ZX Spectrum
Encyclopedia
The ZX Spectrum is an 8-bit
personal home computer
released in the United Kingdom in 1982 by Sinclair Research Ltd
. Referred to during development as the ZX81 Colour and ZX82, the machine was launched as the ZX Spectrum by Sinclair to highlight the machine's colour display, compared with the black-and-white
of its predecessor, the Sinclair ZX81
. The Spectrum was ultimately released as eight different models, ranging from the entry level model with 16 kB
RAM released in 1982 to the ZX Spectrum +3 with 128 kB RAM and built in floppy disk
drive in 1987; together they sold in excess of 5 million units worldwide (not counting clones, which were numerous).
The Spectrum was among the first mainstream audience home computers in the UK, similar in significance to the Commodore 64
in the USA. 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 UK IT industry. Licensing deals and clones followed, and earned Clive Sinclair
a knighthood for "services to British industry".
The Commodore 64
, BBC Microcomputer and later the Amstrad CPC
range were major rivals to the Spectrum in the UK market during the early 1980s. Over 20,000 software titles have been released since the Spectrum's launch and new titles continue to be released, with over 90 new ones in 2010.
The Spectrum is based on a Zilog Z80
A CPU
running at 3.5 MHz (or NEC D780C-1 clone). The original model Spectrum has 16 kB (16×1024 byte
s) of ROM
and either 16 kB or 48 kB of RAM. Hardware design was by Richard Altwasser
of Sinclair Research, and the machine's outward appearance was designed by Sinclair's industrial designer Rick Dickinson
.
Video output is through an RF modulator
and was designed for use with contemporary portable 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
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
is 256×192 with the same colour limitations. To conserve memory, colour is stored separate from the pixel bitmap
in a low resolution, 32×24 grid overlay, corresponding to the character cells. 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
with some bizarre effects in the animated graphics of arcade style games. This became a distinctive feature of the Spectrum and an in-joke among Spectrum users, as well as a point of derision by advocates of other systems. Other machines available around the same time, for example the Amstrad CPC
, did not suffer from this limitation. The Commodore 64
used colour attributes in a similar way, but a special multicolour mode, hardware sprite
s and hardware scrolling
were used to avoid attribute clash.
Sound output is through a beeper on the machine itself. This is capable of producing one channel with 10 octaves. The machine also includes an expansion bus
edge connector
and audio in/out ports for the connection of a cassette recorder for loading and saving programs and data.
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
(on top of a membrane, similar to calculator keys) is marked with BASIC keywords, so that, for example, pressing "G" when in programming mode would insert the BASIC command GOTO
.
The BASIC interpreter was developed from that used on the ZX81 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
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 also supported multi-statement lines. The cassette interface was also much more advanced, saving and loading around four times faster than the ZX81, and much more reliably. As well as being able to save programs, the Spectrum could in addition save the contents of arrays, the contents of the screen memory, and the contents of any defined range of memory addresses.
, diminutive size and distinctive rainbow motif. It was originally released in 1982 with 16 kB of RAM for £125 Sterling
or with 48 kB for £175; these prices were later reduced to £99 and £129 respectively. Owners of the 16 kB model could purchase an internal 32 kB RAM upgrade, which for early "Issue 1" machines consisted of a daughterboard
. Later issue machines required the fitting of 8 dynamic RAM
chips and a few TTL
chips. Users could mail their 16K Spectrums to Sinclair to be upgraded to 48 kB versions. To reduce the price, the 32 kB extension used eight faulty 64 kilobit
chips with only one half of their capacity working and/or available. Links on the PCB were configured accordingly so as to place these faulty memory locations in the other (unused) half of each IC. External 32 kB RAM packs that mounted in the rear expansion slot were also available from third parties. Both machines had 16 kB of onboard ROM.
About 60,000 "Issue 1" ZX Spectrums were manufactured; they can be distinguished from later models by the colour of the keys (light grey for Issue 1, blue-grey for later models).
-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 £179.95. A DIY
conversion-kit for older machines was also 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%.
The appearance of the ZX Spectrum 128 was similar to the ZX Spectrum +, with the exception of a large external heatsink for the internal 7805 voltage regulator
added to the right hand end of the case, replacing the internal heatsink in previous versions.
New features included 128 kB RAM, three-channel audio via the AY-3-8912 chip, MIDI compatibility, an RS-232
serial port, an RGB 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 £179.95. No external keypad was available for the UK release, although the ROM routines to use it and the port itself, which was hastily renamed "AUX", remained.
The Z80 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
so that the new memory would be available as eight pages of 16 kB at the top of the address space. The same technique was also 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 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 way 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 some BASIC programs.
The ZX Spectrum 128 had no internal speaker like its predecessors. The sound was produced from the television speaker instead.
The Spanish version had the "128K" logo
in white while the English one had the same logo in red.
'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. These changes resulted in minor incompatibility problems with software that accessed ROM routines at certain addresses. 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. This was not a major issue however, as 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.
The +2A was derived from Amstrad's +3 4.1 ROM model, using a new motherboard which vastly reduced the chip count, integrating many of them into a new ASIC
. The +2A replaced the +3's disk drive and associated hardware with a tape drive, as in the original +2. Originally, Amstrad planned to introduce an additional disk interface, but this never appeared. If an external disk drive was added, the "+2A" on the system OS menu would change to a +3. As with the ZX Spectrum +3, some older 48K, and a few older 128K, games were incompatible with the machine.
The ZX Spectrum +2A had a more substantial power supply compared to previous models. This powers supply was slightly larger with air vents and a DIN plug to supply +/- 5 volts and +/- 12 volts. This supply could also be used with the +2B and +3. However, the power supply purchased with the +2A/B had "Sinclair +2" written on the case.
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
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 AMSDOS
, 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:
Some older 48K, and a few older 128K, games were incompatible with the machine. The ZX Interface 1 was incompatible due to differences in ROM and expansion connector; therefore it was not possible to connect and use the Microdrive units.
The ZX Spectrum +3 had an identical power supply to the +2A/B. This supply could also be used with the +2A/B. However, the power supply purchased with the +3 had "Sinclair +3" written on the case.
