Chapter 2
Computer Evolution and
Performance
Contents
• Key points
• Brief history of computers
—Vacuum tubes
—Transistors
—ICs
• Designing for performance
—microprocessor speed
—performance balance
• Pentium and PowerPC evolution
Key points
• Evolution of computers
— increased processor speed
— decreased component size
— increased memory size
— increased I/O capacity and speed
• Increased processor speed
— size of the components has been reduced
— use of pipelining and parallel execution
— use of speculative execution technique
• Balancing the performance of various elements
— gains in performance in one area should not be handicapped by
a lag in other areas
— processor speed vs. memory access time
– caches, wider data paths
ENIAC - background
• Electronic Numerical Integrator And Computer
—first general-purpose electronic digital computer
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Eckert and Mauchly
University of Pennsylvania
Trajectory tables for weapons
Started 1943
Finished 1946
—Too late for war effort
• Used until 1955
ENIAC - details
• Decimal machine(not binary)
• 20 accumulators of 10 digits
—each digit is represented by 10 vacuum tubes
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Programmed manually by switches
18,000 vacuum tubes
30 tons
15,000 square feet
140 KW power consumption
5,000 additions per second
von Neumann Machine
• Stored Program concept
—not setting switches manually from outside
—but storing the instructions and data inside
• John von Neumann
—IAS computer
– Started 1946, completed 1952
– Prototype of all subsequent computers
• General structure of IAS computer
—Main memory storing programs and data
—ALU operating on binary data
—Control unit interpreting instructions
—I/O equipment operated by control unit
Structure of von Neumann machine
IAS - details
• 1000 x 40 bit words
—Binary number
—2 x 20 bit instructions
• Set of registers (storage in CPU)
—Memory Buffer Register
—Memory Address Register
—Instruction Register
—Instruction Buffer Register
—Program Counter
—Accumulator
—Multiplier Quotient
Structure of IAS –
detail
IAS - instructions
• Total of 21 instructions(Table 2.1)
—Data transfer
—Unconditional branch
—Conditional branch
—Arithmetic
—Address modify
Commercial Computers - UNIVAC
• 1947 - Eckert-Mauchly Computer Corporation
—UNIVAC I (Universal Automatic Computer)
—US Bureau of Census 1950 calculations
—Became part of Sperry-Rand Corporation
• Late 1950s - UNIVAC II
—Faster, more memory
—Upward compatible with the older machines
Commercial Computers - IBM
• Punched-card processing equipment
• 1953 - 701
—IBM’s first stored program computer
—Scientific calculations
• 1955 - 702
—Business applications
• Lead to 7000 series
Transistors
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Replaced vacuum tubes
Smaller
Cheaper
Less heat dissipation
Solid State device made from Silicon
Invented 1947 at Bell Labs
William Shockley et al.
Transistor Based Computers
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Second generation machines
NCR & RCA produced small transistor machines
IBM followed with 7000 series
DEC - 1957
—Produced PDP-1
—mini-computer phenomenon began
IBM 7094
• From 700 series to 7094 series
—increased performance
—increased capacity
—lower cost
Microelectronics
• What do we need for a digital computer?
— they need to perform storage, movement, processing, and
control functions
— gates and memory cells
• Gate
— a device that implements a simple logical function
• Memory cell
— a device that can store one bit of data
• Which functions are supported by which device?
