The Alto and Ethernet System Xerox PARC in the 1970’sInfluences—“On the shoulders of giants”Alto in ContextOrganizationTimelineThemesPersonal Distributed ComputingInformation Convenient For A PersonPrinciplesAlto HardwareAlto Block DiagramHardwareHardware ComparisonKey Ideas For HardwareAlto In UseAlto Awaiting RestorationEthernetLaser PrintersSLOT Printer, 1972The softwareProgramming: OS, languagesServersUser interfacesSmalltalkBravoSlide 26Slide 27Laurel Email Header PaneLaurel/GrapevineSlide 30Markup’s Popup MenuUser interfaces: Displaying thingsMarkupDrawSIL for Logic DrawingsCedarApplicationsWhat the Alto system was likeBoca Raton—1976What Xerox did with the AltoXerox Products: PrintingXerox Products: Star Office SystemWhat Went Wrong?What Others Did with the AltoSlide 45TodayTomorrow10/17/06 Alto Personal Distributed Computing 1The Alto and Ethernet SystemXerox PARC in the 1970’sButler LampsonMicrosoft ResearchOctober 17, 200610/17/06 Alto Personal Distributed Computing 2Influences—“On the shoulders of giants”ARPA communityMan-computer symbiosis—LickliderTime-sharing: CTSS, SDS 940, TenexEngelbart’s On-Line SystemFlex machine—KayArpanetAloha packet radio networkXerox—“Office of the future”The electronic office10/17/06 Alto Personal Distributed Computing 3Alto in Context10/17/06 Alto Personal Distributed Computing 4OrganizationCSLHardware: Alto, EthernetOS, Languages (BCPL, Mesa, Lisp)Printing, file serversNetworkingBravo (→Word), Draw (→Illustrator), fontsGrapevine (email transport, server)Laurel (email client)SSLPrinting, file serversSmalltalkGypsy (→Word)Markup (→Paint)10/17/06 Alto Personal Distributed Computing 5Timeline1960s Time-sharing, Sketchpad, NLS1970s Xerox PARCAlto, Ethernet, laser printersBravo, Draw, Pup, SmalltalkAltair, Apple IIInternet1980s81 Xerox Star, IBM PC84 Macintosh, Laserwriter, MS Word/Excel1990s Windows, Web10/17/06 Alto Personal Distributed Computing 6ThemesBut a man’s reach should exceed his grasp, or what’s a heaven for? —BrowningComputers can be used as tools to help people think and communicateLickliderARPA time-sharing and networkingEngelbart and NLSAlan Kay and FlexXerox: Office of the FutureHow do we grow after copiers?10/17/06 Alto Personal Distributed Computing 7Personal Distributed Computing Personal Under the control of a person and serves his needs. Performance is predictable, and fast enough Reliable and available. Not too hard to use DistributedEverything in the real world is distributedThe computer is a communication devicePersonal + communication = distributedNeed to share expensive devices too, esp. printersComputingWe programmed, but users didn’t10/17/06 Alto Personal Distributed Computing 8Information Convenient For A PersonUniversalAny (black-and-white) image, data, any software▬Words, pictures, music, ...Specialize with softwareInk on paperPresent imagesPoint at places in the imageThe Alto can do this quite wellFor a single 8.5" x 11" sheet of paperWith black inkNo restrictions on the form of the imagesCannot read imagesVoice and other sounds.Later, less important10/17/06 Alto Personal Distributed Computing 9Principles“Time machine”—simulate the futureUse what you buildGood for text, pictures, printing, sound, emailBad for spreadsheets, databasesPersonal machine“People are fast, machines are slow”Performance is predictableNo grand plan for the system: integrationNot enough experience, cycles or memoryOpen OS, world-swapException: Smalltalk10/17/06 Alto Personal Distributed Computing 10Alto Hardware0.3 MIPS128 KB RAM 2.5 MB disk 3 Mbit Ethernetfor 50 Altos600x800 x l display$12,000 to make10/17/06 Alto Personal Distributed Computing 11Alto Block DiagramuCodeI/ORAMComputeRegisters10/17/06 Alto Personal Distributed Computing 12HardwareMoore’s law: live in the future if you canPrice X CPU RAM Disk NetAlto MIPS MB MB MB/s1974: Alto $40k 1 0.3 0.1 2.5 .051984: Mac $3k 1 1 0.5 1.5 .031995: PC $3k 100 50 16 300 .12006: PC $1k 10000 2000 1000 300G 10010/17/06 Alto Personal Distributed Computing 13Hardware ComparisonItem Alto,1973Desktop PC2006FactorCPU clock 6 MHz 3 GHz 500RAM size 128 KB 1 GB 8000RAM access 850 ns 100 ns 8.5Display pixels 606 x 808 x 1 1600 x 1200 x 32 4 (pixels)128 (bits)Network 3 Mb Ethernet 1 Gb Ethernet 300Disk capacity 2.5/5 MB 250 GB 100KCost $12,000 to make $1,000 to buy 1210/17/06 Alto Personal Distributed Computing 14Key Ideas For HardwareKISSHad to be cheap enough to build lots of themBitmap displayDisplay anything – like paperProgrammable at all levelsCould change the instruction set and add new operations easilyFlexible and powerful input-outputEthernet and Laser Printer controllers were add-insDistributed systemConnect many systems together with Ethernet10/17/06 Alto Personal Distributed Computing 15Alto In Use10/17/06 Alto Personal Distributed Computing 16Alto Awaiting Restoration10/17/06 Alto Personal Distributed Computing 17EthernetCSMA/CDBased on AlohaCollision detectExp. Backoff3 Mbits/secShared by 50 AltosRepeatersMuch later, switches10/17/06 Alto Personal Distributed Computing 18Laser PrintersMarriage of Xerography and ComputingEARS was the first (1974) print serverEthernetAltoResearch Character GeneratorScanning Laser Output Terminal1 copy/second, 500 dots/inchLower-cost and color versions developed laterDover: 300 dpi, small Alto interface. 100 copiesXerox understood it, built a successful business10/17/06 Alto Personal Distributed Computing 19SLOT Printer, 197210/17/06 Alto Personal Distributed Computing 20The softwareProgrammingServersUser interfaceApplicationsSoftware is “thought-stuff”10/17/06 Alto Personal Distributed Computing 21Programming: OS, languagesMain problem: live with .1 MIPS, 128 KB RAM, 5 MB diskOS: files, programs, network, command lineOpen: get rid of any parts you don’t needWorld-swap to change environmentsLanguagesBCPL: father of CMesaSmalltalk10/17/06 Alto Personal Distributed Computing 22ServersNetwork: Ethernet and PupFirst internet: Ethernet, Arpanet, phone lines, ...Printing3 generations of
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