Mini-Computers - Techniongotsman/236801/3-mini-computers.pdf · 1 Seminar in computer History CS236801 1 Mini-Computers Yaniv Frishman Seminar in computer History CS236801Seminar

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Seminar in computer History CS236801Seminar in computer History CS236801 11

MiniMini--ComputersComputersYanivYaniv FrishmanFrishman


Origin of the NameOrigin of the Name

•• MiniMini--minorminor•• MiniMini--skirtskirt•• DEC Europe sales personDEC Europe sales person


Comparison with MainComparison with Main--FramesFramesMainframes:Mainframes:•• Leased (rented)Leased (rented)•• HW modifications not allowedHW modifications not allowed•• HW & SW sold togetherHW & SW sold togetherMinicomputers:Minicomputers:•• Sold, not rentedSold, not rented•• Much cheaperMuch cheaper•• Open spec, modifications Open spec, modifications

encouragedencouraged•• OEM model OEM model


Defining FacetsDefining Facets

1.1. ArchitectureArchitecture2.2. PackagingPackaging3.3. Role of thirdRole of third--party in apps developmentparty in apps development4.4. PricePrice5.5. FinancingFinancing


Word LengthWord Length

•• Typical 1960s IBM Mainframes used 36Typical 1960s IBM Mainframes used 36--bitsbits–– 10 decimal digits10 decimal digits

•• Manufacturers assumed less would not be Manufacturers assumed less would not be enoughenough

•• Shorter instructions reduce addressing Shorter instructions reduce addressing abilitiesabilities


Short Word WorkaroundsShort Word Workarounds

•• More complex instructionsMore complex instructions–– Address stored in a different register Address stored in a different register

•• Using double precision math (add with Using double precision math (add with carry)carry)

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DEC PDPDEC PDP--11

•• Included many of the TXIncluded many of the TX--0 features0 features•• Designed from the ground using Designed from the ground using

transistorstransistors•• Capable of 100,000 additions per secondCapable of 100,000 additions per second•• Core memory of 4K wordsCore memory of 4K words•• About 50 machines soldAbout 50 machines sold


PDPPDP--1 I/O 1 I/O -- DMADMA•• I/O flows directly from the device to memoryI/O flows directly from the device to memory•• Multiple interruptsMultiple interrupts•• HW support for correct handling (priority)HW support for correct handling (priority)•• Cheap: a single IBM I/O channel cost more Cheap: a single IBM I/O channel cost more

than a complete PDPthan a complete PDP--1 ($120K)1 ($120K)


PDPPDP--1 Space Invaders1 Space Invaders

•• Developed by MIT studentsDeveloped by MIT students•• Using 1024x1204 CRTUsing 1024x1204 CRT•• Planet MapPlanet Map•• Simulated GravitySimulated Gravity


PDPPDP--1 Space Invaders1 Space Invaders

Applet demo Applet demo –– seeseehttp://http://spacewar.oversigma.comspacewar.oversigma.com//


Business Model / Business Model / Interaction with CustomersInteraction with Customers

•• IBM rented its computersIBM rented its computers–– Modifications need IBM approvalModifications need IBM approval

•• DEC model:DEC model:–– PDPPDP--1 was sold, not leased1 was sold, not leased


DEC opennessDEC openness

•• Encouraged modification by the customersEncouraged modification by the customers•• Published detailed specs on cheap paperPublished detailed specs on cheap paper•• DidnDidn’’t develop specialized HW and SWt develop specialized HW and SW

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DEC PDPDEC PDP--88

•• 12 bit word length12 bit word length•• 50,000 computers installed50,000 computers installed•• Successful Successful -- performance, storage, packaging, performance, storage, packaging,

priceprice•• Improvements in logic and core memory reduced Improvements in logic and core memory reduced

the cycle time to 1.6 the cycle time to 1.6 microsecmicrosec..Seminar in computer History CS236801Seminar in computer History CS236801 1414

