Difference between revisions of "Microprocessor"
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A '''microprocessor''' is a [[Central Processing Unit|CPU]] which is implemented on a single [[integrated circuit]]. A few special-purpose microprocessors have also included [[main memory]] and/or [[ROM]] in the IC chip, but generally (even now) this is usually not included - although for performance reasons, there are generally main memory [[cache]]s on modern microprocessor chips. | A '''microprocessor''' is a [[Central Processing Unit|CPU]] which is implemented on a single [[integrated circuit]]. A few special-purpose microprocessors have also included [[main memory]] and/or [[ROM]] in the IC chip, but generally (even now) this is usually not included - although for performance reasons, there are generally main memory [[cache]]s on modern microprocessor chips. | ||
| − | Microprocessors have completely changed the ways in which computers are used. When CPUs were large, and built out of many smaller chips, they were | + | Microprocessors have completely changed the ways in which computers are used. When CPUs were physically large, and built out of many smaller chips, they were expensive. This more or less mandated their use in ways such as [[time-sharing]], which allowed their costs and overheads to be amortized. Once they became very cheap, constructs such as [[personal computer]]s, and later [[smart-phone]]s, etc, became economically feasible. |
| − | The first microprocessors were relatively limited, in architectural terms; IC's of that era were not very large (in terms of the number of [[transistor]]s they contained, which severely limited the complexity of microprocessors built on them. Contemporary microprocessors have no such limits, and contain tens of millions of transistors, enabling them to use complex techniques such as [[pipeline]]s, [[superscalar]] processing, etc. | + | The first microprocessors were relatively limited, in architectural terms; IC's of that era were not very large (in terms of the number of [[transistor]]s they contained), which severely limited the complexity of microprocessors built on them. Contemporary microprocessors have no such limits, and contain tens of millions of transistors, enabling them to use complex techniques such as [[pipeline]]s, [[superscalar]] processing, etc. |
The use of these advanced techniques, added to the reduction in size (thereby reducing speed-of-light signal delays), allows microprocessors to have greatly increased performance over all earlier computers, including [[mainframe]]s. Microprocessors have therefore made essentially all other types of computers obsolete. | The use of these advanced techniques, added to the reduction in size (thereby reducing speed-of-light signal delays), allows microprocessors to have greatly increased performance over all earlier computers, including [[mainframe]]s. Microprocessors have therefore made essentially all other types of computers obsolete. | ||
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==Alternative meaning== | ==Alternative meaning== | ||
| − | Before IC microprocessors were common, the term "microprocessor" was in rare use as a portmanteau of "microcode processor". Examples of this type of usage include [[BCC 500]], [[ | + | Before IC microprocessors were common, the term "microprocessor" was in rare use as a portmanteau of "[[microcode] processor". Examples of this type of usage include [[BCC 500]], [[Maxc]], [[Xerox Alto|Alto]], [[NORD-10]], [[International Business Machines|IBM]]'s [[PALM]], and the processor in the [[DV11 Communications Multiplexer]]. |
==External links== | ==External links== | ||
Revision as of 14:04, 14 November 2021
A microprocessor is a CPU which is implemented on a single integrated circuit. A few special-purpose microprocessors have also included main memory and/or ROM in the IC chip, but generally (even now) this is usually not included - although for performance reasons, there are generally main memory caches on modern microprocessor chips.
Microprocessors have completely changed the ways in which computers are used. When CPUs were physically large, and built out of many smaller chips, they were expensive. This more or less mandated their use in ways such as time-sharing, which allowed their costs and overheads to be amortized. Once they became very cheap, constructs such as personal computers, and later smart-phones, etc, became economically feasible.
The first microprocessors were relatively limited, in architectural terms; IC's of that era were not very large (in terms of the number of transistors they contained), which severely limited the complexity of microprocessors built on them. Contemporary microprocessors have no such limits, and contain tens of millions of transistors, enabling them to use complex techniques such as pipelines, superscalar processing, etc.
The use of these advanced techniques, added to the reduction in size (thereby reducing speed-of-light signal delays), allows microprocessors to have greatly increased performance over all earlier computers, including mainframes. Microprocessors have therefore made essentially all other types of computers obsolete.
The first widely sucessful microprocessor was the Intel 4004.
Alternative meaning
Before IC microprocessors were common, the term "microprocessor" was in rare use as a portmanteau of "[[microcode] processor". Examples of this type of usage include BCC 500, Maxc, Alto, NORD-10, IBM's PALM, and the processor in the DV11 Communications Multiplexer.
