Synchronous processors have one central clock, which synchronizes and coordinates the progress of operations throughout a processor. Synonym: clocked. All parts and stages work to its unifying beat signal, at the same rate, in lock step, handing off work to the next stage as the clock ticks. Almost all computers made, and in use, are synchronous. Clock speed is a primary performance trait. For personal computers, it is used as an identifier and for marketing, shown in units of megahertz (MHz) or gigahertz (GHz). Asynchronous processors have no clock. Synonyms: asynchronous logic, clockless, unclocked; self-timed; hand-shaking. All parts and stages work independently, handing off work to the next stage as it is finished. Different stages stop between tasks. All stages can work at the same or different rates. This is more complex to implement, but lowers power use, current peaks, and emitted heat and electromagnetism (raising security). Only a small fraction of computers made, and fewer in use, mainly in embedded systems, are asynchronous.
Research focusing on methods and tools for designing high-performance and low-energy asynchronous digital circuits. Home of MiniMIPS asynchronous MIPS R3000 RISC processor. [Department of Computer Science, Caltech]
It's growing harder and more costly to make computer clocks work right. The solution may be to eliminate clocks. Benefits: more performance, reliability; lower cost. But commercialization will be hard. [Computerworld]
Time is running out for the clocks that make our computers tick as scientists develop a new generation of hardware and software based on the simpler designs of the 1950s. [SpaceDaily]
With components maybe as small as individual molecules, such computers will likely need new designs. [Technology Research News]
Database on circuits, almost 2000 items, download formats: BiBTeX, HTML, PDF, PostScript. Page links: web pages and sites, conferences, produced chips.
Brief article explains why such processors promise more speed, safety, security, miniaturization. [Dataweek]
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