PDPPDP--8 Addressing8 Addressing

•• 7bits were used for the address field 7bits were used for the address field (small)(small)

•• Memory: 32 blocks of 128 words Memory: 32 blocks of 128 words (4KW)(4KW)

•• Access across a block achieved by Access across a block achieved by setting bits in the setting bits in the opcodeopcode


PDP8 packagingPDP8 packaging

•• Constructed from a series of Constructed from a series of compact modulescompact modules–– Each performed a specific function Each performed a specific function

•• Modules plugged into a chassis Modules plugged into a chassis •• Wire wrap connectionWire wrap connection•• Small: embedded in other Small: embedded in other

equipmentequipment•• 8 cubic feet (volume), 250 8 cubic feet (volume), 250

poundspounds


PDP8 pricingPDP8 pricing

•• Very cheap: $18K Very cheap: $18K •• Price dropped to $10K after a few yearsPrice dropped to $10K after a few years•• Price shocked the industry, many ordersPrice shocked the industry, many orders•• Once again estimates of the computer Once again estimates of the computer

market size were proved incorrectmarket size were proved incorrect


PDP8 programmingPDP8 programming

•• Limited memory prevented highLimited memory prevented high--level level programmingprogramming

•• Simple, easy to understand computerSimple, easy to understand computer•• Gave rise to OEMsGave rise to OEMs


OEMsOEMs•• OEM: a separate company that bought OEM: a separate company that bought

minicomoputersminicomoputers, added specialized HW & , added specialized HW & SW and sold them under their own labelSW and sold them under their own label

•• Relieved DEC of developing specialized SWRelieved DEC of developing specialized SW•• Ranged across all segment of society:Ranged across all segment of society:

–– Medical instrumentationMedical instrumentation–– Small business recordsSmall business records–– Industrial controllersIndustrial controllers

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OEM exampleOEM example

•• LSLS--8 used to operate theatrical stage lighting8 used to operate theatrical stage lighting•• Cited as a key element in the success of the Cited as a key element in the success of the

Broadway hit Broadway hit ““A Chorus LineA Chorus Line””•• Contained a PDPContained a PDP--8A, introduced 19758A, introduced 1975•• Application specific control panelApplication specific control panel


DEC PDPDEC PDP--1010

•• One of the most influential computersOne of the most influential computers•• The machine that made timeThe machine that made time--sharing commonsharing common

–– The basis of the ARPANET The basis of the ARPANET –– The platform upon which many applications were The platform upon which many applications were

first developed:first developed:•• EMACSEMACS•• TeXTeX•• ISPELLISPELL•• KermitKermit


PDPPDP--10 Architecture10 Architecture

•• An improved HW implementation of the An improved HW implementation of the PDPPDP--66

•• Shared the same 36Shared the same 36--bit word lengthbit word length•• Slightly extended the instruction set Slightly extended the instruction set


KAKA--1010

•• The original PDPThe original PDP--10 processor was the 10 processor was the KA10KA10


Wire Wrap BackplaneWire Wrap Backplane

•• Backplanes wire wrapped, semiBackplanes wire wrapped, semi--automated manufacturing processautomated manufacturing process


PDPPDP--10 Memory Management10 Memory Management

•• KA10: maximum main memory of 256 KA10: maximum main memory of 256 KwordsKwords

•• Management consisted of 2 sets of Management consisted of 2 sets of protection & relocation registers protection & relocation registers --"base "base and bounds" registersand bounds" registers

•• This allowed separate readThis allowed separate read--only shareable only shareable code segment and readcode segment and read--write data/stack write data/stack segment segment

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PDPPDP--1111

•• A successor to the PDPA successor to the PDP--8 8 •• Was easier to program than its Was easier to program than its

predecessorspredecessors•• the world's most successful family of the world's most successful family of

minicomputersminicomputers•• Was replaced by VAXWas replaced by VAX--1111


PDPPDP--11 Instruction Set11 Instruction Set

•• A highlyA highly--orthogonal instruction set:orthogonal instruction set:Operation ; operand access mode Operation ; operand access mode

