CIS 9000 1

Chapter 6:

Information TechnologyHardware

CIS 9000 2

Computer Hardware

What is a computer system? Number Systems and Character

Representation The CPU and primary storage Secondary Storage New Trends in Computer Hardware

CIS 9000 3

What is a computer system?

Central Processing Unit (CPU) Primary storage Input devices Output devices Communication devices

CIS 9000 4

Components of Hardware

CPU

PrimaryStorage

SecondaryStorage

CommunicationsDevices

OutputDevices

Input Devices

Buses

CIS 9000 5

Number Systems

Humans represent numbers in Base10Humans represent numbers in Base10

10100 0 101033 101022 101011

77999911

1 x 101 x 1033 = 1,000 = 1,0009 x 109 x 1022 = 900 = 9009 x 109 x 1011 = 90 = 907 x 107 x 1000 = 7 = 7

Decimal Value:Decimal Value:

Numeric Expression:Numeric Expression:

Digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9Digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

CIS 9000 6

Computers use Base2 (0, 1)

11 00 11 11 11 00 11

22002266 2255 2244 2233 2222 2211

Decimal Value:Decimal Value:6464 3232 1616 88 44 22 11

Numeric Expression:Numeric Expression:

Base2: 1011101 Base2: 1011101 == Base10:Base10:1 x 21 x 266

0 x 20 x 255

1 x 21 x 244

1 x 21 x 233

1 x 21 x 222

0 x 20 x 211

1 x 21 x 200

646400161688440011

== 9393

CIS 9000 7

Character representation

ASCII: American Standard Code for ASCII: American Standard Code for Information Interchange (ASCII-8)Information Interchange (ASCII-8)

Formula: 128 + 32 + Position in AlphabetFormula: 128 + 32 + Position in Alphabet

10100001: ‘A’10100001: ‘A’10100010: ‘B’10100010: ‘B’10100011: ‘C’10100011: ‘C’10100100: ‘D’10100100: ‘D’10100101: ‘E’10100101: ‘E’

01010000: ‘0’01010000: ‘0’01010001: ‘1’01010001: ‘1’01010010: ‘2’01010010: ‘2’01010011: ‘3’01010011: ‘3’01010111: __01010111: __

CIS 9000 8

Size of data storage

Bit: 1 or 0 Byte: 8 bits (equals 1 character) Kilobyte: 1,000 bytes (exactly

1024) Megabyte: 1,000,000 bytes Gigabyte: 1,000,000,000 bytes Terabyte: 1,000,000,000,000 bytes

CIS 9000 9

Measurements of Time

Millisecond: 1/1,000 second Microsecond: 1/1,000,000 second Nanosecond: 1/1,000,000,000

second Picosecond: 1/1,000,000,000,000

second

CIS 9000 10

Microprocessor: Very large-scale integrated circuit technology that integrates the computer's memory, logic, and control on a single chip.

Central Processing Unit (CPU) Area of the computer system that manipulates symbols, numbers, and letters, and controls the other parts of the computer system.

Primary Storage Part of the computer that temporarily stores program instructions and data being used by the instructions.

Arithmetic-logic Unit (ALU) Component of the CPU that performs the principal logic and arithmetic operations of the computer.

Control Unit Component of the CPU that controls and coordinates the other parts of the computer system.

CIS 9000 11

Primary Storage

RAM: Random Access Memory

ROM: Read Only Memory PROM: Programmable ROM Cache Memory

CIS 9000 12

What is RAM? RAM: Random Access Memory Primary Storage No moving parts Accessed at electronic speeds Volatile (electrical interruption loses

data)

CIS 9000 13

Understanding RAM Programs and data are transferred to

RAM from input devices or secondary storage

Nothing happens until data and program instructions are transferred from RAM to the CPU

Cache: a special kind of RAM, faster, more expensive, of smaller capacity

CIS 9000 14

What is the difference between RAM and a floppy diskette?

RAM is primary storage, floppies are secondary storage.