Production of the +3 ceased in December 1990. Although still accounting for one third of all home computer sales in the UK at the time, production of the model was ceased by Amstrad at that point.
Sinclair licensed the Spectrum design to Timex Corporation in the United States. An enhanced version of the Spectrum with better sound, graphics and other modifications was marketed in the USA by Timex as the Timex Sinclair 2068
. Timex's derivatives were largely incompatible with Sinclair systems. However, 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 TS2068. Pandora had a flat-screen monitor and Microdrives and was intended to be Sinclair's business portable. After 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.
In the UK, Spectrum peripheral vendor Miles Gordon Technology
(MGT) released the SAM Coupé
as a potential successor with some Spectrum compatibility. However, by this point, the Commodore Amiga and Atari ST
had taken hold of the market, leaving MGT in eventual receivership.
Many unofficial Spectrum clones were produced, especially in the former Eastern Bloc
countries (e.g. in Romania
, several models were produced (Tim-S, HC85, HC91, Cobra, Junior, CIP, CIP 3, Jet), some featuring CP/M
and a 5.25"/3.5" floppy disk
) and South America (e.g. Microdigital TK 90X
and TK 95
). In the Soviet Union
, 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
and ATM Turbo. In India, Decibells Electronics introduced a licensed version of the Spectrum+ in 1986. Dubbed the "db Spectrum+", it did reasonably well in the Indian market and sold quite a few thousand until 1990 when the market died away.
was already on the market, as the ZX Spectrum expansion bus
was backwards-compatible with that of the ZX81.
The ZX Interface 1
add-on module included 8 kB of ROM, an RS-232
serial port, a proprietary LAN
interface (called ZX Net), and an interface for the connection of up to eight ZX Microdrive
s – somewhat unreliable but speedy tape-loop cartridge storage devices released in July 1983. These were later used in a revised version on the Sinclair QL
, 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 port.
There were also a plethora of third-party hardware addons. The better known of these included the 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
, a snapshot and disassembly tool from Romantic Robot. Keyboards were especially popular in view of the original's notorious "dead flesh" feel.
There were numerous disk drive interfaces, including the Abbeydale Designers/Watford Electronics
SPDOS, Abbeydale Designers/Kempston
KDOS and Opus Discovery. The SPDOS and KDOS interfaces were the first to come bundled with Office productivity software (Tasword
Word Processor, Masterfile database and OmniCalc spreadsheet). This bundle, together with OCP's Stock Control, Finance and Payroll systems, introduced many small businesses to a streamlined, computerised operation. The most popular floppy disk systems (except in East Europe) were the DISCiPLE
and +D
systems released by Miles Gordon Technology
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 also 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
to a viewdata
service known as Micronet 800
, hosted by Prestel
. This service pre-dated the World Wide Web
, but offered many of the services now considered commonplace.
implementations, database
s (e.g. VU-File), word processor
s (e.g. Tasword
II), spreadsheet
s (e.g. VU-Calc), drawing and painting tools (e.g. OCP Art Studio), and even 3D-modelling (e.g. VU-3D) and archaeology
software amongst many other types.
The hardware limitations of the Spectrum imposed a special level of creativity on game
designers, and so many Spectrum games are very creative and playable even by today's standards. 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.
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
software and Trans Express, (a tape to microdrive copying utility). No games are known to be exclusively released on Microdrive.
Despite the popularity of the DISCiPLE and +D systems, most software released for them took the form of utility software. The ZX Spectrum +3 enjoyed much more success when it came to commercial software releases on floppy disk. More than 700 titles were released on 3-inch disk from 1987 to 1997.
Software was also distributed through print media; magazine
s and book
s. The reader would type the Sinclair BASIC
program listing into the computer by hand, run it, and could save it to tape for later use. The software distributed in this way was in general simpler and slower than its assembly language
counterparts. Magazines also printed long lists of checksum
med hexadecimal
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" 33⅓ rpm flexidisc records, a variant of regular vinyl records which could be played on a standard record player. These disks were known as floppy ROMs.
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
like in Silicon Dreams trilogy
—or another physical device distributed with the software—e.g. Lenslok
as used in Elite. Special hardware, such as Romantic Robot's Multiface
, 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, in recent years, 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
, or—through a simple home-built device—to the parallel port
of a PC. Once in files on a host machine, the software can be executed on one of many emulator
s, on virtually any platform available today.
The largest on-line archive of ZX Spectrum software is World of Spectrum
, with more than 21,000 titles. The legality of this practice is still in question and while a number of copyright holders have explicitly objected to the posting of their software, others have given their permission for their games to be archived as part of the preservation project.
A number of current leading games developers and development companies began their careers on the ZX Spectrum, including David Perry of Shiny Entertainment
, and Tim and Chris Stamper
(founders of Ultimate Play The Game
, now known as Rare, maker of many famous titles for Nintendo
and Microsoft
game consoles). Other prominent games developers include Julian Gollop
(Chaos, Rebelstar, X-COM series), Matthew Smith
(Manic Miner
, Jet Set Willy
), Jon Ritman
(Match Day
, Head Over Heels
), The Oliver Twins
(the Dizzy series
), Clive Townsend (Saboteur), Pete Cooke
(Tau Ceti), Mike Singleton
(The Lords of Midnight
,War In Middle Earth), and Alan Cox
. Although the 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 the machine.
Jeff Minter
ported some of his Commodore VIC-20
games to the ZX Spectrum.
(1982), Your Sinclair
(1983) and CRASH
(1984). Early on they were very technically oriented with type-in programs and machine code tutorials. Later on they became almost completely game-oriented. Several general contemporary computer magazines covered the ZX Spectrum in more or less detail. They included Computer Gamer
, Computer and Video Games
, Computing Today
, Popular Computing Weekly
, Your Computer
and The Games Machine
.
The Spectrum is affectionately known as the Speccy by elements of its fan following.
More than 80 electronic magazines existed, many in Russian. Most notable of them were AlchNews (UK), ZX-Format (Russia), and Spectrofon
(Russia).
