The word computer can be defined in many ways and can also take many different meanings; a somewhat common definition may be this: computer is a machine that automatically performs mathematical computations. We can also see it as a machine for processing information or, very generally, as any tool that helps computation, in which case one's fingers or even a mathematical formula itself can be considered a computer. Here we are of course mostly concerned with electronic digital computers.
We can divide computers based on many attributes, e.g.:
Computers are theoretically studied by computer science. The kind of computer we normally talk about consists of two main parts:
The power of computers is limited, Alan Turing mathematically proved that there exist problems that can never be completely solved by any algorithm, i.e. there are problems a computer (including our brain) will never be able to solve (even if solution exists). This is related to the fact that the power of mathematics itself is limited in a similar way (see Godel's theorems). Turing also invented the theoretical model of a computer called the Turing machine. Besides the mentioned theoretical limitation, many solvable problems may take too long to compute, at least with computers we currently know (see computational complexity and P vs NP).
Computers we normally talk about in daily conversations are electronic digital mostly personal computers such as desktops and laptops, possibly also cell phones, tablets etc.
Such a computer consists of some kind of case (chassis), internal hardware plus peripheral devices that serve for input and output -- these are for example a keyboard and mouse (input devices), a monitor (output device) or harddisk (input/output device). The internals of the computer normally include:
Here is a list of notable computers.
{ Some nice list of ancient computers is here: https://xnumber.com/xnumber/frame_malbum.htm. ~drummyfish }
name | year | specs (max, approx) | comment |
---|---|---|---|
abacus | -2500 | one of the simplest digital counting tools | |
Antikythera mechanism | -125 | ~30 gears, largest with 223 teth | 1st known analog comp., by Greeks (mechanical) |
slide rule | 1620 | simple tool for multiplication and division | |
Shickard's calculating clock | 1623 | 17 wheels | 1st known calculator, could multiply, add and sub. |
Arithmometer | 1820 | 6 digit numebrs | 1st commercial calculator (add, sub., mult.) |
Difference Engine | 1822 | 8 digit numbers, 24 axles, 96 wheels | mech. digital comp. of polynomials, by Babbage |
Analytical Engine design | 1837 | ~16K RAM, 40 digit numbers | 1st general purpose comp, not realized, by Babbage |
nomogram | 1884 | graphical/geometrical tools aiding computation | |
Z3 | 1941 | 176B RAM, CPU 10Hz 22bit 2600 relays | 1st fully programmable electronic digital computer |
ENIAC | 1945 | ~85B RAM, ~5KHz CPU, 18000 vaccum tubes | 1st general purpose computer |
PDP 11 | 1970 | 4M RAM, CPU 1.25Mhz 16bit | legendary mini |
Apple II | 1977 | 64K RAM, 1MHz CPU 8bit | popular TV-attached home computer by Apple |
Atari 800 | 1979 | 8K RAM, CPU 1.7MHz 8bit | popular TV-attached home computer by Atari |
VIC 20 | 1980 | 32K RAM, 1MHz CPU 8bit, 20K ROM | successful TV-connected home computer by Commodore |
IBM PC | 1981 | 256K RAM, CPU 4.7MHz 16bit, BASIC, DOS | 1st personal computer as we know it now, modular |
Commodore 64 | 1982 | 64K RAM, 20K ROM, CPU 1MHz 8bit | very popular TV-connected home computer |
ZX Spectrum | 1982 | 128K RAM, CPU 3.5MHz 8bit | successful UK TV-connected home comp. by Sinclair |
NES/Famicom | 1983 | 2K RAM, 2K VRAM, CPU 1.7MHz 8bit, PPU | TV-connected Nintendo game console |
Macintosh | 1984 | 128K RAM, CPU 7MHz 32bit, floppy, 512x342 | very popular personal computer by Apple |
Amiga | 1985 | 256K RAM, 256K ROM, CPU 7MHz 16bit, AmigaOS | personal compuer by Commodore, ahead of its time |
SNES | 1990 | 128K RAM, 64K VRAM, CPU 21MHz 16bit | game console, NES successor |
PlayStation | 1994 | 2M RAM, 1M VRAM, CPU 33MHz 32bit, CD-ROM | popular TV-connected game console by Sony |
TI-80 | 1995 | 7K RAM, CPU 980KHz, 48x64 1bit screen | famous programmable graphing calculator |
Deep Blue | 1995 | 30 128MHz CPUs, ~11 GFLOPS | 1st computer to defeat world chess champion |
Nintendo 64 | 1996 | 8M RAM, CPU 93MHz 64bit, 64M ROM cartr. | famous TV-connected game console |
GameBoy Color | 1998 | 32K RAM, 16K VRAM, CPU 2MHz 8bit, 160x144 | handheld gaming console by Ninetendo |
GameBoy Advance | 2001 | ~256K RAM, 96K VRAM, CPU 16MHz 32bit ARM, 240x160 | successor to GBC |
Xbox | 2001 | 64M RAM, CPU 733MHz Pentium III | TV-connected game console by Micro$oft |
Nintendo DS | 2004 | 4M RAM, 256K ROM, CPU ARM 67MHz, touchscreen | famous handheld game console by Nintendo |
iPhone (aka spyphone) | 2007 | 128M RAM, CPU ARM 620MHz, GPU, cam., Wifi, 480x320 | 1st of the harmful Apple "smartphones" |
ThinkPad X200 | 2008 | 8G RAM, CPU 2.6GHz, Wifi | legendary laptop, great constr., freedom friendly |
ThinkPad T400 | 2008 | 8G RAM, CPU 2.8GHz, Wifi | legendary laptop, great constr., freedom friendly |
Raspberry Pi 3 | 2016 | 1G RAM, CPU 1.4GHz ARM, Wifi | very popular tiny inexpensive SBC |
Arduboy | 2016 | 2.5K RAM, CPU 16MHz AVR 8bit, 1b display | tiny Arduino open console |
Pokitto | 2017 | 36K RAM, 256K ROM, CPU 72MHz ARM | indie educational open console |
Raspberry Pi 4 | 2019 | 8G RAM, CPU 1.5GHz ARM, Wifi | tiny inexpensive SBC, usable as desktop |
Deep Thought | fictional computer from Hitchhiker's Guide ... | ||
HAL 9000 | fictional AI computer (2001: A Space Oddysey) | ||
PD computer | planned LRS computer | ||
Turing machine | important theoretical computer by Alan Turing |
TODO: mnt reform 2, pinephone, NeXT, ti-89, quantum?, wii?
All content available under CC0 1.0 (public domain). Send comments and corrections to drummyfish at disroot dot org.