RAM is volatile, floppies are non-volatile.

RAM is online, floppies are stored off-line and placed online as needed.

RAM represents bits with electrical current, floppies represent bits with a magnetic field.

CIS 9000 15

Control Unit

Reads and interprets program instructions Direct internal processor components Moves programs and data in & out of RAM Components

Decoder: to decode instruction Registers: to store instruction, data Accumulator: to store results

CIS 9000 16

Arithmetic & Logic Unit

Performs computations Performs logic operations (>,

<, =, AND, OR, XOR)

CIS 9000 17

Machine Cycle Series of operations that are necessary

to operate a single program instruction Involves the following elements:

Control Unit ALU Primary Storage

CIS 9000 18

Machine Cycle cont.

1. Fetch InstructionRAM to the Control Unit

2. Decode Instruction

Control Unit

3. Execute InstructionALU

4. Place Resultsin Memory

ALU to RAM

InstructionTime

ExecutionTime

CIS 9000 19

Processor Characteristics

Word Size Speed

Micros: Megahertz (MHz) Mainframes: MIPS Supercomputers: FLOPS/GFLOPS

RISC vs CISC architecture Data Bus Width

CIS 9000 20

Processor Terms

RISC (reduced instruction set computing)Microprocessors that “have only the most frequently used instruction embedded in them”

MIPS: Millions of Instructions per second. MIPS are used to measure the speed of mainframes.

FLOPS: Floating point operations per second. A single floating point operation consists of multiple instructions (e.g. division). FLOPS are used to measure the speed of supercomputers.

CIS 9000 21

Evolution of Computer Hardware

Vacuum tube technology - 1946-56 Transistors - 1957-63 Integrated Circuits - 1964-79 VLSI (Very Large Scale Integrated

Circuits) - 1980-present

CIS 9000 22

Popular Microprocessors

Intel’s 80486, 100 MHz Intel’s Pentium, 200+ MHz Intel’s Pentium II, 333 MHz Intel’s Pentium III, 700+ MHz Motorola, IBM, Apple’s PowerPC,

450+ MHz

CIS 9000 23

Classifying computers

Personal Computer (PC) Small desktop or portable computer

Workstation Desktop computer with powerful graphics and mathematical

capabilities Server

Computer designed to provide resources to other computers over a network

Mainframe Used for high volume of business processing

Supercomputer Designed to support complex computations

CIS 9000 24

Classifying computers continued

Differences blurring due to increased processor speed and storage capacities.

Classes such as “minicomputers” are being eliminated.

I/O intensive applications served by mainframes.

Processing intensive applications served by supercomputers.

CIS 9000 25

Secondary Storage Magnetic Tape Magnetic Disks

hard disks floppy disks

Optical Laser Disks Audio CDs CD-ROMs DVDs W/R optical disks

CIS 9000 26

Sequential Processing

P ro g ra m

C P U

P ro g ra m

P ro g ra m

C P U

Tas k 1

Tas k 2

R e s u l t

R e s u l t

Parallel Processing:Type of processing in which more than one instruction can be processed at a time by breaking down a problem into smaller parts and processing them simultaneously with multiple processors.

C P UTask

2

P ro g ra m

C P UTask

3

R e s ult

C P UTask

4

C P UTask

1

C P UTask

5

CIS 9000 27

Client/Server Computing

R e q u e s t s

D at a an d S e r v i c e s

C lie n t

S e rv e r

Us e r I n te rfa ceA pplica t io n fu n ct io n

D a taA pplica t io n fu n ct io nNe two rk re s o u rce s

CIS 9000 28

Computer Networks and Client/Server Computing

Distributed processing: The distribution of computer processing work among multiple computers linked by a communications network.

Centralized processing: Processing that is accomplished by one large central computer.

Client/server computing: A model for computing that splits processing between "clients" and "servers" on a network, assigning functions to the machine most able to perform the function.

Client: The user point-of-entry for the required function in client server computing. Normally a desktop computer, workstation, or laptop computer.