8-bit
The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...
personal home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
released in the United Kingdom in 1982 by Sinclair Research Ltd
Sinclair Research Ltd
Sinclair Research Ltd is a British consumer electronics company founded by Sir Clive Sinclair in Cambridge. Originally incorporated in 1973 as Ablesdeal Ltd., it remained dormant until 1976, and did not adopt the name Sinclair Research until 1981....
. Referred to during development as the ZX81 Colour and ZX82, the machine was launched as the ZX Spectrum by Sinclair to highlight the machine's colour display, compared with the black-and-white
Black-and-white
Black-and-white, often abbreviated B/W or B&W, is a term referring to a number of monochrome forms in visual arts.Black-and-white as a description is also something of a misnomer, for in addition to black and white, most of these media included varying shades of gray...
of its predecessor, the Sinclair ZX81
Sinclair ZX81
The ZX81 was a home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and was designed to be a low-cost introduction to home computing for the general public...
. The Spectrum was ultimately released as eight different models, ranging from the entry level model with 16 kB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
RAM released in 1982 to the ZX Spectrum +3 with 128 kB RAM and built in floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
drive in 1987; together they sold in excess of 5 million units worldwide (not counting clones, which were numerous).
The Spectrum was among the first mainstream audience home computers in the UK, similar in significance to the Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
in the USA. The introduction of the ZX Spectrum led to a boom in companies producing software and hardware
Hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
for the machine, the effects of which are still seen; some credit it as the machine which launched the UK IT industry. Licensing deals and clones followed, and earned Clive Sinclair
Clive Sinclair
Sir Clive Marles Sinclair is a British entrepreneur and inventor, most commonly known for his work in consumer electronics in the late 1970s and early 1980s....
a knighthood for "services to British industry".
The Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
, BBC Microcomputer and later the Amstrad CPC
Amstrad CPC
The Amstrad CPC 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 Sinclair ZX Spectrum, where it successfully established itself primarily in the United Kingdom,...
range were major rivals to the Spectrum in the UK market during the early 1980s. Over 20,000 software titles have been released since the Spectrum's launch and new titles continue to be released, with over 90 new ones in 2010.
Hardware
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
A CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
running at 3.5 MHz (or NEC D780C-1 clone). The original model Spectrum has 16 kB (16×1024 byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
s) of ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
and either 16 kB or 48 kB of RAM. Hardware design was by Richard Altwasser
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 Sinclair Research in September 1980...
of Sinclair Research, and the machine's outward appearance was designed by Sinclair's industrial designer Rick Dickinson
Rick Dickinson
Rick Dickinson is a British industrial designer.-Early life:Dickinson graduated from Newcastle Polytechnic in 1979 with a First Class Bachelor of Arts Honours degree in Design for Industry. The 'Design for Industry' degree was the first of its kind, formerly a three-year 'Industrial Design' degree...
.
Video output is through an RF modulator
RF modulator
An RF modulator is a device that takes a baseband input signal and outputs a radio frequency-modulated signal....
and was designed for use with contemporary portable 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
ZX Spectrum character set
The ZX Spectrum character set is the variant of ASCII used in the British Sinclair ZX Spectrum computers. It is based on ASCII-1967 , but with one character from ASCII-1963 , two non-standard graphics characters, an idiosyncratic use of the control code area and use of the 128 high-bit...
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
Image resolution is an umbrella term that describes the detail an image holds. The term applies to raster digital images, film images, and other types of images. Higher resolution means more image detail....
is 256×192 with the same colour limitations. To conserve memory, colour is stored separate from the pixel bitmap
Bitmap
In computer graphics, a bitmap or pixmap is a type of memory organization or image file format used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped array of bits. Now, along with pixmap, it commonly refers to...
in a low resolution, 32×24 grid overlay, corresponding to the character cells. Altwasser received a patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
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 clash
Attribute clash was a display artifact caused by limits in the graphics circuitry of a number of early color 8-bit home computers, most notably the Sinclair Research ZX Spectrum, where it meant that only two colors could be used in any area of 8×8 pixels...
with some bizarre effects in the animated graphics of arcade style games. This became a distinctive feature of the Spectrum and an in-joke among Spectrum users, as well as a point of derision by advocates of other systems. Other machines available around the same time, for example the Amstrad CPC
Amstrad CPC
The Amstrad CPC 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 Sinclair ZX Spectrum, where it successfully established itself primarily in the United Kingdom,...
, did not suffer from this limitation. The Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
used colour attributes in a similar way, but a special multicolour mode, hardware sprite
Sprite (computer graphics)
In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
s and hardware scrolling
Scrolling
In computer graphics, filmmaking, television production, and other kinetic displays, scrolling is sliding text, images or video across a monitor or display. "Scrolling", as such, does not change the layout of the text or pictures, or but incrementally moves the user's view across what is...
were used to avoid attribute clash.
Sound output is through a beeper on the machine itself. This is capable of producing one channel with 10 octaves. The machine also includes an expansion bus
Expansion bus
An expansion bus is made up of electronic pathways which move information between the internal hardware of a computer system and peripheral devices. It is a collection of wires and protocols that allows for the expansion of a computer.- History :The first kit-built microcomputers used a bus design...
edge connector
Edge connector
An edge connector is the portion of a printed circuit board 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 single discrete female connector , and they also tend to be...
and audio in/out ports for the connection of a cassette recorder for loading and saving programs and data.
Firmware
The machine's Sinclair BASICSinclair BASIC
Sinclair BASIC is a dialect of the BASIC programming language used in the 8-bit home computers from Sinclair Research and Timex Sinclair...
interpreter is stored in ROM (along with fundamental system-routines) and was written by Steve Vickers
Steve Vickers (academia)
Steve Vickers is the author of the Sinclair ZX Spectrum home computer ROM firmware. He is currently a Senior Lecturer at the University of Birmingham, UK.- Education :...
on contract from Nine Tiles Ltd. The Spectrum's chiclet keyboard
Chiclet keyboard
A chiclet keyboard or island-style keyboard is a computer keyboard built with 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 shape of small squares with rounded corners...
