 |
 |
Computers
In The Beginning
Sinclair ZX81
|
|
Sinclair ZX81 [Sinclair Programs]. 7,000 (€20.54c) drachmas in the British market and 12,900 (€37.86c) in the Greek market. In the United States of America, there is a ZX81 version which is known as TS1000. Dimensions: approximately 6.69 x 6.30 x 1.18 inches. Weight: 13.06 ounches. Based on the Z80 processor, comes with just 1 KByte of RAM, but you can expand it by purchasing a 16 KBytes RAM pack, which fits on the back of the computer.
The RAM pack and the printer share the same port. So if you own both a RAM pack and a printer, you must plug the RAM pack on the back of the computer and the printer on the RAM pack. A 16 KBytes RAM pack will cost you 16,000 drachmas (€46.96c) and is approximately 5.91 inches wide, 0.79 inches deep and 2.76 inches high. The keys on the keyboard are fingertip controlled (pressure sensitive) and the BASIC statements are "preset". You can key them in by pressing just one key on the keyboard. You cannot key in separate letters, unless the previous statement is a REM, or when you are enclosing a string in double quotes ("). You don't need a special monitor, in fact you cannot use a special monitor, because the ZX81 comes with an UHF/VHF frequency modulator. The only device you can use as a monitor is your TV set. You have to connect ZX81's TV output to your TV set's UHF aerial socket. You then have to tune the television in to channel 36 UHF, since the ZX81 is... broadcasting it's signal on channel 36 UHF. The screen displays 24 rows x 32 characters. It provides low resolution graphics thus dividing the screen into 64 x 44 squares. The ZX81 is not accompanied by a storage device and since everything is lost when you turn it off, you must save your work on a cassette tape. For about 5,500 drachmas (€16.14c) you can record/save the programs you are developing, on tape, but while loading them you must be extremely careful regarding the volume level. If it is too high, the signal is distorted and the ZX81 will keenly refuse to admit that what you are trying to load is a saved program. The printer is approximately 4.72 inches wide, 3.54 inches deep and 3.54 inches high. It is a thermal printer and will print only on thermal paper which you have to buy in rolls. The power consumption of the printer is as high as 1.2 amperes and this is the reason why the printer itself needs a separate power supply. Richard Francis, in his book "The Cambridge Collection/30 Programs for the ZX81", gives six pieces of advice regarding what programmers should do in order to squeeze their programs into 1 KByte of memory. In his sixth and final advice he clearly states that "If all else fails admit defeat and buy a RAM PACK".
Sinclair ZX81
06-04-2004