The ZX Spectrum was a British 8 bit computer ''Taken from Sinclair Research based on a [[Z80]] CPU, like the Amstrad CPC, and was released earlierhttp://en.It is known affectuously as the "Speccy"wikipedia.org/w/index.php?title=ZX_Spectrum Wikipedia']'
It was in many respect like the Amstrad to the point that so many Amstrad CPC games were in fact The '''ZX Spectrum ports : ''' (the shamefull "Z" is pronounced "Zed" in its original [[Speccy Port|Speccy portsBritish English]]branding) 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 released in eight different models, ranging from the entry level model with 16KB 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.
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, 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".
==an awesome Graphic Genius==The [[c64|Commodore 64]], BBC Microcomputer and later the [[CPC|Amstrad CPC]] range were major rivals to the Spectrum in the UK market during the early 1980s. The ZX Spectrum has enjoyed a resurgence in popularity thanks to the accessibility of ZX Spectrum emulators, allowing 1980s video game enthusiasts to enjoy classic titles without the long loading times associated with data cassettes. Over 20,000 titles have been released since the Spectrum's launch and new titles continue to be released, with over 90 new ones in 2010.
The main difference between those 2 systems was the Video Display method==Hardware==[[File:ZXspectrum mb.jpg|right|350px|thumb|ZX Spectrum 48K motherboard (Issue 3B — 1983, heat sink removed)]]
The Spectrum is based on a [[Z80|Zilog Z80]]A Central processing unit running at 3.5MHz (or NEC D780C-1 clone). The original model Spectrum has 16KB (16*1024 bytes) of ROM and either 16KB or 48KB 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.
The good Old Speccy Video output is well known through an RF modulator and was designed for his dreaded "'''Colour Clashes'''" thanks to it ability to only display 1 bits graphics use with attributes (2 colours per 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 256x192 low resolution, 32*24 grid overlay, corresponding to the character cells. Altwasser received a patent for this design.
It could An "attribute" consists of course display more than 2 colours on a foreground and a background colour, a brightness level (normal or bright) and a flashing "flag" which, when set, causes the screen thank two colours to swap at regular intervals. Unfortunately, this scheme leads to what was dubbed ''colour clash'' or ''[[attribute clash]]'' with some bizarre effects in the technic called animated graphics of arcade style games. This problem 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 [[CPC|Amstrad CPC]], did not suffer from this limitation. The [[C64|Commodore 64]] used colour attributes (in a grid is applied similar way, but a special multicolour mode, hardware sprites and hardware scrolling were used to the screen to give "attributes" to each caracters)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.
==DifferencesFirmware==The machine's Sinclair BASIC 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 Speccy Video Ram BASIC was developed from that used only 6Ko per screenon 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 Amstrad CPC ZX Spectrum character set was 16Koexpanded 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.
As a result, the Amstrad seemed less efficient concerning animation because the Video Ram was far more demanding==Sinclair Research models==[[File:ZXSpectrum48k.jpg|right|350px|thumb|ZX Spectrum 16K/48K (Dimensions (mm): 233*144*30 (W*H*D) @ ~552 grams)]][[File:ZX Spectrum+.jpg|thumb|ZX Spectrum+ (Dimensions (mm): 319?149?38 (W?H?D))]]But a proper coding could give better result than simply porting codes from a speccy[[File:ZX Spectrum128K.jpg|thumb|ZX Spectrum 128]]
The ZX Spectrum Killed the Amstrad CPC...sort of.
Also Amstrad bought ===Pre-production designs===Rick Dickinson came up with a number of designs for the "ZX82" project before the final ZX Spectrum range design. A number of the keyboard legends changed during the design phase including ''ARC'' becoming ''CIRCLE'', ''FORE'' becoming ''INK'' and released its own ZX spectrum range''BACK'' becoming ''PAPER''.
And this also killed ===ZX Spectrum 16K/48K===The original ZX Spectrum is remembered for its Chiclet keyboard, diminutive size and distinctive rainbow motif. It was originally released in 1982 with 16KB of RAM for £125 or with 48 KB for £175; these prices were later reduced to £99 and £129 respectively. Owners of the Amstrad CPC commercially16 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 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 64Kb 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.
As an exempleAbout 60, the 000 "Issue 1" ZX Spectrum 2+ (equivalent to Spectrums were manufactured; they can be distinguished from later models by the CPC 464colour of the keys (light grey for Issue 1, blue-grey for later models) released by Amstrad did have 128Ko Ram.
