Computer Architecture
Lecture Notes
Spring 2005
Dr. Michael P. Frank
Competency Area 1:
Computer System Components
Lecture 2
ENIAC - background
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Electronic Numerical Integrator And Computer
Eckert and Mauchly
University of Pennsylvania
Proposed to develop a computer for the
calculation of Trajectory tables for weapons
during WWII (Army Ballistics Research
Laboratory)
• Started 1943
• Finished 1946
—Too late for war effort
—Used to help determine
feasibility of H-bomb
• Used until 1955
ENIAC - details
• Decimal (not binary)
• Its memory contained 20 accumulators of 10
digits.
• 10 vacuum tubes represented each digit.
• Programmed manually by switches
• 18,000 vacuum tubes
• 30 tons
• 1500 square feet
• 140 kW power consumption
• 5,000 additions per second
von Neumann/Turing
• Stored Program concept
• Main memory storing programs and data
• “Turing Machine” (Alan Turing): Given enough memory
and sufficient time the general purpose computer can
compute all functions that are computable.
• ALU operating on binary data
• Control unit interpreting instructions from memory and
executing
• Input and output equipment operated by control unit
• Princeton Institute for Advanced Studies
— IAS Computer (major components in a computer system)
— Foundation for general-purpose computer
• Completed 1952
Picture of the IAS Computer
Smithsonian Image 95-06151
Structure of von Neumann machine
IAS - details
• 1000 x 40 bit words
—1000 storage locations of 40-bit words
—Binary number
—2 x 20 bit instructions
• Set of registers (storage in CPU)
—Memory Buffer Register (MBR)
—Memory Address Register (MAR)
—Instruction Register (IR)
—Instruction Buffer Register (IBR)
—Program Counter (PC)
—Accumulator (AC)
—Multiplier Quotient (MQ)
Structure of IAS –
detail
MBR
Contains a word to be stored
In memory, or is used to receive a
Word from memory.
MAR
Specifies the address in memory
of the word to be written from or
into MBR
IR
Contains the 8-bit opcode
instruction being executed
IBR
Temporarily holds the right hand
instruction from a word in
memory
PC
Contains the address of the next
instruction pair to be fetched from
memory
IAS - details
• The IAS computer had 21 instructions which are
grouped as follows:
—Data Transfer: Moves data between memory and
ALU registers or between two ALU registers
—Unconditional Branch: Changes the sequence of
instructions to execute repetitive operations
—Conditional Branch: The branch can be made
dependent on a condition, thus, allowing decision
points.
—Arithmetic: Operations performed by the ALU
— Address /modify: Permits addresses to be
computed in the ALU and then inserted into
instructions stored in memory.
Commercial Computers
• 1947 – Eckert-Mauchly developed their own
Computer Corporation
• UNIVAC I (Universal Automatic Computer)
• Designed to perform mainly scientific
calculations (e.g. US Bureau of Census 1950
calculations)
• Became part of Sperry-Rand Corporation
• Late 1950s - UNIVAC II
—Faster
—More memory
IBM
• Punched-card processing equipment
• 1953 - the 701
—IBM’s first stored program
computer
—Scientific calculations
• 1955 - the 702
—Business applications
• Lead to 700/7000 series
Transistors
• The second generation of technology:
Transistors replaced vacuum tubes
• Smaller
• Cheaper
• Less heat dissipation
• Solid State device
• Made from Silicon (Sand)
• Invented 1947 at Bell Labs
• William Shockley et al.
• Discrete components
Transistor Based Computers
• Second generation machines
• More complex arithmetic and logic units
• Incorporated the use of high-level programming
languages
• Also used system software with machines (e.g.
operating systems)
• NCR & RCA produced small transistor machines
• IBM 7000 Series
• Digital Equipment Corporation (DEC) - 1957
—Produced PDP-1 which began the minicomputer
phenomenon
Transistors
Computer Generations:
Generation
Approximate
Dates
Technology
Typical
Speed
(ops/sec)
1
1946-1957
Vacuum Tubes
40,000
2
1958-1964
Transistor
200,000
3
1965-1971
Small and
medium scale
integration
1,000,000
4
1972-1977
Large-scale
integration
(LSI)
10,000,000
5
1978-
Very LSI
100,000,000
Microelectronics
• Up to this point, computers were manufactured
using discrete components which was becoming
more expensive and cumbersome as computers
continued to improve in performance.
• Microelectronics dominated the next generation
of computers.
• Literally - “small electronics”
• A computer is made up of gates, memory cells
and interconnections
• These can be manufactured on a semiconductor
• e.g. silicon wafer
Generations of Computer
• 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
• As microelectronics grew in the computer industry, an
increase in the density of components on chip became
evident.
• Gordon Moore - cofounder of Intel
• Gordon’s Observation: 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
• Cost of a chip has remained almost unchanged
• Higher packing density means shorter electrical paths,
giving higher performance
• Smaller size gives increased flexibility
• Reduced power and cooling requirements
• Fewer interconnections increases reliability
Moore’s Law
Formal Consequences of Moore’s Law:
1.
Cost of chip has remained relatively stable during a period of
rapid growth in density. This implies the cost of computer logic
and memory circuitry has fallen at a drastic rate.
2.
