Evaluation of computer architecture

1. Evaluation of Computer
Archicture

2. Definitions
⚫ The various definitions of computer architecture are
given below
⚫ Hayes: ‘The study of the structure, behavior and
design of computers
⚫ Hennessy and Patterson: ‘The interface between the
hardware and the lowest level software
⚫ Foster: ‘The art of designing a machine that will be a
pleasure to work.

3. Definitions
⚫ Computer architecture is the science and art of
selecting and interconnecting hardware components
to create computers that meet functional performance
and cost goals.
⚫ It refers to those attributes of the system that are
visible to a programmer and have a direct impact on
the execution of a program. Computer architect
coordinate of many levels of abstraction and translates
business and technology drives into efficient systems
for computing tasks.

4. Definitions
⚫ Computer architecture concerns machine
Organization, interfaces, application, technology,
measurement and simulation.
⚫ It includes:
⚫ Instruction set
⚫ Data formats
⚫ Principle of operation (textual or formal description of
every operation)
⚫ Features (organization of programmable storage,
registers used, interrupts mechanism, and so on)

5. Definitions
⚫ In short, it is the combination of instruction set
architecture, machine organization and the underline
hardware.
⚫ The design of a computer’s CPU architecture, instruction
set, addressing modes.
⚫ Description of the requirements (especially speeds and
interconnection requirements) or design implementation
for the various parts of a computer, such as memory,
motherboard, electronic peripherals, or most commonly
the CPU)
⚫ Architecture is often defined as the set of machine
attributes that a programmer should understand in order
to successfully program the specific computer.
⚫ So, in general, computer architecture refers to attributes of
the system visible to a programmer that have a direct
impact on the execution of a program.

6. Brief History of Computer Architecture
First Generation (1945-1958)
⚫ Vacuum tubes
⚫ Machine code, assembly language
⚫ Computers contained a central processor that was unique
to that machine
⚫ Different types of supported instructions, few machines
could be considered ‘general purpose’
⚫ Use of drum memory or magnetic core memory, programs
and data are loaded using paper tape or punch cards
⚫ 2 Kb memory

7. Two types of models for a computing machine
⚫ Harvard architecture - physically separate storage
and signal pathways for instructions and data. The
term originated from the Harvard Mark I, relay-based
computer, which stored instructions on punched tape
and data in relay latches
⚫ Von Neumann architecture- a single storage
structure to hold both the set of instructions and the
data. Such machines are also known as
stored-program computers. Von Neumann bottleneck
- the bandwidth, or the data transfer rate, between the
CPU and memory is very small in comparison with the
amount of memory.

9. ENIAC (Electronic Numerical Integrator and Calculator)
⚫ 1943-46, by J. Mauchly and J. Presper Eckert, first
general purpose electronic computer. The size of its
numerical word was 10 decimal digits, and it could
perform 5000 additions and 357 multiplications per
second. It was built to calculate trajectories for ballistic
shells during World War II, programmed by setting
switches and plugging and unplugging cables. It used
18000 tubes, weighted 30 tones and consumed 160
kilowatts of electrical power.

10. Whirlwind computer
⚫ 1949, by Jay Forrester with 5000 vacuum tubes, main
innovation - magnetic core memory 1951 UNIVAC
(Universal Automatic Computer) - the first commercial
computer, built by Eckert and Mauchly, cost – around $1
million, 46 machines sold. UNIVAC had an add time of
120 microseconds, multiply time of 1800 microseconds
and a divide time of 3600 microseconds, used magnetic
tape as input.

11. IBM’s 701
⚫ 1953, the first commercially successful general-purpose
computer. The 701 had electrostatic storage tube memory,
used magnetic tape to store information, and had binary,
fixed-point, single address hardware.

