Global MicroComputer Specifications
The table below shows the technical characteristics of some old computers, like the type of CPU unit, RAM memory capacity, ROM capacity which stored the basic firmware or Operating system, and dedicated Video RAM for graphics display.
The latter was quite important, because the more video RAM (VRAM) there was, the better the graphics were.
In the early 80s, a personal computer that could use 16kb of VRAM was a very good machine! Now nobody wants a GPU with less than 4GB of RAM :D
The ROM is now a bit like the Flash we have on our phones, except that the firmware or OS was not updated as easily, as it was not erasable.
If you find any inaccuracies, or if you have any questions about retro computing, please leave me a message below.
Zilog Z80 @ 3.25Mhz - 1 KB (up to 64KB) 8 KB
TMS9900 @ 3Mhz - 256 bytes 16bits (up to 32KB) 26 KB 16 KB
MoS 6510 @ 0.985 MHz - 64 KB 16 KB (20KB for the 64C) up to 20KB of RAM used
MoS 65c02 @ 1Mhz - 64KB 16KB up to 16KB of RAM used
Motorola 6809E @ 0.895 MHz
16 KB 16 KB
Zilog Z80A @ 5Mhz - 64KB 16KB
MoS 6502C @ 1.77 MHz - 64KB 24KB up to 8KB of RAM used
MoS 6502A @ 1 MHz
48 KB 16 KB 8 KB of RAM used
FR
1984
Motorola 6809e @ 1Mhz
-
32 KB
16 KB
Zilog Z80 @ 3.58MHz - 64 KB 32 KB 16 KB
Zilog Z80 @ 3.58MHz - 16 KB 16 KB 2 KB
FR
1984
TI tms 7041 + tms 7020 @ 4.91 MHz -
32 KB up to 290
4 KB
MOS 8502 @ 1.97/0.985MHz
+ Zilog Z80A @ 4Mhz - 128 KB 64 KB 16KB + up to 20KB of RAM used
Motorola 6809e @ 1MHz - 128 KB 64 KB 16 KB of RAM used
Zilog Z80A @ 4MHz - 128 KB 128 KB (64 KB used by a demo game!) 16 KB of RAM used
Motorola 68000 @ 8MHz - 512 KB 192 KB 32 KB of RAM used
US
1987
Motorola 68020 @ 16Mhz
68881 FPU
1 MB
256 KB
external video card (300 KB typ.)
Motorola 68000 @ 7.14MHz - 1 MB 512 KB up to 1 MB of RAM used (2 MB with extension)
Motorola 68030 @ 15.77Mhz 68882 FPU 4 MB 256 KB
Books
If you're interested in Retrocomputing, I would also recommend reading the following books. I find very interesting how these computer industry pioneers, with brilliant ideas, made history and begun to earn millions of dollars !
none 3 voices (square wave), noise and volume
Video composite, 1 Joystick, Cardridge, Tape, Serial, User Port (RS232 compatible)
- 256x182 B/W with 16KB RAM expansion none none
RF video, Expansion slot, Tape
- 256x192 16 colors, 2 colors per 1x8 block
- 64x48 16 colors 32 sprites TMS9919 3 voices, 1 noise
ROM cartridge, tape, Audio/Video output, Joystick, bus expansion
- 320x200 16 colors (1 color per 1x8 block) - 160x200 16 colors (4 colors per 4x8 block)
- 160x200 16 colors
yes SID 6581: An advanced 3 voices synthetizer
Video composite, Joystick x2, Cardridge, Tape, Serial, User Port (RS232 compatible)
- 80x24 (with 80 columns card) - 40x48 16 colors
- 280x192 6 colors with constraints
- 560x192 16 colors with constraints none 1 channel
Composite video, Internal slots *7, Tape, Joystick *2
- 64x32x8
- 128x96x2 or 4
- 128x192x2 or 4
- 256x192x2 none 1 voice
Tape, RGB, Joystick x2, Cardridge, Serial RS232
RGB, Centronics, Cardridge, Joystick * 2
256 colors palette - up to 320 x 192 1 color
- up to 160 x 192 4 colors
- up to 80 x 192 16 colors
256 colors palette, flexible video chip (ANTIC) 4 sprites 8x256 1 color, 4 sprites 2x256 1 color, H/V scrolling Atari POKEY, 4 voices
Composite Video, Bus, Cardridge (16KB), Joystick * 2, Tape+Serial Bus
RBG, RF video, Bus, Printer, Tape
none
1 voice (8 bits DAC)
RGB (Scart), Light Pen, Tape Cardridge, Bus
RGB, Centronics, Cardridge *2, Tape, Joystick *2
- 128 x 64 8 colors none beeper, 1 voice
RGB, Tape, Centronics (opt), Expansion bus
- 80x25
- 320x250 8 colors
?
