1-bit computing: Difference between revisions

Revision as of 07:51, 22 November 2024

Latest revision as of 07:47, 8 August 2025

(2 intermediate revisions by one other user not shown)

Line 10:

There are no computers or [[microcontroller]]s of any kind that are exclusively 1-bit for all registers and [[address bus]]es. A 1-bit register can only store two different values. This is very restrictive and therefore not enough for a [[program counter]] which, on modern systems, is implemented in an on-chip register, but is not implemented on-chip in some 1-bit systems. [[Opcode]]s for at least one 1-bit processor architecture were 4-bit and the address bus was 8-bit.

While 1-bit computing is mostly obsolete, 1-bit [[serial communication]] is still used in modern computers, that are otherwise e.g. 64-bit, and thus also have much larger buses.

While 1-bit CPUs are obsolete, the first (research) [[carbon nanotube computer]] from 2013 is a 1-bit [[one-instruction set computer]] (and has only 178 transistors; since it has only one instruction<!-- SUBNEG (subtract and branch if negative) --> though it can emulate 20 [[MIPS architecture|MIPS]] instructions).<ref name="Courtland_2013"/>

== 1-bit ==

Line 42:

Other examples of 1-bit architectures are [[programmable logic controller]]s (PLCs), programmed in [[instruction list]] (IL).

Such as the 1969 [[PDP-14]].<ref name=CHD>

{{cite web |url=http://www.chdickman.com/pdp14 |title=DEC PDP-14 Industrial Controller}}

</ref>

Several early [[massively parallel]] computers used 1-bit architectures for the processors as well. Examples include the May 1983 [[Goodyear MPP]] and the 1985 [[Connection Machine]]. By using a 1-bit architecture for the individual processors a very large array (e.g. the Connection Machine had 65,536 processors) could be constructed with the chip technology available at the time. In this case the slow computation of a 1-bit processor was traded off against the large number of processors.