Sinclair's ZX-80

Sinclair's ZX-81

Sinclair's ZX Spectrum 16K/48K

Sinclair's ZX Spectrum 128K+

Amstrad's ZX Spectrum 128K +2/+2A

Amstrad's ZX Spectrum 128K +3
All began in February of 1980, when Sir Clive Sinclair decided to iniciate his projects and make some realities out of them! ZX-80 was his first and "true" invention. Its price was less than 100 and it was extremely limited. It didn't have a graphical mode or a sound generator. The programming language incorporated was the known BASIC, limited to some simple integer math operations.
This computer sold aproximately 50.000 copies worldwide, not a very high value, but acceptable. The ZX-80 had a plain ROM (Read Only Memory), expansible to 4KB and a 1KB RAM (Random Access Memory), expansible to some extraordinary 16KB! Later, on September of the same year, another version of this computer was out on the market - the ZX-80 16KB RAM pack, including 16KB of RAM.

But Sir Clive Sinclair didn't stop, and as promised, he made the ZX-81 in March of 1981. It was presented slightly different than ZX-80. This second machine stood still with no sounds, but had the new possibility of creating simple and tiny graphics. The size of some of its chips were reduced and its ROM was considerably expanded to 8KB. The ZX-81 could now realize floating point operations, and incorporated a switch to increase or decrease the general CPU speed. Compared to the ZX-80, this computer sold out six times more, fact that motivated Sinclair to do his third computer.

The public awaited Sinclair's new computer, which proved to be even better! After the success of ZX-80 and ZX-81, the Spectrum 16K (also known as ZX-82) was finally on the market in April 1982. The given answer with this new machine, went against the detected technical failures of the last two computers. The ZX-82 presented new charateristics, such as graphical capability to create colorful images and a sound generator. All this with a competitive price when compared to its rivals (125).
The hardware of this machine has been designed by Richard Altwasser, who later formed his own company - Cantab. The first model of this Spectrum had a 16K memory, expandable to some incredible 48KB!! Besides, it now supported a graphic resolution of 192x256 pixels and the BASIC version of its programming language was seriously upgraded, allowing users to work with the graphics, colors and sounds!

But this ultimate Spectrum version wasn't definitely the end. Later on October 1984 appeared the substitution of the ZX-82, which name was Spectrum +. Few differences could be noticed, such as a new mechanical structure of the keyboard and a reset button.

February of 1986 was a year of great expectations to the Spectrum market. Sir Clive Sinclair did a new computer, the ZX Spectrum 128K+, a highly improved system. The technological jumps done were even bigger, and this was the machine everyone wanted to possess!
The hardware was improved too and this Spectrum now possessed a great sound chip (AY-3-8912), as well as 128KB of RAM and 32KB of ROM! The operative system was also strongly perfected, including a really nice BASIC editor, with two new commands (SPECTRUM and PLAY). The first allowed the user to change to 48K mode with a 128KB memory, and the second command could be used to elaborate some well designed musical melodies.

When everyone thought that the Spectrum would finally stuck in this model (128K+), Amstrad came, in "association" with Sinclair, to prove that wrong! In December of 1987, the public knew another Spectrum computer, called ZX Spectrum +2. Actually, Amstrad bought the rights of Sinclair, but decided to mantain the identical structure of the last model. The first difference detected was the cassette deck incorporated next to the keyboard, like an "All-in-One" machine! The other difference could be seen in the messages at the bottom of the initial screen, where the copyrights read "Amstrad" instead of "Sinclair". The Tape Tester program in the initial menu was removed, who knows why!
In the same year, Amstrad presented a second version of this computer, the ZX Spectrum +2A, which differences were an additional memory of 32KB and a black color case instead of gray.

Finally, as Amstrad's last computer, came ZX Spectrum +3 in 1988, with a really new improvement - a 3" diskette drive! The floppy disks were compatible with the text format of Amstrad PCW8256, and the maximum capacity per disk was about 344KB, 172KB on each side.
The reserved commands to hardware usage changed a little, ressembling the PCs. Examples of that was the sentence required to access the diskette or tape modes. Like the ZX Spectrum +2A, this computer also included 32KB of extra memory, good for programming tasks.
Many people reported some incompatibilities with this new machine, which really happened with old software. Although, since the +2A release, Amstrad solved a common problem in the Sinclair's computers. Now, during a program loading, the user could safely insert, for example, a joystick into the port with no harm to the loading sequence, something similar to the Bill Gate's "Plug & Play".
However, this computer didn't have the famous line the others had. This was probably due to the expensive price it was sold (250), problem also noticed in the floppy diskettes.
The Spectrum's future ended here, quickly and quietly. A sad end for a "fruit" more than wished!

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