1 Configuring Internet- related services (April 22, 2015) © Abdou Illia, Spring 2015.
1 Review For Final © Abdou Illia (Fall 2007). 2 Computer Hardware.
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Transcript of 1 Review For Final © Abdou Illia (Fall 2007). 2 Computer Hardware.
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The Core Computer Components Three subsystems in a computer system:
1. Input subsystem2. Processing subsystem3. Output subsystem
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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
Touch screens Input and output via display device
Monitor size Common resolution
15 inches 640 x 480
17 inches 800 x 600 or 1024 x 768
19 inches 1024 x 768 or 1280 x 1024
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Printers Speed and resolution
Pages per minute (PPM) 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 devices or Secondary Storage Nonvolatile storage of digital data Magnetic or optical Magnetic storage (Floppy disk, Magnetic
tape, Zip disk, Hard disk) Sequential access (tape) or direct access (HDD) Hard disk drives
Two main standards: IDE (Integrated Drive Electronics) aka ATA (AT Attachment) SCSI (Small Computer System Interface)
SCSI allows disk fault-tolerance through RAID – Redundant Array of Inexpensive Disks
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)
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Processing subsystem Two major components
CPU (Central Processing Unit) or Processor(s) Primary Storage:
Random Access Memory (RAM) Read Only Memory (ROM)
CPU
Primary Storage
Busses that transfer data
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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 three 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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Main Types of Software Systems software
Programs that manage computer hardware and application software
Three types of systems software: Operating systems (e.g. Windows, Linux) Language translators (C++ compiler, VB compiler) Utility programs (e.g. Norton Utilities)
Systems Software
Application Software
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Main Types of Software Application software
Programs that allow users to accomplish specific tasks
Examples Word processing Web browser Tax preparation Data management Desktop publishing E-mail Groupware Presentation graphics Programming editors Spreadsheet
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Operating Systems (OS) Software platform on which other programs run Provides a connection between application
programs and the computer hardware Major tasks
Starting the computer Managing files Managing Programs and Memory (RAM) Ensuring security Providing a user interface
Example of OS: Linux, Windows XP, Windows 2000, UNIX.
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■ A technique that “extends” primary memory (RAM) by using secondary storage devices
■ Needed when there is not enough RAM to hold programs
Managing Memory: Virtual Memory
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Summary QuestionsBook Notes
1) What are the functions (or tasks) of an OS?
2) What do application programs allow?
3) What is the function of the Instruction Control Unit or ICU found in the processing subsystem?
4) What is meant by virtual memory?
5) What is meant by multiprogramming?
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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
Fiber optic Thin glass fibers surrounded by coating Uses lasers for light source Very fast (10+ Gbps, 100 miles without any repeater) Very secure
SourcePhoto diode(LED or LD)
DestinationPhoto receptor(LED or LD)Fiber optic cable
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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
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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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Protocols An agreed upon set of rules that govern
communications in a network Example: TCP/IP suite, Ethernet, Token Ring
Computer 1
Rules for Task 1
Rules for Task 2
Rules for Task 3
Rules for Task 4
Rules for Task 5
Computer 2
Rules for Task 1
Rules for Task 2
Rules for Task 3
Rules for Task 4
Rules for Task 5
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TCP/IP TCP/IP suite is named after its two main protocols: TCP and IP Transmission Control Protocol (TCP)
Provides a reliable byte-stream transfer service between two endpoints on an internet
Internet Protocol (IP) Defines a delivery mechanism for packets of data sent between all
systems on an Internet It’s the protocol suite for the Internet
Task Sample rules/protocols
Application HTTP, FTP, SMTP
Transport TCP, UDP
Internet IP
Physical Ethernet, Token Ring, PPP, Modem standards
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Ethernet
A set of rules for transmitting messages in LANs Most widely used protocol for LANs Uses a method called CSMA/CD* for wired LANs
1) All computers (“carriers”) listen (“sense”) for traffic on the LAN2) If no traffic, computer that wishes to transmit may transmit3) If collision occurs, computers must wait a random amount of time4) The computer with smallest random number send again first.
* Carrier Sense Multiple Access with Collision Detection
CSMA/CD*
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Token Ring Other set of rules for transmitting messages in LANs Only one node “talks” at a time A node only transmit when it receives a special packet called
a “Token” Only one Token on the ring No collisions
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Transmitting Data in a Network
Two major techniques:
1) Circuit switching network Traditionally used for voice transmission
2) Packet switching network Used for computer data transmission.
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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
6) Could collisions occur in Token Ring networks? In Ethernet networks?
7) What is TCP/IP?
8) Distinguish between circuit switching and packet switching.