1. Technology Guide 1
Hardware

2. What is a Computer System
Computer hardware is composed of the following components:
Central processing unit (CPU)
Input devices
Output devices
Primary storage
Secondary storage
Communication devices

3. Computer System

4. Representing Data
Today’s computers are based on integrated circuits (chips), each of which include millions of subminiature transistors.
The “on-off” states of the transistors are used to establish a binary 1 or 0 for storing one binary digit, or bit.
A byte is a sufficient number of bits to represent specific characters— usually 8 bits.
The two most commonly used coding schemes are:
ASCII (American National Standard Code for Information Interchange)
EBCDIC (Extended Binary Coded Decimal Interchange Code)

5. Representing Pictures
Pictures are represented by a grid overlay of the picture.
The computer measures the color (or light level) of each cell of the grid. The unit measurement of this is called a pixel.

6. Representing Time
Time is represented in fractions of a second. The following are common measures of time:
Millisecond 1/1000 seconds
Microsecond 1/1,000,000 seconds
Size is measured by the number of bytes. Common measures of size are:
Kilobyte 1,000 bytes (actually 1024)
Megabyte 1,000 kilobytes 106 bytes

7. Evolution of Computers
The first generation of computers, 1946–1956
Used vacuum tubes to store process information
The second generation of computers, 1957–1963
Used transistors for storage and processing information
Third-generation of computers, 1964–1979
Used integrated circuits for storing and processing information
Early to middle fourth-generation computers, 1980–1995
Used very large-scale integrated (VLSI) circuits to store/ process information

8. Evolution of Computers (cont.)
Late fourth-generation computers, 1996–present
Use grand-scale integrated (GSI) circuits to store/ process information
Fifth Generation of Computers, Present
Uses massively parallel processing to process multiple instructions simultaneously
Future Generations of computers
DNA Computers
Optical Computers

9. Types of Computers Supercomputers Massively parallel computers
The computers with the most processing power
Use the technology of parallel processing
Massively parallel computers
Uses a large number of processors
The processors divide up and independently work on small chunks of a large problem
Mainframes
Not as powerful and generally not as expensive as supercomputers
Most often used by large corporations

10. Types of Computers (cont.)
Minicomputers (midrange computers)
Smaller and less expensive than mainframe computers
Designed to accomplish specific tasks
Workstations
Based on RISC (reduced instruction set computing) architecture
Provide high-speed calculations and high-resolution graphic displays
Microcomputers (micros or personal computers, PCs)
The smallest and least expensive category of general-purpose computers
Four classifications based on their size:
Desktops - Note books
Laptops - Palmtops

11. Types of Computers (cont.)
Personal digital assistant (PDA)
A palmtop computer that combines a fast processor with a multitasking operating system
Smart Card
An even smaller form of computer that has resulted from the continuing shrinkage of integrated circuits
Uses for smart cards are appearing rapidly and include;
Checkbooks
a bank ATM that can “deposit money” into the card’s memory for “withdrawal” at retail stores
transporting data between computers

12. Network Computers & Terminals
Network computer (NC)
“thin” computer
desktop terminal that does not store software programs or data permanently
Windows-based terminals (WBTs)
subset of the Network computer
reduces maintenance & support costs

13. Central Processing Unit
The central processing unit (CPU) is also referred to as a microprocessor because of its small size.
The CPU is the center of all computer-processing activities, where all processing is controlled, data are manipulated, arithmetic computations are performed, and logical comparisons are made.
The CPU consists of the;
Control unit
Arithmetic-logic unit (ALU)
Primary storage (or main memory)

14. Primary Storage
Primary storage, or main memory, stores data and program statements for the CPU. It has four basic purposes.
To store data that have been input until they are transferred to the ALU for processing.
To hold data after processing until they are transferred to an output device.
To hold program statements or instructions received from input devices and from secondary storage.

15. Buses
A bus is a channel (or shared data path) through which data is passed in electronic form.
Three types of buses link the CPU, primary storage, and the other devices in the computer system.
The data bus moves data to and from primary storage.
The address bus transmits signals for locating a given address in primary storage.
The control bus transmits signals specifying whether to “read” or “write” data to or from a given primary storage address, input device, or output device.

16. Control Unit
The control unit reads instructions and directs the other components of the computer system to perform the functions required by the program.
The control unit does not actually change or create data; it merely directs the data flow within the CPU.
The Machine cycle is the series of operations required to process a single machine instruction.
Each machine cycle consists of the;
instruction cycle, and the
execution cycle

17. Memory There are two categories of memory: The register
This is part of the CPU and is very fast.
It allows for the fast storage and retrieval of data and instructions during the processing.
Internal memory chips
These reside outside the CPU and are slower.
The internal memory is used to store data just before they are processed by the CPU.

