8-bit Legacy

The Home Computer market began in the early 1980s when the price-reduction of hardware components made computers affordable for the average European and American family.

 During the first half of the decade, many 8-bit computers were released, most of which were based on Z80 and MOS 6510 CPUs.

Table: Popular 8-bit Computers and their CPUs

• Introduced in 1978, the Motorola 6809 is an 8-bit processor with some 16-bit features
• Introduced in 1982, the Motorola 68008 is an 8/32-bit processor (8-bit external data & address bus)

Amstrad CPC (Colour Personal Computer)

Manufactured between 1984 and 1990, the Amstrad CPC is a series of Z80-based home computers. The CPC competed with ZX Spectrum and Commodore 64 for a market share in the promising 8-bit home computing market. The 464/6128 CPC sold very well in Europe, especially in France and the United Kingdom. In 1990, Amstrad announced the CPC Plus series, featuring improved graphics and stereo sound, however, it was too little too late.

• Zilog Z80 CPU running at 4 MHz
• AMDOS and CP/M operating system
• 27 colors palette (up to 16 on-screen)
• AY-3-8912 sound chip with three channels, generating square waves (white noise or both)

CPC 464

Released in 1984, the CPC 464 sold more than two million units. It was the lower-end CPC computer, offering 64K of RAM and a built-in cassette drive.

CPC 664

Released in 1985, the CPC664 offered 64K of RAM and a built-in 3-inch floppy disk drive. It is a rare machine these days.

CPC 6128

Released in 1985, a few months after the 664 CPC, the 6128 offered the CP/M+ operating system, 128K of RAM, and an internal 3-inch floppy disk drive. It was a successful model for Amstrad, as it sold more than 1 million units.

The Later CPC+ (464+/6128+)

Released in 1990, the CPC+ home computers were also based on Z80 at 4 MHz, offering a 12-bit color palette  (4,096 colors) and stereo sound. The Plus series sold well in France, but not as well in the rest of Europe. The US home computer market was out of the radar of CPC+.

• The Plus series included the 464+ and 6128+
• CP/M 3.0 operating system and an improved BASIC command set for disc access
• 4,096 colors palette (12bit), 16 colors on-screen, and hardware sprites
• 3 stereo voices, 8 octaves+1 noise channel
• There was also the Amstrad GX4000 game console with the same chipset

CPC Video Modes (27-color palette)

• 160×200 pixels with 16 colors (Mode 0)
• 320×200 pixels with 4 colors (Mode 1)
• 640×200 pixels with 2 colors (Mode 2)

Amstrad Sales

Table: Amstrad 8-bit computers

Commodore 8-bit Computers

Founded by Jack Tramiel, in 1958, Commodore International was an American computer manufacturer. They released a wide variety of 8/16/32-bit computers, including the Amiga line of personal computers. Their most successful model was the C64 which sold more than 14 million units between 1982 and 1994.

• Based on MOS CPUs
• The C64/C128 offered 16 colors, 8 hardware sprites (24×21 pixels), and smooth screen scrolling
• The sound chip was the impressive SID chip by MOS with 3 channels, 8 octaves, and 4 waveforms per audio channel (triangle, sawtooth, variable pulse, noise)
• The SID chip was included in the models C64, C128, CBM-II, and MAX

C64 Basic Video Modes

• 320x200 pixels with 16 colors (HiRes mode)
• 320x200 pixels with 4 colors, by allowing mixing colors (MCI Mode)
• There are 5 additional video modes

Commodore Sales

Table: Commodore International 8-bit computers

Sinclair 8-bit Computers

Released in 1982 by Sinclair Research, the ZX Spectrum was the first 8-bit computer that anyone could afford to buy.

The legendary Clive Sinclair wanted to create a home computer for every family. Early models were even released as a Kit to be further affordable. The ZX-80 starter Kit was sold for as low as £79.95 (fully assembled at £99.95). The ZX80 sold about 50,000 units. The first very successful ZX Spectrum was the ZX81 which sold 500,000 units only in the first year. Later ZX Spectrum models offered the same Z80 CPU, but they were more technically advanced in other fields.

• All ZX Spectrum models are based on the Zilog Z80 CPU
• Richard Altwasser made the hardware design
• Spectrum was sold as Timex in the US after Sinclair licensed the design to Timex Corporation
• There were many Spectrum clones in Russia and Eastern Europe, these clones were re-engineered to deal with the lack of components
• In 1986, Amstrad bought the entire line of Spectrum computers
• The ZX Spectrum family of computers sold about 5 million units worldwide before it was officially discontinued in 1992

128K -The advanced ZX Spectrum

The last ZX Spectrum manufactured by Sinclair was the 128K. The new 128K was significantly improved compared to the old ZX spectrums:

• 128 KB of RAM, with disc commands
• 32 KB of ROM (including improved BASIC)
• 3-channel audio (AY-3-8912 chip)
• RGB monitor port, RS-232 serial port, and MIDI compatibility

+2/+3 Spectrum Computers (made by Amstrad)

In 1986, the entire line of Spectrum computers was sold to Amstrad. Amstrad released the +2 and +3 Spectrum models.

• The +2 is a 128K with a built-in cassette
• The +3 is a 128K with a built-in 3-inch disk drive (similar to the CPC 6128)
• The new Spectrums from Amstrad offered a spring-loaded keyboard and dual joystick ports

Sinclair QL (Quantum Leap)

Released in 1984, the Sinclair QL was a commercial failure for Sinclair. The QL is based on the Motorola 68008, offering a pre-emptive multitasking operating system.

• Motorola 68008 CPU running at 7.5 MHz (32-bit internal data registers, but an 8-bit external data bus)
• Pre-emptive multitasking operating system (ROM)
• 128 KB of RAM (expandable to 640 KB)
• Two (built-in) Microdrive tape-loop cartridge drives
• ROM cartridge socket, 2 RS-232 ports, QLAN, expansion slot, and 2 joystick ports
• Video modes: 256×256 pixels with 8 colors and 512×256 pixels with 4 colors
• Bundled with an office suite (database, word processor, spreadsheet, and business graphics)

Spectrum Colors & Video Modes

• The ZX Spectrum offered a palette of 7 colors at 2 two levels of brightness each, plus black.
• 15 color shades, at an image resolution of 256×192 pixels

Sales

Table: Sinclair 8-bit computers

■ 8-bit Computers

Binaryvalue.com (c) -Sources: CPCWiki.eu, Wikipedia, c64-wiki.com, studiostyle.sk