Computer Basics

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Computer Basics
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Which computer should I buy? What do I get for
an extra 775 and do I even need it?
Desktop
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We need to understand several things before going
out and buying a computer.

• What are the different components of a computer
  system and how do they work?
• What are the different options available for
  each of these components?
• How will you be using your computer and therefore
  which components/options will you need?

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Basic Computer Components
Tower Box Central Processing Unit - CPU
(motherboard), power supply, Main Memory (RAM),
Auxiliary Memory devices Hard drive, CD, DVD,
etc.
CPU
Monitor
A Laptop with CPU, monitor, keyboard, touch pad
speakers
keyboard
mouse
speakers
printer
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How these Components Work Together
Main/Primary Memory (RAM)
Bus

• CPU- Central Processing Unit
• Control Unit
• Arithmetic Logic Unit (ALU)

Input devices
Monitor, Printer
Keyboard, Mouse
Bus
Auxiliary (Secondary) Memory
Hard drive CD R/W, DVD, floppy drive, ZIP drive,
Flash memory
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An inside view the Motherboard
Cards Video, Sound Network, Modem
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An inside view Hard Drive Bus cables
Hard Drive Bus
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CPU Central Processing Unit works with memory
to execute the arithmetic and logical processes
The performance of the CPU is dependent on both
its speed and memory
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1.66GHz vs 2.8GHz..whats a GHz?

• Clock Frequency This is also sometimes called
  the clock rate or clock speed. It is simply the
  reciprocal of the cycle time, and is therefore
  the number of cycles that occur each second (as
  opposed to the number of seconds per cycle). It
  is usually measured in MHz or GHz, where "Hz" is
  the abbreviation for Hertz, the standard SI unit
  for measuring frequency. One Hertz is one cycle
  per second. So for example, if a clock's cycle
  time is 1.25 ns, its frequency is
  1/(0.00000000125) 800,000,000 Hertz, or 800
  MHz.

• Clock Frequency This is also sometimes called
  the clock rate or clock speed. It is simply the
  reciprocal of the cycle time, and is therefore
  the number of cycles that occur each second (as
  opposed to the number of seconds per cycle). It
  is usually measured in MHz or GHz, where "Hz" is
  the abbreviation for Hertz, the standard SI unit
  for measuring frequency. One Hertz is one cycle
  per second. So for example, if a clock's cycle
  time is 1.25 ns, its frequency is
  1/(0.00000000125) 800,000,000 Hertz, or 800
  MHz.

• Clock Frequency This is also sometimes called
  the clock rate or clock speed. It is simply the
  reciprocal of the cycle time, and is therefore
  the number of cycles that occur each second (as
  opposed to the number of seconds per cycle). It
  is usually measured in MHz or GHz, where "Hz" is
  the abbreviation for Hertz, the standard SI unit
  for measuring frequency. One Hertz is one cycle
  per second. So for example, if a clock's cycle
  time is 1.25 ns, its frequency is
  1/(0.00000000125) 800,000,000 Hertz, or 800
  MHz.

• Clock Frequency This is also sometimes called
  the clock rate or clock speed. It is simply the
  reciprocal of the cycle time, and is therefore
  the number of cycles that occur each second (as
  opposed to the number of seconds per cycle). It
  is usually measured in MHz or GHz, where "Hz" is
  the abbreviation for Hertz, the standard SI unit
  for measuring frequency. One Hertz is one cycle
  per second. So for example, if a clock's cycle
  time is 1.25 ns, its frequency is
  1/(0.00000000125) 800,000,000 Hertz, or 800
  MHz.

• Clock Frequency This is also sometimes called
  the clock rate or clock speed. It is simply the
  reciprocal of the cycle time, and is therefore
  the number of cycles that occur each second (as
  opposed to the number of seconds per cycle). It
  is usually measured in MHz or GHz, where "Hz" is
  the abbreviation for Hertz, the standard SI unit
  for measuring frequency. One Hertz is one cycle
  per second. So for example, if a clock's cycle
  time is 1.25 ns, its frequency is
  1/(0.00000000125) 800,000,000 Hertz, or 800
  MHz.