Downsizing: The process of transferring applications from large computers to smaller ones.

CIS 9000 29

Network Computers

Network computer (NC) Simplified desktop computer that does not store software programs or data permanently. Users download whatever software or data they need from a central computer over the Internet or an organization's own internal network.

Total cost of ownership (TCO) Designates the total cost of owning technology resources, including initial purchase costs, the cost of hardware and software upgrades, maintenance, technical support, and training.

CIS 9000 30

Magnetic Tapes In the past, information systems used

magnetic tapes for sequential processing.

Today, magnetic tapes are primarily used for: Backup of valuable files Archiving files File portability between computers

CIS 9000 31

Magnetic Disks

Provide random/direct processing of files Hard disks Floppy disks: Removable magnetic disk storage

primarily used with PCs. 5 1/4 inch (1.2 MB) 3 1/2 inch (1.44 MB)

Zip Drives RAID (Redundant Array of Inexpensive Disks) Disk

storage technology to boost disk performance by packaging more than 100 smaller disk drives with a controller chip and specialized software in a single large unit to deliver data over multiple paths simultaneously.

CIS 9000 32

Magnetic Disks

Tracks

Sectors

Read/Write Head

Access Arm

CIS 9000 33

Optical Disks

Laser technology Audio CDs CD-ROM DVDs R/W CD ROMS

CIS 9000 34

Input Devices

Computer mouse: Handheld input device whose movement on the desktop controls the position of the cursor on the computer display screen.

Touch screen Input device technology that permits the entering or selecting of commands and data by touching the surface of a sensitized video display monitor with a finger or a pointer.

CIS 9000 35

Input Devices Source data automation: Input technology that captures

data in computer-readable form at the time and place the data are created.

Optical character recognition (OCR): Form of source data automation in which optical scanning devices read specially designed data off source documents and translate the data into digital form for the computer.

Bar code: Form of OCR technology widely used in supermarkets and retail stores in which identification data are coded into a series of bars.

Magnetic ink character recognition (MICR): Input technology that translates characters written in magnetic ink into digital codes for processing.

CIS 9000 36

Input Devices

Pen-based input: Input devices such as tablets, notebooks, and notepads consisting of a flat-screen display tablet and a pen-like stylus that digitizes handwriting.

Digital scanners: Input devices that translate images such as pictures or documents into digital form for processing.

Voice input devices: Technology that converts the spoken word into digital form for processing.

Sensors: Devices that collect data directly from the environment for input into a computer system.

CIS 9000 37

Batch and On-Line Input and Processing

Batch processing: A method of collecting and processing data in which transactions are accumulated and stored until a specified time when it is convenient or necessary to process them as a group.

On-line processing: A method of collecting and processing data in which transactions are entered directly into the computer system and processed immediately.

CIS 9000 38

A Comparison of Batch & On-line Processing

E r r o rR e p o r t s

K e yb o ar dIn p u t

M a s te rfile

R e po rts

E n t e rd i r e c t l y

V a l i d a t e an du p d at e

T ra ns a c tio nsg ro upe din ba tc he s

B atch P roces s in g

S o rte dtra ns a c tio nfile

O ldm a s te rfile

N e wm a s te rfile

O n -lin e P roces s in gT ra n s a c tio n s

P ro c e s s /upda te

m a s te r fileIm m e dia teinput

Im m e dia tefile upda te

Im m e dia tepro c e s s ing

CIS 9000 39

New Trends in Computer Hardware

Multimedia: Technologies that facilitate the integration of two or more types of media such as text, graphics, sound, voice, fulI-motion video, or animation into a computer based application.

Streaming technology Technology for transferring data so that they can be processed as a steady and continuous stream.

Network Computers. Massively Parallel Computers: Computers that

use hundreds or thousands of processing chips to attack large computing problems simultaneously.

CIS 9000 40

New Trends in Computer Hardware

Smart card: A credit card-size plastic card containing embedded storage and a microprocessor.

More Integration. Lower Costs. Optical computers. Solid-state storage devices.