Encyclopedia of Computer Science and Technology

Microsoft Corporation 305amount of memory. For example, the Intel 80386 was thefirst 32-bit processor for PCs and could address 4 GB ofmemory. (Earlier processors such as the 80286 had to dividememory into segments or use paging to swap memory inand out of a smaller space to make it look like a larger one.)Over the years microprocessors tended to add more built-incache memory, enabling them to have more instructions ordata ready for immediate use.Another way to get more performance out of a microprocessoris to increase the speed with which instructionscan be executed. One technique, called pipelining, breaksthe processor into a series of segments, each of which canexecute a particular operation. Instead of waiting until aninstruction has been completely executed and then turningto the next one, a pipelined microprocessor moves theinstruction from segment to segment as its operations areexecuted, with following instructions moving into thevacated segments. As a result, two or more instructions canbe undergoing execution at the same time.In addition to pipelining, the Pentium series and otherrecent chips can have instructions executing simultaneouslyusing different arithmetic logic units (ALUs) or floating-pointunits (FPUs).Another way to improve instruction processing is to usea simpler set of instructions. First introduced during the1980s for minicomputers and high-end workstations (suchas the Sun SPARC series), reduced instruction set computer(RISC) chips have smaller, more uniform instructions thatcan be more easily pipelined, as well as many registers forholding the results of the intermediate processing. Duringthe 1990s, RISC concepts were also adopted in PC processordesigns such as the 80486 and Pentium (see reducedinstruction set computer).The latest major development has been the multicoremicroprocessor, which has two, four, or more separate processingunits. The Intel Core Duo and Core 2 Duo chipsand similar processors from AMD are now included in mostnew PCs.The equivalent of a supercomputer on a chip is on theway. Cisco’s 192-core Metro chip powers its most capablenetwork routers, while Nvidia’s GeForce 8800 graphics processorsports 128 cores. In addition to these specializedprocessors, in early 2007 Intel demonstrated a prototype80-core processor that could form the basis of a new generationof general-purpose processors.Another significant multicore processor architecture isthe Cell chip, developed by Sony, IBM, and Toshiba. Thischip includes a multithreaded (able to run multiple streamsof code) controller processor plus numerous architecturalfeatures that maximize efficiency and throughput. The firstappearance of this 2 “teraflop” (trillion calculations per second)chip was not on a scientific computer, but rather theSony Play Station 3—see game console.Multicore processors create new challenges for programmerswho have to create code that will apportion programtasks efficiently among the cores (see multiprocessing).In the new century, it is unclear when physical limitationswill eventually slow down the tremendous rate ofincrease in microprocessor power. As the chips get denserand smaller, more heat is generated with less surfacethrough which it can be removed. At still greater densities,quantum effects may also begin to be a problem. On theother hand, new technologies might take the elements ofthe processor down to a still smaller level (see molecularcomputing and nanotechnology).While the stand-alone desktop, laptop, or handheldcomputer is the most visible manifestation of the microprocessingrevolution, there are hundreds of “invisible”microprocessors in use for every visible computer. Todaymicroprocessors help monitor and control everything fromhome appliances to cars to medical devices (see embeddedsystems).Further ReadingKim, Ryan. “New Era of Game Devices Arrives: Sony and NintendoMeet the Challenge of Microsoft Xbox.” San FranciscoChronicle, November 13, 2006, p. F1, F6.Markoff, John. “Intel Prototype May Herald a New Age of Processing.”New York Times, February 12, 2007.Sperling, Ed. “Special Report: Inside the New Multicore Processors.”Electronic News, April 13, 2007. Available online.URL: http://www.edn.com/article/CA6434384.html. AccessedAugust 15, 2007.Stokes, John. Inside the Machine: An Illustrated Introduction toMicroprocessors and Computer Architecture. San Francisco: NoStarch Press, 2006.Tom’s Hardware. “CPU.” Available online. URL: http://www.tomshardware.com/cpu/.Accessed August 15, 2007.Microsoft CorporationMicrosoft Corporation (NASDAQ symbol: MSFT) is theworld’s largest computer software company, with almost80,000 employees worldwide and annual revenue exceeding$51 billion.Microsoft was founded in the mid-1970s by Bill Gates(see Gates, William) in order to sell his version of theBASIC programming language for early microcomputerssuch as the Altair 8800. The BASIC software was moderatelysuccessful, but it would be an operating system called MS-DOS (or PC-DOS) that would catapult Microsoft to industryleadership, thanks to an agreement with IBM, which introducedwhat would become the industry standard personalcomputer in 1982 (see ibm pc).In the mid-1980s Microsoft partnered with IBM todevelop OS/2, which was intended to be a more powerfulmultitasking operating system to replace DOS. However,Microsoft’s real interest was in the development ofWindows (see Microsoft Windows), which first becamesuccessful with version 3.0 in 1990. Meanwhile, Microsoftleveraged its experience with Windows to release MicrosoftOffice, which soon displaced WordPerfect, the previousmarket leader.Shifting Strategies and Legal IssuesMany observers have noted that Microsoft was slow in appreciatingthe importance of networking and particularly theWorld Wide Web in the mid-1990s. Novell was the marketleader in networking at the time, and Netscape’s graphical