(on top of a membrane, similar to calculator keys) is marked with BASIC keywords, so that, for example, pressing "G" when in programming mode would insert the BASIC command GOTO
Goto
goto is a statement found in many computer programming languages. It is a combination of the English words go and to. It performs a one-way transfer of control to another line of code; in contrast a function call normally returns control...
.
The BASIC interpreter was developed from that used on the ZX81 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
ZX Spectrum character set
The ZX Spectrum character set is the variant of ASCII used in the British Sinclair ZX Spectrum computers. It is based on ASCII-1967 , but with one character from ASCII-1963 , two non-standard graphics characters, an idiosyncratic use of the control code area and use of the 128 high-bit...
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 also supported multi-statement lines. The cassette interface was also much more advanced, saving and loading around four times faster than the ZX81, and much more reliably. As well as being able to save programs, the Spectrum could in addition 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.ZX Spectrum 16K/48K
The original ZX Spectrum is remembered for its rubber keyboardChiclet keyboard
A chiclet keyboard or island-style keyboard is a computer keyboard built with 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 shape of small squares with rounded corners...
, diminutive size and distinctive rainbow motif. It was originally released in 1982 with 16 kB of RAM for £125 Sterling
Pound sterling
The pound sterling , commonly called the pound, is the official currency of the United Kingdom, its Crown Dependencies and the British Overseas Territories of South Georgia and the South Sandwich Islands, British Antarctic Territory and Tristan da Cunha. It is subdivided into 100 pence...
or with 48 kB for £175; these prices were later reduced to £99 and £129 respectively. Owners of the 16 kB model could purchase an internal 32 kB RAM upgrade, which for early "Issue 1" machines consisted of a daughterboard
Daughterboard
A daughterboard, daughtercard or piggyback board is a circuit board meant to be an extension or "daughter" of a motherboard , or occasionally of another card...
. Later issue machines required the fitting of 8 dynamic RAM
Dynamic random access memory
Dynamic random-access memory is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1...
chips and a few TTL
Transistor-transistor logic
Transistor–transistor logic is a class of digital circuits built from bipolar junction transistors and resistors. It is called transistor–transistor logic because both the logic gating function and the amplifying function are performed by transistors .TTL is notable for being a widespread...
chips. Users could mail their 16K Spectrums to Sinclair to be upgraded to 48 kB versions. To reduce the price, the 32 kB extension used eight faulty 64 kilobit
Kilobit
The kilobit is a multiple of the unit bit for digital information or computer storage. The prefix kilo is defined in the International System of Units as a multiplier of 103 , and therefore,...
chips with only one half of their capacity working and/or available. Links on the PCB were configured accordingly so as to place these faulty memory locations in the other (unused) half of each IC. External 32 kB RAM packs that mounted in the rear expansion slot were also available from third parties. Both machines had 16 kB of onboard ROM.
About 60,000 "Issue 1" ZX Spectrums were manufactured; they can be distinguished from later models by the colour of the keys (light grey for Issue 1, blue-grey for later models).
ZX Spectrum+
Planning of the ZX Spectrum+ started in June 1984, and the machine was released in October the same year. This 48 kB Spectrum (development code-name TB) introduced a new QLSinclair QL
The Sinclair QL , was a personal computer launched by Sinclair Research in 1984, as the successor to the Sinclair ZX Spectrum...
-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 £179.95. A DIY
Do it yourself
Do it yourself is a term used to describe building, modifying, or repairing of something without the aid of experts or professionals...
conversion-kit for older machines was also 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%.
ZX Spectrum 128
Sinclair developed the ZX Spectrum 128 (code-named Derby) in conjunction with their Spanish distributor Investrónica. 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.The appearance of the ZX Spectrum 128 was similar to the ZX Spectrum +, with the exception of a large external heatsink for the internal 7805 voltage regulator
Voltage regulator
A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components...
added to the right hand end of the case, replacing the internal heatsink in previous versions.
New features included 128 kB RAM, three-channel audio via the AY-3-8912 chip, MIDI compatibility, an RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
serial port, an RGB 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
SIMO TCI
SIMO TCI is an International Data Processing, Multimedia and Communications Show held every autumn in Madrid, Spain...
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 £179.95. No external keypad was available for the UK release, although the ROM routines to use it and the port itself, which was hastily renamed "AUX", remained.
The Z80 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
Bank switching is a technique to increase the amount of usable memory beyond the amount directly addressable by the processor. It can be used to configure a system differently at different times; for example, a ROM required to start a system from diskette could be switched out when no longer...
so that the new memory would be available as eight pages of 16 kB at the top of the address space. The same technique was also 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 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 way 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 some BASIC programs.
The ZX Spectrum 128 had no internal speaker like its predecessors. The sound was produced from the television speaker instead.
The Spanish version had the "128K" logo
Logo
A logo is a graphic mark or emblem commonly used by commercial enterprises, organizations and even individuals to aid and promote instant public recognition...
in white while the English one had the same logo in red.
Amstrad models
ZX Spectrum +2
The ZX Spectrum +2 was AmstradAmstrad
Amstrad is a British electronics company, now wholly owned by BSkyB. As of 2006, Amstrad's main business is manufacturing Sky Digital interactive boxes....
'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. These changes resulted in minor incompatibility problems with software that accessed ROM routines at certain addresses. 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. This was not a major issue however, as 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 +2A
The ZX Spectrum +2A was produced to homogenise Amstrad's range in 1987. Although the case reads "ZX Spectrum +2", the +2A/B is easily distinguishable from the original +2 as the case was restored to the standard Spectrum black.The +2A was derived from Amstrad's +3 4.1 ROM model, using a new motherboard which vastly reduced the chip count, integrating many of them into a new ASIC
Application-specific integrated circuit
An application-specific integrated circuit is an integrated circuit customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC...
. The +2A replaced the +3's disk drive and associated hardware with a tape drive, as in the original +2. Originally, Amstrad planned to introduce an additional disk interface, but this never appeared. If an external disk drive was added, the "+2A" on the system OS menu would change to a +3. As with the ZX Spectrum +3, some older 48K, and a few older 128K, games were incompatible with the machine.