18. Random-Access Memory
Random-access memory (RAM) is the place in which the CPU stores the instructions and data it is processing.
The advantage of RAM is that it is very fast in storing and retrieving any type of data.
Dynamic random access memories (DRAMs) are the most widely used RAM chips.
Synchronous DRAM (SDRAM) is a relatively new and different kind of RAM.

19. Read-Only Memory
Read-only memory (ROM) is that portion of primary storage that cannot be changed or erased.
Programmable read-only memory (PROM) is a memory chip on which a program can be stored.
Erasable programmable read-only memory (EPROM) is a special type of PROM that can be erased by exposing it to ultraviolet light.

20. The speed of a chip depends on four things:
Microprocessor Speed
The speed of a chip depends on four things:
Clock speed
Word length
Data bus width
Design of the chip

21. Parallel Processing
A Parallel Processing System is a computer system with two or more processors.
Today, some PCs have 2 to 4 processors while workstations have 20 or more.
Processing data in parallel speeds up processing.
Massively parallel processor (MPP) systems are systems with large numbers of processors.

22. Microprocessor Evolution
Microprocessors have become dramatically faster, more complex, with increasing numbers of transistors embedded in the silicon wafer.
Chips are now being manufactured from gallium arsenide (GaAs), a semiconductor material inherently much faster than silicon.
Intel has incorporated MMX (multimedia extension) technology in its Pentium microprocessors.
MMX improves video compression/decompression, image manipulation, encryption, and input/output processing.

23. Microprocessor Architecture
Computer architecture refers to the arrangement of the components and their interactions. It includes;
the instruction set
the number of the processors
the structure of the internal buses
the use of caches
the types and arrangements of input/output (I/O) device interfaces.
An instruction set is the set of machine instructions that a processor recognizes and can execute.
Today, there are two main instruction set strategies:
Complex instruction set computer (CISC)
Reduced instruction set computer (RISC)

24. Input/ Output Devices
The input/output (I/O) devices of a computer are not part of the CPU, but are channels for communicating between the external environment and the CPU.
Input devices deliver data and instructions into the computer.
Output devices provide processing results.
I/O devices are subclassified into the following categories;
Secondary storage devices: primarily disk and tape drives
Peripheral devices: any input/output device that is attached to the computer

25. Secondary Storage
Secondary Storage is separate from primary storage and the CPU, but directly connected to it. It provides the computer with vastly increased space for storing and processing large quantities of software and data.
Secondary storage media include;
Magnetic tape
Magnetic disk
Magnetic diskette
Optical storage
Digital videodisk (DVD)

26. Input Devices
Users can command the computer and communicate with it by using one or more of the following input devices.
Keyboard. The most common input device is the keyboard. The keyboard is designed like a typewriter but with many additional special keys.
Mouse. The computer mouse is a hand-held device used to point a cursor at a desired place on the screen.
Touch Screen. The user activates an object on the screen by touching it with his or her finger.

27. Input Devices (cont.)
Touchpad. A touchpad or trackpad is a small, flat, rectangular pointing device that is sensitive to pressure and motion.
Light Pen. A light pen is a special device with a light-sensing mechanism, which is used to touch the screen.
Joystick. Joysticks are used primarily at workstations that can display dynamic graphics. They are also used in playing video games. The joystick moves and positions the cursor at the desired object on the screen.

28. Input Devices (cont.)
Automated Teller Machines (ATMs). ATMs are interactive input/output devices that enable people to obtain cash, make deposits, transfer funds, and update their bank accounts instantly from many locations.
Electronic Form. In form interaction, the user enters data or commands into predesignated spaces (fields) in a form. The headings of the electronic form serve as a prompt for the input.
Whiteboard. A whiteboard is an area on a display screen that multiple users can write or draw on.

29. Source Data Automation
Source data automation captures data in computer-readable form at the moment the data are created.
Examples of Source Data Automation:
Point-of-sale systems
Optical bar-codes
Code scanners
Handwriting recognizers
Voice recognizers
Magnetic ink character readers (MICR)
Digitizers
Digital Cameras

30. Output Devices

31. Output Devices (cont.)
The output generated by a computer can be transmitted
to the user via several devices and media.
Monitors
Impact Printers
Nonimpact Printers
Plotters
Voice Output

32. Communications Media Computer Motion image CRT and terminals CD-ROM
Computer interactive videodisc
Digital video interactive
Compact disc interactive
Computer simulation
Motion image
Videodisc (cassette)
Motion pictures
Broadcast television
Teleconference/videoconference
Animation & Virtual Reality

33. Communications Media (cont.)
Projected still visuals
Slide & Overhead
Graphic materials
Pictures
Printed job aids
Visual Displays
Text
Printouts
Audio
Tape/cassette/record
Teleconference
Audioconference
Sound digitizing
Microphone
Compact disc
Music