— Storage : provided by memory cells
— Processing : provided by gates
— Movement : provided by the interconnection(paths) between
components
— Control : control signals can be carried by the interconnection
Computer Generations
• Vacuum tube - 1946-1957
• Transistor - 1958-1964
• Small scale integration - 1965 on
—Up to 100 devices on a chip
• Medium scale integration - to 1971
—100-3,000 devices on a chip
• Large scale integration - 1971-1977
—3,000 - 100,000 devices on a chip
• Very large scale integration - 1978 to date
—100,000 - 100,000,000 devices on a chip
• Ultra large scale integration
—Over 100,000,000 devices on a chip
Moore’s Law
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Increased density of components on a chip
Gordon Moore - cofounder of Intel
Number of transistors on a chip will double every year
Since 1970’s development has slowed a little
— Number of transistors doubles every 18 months
• Consequences of Moore’s law
— Cost of a chip has remained almost unchanged
— Higher packing density means shorter electrical paths,
increasing operating speed
— Smaller size, making it more convenient to place in a variety of
environments
— Reduced power and cooling requirements
— Fewer interconnections increases reliability
Growth in CPU Transistor Count
IBM 360 series
• 1964
• Replaced & not compatible with 7000 series
—to produce a system with new IC technology
• First planned “family” of computers
—Similar or identical instruction sets
—Similar or identical O/S
—Increasing speed
—Increasing number of I/O ports (i.e. more terminals)
—Increasing memory size
—Increasing cost
DEC PDP-8
• 1964
• First minicomputer
—could not do everything the mainframe could
• Small enough to sit on a lab bench
• $16,000
—$100k+ for IBM 360
• Use bus structure
—Omnibus
DEC - PDP-8 Bus Structure
Console
Controller
CPU
Main Memory
OMNIBUS
I/O
Module
I/O
Module
Semiconductor Memory
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1970 : from core to ICs
Fairchild
Size of a single core could hold 256 bits
Non-destructive read(compared to destructive
core)
• Much faster than core
• Capacity approximately doubles each year
—since 1970, 11 generations
—1K, 4K, 16K, 64K, 256K, 1M, 4M, 16M, 64M, 256M,
1G
Speeding it up
• Besides the number of transistors in a chip…
—Pipelining
—On board cache
– L1 & L2 cache
—Branch prediction
– if the guess is right most of the time, we can prefetch the
correct instructions
—Data flow analysis
– analyze which instructions are dependent on which
– create an optimized schedule of instructions
—Speculative execution
– speculatively execute instructions ahead of their actual
appearance
Performance Mismatch
• Processor speed increased
• Memory capacity increased
• Memory speed lags behind processor speed
DRAM and Processor Characteristics
Solutions
• Increase number of bits retrieved at one time
—Using wide bus data paths
• Change DRAM interface
—Cache
• Reduce frequency of memory access
—More complex cache
• Increase interconnection bandwidth
—High speed buses
—Hierarchy of buses
Pentium Evolution (1)
• 8080
— first general purpose microprocessor
— 8 bit data path
— Used in the first personal computer – Altair
• 8086
— much more powerful
— 16 bit data path and registers
— instruction cache for prefetching few instructions
— 8088 (8 bit external bus) used in the first IBM PC
• 80286
— 16 MB memory addressable
• 80386
— Intel’s first 32 bit processor
— Support multitasking
Pentium Evolution (2)
• 80486
—sophisticated powerful cache and instruction
pipelining
—built-in math coprocessor
• Pentium
—superscalar technique
– multiple instructions executed in parallel
• Pentium Pro
—increased superscalar organization
—aggressive register renaming
—branch prediction
—data flow analysis
—speculative execution
Pentium Evolution (3)
• Pentium II
—MMX technology
– graphics, video & audio processing
• Pentium III
—Additional floating point instructions for 3D graphics
• Pentium 4
—Further floating point and multimedia enhancements
• Itanium
—64 bit machine with IA-64 architecture
—details in Chap 15
• See Intel web pages for detailed information on
processors
PowerPC (1)
• A superscalar RISC system
—companies involved
– IBM, Motorola, Apple
—used in Apple Macintosh machines
• 601
—32 bit machine
• 603
—intended for low-end desktop and portable computers
• 604
—uses advanced superscalar techniques
PowerPC (2)
• 620
—intended for high-end servers
—full 64 bit architecture
– 64 bit registers and data paths
• 740/750
—also known as G3 processor
—two level cache
• G4
—increased parallelism and speed
Internet Resources
• http://www.intel.com/
—Search for the Intel Museum
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http://www.ibm.com
http://www.dec.com
Charles Babbage Institute
PowerPC
Intel Developer Home
Problem Solving Assignment 1
• Solve the following problems of Chapter 2:
—1
Reading Assignment 1
• Read and report on the following paper from the
research literature. Your report should be one
to two pages long; three-quarters of the report
should summarize the paper, and one-quarter of
the report should be a critique. Introduce your
report with a formal citation of the paper, using
the format found in the References section of
the textbook.
• Flynn, M. “What’s Ahead in Computer Design?”
Euromicro ‘97 Proceedings, September 1997.
Http://umunhum.stanford.edu/papers.html