Computers: Information Technology in Perspective
By Long and Long
Copyright 2002 Prentice Hall, Inc.
Jaana Holvikivi 2012

6.2
Quit
Seeking ways to interface, or connect, a diverse set of hardware, software, and databases.

6.3
Quit
Companies must cooperate
 Internally (for company resources) via
 Intracompany networking
 Intranets
 Externally (for world competition) via
 Intercompany networking
 Business-to-business (B2B)
 E-commerce (electronic commerce)
 Extranets

6.4
Quit
WAN
Wide Area Network
Wireless Local Area Network
WLAN
LAN
Local Area Network
PANS & BANs & NFC
Potentially any / personal area network service

6.5
Courtesy of
Orbital
Sciences
Corporation
Quit
 Applications software & groupware
 Links to other LANs: campus networks
 Communications capabilities: within
LAN, internet, remote computers
 I/O devices - printers
 Storage devices - file servers, central back-ups
 Data base servers
 Security

6.6
Quit
 One node at a time can send


Token Access Method
Ethernet protocols
 Transmission media
 Twisted-pair, coax, and fiber optic cable
 Wi-Fi
 LAN Servers



File Server
Print Server
Communications Server

6.7
Quit
 Workstations
 PC, NIC (integrated), software
 LAN Servers
 computer, NIC, software
 LAN operating system
 management of resources
 access control
 Protection
 Firewall, UTM (Unified Threat
Management)

6.8
Quit
 Operating Systems
 Peer to Peer LANs
 LANs with dedicated servers: Novell
Netware, Windows Server
 Applications Software
 Shared software
 Groupware
 Networks on the Fly
 Portable networks

6.9
Quit
LAN storage options
Network Access storage

6.10
Data Communications Channel
Quit
 Same as line, link or pipe
 Special hardware transmits the digital information between computers

6.11
Quit
 Bandwidth is channel capacity
 # of bits channel can transmit/second
 56 K bps (bits per second) to over 100T bps
 Bps nearly same as baud
 High bandwidth = Broadband
 Low bandwidth = Narrowband
 Broadband Access is high-speed
Internet access

6.12
Quit
 Sending photos to be printed
 The upload speed is 512 kbps
 One file is about 1 MB
 There are 41 photos
 How long does it take?

6.13
Quit
 Downloading security software
 The download speed is max 2 Mbps
 Realistic maximum is 210 kB/s
(achieved 70% time)
 The update size 108660 kB
 How long does it take at least?

6.14
Quit
Coaxial cable
Twisted-pair wire
Wireless
Fiber optic cable

6.15
Quit
Telephone company services
 POTS (Plain old telephone service)
 56 K bps
 ISDN (Integrated Services Digital Network)
 Line & Modem 128 K bps
 DSL (Digital Subscriber Line)
 Line & Modem 1.5 to 24 M bps
Transmission
Media

6.16
Quit
 Minimum signal distortion
 Hundreds of times faster than POTS
 100 times faster than ISDN
 Ethernet standard 10Base-T in 1990
 100Base-Tx in 1995 (100Mbits)

6.17
Quit
 Carries data as laser-generated pulses of light
 Foundation transmission medium for Internet backbone
 Better for data security
 40 and 100 Gb Ethernet standards in 2010
 max bandwidth 14 Tb/s over 1,2 km

Quit 6.18
 Carries data via microwave or radio signals
 Transmission is line-of-sight
 Use transceivers/repeater stations
 Satellites
 Eliminate line-of-sight limitation
 Geosynchronous orbit
 Everyone has satellite access
 Need dish and modem
 Somewhat slower than DSL and Cable

6.19
Quit
 Rules that govern the way data are transmitted
 TCP/IP (Transmission Control Protocol/Internet
Protocol

6.20
Quit
 Hardware and software used to ease the problems of linking incompatible networks
 Routes messages to proper destinations
 Backbone is a system of routers and transmission media that link computers.

6.21
Quit
Network Topology is a description of the possible physical connections within a network. It is a configuration of hardware and it shows which pairs of nodes can communicate.
Networks

6.22
Quit
Star
Ring
Bus

6.23
Quit
 Services distributed over network
 Google applications, Youtube,
Facebook, etc.
 Servers, data and applications
 Case NYTimes archives
 4tB TIFF-files > 11 mil. PDFs
 Using Amazon EC2 servers: 100 servers, 24 hours, cost 240$

The End
Computers: Information Technology in Perspective
By Long and Long
Copyright 2002 Prentice Hall, Inc.