==Common grounds=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 Sinclair QL-style case with an injection-moulded keyboard and a reset button. Electronically, it was identical to the previous 48 KB model. 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 Spectrum128 ===ZX Spectrum 128===Sinclair developed the '''ZX Spectrum 128''' (or code-named ''Derby'') in conjunction with their Spanish distributor Investronica. Investronica had helped adapt the ZX Spectrum+2/+3to the Spanish market after the Spanish government introduced a special tax on all computers with 64KB RAM or less, and a law which obliged all computers sold in Spain to support the Spanish alphabet (such as n-tilde) specs shared quite some CPC's stuffand show messages in Spanish.
*[[PSG]] : New features included 128KB RAM, three-channel audio via the speccy's one benefited from a superior frequency (2Mhz instead AY-3-8912 chip, MIDI compatibility, an RS-232 serial port, an RGB monitor port, 32KB of 1mhz...) ROM including an improved BASIC editor, and faster memory managementan external keypad.
*[[Z80]] : quite more efficient on speccy due 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 inability 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 get real graphicsuse it and the port itself, which was hastily renamed "AUX", remained.
==Speccy Porks==The Z80 processor used in the Spectrum has a 16-bit address bus, which means only 64KB of memory can be directly addressed. To facilitate the extra 80KB of RAM the designers used bank switching so that the new memory would be available as eight pages of 16KB at the top of the address space. The same technique was also used to page between the new 16KB editor ROM and the original 16KB BASIC ROM at the bottom of the address space.
CPC's [[Speccy Port|Speccy ports]] The new sound chip and MIDI out abilities were not alway that badexposed 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).Some of them managed To enable BASIC programmers to access the additional memory, a RAM disk was created where files could be quite good despite allstored in the additional 80KB of RAM. The new commands took the place of two existing user-defined-character spaces causing compatibility problems with some BASIC programs.
The Spanish version had the "128K" logo in white while the English one had the same logo in red.
But those games usually had the same kind of flaws ==Amstrad models==[[File:ZX Spectrum Plus2.jpeg|thumb|ZX Spectrum +2]][[File:Spectrum 128-2.png|thumb|ZX Spectrum +2A]][[File:ZX Spectrum Plus3.jpeg|thumb|ZX Spectrum +3]]
--Monocolor : ===ZX Spectrum +2===The '''ZX Spectrum +2 bit codes for ''' was Amstrad's first Spectrum, coming shortly after their purchase of the Graphics (spritesSpectrum range and "Sinclair" brand in 1986. The machine featured an all-new grey case featuring a spring-loaded keyboard, tilesdual joystick ports, and a built-in cassette recorder dubbed the "Datacorder" (like the [[CPC_Old_Generation|Amstrad CPC 464]]) meant that those games were often monochromatic, but was in most respects identical to the ZX Spectrum 128.But The main menu screen lacked the developpers cheated this by puting extra colours in Spectrum 128's "Tape Test" option, and the HUD often thanks ROM was altered to Rasters interruptsaccount for a new 1986 Amstrad copyright message.Of course those Extra colours were useless indeedThese 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.
--Smaller screen : To match The new keyboard did not include the actual resolution of the SpeccyBASIC keyword markings that were found on earlier Spectrums, those games used except for the Mode 1 keywords ''LOAD'', ''CODE'' and reduced the screen resolution (''RUN'' which were useful for loading software. This was lower on not a major issue however, as the Speccy+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.
Typical exemples or notorious speccy ports : Black tiger===ZX Spectrum +2A===The '''ZX Spectrum +2A''' was produced to homogenise Amstrad's range in 1987. Although the case reads "ZX Spectrum +2", R-Type or PacManiathe +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 [[Application-specific integrated circuit|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.
===ZX Spectrum +2B===
The '''ZX Spectrum +2B''' signified a manufacturing move from Hong Kong to Taiwan later in 1987.
==The Amstrad Models=ZX Spectrum +3===The '''ZX Spectrum +3''' looked similar to the +2 but featured a built-in 3-inch floppy disk 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.
[[File:Zx spectrum graphics-spectrum plus2The +3 saw the addition of two more 16 kB ROMs.jpg]]Sinclair spectrum One was home to the second part of the reorganised 128 ROM and the other hosted the +2 : 3's disk operating system. This was a 128K Ram speccy with Tapedrivemodified 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.
[[FileSuch core changes brought incompatibilities:Zx spectrum graphics-spectrum plus3 * 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.jpg]]Sinclair spectrum +3 : * 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 ''Arkanoid'' 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 Ram speccy , games were incompatible with the machine.The ZX Interface 1 was incompatible due to differences in ROM and expansion connector, therefore wasn't possible to connect and use the Microdrive units. Production of the +3" DiskDriveceased 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.
[[Category: Non CPC Computers| ]][[Category:Amstrad Products|*]][[Category:CPC History]]