The ZX Spectrum +2A had a more substantial power supply compared to previous models. This powers supply was slightly larger with air vents and a DIN plug to supply +/- 5 volts and +/- 12 volts. This supply could also be used with the +2B and +3. However, the power supply purchased with the +2A/B had "Sinclair +2" written on the case.
ZX Spectrum +2B
Early Black +2 case mouldings bear the legend "128K Spectrum +2A Made in Taiwan", but in later examples this changed to "128K Spectrum +2B Made in China".ZX Spectrum +3
The ZX Spectrum +3 looked similar to the +2 but featured a built-in 3-inch floppy diskFloppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
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
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
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 AMSDOS
AMSDOS
AMSDOS is a disk operating system for the 8-bit Amstrad CPC Computer . The name is a contraction of Amstrad Disc Operating System....
, 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 2 lines, to disable both ROMs
- Reading a non-existent I/O port no longer returned the last attribute; caused some games such as ArkanoidArkanoidis an arcade game developed by Taito in 1986. It is based upon Atari's Breakout games of the 1970s. The title refers to a doomed "mothership" from which the player's ship, the Vaus, escapes.-Overview:...
to be unplayable - Memory timing changes; some of the 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 a few older 128K, games were incompatible with the machine. The ZX Interface 1 was incompatible due to differences in ROM and expansion connector; therefore it was not possible to connect and use the Microdrive units.
The ZX Spectrum +3 had an identical power supply to the +2A/B. This supply could also be used with the +2A/B. However, the power supply purchased with the +3 had "Sinclair +3" written on the case.
Production of the +3 ceased in December 1990. Although still accounting for one third of all home computer sales in the UK at the time, production of the model was ceased by Amstrad at that point.
Clones
Timex Sinclair 2068
The Timex Sinclair 2068 , released in November 1983, was Timex Sinclair's fourth and last home computer for the United States market...
. Timex's derivatives were largely incompatible with Sinclair systems. However, 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 TS2068. Pandora had a flat-screen monitor and Microdrives and was intended to be Sinclair's business portable. After Amstrad
Amstrad
Amstrad is a British electronics company, now wholly owned by BSkyB. As of 2006, Amstrad's main business is manufacturing Sky Digital interactive boxes....
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.
In the UK, Spectrum peripheral vendor Miles Gordon Technology
Miles Gordon Technology
Miles Gordon Technology, known as MGT, was a small British company, initially specialising in high-quality add-ons for the Sinclair ZX Spectrum home computer. It was named for its founders, Alan Miles and Bruce Gordon and was founded in Cambridge, England in June 1986, by the two ex-Sinclair...
(MGT) released the SAM Coupé
SAM Coupé
The SAM Coupé is an 8-bit British home computer that was first released in late 1989. It is commonly considered a clone of the Sinclair ZX Spectrum computer, since it features a compatible screen mode and emulated compatibility, and it was marketed as a logical upgrade from the Spectrum...
as a potential successor with some Spectrum compatibility. However, by this point, the Commodore Amiga and Atari ST
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...
had taken hold of the market, leaving MGT in eventual receivership.
Many unofficial Spectrum clones were produced, especially in the former Eastern Bloc
Eastern bloc
The term Eastern Bloc or Communist Bloc refers to the former communist states of Eastern and Central Europe, generally the Soviet Union and the countries of the Warsaw Pact...
countries (e.g. in Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
, several models were produced (Tim-S, HC85, HC91, Cobra, Junior, CIP, CIP 3, Jet), some featuring CP/M
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
and a 5.25"/3.5" floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
) and South America (e.g. Microdigital TK 90X
TK 90X
The TK 90X was the first Brazilian ZX Spectrum clone made in 1985 by Microdigital Eletronica, a company located at São Paulo, Brazil, that manufactured some ZX81 clones before and a ZX80 clones ....
and TK 95
TK 95
The TK 95 microcomputer was the evolution of TK 90X made in the 1980s by Microdigital Eletronica, a company located at São Paulo, Brazil that manufactured some ZX81 clones before and a ZX80 clone...
). In the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
, 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
Pentagon (computer)
The Pentagon home computer was a clone of the British-made Sinclair ZX Spectrum 128. It was manufactured by amateurs in the former Soviet Union. Its PCB was copied all over the USSR, which made it the most widespread Soviet ZX Spectrum clone...
and ATM Turbo. In India, Decibells Electronics introduced a licensed version of the Spectrum+ in 1986. Dubbed the "db Spectrum+", it did reasonably well in the Indian market and sold quite a few thousand until 1990 when the market died away.
Peripherals
Several peripherals for the Spectrum were marketed by Sinclair: the ZX PrinterZX 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....
was already on the market, as the ZX Spectrum expansion bus
Computer bus
In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...
was backwards-compatible with that of the ZX81.
The ZX Interface 1
ZX Interface 1
A peripheral from Sinclair Research for its ZX Spectrum home computer, the ZX Interface 1 was launched in 1983. Originally intended as a local area network interface for use in school classrooms, it was revised before launch to also act as the controller for up to eight ZX Microdrive high-speed...
add-on module included 8 kB of ROM, an RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
serial port, a proprietary LAN
Län
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
interface (called ZX Net), and an interface for the connection of up to eight ZX Microdrive
ZX Microdrive
The ZX Microdrive is a magnetic tape data storage system launched in July 1983 by Sinclair Research for their ZX Spectrum home computer. The Microdrive technology was later also used in the Sinclair QL and ICL One Per Desk personal computers.-Development:...
s – somewhat unreliable but speedy tape-loop cartridge storage devices released in July 1983. These were later used in a revised version on the Sinclair QL
Sinclair QL
The Sinclair QL , was a personal computer launched by Sinclair Research in 1984, as the successor to the Sinclair ZX Spectrum...
, whose storage format was electrically compatible but logically incompatible with the Spectrum's. Sinclair also released the ZX Interface 2
ZX Interface 2
The ZX Interface 2 was a peripheral from Sinclair Research for its ZX Spectrum home computer released in September 1983. It had two joystick ports and a ROM cartridge slot, which offered instant loading times. The joystick ports were not compatible with the popular Kempston interface, and thus...
which added two joystick ports and a ROM cartridge port.