•• Any Any addressing modeaddressing mode would work with any would work with any operationoperation


PDPPDP--11 I/O11 I/O

•• New architecture: no dedicated I/O busNew architecture: no dedicated I/O bus•• It had only a memory bus, the It had only a memory bus, the UnibusUnibus•• I/O devices are memory mappedI/O devices are memory mapped

–– No need for special I/O instructionsNo need for special I/O instructions•• Four levels of interruptsFour levels of interrupts•• Interrupting device puts Interrupting device puts

its address on the busits address on the bus

DEC VAX DEC VAX MinicomputersMinicomputers


VAXVAX

•• An extension of the PDPAn extension of the PDP--11, with mainframe 11, with mainframe performanceperformance

•• Design began 1974Design began 1974•• VAX = VAX = VVirtual irtual AAddress ddress eeXXtensiontension (of PDP(of PDP--11)11)•• VAX was able to execute PDPVAX was able to execute PDP--11 instructions in 11 instructions in

a 32 instead of 16a 32 instead of 16--bit address spacebit address space•• PDPPDP--11 compatibility bit that was later dropped11 compatibility bit that was later dropped


VAX VAX -- a virtual memory a virtual memory computercomputer

•• Making small but fast main memory seem Making small but fast main memory seem to be bigger by swapping data from a to be bigger by swapping data from a slower diskslower disk

•• Overall performance not seriously Overall performance not seriously degradeddegraded

•• User is not aware that swapping is doneUser is not aware that swapping is done•• The VAX provided a 32The VAX provided a 32--bit virtual addressbit virtual address•• Memory divided into pagesMemory divided into pages

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VAX Instruction SetVAX Instruction Set

•• Sixteen general purpose 32Sixteen general purpose 32--bit registersbit registers•• Rich set of 250 instructionsRich set of 250 instructions•• Two and three operand formatsTwo and three operand formats•• Register or memory operand in most Register or memory operand in most

instructionsinstructions•• The quintessential CISC processing The quintessential CISC processing

architecturearchitecture


VAX Commercial AspectsVAX Commercial Aspects

•• Successful: 100,000 units in 10 yearsSuccessful: 100,000 units in 10 years•• General purpose computer that came with General purpose computer that came with

standard languages and SWstandard languages and SW•• Biggest impact in engineering and scienceBiggest impact in engineering and science•• Prices started at $120KPrices started at $120K•• Cheap enough to serve a division in the Cheap enough to serve a division in the

aerospace, automotive, chemical firmsaerospace, automotive, chemical firms


MIPSMIPS

•• The performance of VAX 11/780 became The performance of VAX 11/780 became known as MIPS (million instructions per known as MIPS (million instructions per second)second)

•• Later used as a benchmark of Later used as a benchmark of performanceperformance

A Brief VAX TimelineA Brief VAX Timeline


VAX KickoffVAX Kickoff

•• The VAX Architecture Committee began The VAX Architecture Committee began work on a computer with 32work on a computer with 32--bit bit architecturearchitecture

•• Image: inside of VAXImage: inside of VAX--11/78011/780


First VAXFirst VAX

•• VAXVAX--11/780 introduced11/780 introduced

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VAX OSVAX OS

•• V1.0 of the V1.0 of the VMSVMS operating system ships operating system ships •• FORTRAN IV and FORTRAN IV and DECnetDECnet, a 64 megabyte , a 64 megabyte

memory limit, an event driven priority memory limit, an event driven priority scheduler, process swapper, process scheduler, process swapper, process deletion/creation/control deletion/creation/control


LSI VAXLSI VAX

•• Introduction of the Introduction of the VAXVAX--11/75011/750•• The industry's first Large Scale Integration The industry's first Large Scale Integration

