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Chapter 5 1961-1975
The “Go-Go” Years &
System/360
IBM & The Others 1963- $1.2 billion (70%) 1965- $ 3 billion 1970- $ 7 billion Sperry – Rand (UNIVAC)- mid 1960’s - $
145 million CDC (mini), Honeywell, Philco, RCA, GE,
Burroughs, NCR- mainframe builders Snow White & 7 Dwarfs 1970’s BUNCH Stable until 1980’s personal computers
System/ 360 Announced April 1964 - “full-circle” of
customers – business & scientific Line, 6 models-sw upward compatible
25:1 performance range Plus 150 different items
Fortune Magazine: “You bet your company”
1100 orders in 1st month In 5 months, 2200 orders
Success was a “threat” Could not meet demand
IBM 360 - 1964
SPREAD - IBM committeeMet daily 2 months in 1961Review past & decide the future
Couldn’t continue to “upgrade” Needed a “unified product line”“Scalability”
Fred Brooks, Gene Amdahl“can’t be done”
Scalability 1951- Maurice Wilkes, Manchester
University “best way to build an automatic
calculating machine” was to build its control section as a little stored – program computer of its own
“Micro- programmer”; microcode Page 148
Scalability – Adopted for 360
Allowed common instruction set Specialization & optimization for
models Via microprogramming
Read only memory Compatibility with earlier IBM’s
Emulation Separated design process from
control logic
Compatibility Microprogramming facilitated Emulated earlier IBM models
7070 and 1401 Up to ½ of 360 time was emulating
Due to new HW, new machines “emulated” old ones up to 10 times faster
Honeywell H-2000 + liberator emulated 1401 – sold well!
Software - more permanent than hardware 1401 programs run today
Part of Y2K problem
360 Features 16 General purpose registers 32-bit words
Finally a power of 2!! 8-bit character code – byte (1956)
EBCDIC – true 8 character code Originally also included ASCII; dropped
Channels retained Peripherals PDP-8: real-time, labs, etc.
Side Note on ASCII1963- American National
Standards InstituteAdopted 7 bit ASC II, not 88 holes across paper tape would
weaken it too muchBecame established in mini’s
Time-sharing & 360 System/360=> 360 degrees=> “full
circle of customers” Did not address time-sharing No dynamic addressing
@ this time – interactive=> one user Batch jobs “shared” time – one job in
memory John McCarthy- MIT
Each user has illusion that complete machine & SW at her disposal
THE Time-Sharing Problem
Page 155 Lots of wasted cycles
between key strokes – instructions
No efficient method for program swapping & keeping track
Time Sharing - Mid-1960’s
MIT, IBM 7090 CTSS - Compatible time sharing system Supported just a few users
Defense Dept.- Project MAC Chose G.E. over 360 GE became leader in time-sharing
IBM crisis Problems with program swapping Had not thought it would be important Model 67: TSS failure
Anti-trust lawsuit – premature announcement
Time-sharing
Progress was made – but still slow to develop workable
time-sharing -- Demonstrated feasibility but not practicality
Much turmoil in industry GE sold to Honeywell Movement to PDP machines - UNIX IBM threatened by success
IBM Stretch
IBM System /3IBM 360 could not
compete in mini market
System /3 Incompatible with 360$1000 monthSmall 96 column punch cardEventually floppy disk
The 1960’s Leasing companies
IBM too expensive Development costs Others 20% less Could withhold technology
1970 - IBM 370 360 compat. w/ time-share,
integrated circuits (cpu,mm) 1978 - IBM 4300
360 compat, low cost 1978 – AS/400 Leasing companies in debt
due to upgrades
“Go-GO” years Stocks soared
for all electronics companies
Compatible MainframesPossible attacks on 360
line Information to numerous companies
1964 - CDC 6600 (above) Designer Seymour Cray Supercomputer – Fastest performance
Small sales ~ but impressive ~ serious customers
Sued IBM – announcement 360 model 91
Compatible Mainframes
1964 – RCA – Spectra 70 SeriesRan 360 Software (1st clone)40% less $ than IBM, 4 modelsUsed true integrated circuitsLost in 1970 ~ 370 announced (IC’s)Out of computer business
Another round of buy-outs
Plug Compatible Manufacturers (PCM)
Others targeted 1 part ~IBM systemTape drive, memory, CPUThese companies soared IBM price cuts, packaging
1969-75, 10+ lawsuitsGene Amdahl-1970
Left IBM, own co.Fujitsu, other Japan
Software Houses Industry needed SW!!! Companies providing software
Automatic Data Processing (ADP)~payroll Computer Sciences Corp. (CSC) American Management Systems
IBM Included programming, service in price 1968 agreed to separate (lawsuit) For 360 success need for others to
provide SW & service Bad IBM SW – OS 360, PL/1
Software Houses – cont’d
1962 - EDS – H. Ross Perot Left IBM over “leasing of time” Success with government contracts Based in Dallas
Ramo-Wooldridge TRW Manufacturing + SW + Service Military, space, etc. Later into business apps.
IBM vs. Justice DepartmentFiled January 1969Lasted 12 yearsSell computers, UnbundleDropped January 1982PC Effect? Why didn’t IBM pursue PC
market?
The “BUNCH” Unisys = Burroughs + Univac (86) AT&T hostile take-over of NCR (91) Honeywell
Partnered with NEC, Bull & Olivetti Phased out of computing
CDC – up & down – suffered Cray
departure
PLATO (p. 175) Education system failureAhead of it’s time
Chapter 5 – 1961-1975
The “Go-Go” Years &
System/360
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