There were also a plethora of third-party hardware addons. The better known of these included the Kempston joystick interface
Kempston Interface
The Kempston Interface, produced by Kempston Micro Electronics, was the generic name for any interface on Sinclair's ZX Spectrum series of computers that allowed joysticks complying with the de facto Atari 2600 standard to be used with the machine. It was one of the most widely supported standards...
, the Morex Peripherals Centronics
Centronics
Centronics Data Computer Corporation was a pioneering American manufacturer of computer printers, now remembered primarily for the parallel interface that bears its name.-The beginning:Centronics began as a division of Wang Laboratories...
/RS-232 interface, the Currah
Currah
Currah was a British computer peripheral manufacturer, famous mainly for the speech synthesis cartridges it designed for the ZX Spectrum, Commodore 64, and other 8-bit home computers of the 1980s.-Currah μSource for the ZX Spectrum:...
Microspeech unit (speech synthesis), Videoface
Videoface
Videoface Digitiser is a video digitiser interface for Sinclair ZX Spectrum home computer. It was produced by Data-Skip from The Netherlands and later on Romantic Robot from UK in 1987. It was originally sold for GBP 69, but price dropped to 30 GBP within few years.Videoface takes signal from any...
Digitiser, RAM pack, the Cheetah Marketing
Cheetah Marketing
Cheetah Marketing was a United Kingdom-based company that produced electronic music-related hardware products and software for home computer systems during the 1980s. They later changed their name to Cheetah International Ltd....
SpecDrum, a drum machine, and the Multiface
Multiface
The Multiface was a hardware peripheral released by Romantic Robot UK Ltd. for several 1980s home computers. The primary function of the device was to dump the computer's memory to external storage, and featured an iconic 'red button' that could be pressed at any time in order to activate 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 numerous disk drive interfaces, including the Abbeydale Designers/Watford Electronics
Watford Electronics
Watford Electronics was a British computer electronics company. It was founded in 1972 in a bedroom belonging to Nazir Jessa, and grew to become one of the best-known suppliers of microcomputers and micro peripherals during the 1980s....
SPDOS, Abbeydale Designers/Kempston
Kempston Micro Electronics
Kempston Micro Electronics was an electronics company specialising in computer joysticks and related home computer peripherals during the 1980s. Kempston was based in Kempston, Bedfordshire, England.- Interfaces :...
KDOS and Opus Discovery. The SPDOS and KDOS interfaces were the first to come bundled with Office productivity software (Tasword
Tasword
Tasword is 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 models, the SAM Coupé and the Amstrad CPC range...
Word Processor, Masterfile database and OmniCalc spreadsheet). This bundle, together with OCP's Stock Control, Finance and Payroll systems, introduced many small businesses to a streamlined, computerised operation. The most popular floppy disk systems (except in East Europe) were the DISCiPLE
DISCiPLE
The DISCiPLE was a floppy disk interface for the Sinclair ZX Spectrum home computer. Designed by Miles Gordon Technology, it was marketed by Rockfort Products and launched in 1986....
and +D
+D
The +D was a floppy disk and printer interface for the Sinclair ZX Spectrum home computer, developed as a successor to Miles Gordon Technology's earlier product, the DISCiPLE...
systems released by Miles Gordon Technology
Miles Gordon Technology
Miles Gordon Technology, known as MGT, was a small British company, initially specialising in high-quality add-ons for the Sinclair ZX Spectrum home computer. It was named for its founders, Alan Miles and Bruce Gordon and was founded in Cambridge, England in June 1986, by the two ex-Sinclair...
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 also 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
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
to a viewdata
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 channel. Samuel Fedida was credited as inventor of the...
service known as Micronet 800
Micronet800
Micronet 800 was an information provider 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....
, hosted by Prestel
Prestel
Prestel , the brand name for the UK Post Office's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979...
. This service pre-dated the World Wide Web
World Wide Web
The World Wide Web is a system of interlinked hypertext documents accessed via the Internet...
, but offered many of the services now considered commonplace.
Software
The Spectrum family enjoys a very large software library of more than 20,000 titles which is still increasing. While most of these are games, the library is very diverse, including programming languageProgramming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
implementations, database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
s (e.g. VU-File), word processor
Word processor
A word processor is a computer application used for the production of any sort of printable material....
s (e.g. Tasword
Tasword
Tasword is 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 models, the SAM Coupé and the Amstrad CPC range...
II), spreadsheet
Spreadsheet
A spreadsheet is a computer application that simulates a paper accounting worksheet. It displays multiple cells usually in a two-dimensional matrix or grid consisting of rows and columns. Each cell contains alphanumeric text, numeric values or formulas...
s (e.g. VU-Calc), drawing and painting tools (e.g. OCP Art Studio), and even 3D-modelling (e.g. VU-3D) and archaeology
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...
software amongst many other types.
The hardware limitations of the Spectrum imposed a special level of creativity on game
Computer Games
"Computer Games" is a single by New Zealand group, Mi-Sex released in 1979 in Australia and New Zealand and in 1981 throughout Europe. It was the single that launched the band, and was hugely popular, particularly in Australia and New Zealand...
designers, and so many Spectrum games are very creative and playable even by today's standards. 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.
Distribution
Most Spectrum software was originally distributed on audio cassette tapes. The Spectrum was intended to work with a normal domestic cassette recorder, and despite differences in audio reproduction fidelity, the software loading process was quite reliable, if somewhat slow (by today's standards).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
Word processing
Word processing is the creation of documents using a word processor. It can also refer to advanced shorthand techniques, sometimes used in specialized contexts with a specially modified typewriter.-External links:...
software and Trans Express, (a tape to microdrive copying utility). No games are known to be exclusively released on Microdrive.
Despite the popularity of the DISCiPLE and +D systems, most software released for them took the form of utility software. The ZX Spectrum +3 enjoyed much more success when it came to commercial software releases on floppy disk. More than 700 titles were released on 3-inch disk from 1987 to 1997.
