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Review For Final

© Abdou Illia

(Fall 2009)

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Computer Hardware

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The Core Computer Components

Four subsystems in a computer system:1. Input subsystem 3. Output subsystem2. Processing subsystem 4. I/O (Storage) subsystem

InputProcess

Output

Input/Output (storage)

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Output Devices Monitors

Cathode ray tube (CRTs) Liquid crystal displays (LCDs) Quality of display

Resolution in pixels (e.g. 640 x 480) Dot pitch in millimeters (.26 to .28) Active-Matrix vs. Passive-Matrix display

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Printers Speed and resolution

Pages per minute (PPM) Inkjet: Dots per inch (DPI)

Number of ink dots to fill a square inch Higher DPI = greater page clarity

Impact printers Create image by striking paper and ribbon Dot-matrix printers = most common impact printers

Non-impact printers Create image by spraying or rolling ink on the page

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I/O or Secondary Storage devices

Secondary compared to the main primary memory called RAM Nonvolatile1 storage of digital data Could be Magnetic or Optical Magnetic storage (i.e. data stored on magnetically coated

surface) Examples: Magnetic tape, Hard disk, floppy disk Sequential access (e.g. tape) or direct access (e.g. HDD) Hard disk disks

many standards: Parallel ATA (PATA) or IDE (Integrated Drive Electronics) Serial ATA (SATA)2

SCSI (Small Computer System Interface) SCSI provides disk fault-tolerance by using RAID – Redundant Array of

Inexpensive Disks; that is multiple disks set together to provide continued service in case one disk fails.

Disk speed: Transfer rate in MBps (Megabytes per second) Average Read Time (in milliseconds or ms) Platter rotation speed in RPM (5400/7200/10,000/15,000)

1. Means that the stored data wouldn’t disappear (or be deleted) in case of power shortage2. In SATA and PATA, ATA stands for Advanced Technology Attachment

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Measuring Storage Capacity

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Processing subsystem Motherboard: chipset that all components connect to

Two major components in processing subsys. CPU (Central Processing Unit) or Processor(s) Primary Storage:

Random Access Memory (RAM) Read Only Memory (ROM)

Busses that transfer data

CPU

Primary Storage

Othercomponents

on the Motherboard

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Central Processing Unit

Clock: generate time that synchronize other components

ICU: Fetches instructions from RAM

ALU: Execute instructions (arithmetic & logic operations)

Registers: Store control information, data, intermediate results

Processor

Clock

Instruction Control Unit

Arithmetic Logic Unit

Registers

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CPU speed Speed measured in hertz

Hertz = # of instructions executed per second Megahertz = 1 million of instructions per second Gigahertz = 1 billion of instructions per second

Intel- Celeron

- Pentium 3, Pentium 4, Pentium 4 Xeon, Dual Core

Advanced Micro Devices (AMD)

- K6 series processors (which compete with Intel Pentium 3)

- Athlon series (which compete with Intel Pentium 4)

IBM

- PowerPC 740, 750, 750FX, 750GL, 750GX

Major Processor manufacturers

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Primary Storage

RAM holds running programs and the data they use

ROM contains critical programs such as those that boot the computer

Primary Storage

RAM

ROM

Computer’s memory stored on semiconductor chips Two categories:

RAM (Random Access Memory) which is volatile Synchronous Dynamic RAM (SDRAM) Double Data Rate SDRAM or DDR SDRAM

ROM (Read-Only Memory) which is non-volatile

Capacity in Megabytes (MB) or Gigabytes (GB)

Program Data

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Summary QuestionsBook Notes

1) Name two devices that could be used for both input and output.

2) What is the difference between: (a) a Kilobyte and a Gigabyte? (b) a Megabyte and a byte?

3) What is the function of the Instruction Control Unit or ICU found in the processing subsystem?

4) Explain the difference between RAM and ROM.

5) What is pixel? What is dot pitch

6) What is a byte?

7) What is a Hertz?

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Network Technology

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Computer Network An interconnection of computers and

computing equipment using either wires or radio waves over small or large geographic distances

“Connect to GHI”ABC

DEF GHI

JKLMNO

Once connected to the network, the computer (or another device) becomes a network node

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Transmission Media Physical media

Transmission media used to physically connect nodes in to the network

Transmits electrical or optical signals Could be cooper wire or fiber optic cable

Physical

Wireless

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Transmission Media (Continued) Twisted Pair

Category Use Signal Data rate Distance Problem

Category 1 Telephone Analog/Digital <100Kbps 3-4 miles Security, noise

Category 2 T1, ISDN Digital <2 Mbps 3-4 miles Security, noise

Category 3 LANs Digital 10 Mbps 100 m Security, noise

Category 4 LANs Digital 20 Mbps 100 m Security, noise

Category 5 LANs Digital 100 Mhz 100 m Security, noise

Category 6 LANs Digital 250 Mhz 100 m Security, noise

Category 7 LANs Digital 600 Mhz 100 m Security, noise

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Wireless Media Uses electromagnetic waves or electromagnetic radiation for

data transmission Propagation through space, and indirectly, through solid objects Two kinds of wireless media used

Radio waves (radio Frequency) Affected by Multipath interference Highly vulnerable to snooping Limited distance Blocked by thick objects

Infrared light Close proximity and “line of sight” location required

LaptopComm. Tower

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Network Topologies The configurations of network components

How physically the network looks like How logically data is transferred on the network

Widely used network topologies: Bus Star Ring (Mesh, not common in business setting)

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Bus Network Topology Most simple network topology All devices connected to a common central

cable called a “bus” Inexpensive If cable fails, the entire network will shut

down

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Star Network Topology Centered around

central device called a hub or a switch

All network nodes connect to the hub/switch

Easy to install and update

If hub fails, network fails

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Ring Topology

Node connected to a logical ring in a central device called MAU

More reliable than bus or star Only one node sends at a

time (no collisions)

Expensive and limited speed

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Network Architecture

Defines how the processing takes place on the network

Two primary types Client-server Peer-to-peer (P2P)

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Summary Questions

Malaga Notes

1) What is a node?

2) Name physical and wireless media used in networking

3) What transmission media is used for the telephone?

4) What are the main network topology? What are the differences between them?

5) Distinguish between Client-server and P2P networks

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The Internet and eBusiness

See Exam 3 Review (Part 2) PowerPoint notes in Final

Review Section of course web site

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Managing SecuritySee Exam 3 Review (Part 2)

PowerPoint notes in Final Review Section of course web

site

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Managing the Development and

Purchase of ISSee Exam 3 Review (Part 1)

PowerPoint notes in Final Review Section of course web

site