12. IAS COMPUTER (instruction set architecture)

13. Second Generation (1958-1964)
The features of second generation include
⚫ Transistors – small, low-power, low-cost, more reliable
than vacuum tubes
⚫ Magnetic core memory
⚫ Two’s complement, floating point arithmetic
⚫ Reduced the computational time from milliseconds to
microseconds
⚫ High level languages
⚫ First operating systems: handled one program at a
time
⚫ 1959 - IBM´s 7000 series mainframes were the
company´s first transistorized computers

14. Second Generation…

15. Third Generation (1964-1974)
⚫ The features of third generation include:
⚫ Introduction of integrated circuits combining thousands of
transistors on a single chip
⚫ Semiconductor memory
⚫ Timesharing, graphics, structured programming
⚫ 2 Mb memory
⚫ Use of cache memory
⚫ IBM’s System 360 - the first family of computers making
a clear distinction between architecture and
implementation

16. Microelectronics
⚫ It means small electronics.
⚫ The computer consists of logic gates, memory cells
and interconnections.
⚫ It is manufactured on a semiconductor such as silicon.
Many transistors can be produced on a single wafer of
silicon.

17. Microelectronics…

18. CPU STRUCTURE OF IBM/360-370 S

19. IBM System/360 Model
⚫ The IBM System/360 Model 91 was introduced in 1966 as
the fastest, most powerful computer then in use.
⚫ It was specifically designed to handle high-speed data
processing for scientific applications such as space
exploration, theoretical astronomy, subatomic physics and
global weather forecasting. IBM estimated that each day
in use,
⚫ The Model 91 would solve more than 1,000 problems
involving about 200 billion calculations.

20. Fourth Generation (1974-present)
⚫ Introduction of Very Large-Scale Integration (VLSI)/Ultra
Large-Scale Integration (ULSI) - combines millions of
transistors
⚫ Single-chip processor and the single-board computer emerged
⚫ Smallest in size because of the high component density
⚫ Creation of the Personal Computer
⚫ Widespread use of data communications
⚫ Object-Oriented programming: Objects & operations on
objects
⚫ Artificial intelligence: Functions & logic predicates

21. 1971
⚫ The 4004 was the world’s first universal microprocessor,
invented by Federico Faggin, Ted Hoff, and Stan Mazor.
With just over 2,300 MOS transistors in an area of only 3
by 4 millimeters had as much power as the ENIAC.
⚫ 4-bit CPU
⚫ 1K data memory
⚫ Clock rate: 740kHz
⚫ Just a few years later, the word size of the 4004 was
doubled to form the 8008

22. 1974 – 1977
⚫ The first personal computers – introduced on the market as
kits (major assembly required).
⚫ SCELBI (SCientific, ELectronic and BIological) and designed
by the SCELBI Computer Consulting Company,based on
Intel’s 8008 microprocessor, with 1K of programmable
memory, SCELBI sold for $565 and came, with an additional
15K of memory available for $2760.
⚫ Mark-8 (also Intel 8008 based) designed by Jonathan Titus.
⚫ Altair (based on the new Intel 8080 microprocessor), built by
MITS (Micro Instrumentation Telemetry Systems).
⚫ The computer kit contained an 8080 CPU, a 256 Byte RAM
card, and a new Altair Bus design for the price of $400.

23. 1981
⚫ IBM released their new computer IBM PC which ran on a
4.77 MHz Intel 8088 microprocessor and equipped with
16 kilobytes of memory, expandable to 256k. The PC
came with one or two 160k floppy disk drives and an
optional color monitor. First one built from off the shelf
parts (called open architecture) and marketed by outside
distributors

24. Table Summary

25. Summary
⚫ The evolution of computers has been characterized by increasing processor
speed, decreasing component size, increasing memory size, and increasing
I/O capacity and speed.
⚫ Computer architecture is the science and art of selecting and
interconnecting hardware components to create computers that meet
functional performance and cost goals.
⚫ Computer architecture concerns machine organisation, interfaces,
application, technology, measurement and simulation.
⚫ IBM 7090 is the most powerful data processing system at that time.
⚫ Although the IBM 7090 is a general-purpose data processing system, it is
designed with special attention to the needs of the design of missiles, jet
engines, nuclear reactors and supersonic aircraft.
⚫ The 7090 can perform any of the following operations in one second:
229,000 additions or subtractions, 39,500 multiplications, or 32,700
divisions.
⚫ Microelectronics means ‘small electronics. The computer consists of logic
gates, memory cells and • interconnections.
⚫ The IBM System/360 Model 91 was introduced in 1966 as the fastest, most
powerful computer then in use