Software was also distributed through print media; magazine
Magazine
Magazines, periodicals, glossies or serials are publications, generally published on a regular schedule, containing a variety of articles. They are generally financed by advertising, by a purchase price, by pre-paid magazine subscriptions, or all three...
s and book
Book
A book is a set or collection of written, printed, illustrated, or blank sheets, made of hot lava, paper, parchment, or other materials, usually fastened together to hinge at one side. A single sheet within a book is called a leaf or leaflet, and each side of a leaf is called a page...
s. The reader would type the Sinclair BASIC
Sinclair BASIC
Sinclair BASIC is a dialect of the BASIC programming language used in the 8-bit home computers from Sinclair Research and Timex Sinclair...
program listing into the computer by hand, run it, and could save it to tape for later use. The software distributed in this way was in general simpler and slower than its assembly language
Assembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
counterparts. Magazines also printed long lists of checksum
Checksum
A checksum or hash sum is a fixed-size datum computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. The integrity of the data can be checked at any later time by recomputing the checksum and...
med hexadecimal
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
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" 33⅓ rpm flexidisc records, a variant of regular vinyl records which could be played on a standard record player. These disks were known as floppy ROMs.
Copying and backup software
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 protectionCopy protection
Copy protection, also known as content protection, copy obstruction, copy prevention and copy restriction, refer to techniques used for preventing the reproduction of software, films, music, and other media, usually for copyright reasons.- Terminology :Media corporations have always used the term...
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
Novella
A novella is a written, fictional, prose narrative usually longer than a novelette but shorter than a novel. The Science Fiction and Fantasy Writers of America Nebula Awards for science fiction define the novella as having a word count between 17,500 and 40,000...
like in Silicon Dreams trilogy
Silicon Dreams trilogy
Silicon Dreams is a trilogy of interactive fiction games developed by Level 9 Computing during the 1980s. The first game was Snowball, released in 1983, followed a year later by Return to Eden, and then by The Worm in Paradise in 1985. The following year they appeared together in a bundle as the...
—or another physical device distributed with the software—e.g. Lenslok
Lenslok
Lenslok is a copy protection mechanism found in some computer games and other software on the 8bit Atari, Commodore 64, Sinclair ZX Spectrum, Sinclair QL, MSX and Amstrad CPC. The most famous game to use it was Elite for the ZX Spectrum....
as used in Elite. Special hardware, such as Romantic Robot's Multiface
Multiface
The Multiface was a hardware peripheral released by Romantic Robot UK Ltd. for several 1980s home computers. The primary function of the device was to dump the computer's memory to external storage, and featured an iconic 'red button' that could be pressed at any time in order to activate 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, in recent years, 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
Sound card
A sound card is an internal computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces that use software to generate sound, as opposed to using hardware...
, or—through a simple home-built device—to the parallel port
Parallel port
A parallel port is a type of interface found on computers for connecting various peripherals. In computing, a parallel port is a parallel communication physical interface. It is also known as a printer port or Centronics port...
of a PC. Once in files on a host machine, the software can be executed on one of many emulator
Emulator
In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...
s, on virtually any platform available today.
The largest on-line archive of ZX Spectrum software is World of Spectrum
World of Spectrum
World of Spectrum is a website devoted to cataloging and archiving material for the ZX Spectrum home computer popular in the 1980s, and has been officially endorsed by Amstrad which holds the rights to the ZX Spectrum brand...
, with more than 21,000 titles. The legality of this practice is still in question and while a number of copyright holders have explicitly objected to the posting of their software, others have given their permission for their games to be archived as part of the preservation project.
Notable developers
Shiny Entertainment
Shiny Entertainment was an American video game developer based in Laguna Beach, Southern California, and the creator of several popular titles such as Earthworm Jim, MDK, Sacrifice and The Matrix: Path of Neo. Shiny was founded by David Perry in October 1993...
, and Tim and Chris Stamper
Tim and Chris Stamper
Tim and Chris Stamper are the co-founders of Ashby Computers & Graphics and later Rare...
(founders of Ultimate Play The Game
Ultimate Play the Game
Ultimate Play The Game was a critically acclaimed video game developer of the early home computer era. "Ultimate Play The Game" was the trading name of Ashby Computers & Graphics Ltd. , a software company founded in 1982 by two ex-arcade game developers Tim and Chris Stamper...
, now known as Rare, maker of many famous titles for Nintendo
Nintendo
is a multinational corporation located in Kyoto, Japan. Founded on September 23, 1889 by Fusajiro Yamauchi, it produced handmade hanafuda cards. By 1963, the company had tried several small niche businesses, such as a cab company and a love hotel....
and Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
game consoles). Other prominent games developers include Julian Gollop
Julian Gollop
Julian Gollop is a British designer of strategy video games and founder of the defunct game studios Mythos Games and Codo Technologies.Gollop's career spans over 25 years, during which he has designed games for numerous systems over the years, from the early 8-bit home computers to 32-bit PCs...
(Chaos, Rebelstar, X-COM series), Matthew Smith
Matthew Smith (games programmer)
Matthew Smith is a British computer game programmer. He is best known for his games Manic Miner and Jet Set Willy for the ZX Spectrum, released in 1983 and 1984 respectively...
(Manic Miner
Manic Miner
Manic Miner is a platform game originally written for the ZX Spectrum by Matthew Smith and released by Bug-Byte in 1983 . It is the first game in the Miner Willy series and among the pioneers of the platform game genre. The game itself was inspired by the Atari 800 game Miner 2049er...
, Jet Set Willy
Jet Set Willy
Jet Set Willy is a computer game originally written for the ZX Spectrum home computer. It was published in 1984 by Software Projects and ported to most home computers of the time....
), Jon Ritman
Jon Ritman
Jon Ritman is a software developer, notable for his work on major 1980s video games. Working primarily on games for the ZX Spectrum and Amstrad CPC home computer range. His first experience with a computer was at the age of 13, and first computer was a Sinclair ZX81 that he bought in 1981.His first...