Vocal synthetizer
IR joystick+keyboard, centronics, bus, RAM ROM ext, tape
- 80x25 16 colors
- 80x50 16 colors - 640x200 16 colors (1 color per 8x8 block)
- 320x200 16 colors (1 color per 8x8 block)
- 320x200 16 colors (1 color per 1x8 block)
- 160x200 16 colors (4 colors per 4x8 block)
- 160x200 16 colors
yes SID 6581: An advanced 3 voices synthetizer
RGBI, Video composite, Joystick x2, Expansion port, Tape, Serial, User Port (RS232 compatible)
- 40 x 24 - 160 x 200 16 colors
- 320 x 200 16 colors (1 color per 1x8 block)
- 640 x 200 2 colors
4096 colors palette none 1 voice (8 bits DAC)
RGB (Scart), Light Pen, Joystick, Mouse, Centronics, Cardridge, Stereo, Bus
+ 1 bit audio
Z80 Bus, Numeric Keyboard, RS232 or Midi Out, Audio, RGB, 2 x Joystick
- 80 x 25
- 20 x 25 - 160 x 200 16 colors (32 colors with sprites)
- 320 x 200 4 colors (20 colors with sprites)
- 640 x 200 2 colors
27 or 4096 colors palette 16 sprites (16 x 16 15 colors each in any graphics mode, XY x1 x2 x4 magnification), hardware scrolling, horizontal split screen with independent scrolling 3 voices: AY-3-8912 + possibility to stream data without CPU intervention
RGB, Centronics, Z80 Bus, Joystick x 2, 1 Analog Joystick (SUB-D 15), Light gun (RJ-11), Disk unit, Tape, ROM Cardridge (up to 512 KB)
- 80 x 25 - 320 x 200 16 colors
- 640 x 200 4 colors
- 640 x 400 B/W
512 colors palette NO (Appeared on the MegaST and STe) 3 voice: YM-2149
RGB, Cardridge, Midi in and out, Centronics, RS232c, Hard Disk, Floppy disk, Joystick, Mouse
- 640x480 256 colors (external video card)
Depends on video card
Stereo 8 bits
ADB x2, Serial x2, 6 Nubus slots, 2 integrated FD
- VERY flexible PAL/NTSC chip - up to 320 x 512 from 2 to 64 or 4096 colors - up to 640 x 512 from 2 to 16 colors - up to 1280 x 512 2 or 4 colors - 4096 colors palette. - overscan, dual video output Yes 4 stereo channels 8 bit (28 or 56 Khz sampling rate)
Analog RGB, Composite Video, 2 Stereo Audio RCA, 1 parallel port, PCMCIA T1, 1 internal slot, Mouse/Game port x2, RS-232 (DB-25), External Floppy,
RS232/422 *2; ADB *2 (keyboard, mouse), Stereo, Floppy disk, SCSI, 68030 Processor Direct Slot
Sound chip specs
Since first micro-processors were not fast enough to handle graphics, sounds, and calculations at the same time, the best old computers were equipped with co-processors dedicated with sound generation.
The AY-3-8910, created in 1978, was one of the most popular of them, and was used in many arcade games, pinball machines, game consoles and 8-bits home computers, like the Amstrad CPC, Oric-1, MSX, Sinclair ZX Spectrum.
Here is some of the most frequently used sound generators found in home computers:
→ AY-3-8912: 3 voices 9 octaves 16 volume levels, 1
noise generator, 10 fixed enveloppe paterns (but with programmable
period). It's the same chip as the AY-3-8910, but with less I/O ports.
→ YM-2149: 3 voices 8 octaves 32 volume levels, only 1 waveform (square
wave), 1 noise generator, 10 fixed enveloppe
paterns. similar to AY-3-8912.
→ SID 6581: 3 oscillators (0-4Khz), 4 waveforms per oscillator (Triangle,
Sawtooth, Variable Pulse, Noise), 3 amplitude modulators (8 bits), 3
envelope generators (Full ADSR), ring modulation, programmable filter
(low pass, Bandpass,High pass, Notch with variable resonance), one
channel can be used as a 12 bits PWM (12 bits digital sound in 1983
!!!).
→ YM-2413: FM synthetizer, 9 poly channel or 6 channels and 5 rythm
sounds. Built-in instruments: 15 melody tones, 5 rhythme tones. 1
programmable instrument (ADSR).
→ Atari POKEY: 4 voices of 8-bit pitch-resolution, 4-bit
volume-resolution,
8-distortion sound can be produced. 2 voices (1 and 2, and/or 3 and 4)
can be combined to make 16-bit pitch-resolution. Also 4-bit volume-only
modes can be enabled for digitally sampled sound replay.
Obsolete Microprocessors
I also tried to estimate to power in MIPS of these old processors using the theorical cycles needed for basic machine language instructions.
3 x 16bits (or 6 x 8 bits)
2 x 16bits index (double all these numbers if you count shadow registers) 7 (10*) 7 (16*) 4 7 4 7 7 12-7 11* 0.58 MIPS @4Mhz
2 x 8bits index 2 3-4 2 2 2 2 2 2-3 4 0.43 MIPS @1Mhz
2 x 16bits index 2 4 2 2 2 2 2 3 5 0.42 MIPS @1Mhz
256 x 16bits in fast ext RAM 0.1-0.2 MIPS @3Mhz
4 x 16bits index
4 x segment 4 14 3 4 2 4 3 16 8 1.2 MIPS @8Mhz***
**: Only one register but fast access to the 1st 256 bytes of memory. So the 6502 was close to having 256 registers
***: speed for the 8086. On the 8088 you will get only 60-70% of this speed because of the 8 bits bus and the smaller prefetch buffer.
68000: because of 68000 transistors ;)
Links
Planet Sinclair by Chris Owen
Atari Historical Society's virtual Atari museum
Atari Archives
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