26. Flynn’s Classification
⚫ In 1972 Flynn’s classified Four types of computer
models
⚫ A) SISD
⚫ B) SIMD
⚫ C) MISD
⚫ D) MIMD

28. Single-instruction, single-data (SISD)
systems
⚫ An SISD computing system is a uniprocessor
machine which is capable of executing a single
instruction, operating on a single data stream.
⚫ In SISD, machine instructions are processed in a
sequential manner and computers adopting this
model are popularly called sequential computers.
⚫ Most conventional computers have SISD
architecture.
⚫ All the instructions and data to be processed have to
be stored in primary memory

29. SISD

30. SISD
The speed of the processing element in the SISD
model is limited(dependent) by the rate at which
the computer can transfer information internally.
Dominant representative SISD systems are IBM
PC, workstations.

31. Single-instruction, multiple-data (SIMD)
systems
⚫ An SIMD system is a multiprocessor machine capable of
executing the same instruction on all the CPUs but
operating on different data streams.
⚫ Machines based on an SIMD model are well suited to
scientific computing since they involve lots of vector and
matrix operations.
⚫ So that the information can be passed to all the processing
elements (PEs) organized data elements of vectors can be
divided into multiple sets(N-sets for N PE systems) and
each PE can process one data set.

32. SIMD

33. SIMD
Dominant representative SIMD systems is Cray’s vector
processing machine.

34. Multiple-instruction, single-data (MISD) systems
⚫ An MISD computing system is a multiprocessor machine
capable of executing different instructions on different
PEs but all of them operating on the same dataset
⚫ Example Z = sin(x)+cos(x)+tan(x)
⚫
The system performs different operations on the same data
set. Machines built using the MISD model are not useful
in most of the application, a few machines are built, but
none of them are available commercially.

35. MISD

36. MISD

37. Multiple-instruction,
multiple-data (MIMD) systems
⚫ An MIMD system is a multiprocessor machine which is
capable of executing multiple instructions on multiple data sets.
⚫ Each PE in the MIMD model has separate instruction and data
streams; therefore machines built using this model are capable
to any kind of application. Unlike SIMD and MISD machines,
PEs in MIMD machines work asynchronously.

38. MIMD

39. ⚫ MIMD machines are broadly categorized
into shared-memory MIMD and distributed-memory
MIMD based on the way PEs are coupled to the main
memory.
⚫ In the shared memory MIMD model (tightly coupled
multiprocessor systems), all the PEs are connected to a
single global memory and they all have access to it.
⚫ The communication between PEs in this model takes
place through the shared memory, modification of the
data stored in the global memory by one PE is visible to
all other PEs.
⚫ Dominant representative shared memory MIMD systems
are Silicon Graphics machines and Sun/IBM’s SMP
(Symmetric Multi-Processing).

40. ⚫ Distributed memory MIMD machines (loosely coupled
multiprocessor systems) all PEs have a local memory.
⚫ The communication between PEs in this model takes place through
the interconnection network (the inter process communication
channel, or IPC).
⚫ The network connecting PEs can be configured to tree, mesh or in
accordance with the requirement.
▪ The shared-memory MIMD architecture is easier to program but is
less tolerant to failures and harder to extend with respect to the
distributed memory MIMD model.
⚫ Failures in a shared-memory MIMD affect the entire system,
whereas this is not the case of the distributed model, in which each
of the PEs can be easily isolated. Moreover, shared memory MIMD
architectures are less likely to scale because the addition of more
PEs leads to memory contention. This is a situation that does not
happen in the case of distributed memory, in which each PE has its
own memory.
⚫ As a result of practical outcomes and user’s requirement ,
distributed memory MIMD architecture is superior to the other
existing models.

41. MIMD

42. New Challenges
⚫ Technology of parallel Processing is outgrowth for
several Decades of Research and Industrial
Advancement in
⚫ Microelectronics
⚫ Printed CKT.
⚫ High Density Packaging
⚫ Advanced Processor
⚫ Operating system
⚫ Programming Environment
⚫ Communicational Channels
⚫ Languages Evaluation

43. System Attributes to Performance