(Match Day
Match Day
Match Day was a football computer game, published by Ocean Software in 1984, originally on the ZX Spectrum and then later released on the Amstrad CPC, BBC Micro, & Commodore 64 systems. It is the first game in the Match Day series, and the title and opening music are references to Match of the Day...
, Head Over Heels
Head Over Heels (game)
Head Over Heels is an arcade adventure, released in 1987 for several 8-bit home computers, and subsequently ported to a wide range of formats. Originally, the working title for the game was Foot and Mouth....
), The Oliver Twins
Oliver Twins
The Oliver Twins are two British brothers, Philip and Andrew Oliver, who started to professionally develop computer games while they were still at school. Their first game, Super Robin Hood for the Amstrad CPC, was published in 1985 by Codemasters...
(the Dizzy series
Dizzy series
The Dizzy series of computer games, published by Codemasters, was one of the most successful European computer game brands of the late 1980s. The games were based around a central figure: an intelligent egg-like creature called Dizzy...
), Clive Townsend (Saboteur), Pete Cooke
Pete Cooke
Pete Cooke is a famous British computer games programmer, best known for his work published in the 1980s for the 8-bit home computers, especially the ZX Spectrum....
(Tau Ceti), Mike Singleton
Mike Singleton
Mike Singleton is a British author and video game developer who wrote various well-regarded titles for the ZX Spectrum during the 1980s. His titles include The Lords of Midnight, Doomdark's Revenge, Throne of Fire, Dark Sceptre and War In Middle Earth. He also wrote a novel, The Eternal Empire,...
(The Lords of Midnight
The Lords of Midnight
The Lords of Midnight is a video game, written by Mike Singleton, and released in 1984 for the ZX Spectrum. Conversions for the Amstrad CPC and Commodore 64 soon followed.-Gameplay:The Lords of Midnight is a wargame/adventure game...
,War In Middle Earth), and Alan Cox
Alan Cox
Alan Cox is a British computer programmer who formerly maintained the 2.2 branch of the Linux kernel and continues to be heavily involved in the development of the Linux kernel, an association that dates back to 1991...
. Although the 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
Tim Follin
Timothy John Follin is a former video game music composer who has written tracks for a variety of titles and home gaming systems, including the Sinclair ZX Spectrum, Commodore 64, Commodore Amiga, Atari ST, NES, Super Nintendo, Game Boy, Dreamcast and PlayStation.Follin's early 8- and 16-bit...
produced notable multi-channel music for the machine.
Jeff Minter
Jeff Minter
Jeff 'Yak' Minter is a British computer/video game designer and programmer. He is the founder of software house Llamasoft and his recent works include Neon , a non-game music visualization program that has been built into the Xbox 360 console, and the video games Space Giraffe , and Space Invaders...
ported some of his Commodore VIC-20
Commodore VIC-20
The VIC-20 is an 8-bit home computer which was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PET...
games to the ZX Spectrum.
Community
The ZX Spectrum enjoyed a very strong community early on. Several dedicated magazines were released including Sinclair UserSinclair User
Sinclair User, often abbreviated SU, was a magazine dedicated to the Sinclair Research range of home computers, most specifically the ZX Spectrum...
(1982), Your Sinclair
Your Sinclair
Your Sinclair or YS as it was commonly abbreviated, was a British computer magazine for the Sinclair range of computers, mainly the ZX Spectrum.-History:...
(1983) and CRASH
CRASH (magazine)
Crash was a magazine dedicated to the ZX Spectrum home computer. It was published from 1984 to 1991 by Newsfield Publications Ltd until their liquidation, and then until 1992 by Europress.-Development:...
(1984). Early on they were very technically oriented with type-in programs and machine code tutorials. Later on they became almost completely game-oriented. Several general contemporary computer magazines covered the ZX Spectrum in more or less detail. They included Computer Gamer
Computer Gamer
Computer Gamer was a video game magazine published in the United Kingdom by Argus Specialist Publications, covering home gaming during the late 1980s...
, Computer and Video Games
Computer and Video Games (magazine)
Computer and Video Games is a video game magazine and website published in the United Kingdom.- History :...
, Computing Today
Computing Today
Computing Today was a computer magazine published by Argus Specialist Publications, it was printed in the UK from the late 1970s to the mid 1980s...
, Popular Computing Weekly
Popular Computing Weekly
Popular Computing Weekly was a computer magazine in the UK published from the early 1980s until the early 1990s. It was sometimes referred to as PCW ....
, Your Computer
Your Computer (British magazine)
Your Computer was a British computer magazine published monthly from 1981 to 1988, and aimed at the burgeoning home computer market. At one stage it was, in its own words, "Britain's biggest selling home computer magazine". It offered support across a wide range of computer formats, and included...
and The Games Machine
The Games Machine
The Games Machine was 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 Spectrum is affectionately known as the Speccy by elements of its fan following.
More than 80 electronic magazines existed, many in Russian. Most notable of them were AlchNews (UK), ZX-Format (Russia), and Spectrofon
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 FDD and included both text and program part...
(Russia).
See also
- ZX Spectrum graphic modesZX Spectrum graphic modesThe ZX Spectrum is generally considered to have limited graphical capabilities in comparison to other home computers of the same era such as the Commodore 64, largely due to its lack of a dedicated graphics chip...
- List of ZX Spectrum games
- List of ZX Spectrum clones
- History of computing hardware (1960s-present)History of computing hardware (1960s-present)The history of computing hardware starting at 1960 is marked by the conversion from vacuum tube to solid state devices such as the transistor and later the integrated circuit. By 1959 discrete transistors were considered sufficiently reliable and economical that they made further vacuum tube...
External links
- Online Games
- World of Spectrum
- Page on site VRCP Soft for ZX Spectrum
- Planet Sinclair
- ZXF magazine
- The Incomplete Spectrum ROM Assembly and actual assembly listing
- Sinclair Spectrum development
- The Anatomy/Dissection of a Spectrum +2B
- ZX Spectrum online emulator in Java (Symbol Shift -> Windows; Edit -> Escape)
- ZX Spectrum Basic Handbook
- iSpeccy. Online ZX Spectrum emulator in Javascript for iOS devices (iPhone, iPad, iPod Touch)