Transcript Computing Basics

Computing Basics
Honolulu Community College
Cisco Academy Training Center
Semester 1
Version 2.1.1
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Overview
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Components of the computer.
Role of the computer in networking.
 Internet
is like a tree, and computers are like
leaves on the tree.
 Computers are sources and receivers of
information on the Internet.

Computers are an integral part of a network, and
they play a vital role in the world of work.
 Many
business applications like spreadsheets,
word processors, browsers, etc.
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Major Components of a PC

Small, discrete components:
 Transistor
 Integrated
circuit (IC)
 Resistor
 Capacitor
 LED
(light emitting diode)
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Major Components of a PC (cont.)

Personal computer subsystems:
 CPU
(central processing unit)
 Memory:
 RAM,
ROM
 CD-ROM drive
 Floppy disk drive
 Bus
 System
unit
 Expansion slots
 Power supply
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Major Components of a PC (cont.)

Backplane components:
 Backplane
 network
card (NIC) or LAN adapter
 Video card
 Sound card
 Parallel ports
 Serial ports
 Mouse port

For a laptop, cards and slots are referred to as
PCMCIA.
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Information Flow in a Computer

Some important information flow:
 Boot
instructions (ROM).
 Software applications (moved into RAM).
 Application information (data) -stored in RAM.
 Saved information - from RAM to storage device.
 Exported information - from RAM and CPU to
external devices.
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Almost all data flows in parallel through the bus.
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NIC
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Provides network
communications capabilities.
Also called a LAN adapter.
Communicates serially with
network, in parallel with computer.
Requires an IRQ, I/O address, and upper
memory addresses (for DOS or Windows).
3 factors in selecting NIC.
 Type
of network (Ethernet, Token Ring, or FDDI).
 Type of media.
 Type of system bus.
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Installing a NIC

You may need to install a NIC because:
 there
is none.
 NIC is bad or damaged.
 Need to upgrade from 10Mbps (standard
Ethernet) to 100Mbps (Fast Ethernet).
 Need to alter settings on a NIC using a
jumper.
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Configuring Network Settings on PC
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
Computer software - essentially to get the
computer to do what you want.
Procedure:
 1.select
the NIC for software configuration.
 2.input the correct TCP/IP address.
 3.adjust the display (if necessary).
 4.install and set up the browser.
 5.perform a few other tasks (if necessary).
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Web Browser

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Software application that interprets html
(hypertext markup language).
Two most popular browsers:
 Netscape
Communicator.
 Internet Explorer.

Terms:
 Hyperlinks
- commands that point to another
location in PC or on network.
 Plug-ins - special purpose software used to
display special or proprietary files in browser.
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Binary Number System
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Computers use binary signals either "on" or "off",
corresponding to 1 or 0.
This is a base 2 or binary number system.
 Bits
- individual 1 or 0.
 Byte - group of 8 bits.

In decimal, multipliers for each digit is a power of
10.
 368
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= 3x102 + 6x101 + 8x100
In binary, multipliers for each bit is a power of 2.
 1101
= 1x23 + 1x22 + 0x21 + 1x20 = 13(decimal).
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Binary to Decimal Conversion
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Converting binary to decimal is understanding
what a abase 2 number system is.
Each bit has a multiplier (power of 2).
 Powers
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of 2 are: 1, 2, 4, 8, 16, 32, 64, 128, etc.
10011101(binary) =
1x27
+ 0x26 + 0x25 + 1x24 + 1x23 + 1x22 + 0x21 + 1x20 =
128 + 0 + 0 + 16 + 8 + 4 + 0 + 1 = 157 in decimal.
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Decimal to Binary Conversion
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Note that any decimal number is made up of a
unique sum of powers of 2.
Ex1: 25 decimal = 16 + 8 + 1
 In
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Ex2: 107 decimal = 64 + 32 + 8 + 2 + 1
 In
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binary: 11001 (i.e. 1x16 + 1x8 + 0x4 + 0x2 + 1x1)
binary: 1101011
Note: Curriculum gives a general method to
convert any decimal to binary.
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Other Binary Calculations
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How many different values can you represent with
a 5 bit number?
general: 2n values with n bits.
 25 = 32 different values (from 0 to 31 in decimal).
 In
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What is the largest value you can represent with
an 8 bit number?
general, highest value is 2n-1, with n bits.
 28 - 1 = 255
 Note you can represent 256 values with 8 bits (from
0 to 255 in decimal).
 In
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What is Networking?
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Networking is the interconnection of
workstations, peripherals terminals and other
devices.
Networking addressed 3 problems:
 How
to avoid duplication of equipment and
resources.
 How to communicate efficiently.
 How to set up and manage a network.
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First networks were LANs (local area networks),
in a limited geographical area.
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Networking Protocols
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Networking protocols are a formal set of rules
and conventions, determining how devices
communicate on the network.
Protocols are like languages.
Devices must use the same protocol in order to
communicate.
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Evolution of Networking
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Early 1980s - rapid development of networking.
Manufacturers developed their own equipment,
leading to problem of compatibility between
equipment of different vendors.
Initial networks were LANs, generally using one
manufacturer’s equipment.
As business demands on networking grew,
networks grew to span large geographical areas,
and became WANs (wide area networks).
 WANS
can connect cities or even countries.
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WAN Technologies
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Some common WAN technologies are:
 modems
 ISDN
(Integrated Services Digital Network)
 DSL (Digital Subscriber Line)
 Frame relay
 ATM (Asynchronous Transfer Mode)
 The T (US) and E (Europe) Carrier Series:
 T1,
E1, T3, E3, etc.
 SONET
(Synchronous Optical Network)
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Digital Bandwidth
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Bandwidth - a measure of how much information
can flow from one place to another in a given
amount of time.
Bandwidth represents the capacity of network
connection (max possible data rate).
Bandwidth is measured in bits per second.
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Bandwidth is limited by the media
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Bandwidth is limited by the service
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Bandwidth is limited by the service
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Throughput
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The actual data rate you get.
Often far less then the maximum possible digital
bandwidth of the medium.
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Bandwidth vs Throughput
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When you design a network, you consider the
theoretical bandwidth. Your network will be no
faster than what your media will allow.
When you actually work on networks, you
measure throughput and decide if the throughput
is adequate for the user.
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File Transfer Time Calculations
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Calculations
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A 10 Mbps channel is used to transfer a 5Mbyte
file. What is the fastest time required to transfer
the file?
 T=S/BW
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= 5MB(8bits/byte)/10Mbps = 4 secs.
Due to congestion, the throughput of the channel
is only 40% of capacity. What is the actual time to
transfer the file?
 P = throughput = 40%(10Mbps) = 4Mbps.
 T= S/P = 5MB(8bits/byte)/4Mbps = 10 sec.
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Importance of Bandwidth
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It is finite.
It can save money.
It’s a key measure of network design and
performance.
It’s a key to understanding the Internet.
Demand for it increases constantly.
The End
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