Because logic and memory elements are placed closer together on
more densely packed chips, the electrical path length is
shortened, increasing operating speeds.
3.
The computer becomes smaller, making it more convenient to
placed in a variety of environments.
4.
There is a reduction in power and cooling requirements.
5.
The interconnections on the integrated circuit are much more
reliable than solder connections. With more circuitry on each
chip, there are fewer interchip connections.
Growth in CPU Transistor Count
IBM 360 series
• Introduced in 1964
• Replaced (& not compatible with) 7000 series
• 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)
—Increased memory size
—Increased cost
• Multiplexed switch structure
• The introduction of this family cemented IBM as
a world leader in computer manufacturing
industry.
Picture of IBM 360
DEC PDP-8
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Also introduced in 1964
First minicomputer
Did not need room w. A/C
Small, could sit on a lab bench
Relatively cheap: $16,000
—Compared to $100k+ for IBM 360
• Embedded applications & Original Equipment
Manufacturers (OEM) allowed users to buy PDP8 machines and integrate them into a total
system for resale.
• BUS STRUCTURE
DEC - PDP-8 Bus Structure
Console
Controller
CPU
Main Memory
I/O
Module
OMNIBUS
- Highly flexible
- All systems share a common set of signal paths
- Allows other modules to be plugged into the bus
to create various configurations
I/O
Module
Intel
• 1971 - 4004
—First microprocessor
—Whole CPU on a single chip
—4 bit
• Followed in 1972 by 8008
—8 bit
—Both for specific applications
• 1974 - 8080
—Intel’s first general
purpose
microprocessor
Speeding it up
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Pipelining
On board cache
On board L1 & L2 cache
Branch prediction
Data flow analysis
Speculative execution
Pentium Evolution (1)
• 8080
— first general purpose microprocessor
— 8 bit data path
— Used in first personal computer – Altair
• 8086
— much more powerful
— 16 bit
— instruction cache, prefetch few instructions
— 8088 (8 bit external bus) used in first IBM PC
• 80286
— 16 Mbyte memory addressable
— up from 1Mb
• 80386
— 32 bit
— Support for multitasking
Performance
1970s Processors:
4004
8008
8080
8086
8088
1971
1972
1974
1978
1979
108 KHz
108 KHz
2 MHz
5 MHz, 8MHz,
10MHz
5 MHz, 8MHz
Bus Width
4 bits
8 bits
8 bits
16 bits
8 bits
Number of
Transistors
2300
3500
6000
29,000
29,000
Addressable
Memory
640 bytes
16 KBytes
64 KBytes
1 MB
1 MB
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Introduced
Clock
Speeds
Virtual
Memory
Performance
1980s Processors:
80286
386TM DX
386TM SX
486TM DX
CPU
1982
1985
1988
1989
6 MHz – 12.5
MHz
16 MHz-33
MHz
16 MHz-33
MHz
25 MHz- 50
MHz
Bus Width
16 bits
32 bits
16 bits
32 bits
Number of
Transistors
134,000
275,000
275,000
1.2 million
Addressable
Memory
16 MB
4 GB
4GB
4GB
1 GB
64 TB
64 TB
64 TB
Introduced
Clock
Speeds
Virtual
Memory
Performance
1990s Processors:
486TM SX
Pentium
Pentium
Pentium II
1991
1993
1995
1997
16 MHz133MHz
60 MHz –166
MHz
150 MHz200MHz
200 MHz300MHz
Bus Width
32 bits
32 bits
64 bits
64 bits
Number of
Transistors
1.185 million
3.1 million
5.5 million
7.5 million
Addressable
Memory
4 GB
4 GB
64 GB
64 GB
Virtual
Memory
64 TB
64TB
64 TB
64 TB
Introduced
Clock
Speeds
Performance
Recent Processors:
Pentium III
Pentium 4
1999
2000
450 MHz
1.3-1.8 GHz
Bus Width
64 bits
64 bits
Number of
Transistors
95 million
42 million
Addressable
Memory
64 GB
64 GB
Virtual
Memory
64 GB
64 TB
Introduced
Clock
Speeds
Performance Mismatch
• Processor speed increased
• Memory capacity increased
• Memory speed lags behind processor speed!!
DRAM and Processor Characteristics
Pentium Evolution (2)
• 80486
—sophisticated powerful cache and instruction
pipelining
—built in maths co-processor
• Pentium
—Superscalar
—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
—Note Arabic rather than Roman numerals
—Further floating point and multimedia enhancements
• Itanium
—64 bit
• See Intel web pages for detailed information on
processors
Intel Itanium 2 (McKinley)
• 64b Processor
• 221 million transistors!
(~US adult population)
• How are they used?
• What will we do as
transistor counts
continue to grow?
• Most of chip is used for
memories, inst. decoding,
dynamic scheduling…
• Why is it done this way?
• How much more efficient
could it be if more of area
went to actual processing?
Even More Recent Example
• Runs 64-bit
IA-64 ISA
• Die: 3.74 cm2
• .13µ process
• 410M transistors
• 1.5GHz core
• 1.3V logic
• 130W power
consumption!
• 6.4GB/s bus
• Cost: $2,247$4,226
• 9MB L3 cache
later this year…
Internet Resources
• http://www.williamstallings.com
—Computer Organization and Architecture
• 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