ZX Spectrum Description Models ZX Spectrum (1982)

Video output was to a TV, for a simple colour graphic display. The rubber keyboard (on top of a membrane, similar to calculator keys) was marked with Sinclair BASIC programming language keywords, so that pressing, say, "G" when in programming mode would insert the BASIC command GOTO. Programs and data were stored using a normal cassetteFor the meaning of cassette in genetics, see cassette (genetics). The compact audio cassette audio storage medium was introduced by Philips in 1963. It consists of a length of magnetic tape from BASF inside a protective plastic shell. Four tracks are avai recorder.

The Spectrum's video display, although rudimentary by today's standards, was perfect at the time for display on portable TV sets, and didn't present a much of a barrier to game development. The text mode display was 32 columns × 24 rows of characters from the Spectrum Character SetThe ZX Spectrum character set is the variant of ASCII used in the British Sinclair Spectrum computers. It is based on ASCII-1967 (the standard ASCII on which all modern character sets are based), but with one character from ASCII-1963 (the first version o, with a choice of 8 colours in either normal or bright mode, which gave 15 shades (black was the same in both modes). The graphics resolutionThe image resolution is a term that says something about how much image detail an image can hold. The term is most often used in relation to digital images, but is also used to describe how grainy a "film-based" image is. Higher resolution means more imag was 256×192 with the same colour limitations. The Spectrum had an interesting method of handling colour; the colour attributes were held in a 32×24 grid, separate from the text or graphical data, but was still limited to only two colours in any given character cell. This led to what was called colour clash or attribute clashAttribute clash was a display artifact caused by limitations in the graphics circuity of early colour 8-bit home computers infamously the Sinclair ZX Spectrum. The Spectrum's variant was caused by the idiosyncratic display memory layout. Rather than restr with some bizarre effects in arcade style games.

The Spectrum was the first mainstream audience home computer in the UK, similar in significance to the Commodore 64Commodore 64 C64 CBM 64 was a popular home computer of the 1980s. Announced by Commodore Business Machines (founded and owned by Jack Tramiel) in January 1982 and released in September of that year at a price of US$595, it offered unprecedented value (sou in the USA (the C64 also being the main rival to the Spectrum in the UK market). An enhanced version of the Spectrum with better sound, graphics and other modifications was marketed in the USA by TimexTimex Corporation is the best-known American watch manufacturer, famous for half a century for durable low-cost timepieces. Timex' headquarters are located in Middlebury, Connecticut. The company began in 1854 as Waterbury Clock in Connecticut's Naugatuck as the TS2068.

A number of current leading games developers and development companies began their careers on the ZX Spectrum, including Peter MolyneuxPeter Molyneux ( 1960 in Great Britain) is a computer game designer, responsible for well known " God games" Populous and Black and White among others. He co-founded Bullfrog Productions in 1987 and Lionhead Studios in 1997. Molyneux was inducted into the (ex- Bullfrog Games), Dave Perry of Shiny Entertainment , and Ultimate Play The Game (now known as Rare, Inc, maker of many famous titles for Nintendo game consoles). Other prominent games developers include Matthew Smith ( Manic Miner, Jet Set Willy), and Jon Ritman (Match Day, Head over Heels).

2 Models

2.1 ZX Spectrum (1982)

Released by Sinclair in 1982 and available with either 16KB (£125, later £99) or 48KB (£175, later £129) of RAM and 16KB ROM. Remembered for its rubber keyboard and diminutive size.

2.2 ZX Spectrum+ (1984)

The 48K Spectrum gets a much needed solid keyboard and reset button, retailing for £180. An upgrade package for older machines was also available.

2.3 ZX Spectrum 128 (1986)

The last Spectrum to be produced by Sinclair (although developed by Investronica of Spain) and based on the Spectrum+. New features included three-channel audio via the AY-3-8912 chip, MIDI compatibility, 128 KB of paging RAM, an RS-232 serial port and an RGB monitor output.

2.4 ZX Spectrum +2 (1986)

Shortly after Amstrad's buyout of Sinclair Research in 1986 came the ZX Spectrum +2. It featured a new casing coloured grey, distinguishing itself from the familiar black of previous Spectrums. The new case also integrated a new spring loaded keyboard, dual joystick ports, and a built-in cassette recorder dubbed the "Datacorder" (like the Amstrad CPC 464). Production cost cutting saw the retail price drop to £139-£149. Aside from the tape drive, revised keyboard and casing the +2 was essentially the same as the 128 model.

2.5 ZX Spectrum +2A / +2B (1987)

The +2A was produced to homogenize Amstrad's range. Although the case still reads "ZX Spectrum +2", the +2A/B is easily distinguishable from a +2 as the case was restored to the standard Spectrum black.

The +2A was derived from Amstrad's new +3 model (see below), with 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.

The +2A was intended to merely be a cost-reduced, bug-fixed version of the original +2, but the other hardware and ROM changes inherited from the +3 - removal of the code to drive the MIDI port and external keypad, support for the disk controller and so on - rendered it incompatible with much original Spectrum hardware, such as many external storage interfaces.

2.6 ZX Spectrum +3 (1987)

Amstrad produced disk version based on the +2 but featuring a built-in 3-inch floppy disk drive (like the Amstrad CPC 6128). Most models featured distorted sound thanks to a design fault later rectified in the "4.1 ROM" model. Retailed for £249 then later £199 and the only model capable of running CP/M without additional hardware.

2.7 Clones

Sinclair licensed the Spectrum design to Timex in the USA who produced their own, largely incompatible, derivatives.

In the UK Spectrum peripheral vendor Miles Gordon Technology (MGT) released the SAM Coupe as the natural successor with some Spectrum compatibility however the Commodore Amiga and Atari ST had taken hold of the market by this point leaving MGT in eventual recievership.

Many unofficial Spectrum clones were produced, especially in Eastern Europe and South America. Some of them are still being produced such as Didaktik and the Sprinter from Peters Plus Ltd . Russian clones include the Hobbit, Pentagon and Scorpion.

3 Peripherals

Several peripherals for the Spectrum were marketed by Sinclair: the printer was already on the market, as the Spectrum had retained the protocol for the ZX81's printer. The Interface 1 added a standard RS-232 serial port, a proprietary format local area networking port, and the ability to connect up to eight ZX Microdrives – somewhat unreliable but speedy tape-loop storage devices (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 Interface 2 which added two joystick ports and a ROM cartridge port.

There were also a plethora of third-party hardware addons. These more well-known of these included the Kempston joystick interface, the Currah Microspeech unit (speech synthesis), and the Multiface (snapshot and disassembly tool), from Romantic Robot. There were numerous disk drive interfaces, including the Opus Discovery and the DISCiPLE/ PlusD from Miles Gordon Technology. During the mid- 80s, the company Micronet800 launched a service allowing users to connect their ZX Spectrums to a network known as Prestel. This service had some similarities to the Internet, but was proprietary and fee-based.

4 See also

5 External links

Sinclair computers, derivatives, and clones ( ZX80/81, ZX Spectrum, and QL clones)

By Sinclair Research and Amstrad: ZX80 |

ZX81 | ZX Spectrum, Spectrum+, Spectrum 128, +2 and +3 (the latter two by Amstrad) | Sinclair QL

By others: Timex Sinclair 1000 |

Sinclair ZXSpectrum

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