Even today, I still firmly believe there is no substitute for experience ! Having served my time as an electronic engineer with Ferranti, working on various electronic systems including the Multi Roll Combat Aircraft, which became the Tornado fighter, I was always interested in electronic systems and how to repair them. I was fortunate enough to be involved from the first days of home computing. Working on Ferranti systems for the RAF it was a strict requirement that the job was done to very exacting standards and today I still apply these standards to the jobs I do.
Someone recently asked me if I could repair their old Amstrad PCW8512 floppy drive. I managed to get the spare part for it after a great deal of searching and duly got it up and running again. It amazed me that this old machine still worked perfectly and indeed, that it was still in daily word processing use. During this process it got me thinking about all the machines I had used and repaired over the years (more than I care to remember) and just how far computers have progressed in that time. It started out as a personal walk down memory lane and in the end, I thought it may be of interest to list some of the machines here, with their specifications.
You will also note that many of the early PCs were absent of screens as most had to be connected up to a TV screen.
It is also an interesting fact that most of the companies and branding have now disappeared and that many companies have replaced them and become worldwide household names - Microsoft, Intel, AMD, Acer, Toshiba, Dell etc.
The affordable home PC market I feel, was primarily created by two British companies Amstrad (Alan Michael Sugar Trading) and Sinclair Research ( created by Sir Clive Sinclair) and eventually bought by Amstrad. The Sinclair ZX machines were sold in the USA under the Timex brand name.
Prior to this, the home PC market was ridiculously expensive and was dominated by IBM ( International Business Machines)
If you have one of these old PCs and no longer want it, perhaps you would consider donating it or selling it to me. I would dearly love to add a display of these early ground breaking home computers in the shop. It needn't work - so long as its casing is complete.
This was the first PC I owned and is responsible for all my keen interest in PCs, the Tandy TRS80 which was released in 1980 and discontinued in 1991. The operating system was Color BASIC 1.0, 2.0, OS-9 and was powered by a CPU manufactured by Motorola, the 6809E @ 0.895 MHz / 1.79 MHz. It was sold with a variety of sizes of memory - 4 KB, 16 KB, 32 KB, 64 KB, 128 KB, 512 KB. Please note the memory sizes were in kilobytes and not megabytes as today's are. The 32KB version sold for circa 240.00 pounds.
The zx80 was released in 1980 and had an introductory price 99.95 pounds. It ceased in 1981 when the ZX81 was released. It like so many of the other early machines used a cassette tape to load the operating system, Sinclair Basic. The CPU was the Z80 and worked at 3.25MHz. The memory was only 1 KB up to a maximum of 16 KB. Also note the membrane keyboard as opposed to individual keys.
The Acorn Computers BBC Micro was released in late 1981 and had an introductory price of £299 for Model A and £399 Model B. It was discontinued in 1994 and was succeeded by the Acorn Archimedes. It too had a cassette tape, floppy disk (optional), hard disk (rare), Laser Disc (BBC Domesday Project). The operating system was Acorn MOS and the CPU was MOS Technology 6502/6512 at 2 MHz and had a supplied memory range of 16–32 KB (Model A/B). Its other options were Plus 32–128 KB ROM, expandable to 272 KB, the display was PAL/NTSC, RF/composite/TTL RGB. The Graphics 640×256, 8 colours (various frame buffer modes), 78×75, 8 colours (Teletext). Input options twin joysticks, keyboard, connectivity RS-423 serial, parallel, Econet (optional), 1 MHz bus, Tube coprocessor interface, user port, floppy port.
Yet again, Amstrad came up with the goods when it introduced the CPC 464. It was supplied with its own dedicated screen. Released in 1984 and discontinued in 1990 this was a real trail blazer when it was first released and massively popular. It had a cassette tape and 3-inch floppy disks as a means of input. The operating system was AMSDOS and came bundled with Locomotive BASIC 1.0 or 1.1; CP/M 2.2 or 3.0 Although Locomotive basic was simpler than other types available, it still took some mastering. This was my first venture in to serious programming and even today, it taught me the essential ( in my opinion ) of writing tidy and compact programming code. The CPU was a Zilog Z80A and worked at 4 MHz. The memory supplied was 64 or 128 kb, and was expandable to a massive ( in those days )576 kb.
The Apricot Portable was Apricot Computers' attempt at a portable computer, first released in 1984. It had a 3.5" floppy drive, 4.77 MHz CPU and 256 KB RAM. It was the first computer to use an 80-column/25-line LCD and speech recognition for input/output. The speech recognition software held 4096 words, with only 64 available at a given time. It was also unique in the way that it had an infrared link between it and the keyboard; this was relatively new at the time. However, if an object blocked the infrared beam, communications would be cut off. The Apricot also featured a somewhat Mac-like graphical interface. It was originally priced at 1965 pounds..
