1. Computing Components

2. Computer Components
Consider the following ad
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3. Sizes in Perspective Admiral Grace Murray Hopper
A coil of wire nearly 1,000 feet long
Distance traveled by an electron along the wire in the space of a microsecond
A short piece of wire
In the space of a nanosecond
A bag containing grains of pepper
In the space of a picosecond

4. Sizes in Perspective
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5. History of Computers Abacus invented in Babylonia in 3000BC
Adding machine by Blaise Pascal (1642)
Difference engine and the analytical engine by Charles Babbage (1842)
IBM first electromechanical computer (using relays) designed by Howard Aiken (1937) was based on punched cards.
used to calculate tables of mathematical functions

6. History of Computers
1st Generation Computers (1940s to early 1950s) – based on vacuum tubes technology.
1943 – ENIAC: first fully electronic computer, designed by John Mauchly
1944 – Mark I: Howard Aiken
1946 – EDVAC: first stored program computers, designed by John von Neumann
2nd Generation Computers (late 50s to early 60s) – based on transistors technology.
more reliable, less expensive, low heat dissipation
IBM 7000 series, DEC PDP-1

7. History of Computers
3rd Generation Computers (late 60s to early 80s) – integrated circuits (IC).
IBM 360 series, DEC PDP-8
IC – many transistors packed into single container
low prices, high packing density
4th Generation Computers (present day) LSI/VLSI
small size, low-cost, large memory, ultra-fast PCs to supercomputers
5th Generation Computers (future)
massively parallel, large knowledge bases, intelligent
Japan, Europe and US advanced research programs

8. History of Computers Web sites
ACM Timeline of Computing History (
The Virtual Museum of Computing (
IEEE Annals of the History of Computing (
and others (surf the web)

9. Application Areas
Scientific: weather forecasting, simulation, space-program.
one of the earliest application areas.
heavy computation but small amount of data.
Commercial: accounting, banking, inventory, sales.
changes nature of business – information is money.
high data throughput, simple calculations.
Manufacturing: numerical control, CAD/CAM, integration.
graphics, interfacing, device-drivers, networks.

10. Application Areas
Real-time & Control System: air-traffic control, aircraft,nuclear power station.
real time, very fast, safety-critical.
Educational & Recreational
CAI software, multi-media, games, Internet, World Wide Web.
Telecommunication
Network, SCV, Singapore One.

11. Types of Computers Supercomputers: Mainframes: Mini-computers:
very fast (Gflops) but expensive machine($10m), vector or parallel processors, used in scientific applications and simulations.
Mainframes:
fast (>10mips) but expensive ($1m), high-throughput, used in large commercial organisations, support many concurrent users interactively.
Mini-computers:
fast but affordable ($200k), used in medium-sized organisations (e.g. SoC), support multiple users.

12. Types of Computers Workstations: Micro/Personal/Home Computers:
affordable ($20k) and fast single-user systems (20 riscs mips), good graphics capabilities, engineering, network-based computing.
Micro/Personal/Home Computers:
cheap and affordable ($3k), transportable, home use, good for games and as educational tool, word processing, suitable for small enterprise.

13. Computer Configurations
Stand-alone computer system
Modem connection

14. Computer Configurations
Terminals-host connections

15. Computer Configurations
Network of computers

16. Computers as Information Processors
Driver
Example: An automobile augments our power of locomotion.
A computer is a device capable of solving problems according to designed program. It simply augments our power of storage and speed of calculation.
Programmer

17. Computers as Information Processors
Unlike previous inventions, computers are special because they are general-purpose.
Could be used to perform a variety of tasks.
Computer = Hardware + Software.
Hardware: physical components for computation/processing; should be simple, fast, reliable.
Software: set of instructions to perform tasks to specifications; should be flexible, user-friendly, sophisticated.

18. Computer as Information Processors
Computer are Information Processors
Computer system
Raw data
Processed information
Data Units:
1 bit (binary digit): one of two values (0 or 1)
1 byte: 8-bits
1 word: 1, 2, or 4 bytes, or more (depends on ALU)

19. Basic Machine Hardware Architecture
Main Components:
CPU (Central Processing Unit: controls devices and processes data).
Memory: stores programs and intermediate data.
Input Devices: accept data from outside world.
Output Devices: presents data to the outside world.
An analogy with Human Information Processors:
CPU – brain’s reasoning powers
Memory – brain’s memory
Input Devices – eyes, ears, sensory sub-system
Output Devices – mouth, hands, facial and body expressions

20. Basic Machine Hardware Architecture
Headphone (Output)
Monitor (Output)
Hardware box (has processor, memory, buses etc.)
Mouse and Keyboard (Input)

21. Basic Machine Hardware Architecture
Network card and CRT card
Motherboard (Printed Circuit Board)
Floppy disk drive and Hard disk drive
Slots for RAM chips
Cage for mounting drives
Processor
© above picture: Patterson and Hennessy

22. Stored-Program Concept
Figure 5.1 The von Neumann architecture

23. Memory
Memory is a collection of cells, each with a unique physical address
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24. Arithmetic/Logic Unit
Performing basic arithmetic operations such as adding
Performing logical operations such as AND, OR, and NOT
Most modern ALUs have a small amount of special storage units called registers

25. Input/Output Units
An input unit is a device through which data and programs from the outside world are entered into the computer
Keyboard, the mouse, and scanning devices
An output unit is a device through which results stored in the computer memory are made available to the outside world
Printers and video display terminals

26. Control Unit Control unit is the organizing force in the computer
There are two registers in the control unit
The instruction register (IR) contains the instruction that is being executed
The program counter (PC) contains the address of the next instruction to be executed
ALU and the control unit called the Central Processing Unit, or CPU

27. Flow of Information
The parts are connected to one another by a collection of wires called a bus
Figure 5.2 Data flow through a von Neumann architecture

28. The Fetch-Execute Cycle
Fetch the next instruction
Decode the instruction
Get data if needed
Execute the instruction

29. Figure 5.3 The Fetch-Execute Cycle

30. RAM and ROM RAM stands for Random Access Memory
Inherent in the idea of being able to access each location is the ability to change the contents of each location
ROM stands for Read Only Memory
The contents in locations in ROM cannot be changed
RAM is volatile, ROM is not
This means that RAM does not retain its bit configuration when the power is turned off, but ROM does

31. Secondary Storage Devices
Because most of main memory is volatile and limited, it is essential that there be other types of storage devices where programs and data can be stored when they are no longer being processed
Secondary storage devices can be installed within the computer box at the factory or added later as needed

32. Magnetic Tape
The first truly mass auxiliary storage device was the magnetic tape drive
Figure 5.4 A magnetic tape

33. Magnetic Disks
A read/write head travels across a spinning magnetic disk, retrieving or recording data
Figure The organization of a magnetic disk

34. Compact Disks
A CD drive uses a laser to read information stored optically on a plastic disk
CD-ROM is Read-Only Memory
DVD stands for Digital Versatile Disk

35. Synchronous processing
One approach to parallelism is to have multiple processors apply the same program to multiple data sets
Figure 5.6 Processors in a synchronous computing environment

36. Pipelining
Arranges processors in tandem, where each processor contributes one part to an overall computation
Figure 5.7 Processors in a pipeline

37. Ethical Issues: Facial Recognition/Privacy
An identity verification technique that matches the structure of a person’s face to his/her picture
Cameras scan the peaks and valleys of features
An invasion of privacy?
Critics oppose both clandestine capture (the scanning of faces without consent) and tracking (the use of this technology to monitor a person’s movement)