(LSI) 32(LSI) 32--bit minicomputerbit minicomputer


ECL VAXECL VAX

•• VAX 8600: the first VAX implementation in VAX 8600: the first VAX implementation in ECL technologyECL technology


““Personal Personal ““ VAX VAX

•• VAX station I. VAX station I. •• A powerful, singleA powerful, single--user computing system user computing system

supporting the professional usersupporting the professional user


VLSI VAXVLSI VAX

•• MicroVAX: VAX on a VLSI chipMicroVAX: VAX on a VLSI chip


VAX Station BestVAX Station Best--SellerSeller

•• The The VAXStationVAXStation 2000 is introduced. 2000 is introduced. •• DIGITAL'sDIGITAL's first workstation with a cost of first workstation with a cost of

less than $5,000less than $5,000•• Became the highest volume workstation in Became the highest volume workstation in

the industrythe industry

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Last VAXLast VAX

•• VAX 7000 series, VAX 7000 series, DIGITAL'sDIGITAL's most most powerful VAX system, fieldpowerful VAX system, field--upgradeable to upgradeable to the Alpha 64the Alpha 64--bit processorbit processor


SummarySummary

•• Computer class between bigComputer class between big--iron iron mainframes and personal computersmainframes and personal computers

•• The basis for nowadays servers (VAX)The basis for nowadays servers (VAX)•• Continuing trend of bringing the computer Continuing trend of bringing the computer

to more peopleto more people•• Introduced important architectural aspectsIntroduced important architectural aspects


ReferencesReferences•• WikiPediaWikiPedia•• A History of MTS A History of MTS --

http://www.clock.org/~jss/work/mts/30years.htmlhttp://www.clock.org/~jss/work/mts/30years.html•• Batch VS TS Batch VS TS –– Bruce Bruce LakinLakin, NJ EDU Computer , NJ EDU Computer

Network 1980.Network 1980.•• A History of Modern Computing by Paul E A History of Modern Computing by Paul E CeruzziCeruzzi..•• The McGrawThe McGraw--Hill Computer HandbookHill Computer Handbook•• IEEE Annals of the History of ComputingIEEE Annals of the History of Computing•• 234120 234120 -- Operating Systems Operating Systems –– CS TechnionCS Technion


ReferencesReferences•• House of VAX: House of VAX:

http://http://www.mcmanis.com/chuck/computers/vaxewww.mcmanis.com/chuck/computers/vaxenn//

•• VAX timeline: VAX timeline: http://research.microsoft.com/~gbell/digital/timelihttp://research.microsoft.com/~gbell/digital/timeline/32ne/32--bit.htmbit.htm

•• PDPPDP--1010: : httphttp://://wwwwww..columbiacolumbia..eduedu//acisacis//historyhistory//pdp10pdp10..htmlhtml

•• httphttp://://webcoursewebcourse..cscs..techniontechnion..acac..ilil//234118234118//•• wwwwww..computerhistorycomputerhistory..orgorg


ReferencesReferences

•• http://historyhttp://history..sandiegosandiego..eduedu//GENGEN//recordingrecording//computer1computer1..htmlhtml

•• httphttp://://wwwwww..oldold--computerscomputers..comcom//historyhistory//detaildetail..asp?nasp?n==58&t58&t==44

•• http://http://www.poetproductions.comwww.poetproductions.com•• http://www.ibiblio.org/pub/academic/comphttp://www.ibiblio.org/pub/academic/comp

uteruter--science/history/pictures/pdp1_1.jpgscience/history/pictures/pdp1_1.jpg•• http://http://spacewar.oversigma.comspacewar.oversigma.com//

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Mini-Computers - Techniongotsman/236801/3-mini-computers.pdf · 1 Seminar in computer History CS236801 1 Mini-Computers Yaniv Frishman Seminar in computer History CS236801Seminar