The Commodore 64 was first released in 1982 and discontinued in 1994. The Operating system was Commodore KERNEL/ Commodore BASIC 2.0 and the CPU was MOS Technology 6510 @ 1.023 MHz (NTSC version) and @ 0.985 MHz (PAL version). The supplied memory was 64 kb RAM + 20 kb ROM. The graphics was VIC-II (320 × 200, 16 colors, sprites, raster interrupt), Sound SID 6581 (3× Osc, 4× Wave, Filter, ADSR, Ring). It had connectivity 2× CIA 6526 Joystick, Power, Cartridge, RF, A/V, IEEE-488 Floppy/Printer, Digital tape, GPIO/RS-232. Its predecessor was the popular Commodore VIC-20 and it succeeded by the Commodore 128.
The ZX81 was released in 1981 and succeeded the ZX80. Besides the improvements over the ZX80 it was revolutionary in that you could buy it in two forms - the price was £49.95 for the kit, if you were brave enough to assemble it yourself or £69.95 ready assembled. The machine was discontinued in 1984. The operating system was Sinclair BASIC and it had a CPU Z80 which ran at 3.25 MHz although most machines used the NEC µPD780C-1 equivalent. The memory was only 1 KB but had a maximum of 64 KB of which 56 KB was useable.
The Dragon 32 although comparable to others, never really took off when it was released in late 1982. It died during 1984 having had less than a two year life span. The operating system was Microsoft Extended BASIC and it was powered by the CPU Motorola 6809E @ 0.89 MHz. Its memory was either 32KB or 64KB. Please note however that the name Microsoft was introduced to the home PC market.
The Amstrad PCW was released in September 1985 and the model number PCW8256 / PCW8512 reflected the memory size. Once again Amstrad hit the heights with these machines and popularity soared. If you hadn't heard of Amstrad before, you most certainly had now. The operating system on most models was CP/M Plus but Locoscript also ran as a standalone application. The early fight for a standard operating system was between CP/M and Microsoft and whilst many thought that CP/M should have been adopted, we are all too aware of who won the contest. The machines lasted a long thirteen years which confirms their popularity. The last model (PcW16) used a custom GUI operating system and the CPU Zilog Z80 with a speed of 4 MHz initially.
The IBM PS was released in 1990 and was quickly followed by model 2121 then 2133 then the 2155. The operating system PC-DOS 4.01 (in ROM) with the CPU Intel 80286 @ 10 MHz and a memory of 1MB - 2MB. The later versions had super fast CPUS (in those days) of up to 25MHz and the last models saw the introduction of Windows 3.1 .
The Amstrad PC1512 was first released in 1986 with an introductory price of 499 pounds which was way below that being charged by IBM and others. It had 5¼-inch floppy disks the operating system MS-DOS 3.2 and DOS Plus. It had the CPU Intel 8086 @ 8 MHz and a storage capacity of 10 or 20MB. Its memory was 512K expandable to 640K. Its input was by Keyboard, Joystick and Amstrad mouse. I can remember that PC buffs were looking for any excuse to ridicule this Amstrad machine when it was released and Amstrad had to recall early models to fit a CPU fan although this was unnecessary.
The Atom was Acorn's first personal computer to be aimed directly at the home market. It was released in 1980 with an introductory price of 120 pounds in kit form and 170 pounds already assembled. It only lasted until 1983. It had 100KB 5¼-inch floppy disks and cassette tapes. The CPU was MOS Technology 6502 clocked at 1MHz and came supplied with 2KB RAM expandable to 12 KB, 8KB ROM (expandable to 12 KB). The display was 64x64 (4 colors), 64x96 in 4 colors, 128x96 monochrome, 64x192 4 colors, 128x192 2 colors and 256x192 monochrome. Its successor was the BBC Micro
The Atari 400 first saw the light of day during 1979. It was notable for its membrane keyboard and single width cartridge slot cover. It eventually faded away in 1992. The operating system was the Atari 8-bit OS / with Atari BASIC. The CPU was MOS Technology 6502B, 1.78 MHz (NTSC version) and 1.77 MHz (PAL version). The graphics options were 320x192, 256 colors, 4x sprites, raster interrupts and the sound was 4x oscillators with noise mixing or 2x AM digital. Ports were 2x or 4x Joystick, 1x SIO, 1x or 0x PBI, 1x or 2x ROM cartridge. After its long life it was replaced with the Atari ST.
