Spectrum and other Sinclair products (as well as Timex, Investrónica and many others), located in Cantanhede,
Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...
.LOAD ZX Spectrum
/ref>


See also

* List of computer system emulators#Sinclair ZX Spectrum and clones *
List of ZX Spectrum games This is a sortable list of games for the ZX Spectrum home computer. There are currently games in this incomplete list. __NOTOC__ Original run (1982–1994) Homebrew References External linksSpectrum Computing
an up-to-date database ...
*
ZX Spectrum graphic modes The ZX Spectrum is generally considered to have limited graphical capabilities in comparison to some other home computers of the same era such as the Commodore 64, largely due to its lack of a dedicated graphics chip. Nevertheless, throughou ...
*
ZX Spectrum character set The ZX Spectrum character set is the variant of ASCII used in the ZX Spectrum family computers. It is based on ASCII-1967 but the characters ^, ` and DEL are replaced with ↑, £ and ©. It also differs in its use of the C0 control codes other ...
*
Contended memory Contended memory is Sinclair's name for a portion of the ZX Spectrum's 64 KB addressable memory space. With the full 64 KB, the Z80 microprocessor is the exclusive bus master, so it reads and writes operate at its full bus speed, but contended mem ...


References


Additional sources

* *


External links


ZX Spectrum
BASIC manual
JSSpeccy 3
ZX Spectrum emulator in the browser {{Authority control Computer-related introductions in 1982 Computers designed in the United Kingdom English inventions Home computers Products and services discontinued in 1992 Sinclair Research Z80-based home computers ZX Spectrum