Different Processors have different clock
speeds and different memory bus speeds A
faster clock speed wont necessarily speed up
your processing if the bus speed is too slow!
GHz - a unit of frequency equal to one billion
cycles per second





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What is RAM memory?

• The performance of a computer is also dependent
  on the amount of Primary (Main) Memory Random
  Access Memory (RAM) available.
• This memory temporarily stores information so
  that its readily available to the CPU. This
  includes the program(s) being executed and
  required data.
• If this memory is limited or slow this will
  slow down the computers ability to process
  information.

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How does Memory Work?

• Physically computer memory is made up of
  transistors capacitors - the only information
  they store is a magnetic charges (high low)
  represented by a 0 or 1.
• Computer scientists combine a series of these
  transistor states to represent information - They
  turn information into a binary format so it can
  be easily stored as magnetic charges.

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How is Information Stored in Memory?

• All data is represented by a string of 0s and
  1s.
• Integers, Real Numbers, and characters are stored
  this way. They all are converted to a string of
  0s and 1s in different ways.
• Integers are their base 2 equivalent
• Characters are converted via some standard
  (ASCII, Unicode, etc)

All information is translated by a set of
instructions into this format and then processed
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• Measuring Memory
• Each 0,1- is called a bit
• 1 Byte is 8 bits
• 1 Kilobyte (KB) 210 bytes (1111111111)
• 1000 bytes 1x103 bytes
• 1 Megabyte (MB) 220 bytes
• 1,000,000 bytes 1x106 bytes
• 1 Gigabyte (GB) 230 bytes
• 1,000,000,000 bytes 1x109 bytes
• 1 MB of memory can hold approximately 500 pages
  of text.

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SRAM, DRAM, SDRAM, DDR,RDRAM, ..BLAM.. BLAM
SRAM Static Random Access Memory doesnt need to
be refreshed - but like all RAM, is erased when
the power is OFF
CPU
5-10X slower
10 ns speed
DRAM (Dynamic RAM) is a type of memory that is
constantly refreshed or will loose its contents.
SDRAM (Synchronous Dynamic RAM) designed to
work with the CPU clock to work faster than
DRAM DDR SDRAM (Double Data Rate SDRAM) works
twice as fast as SDRAM
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So how much and what type of memory should you
get?

• It will depend on the type of computer you
  have/or are buying
• Older systems are no always compatible with newer
  memory types
• Sometimes too much memory can cause problems with
  Windows
• It will depend on the applications you wish to
  run
• Photoshop or other graphical applications require
  much more memory than simple word processing
• Do you wish to have many applications running
  simultaneously?

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To save data for later use we can store data on
Secondary (Auxiliary) Memory devices

• Auxiliary Memory is cheaper/slower than Primary
  memory but is not erased when the Power Supply is
  OFF.
• Hard drive A non-removable device 20-250GB
  ranges
• Floppy disk drive- 1.44MB
• CDs DVDs 600 MB. (Read vs. RW)
• Removable Hard drives Zip, Jazz
• Memory Sticks

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Hardware vs. Software

• For computer hardware to work it must follow a
  set of instructions that is supplied to it.
  These instructions or programs are referred to as
  software.
• Some instructions are referred to as the
  Operating System Software, which control the
  basic input/output and memory operations of the
  computer.
• Application Software are programs that work
  with the Operating system to perform specific
  tasks.

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System Software

• Programs to control computer operations are
  called Operating Systems (OS)
• Instructions on loading and executing
  applications and transferring data loaded into
  main memory on startup (booting)
• examples DOS, Unix,, Windows XP, Vista

..and promised soon. VISTA
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Applications Software

• Computer programs written to perform specified
  tasks. They work in tandem with specific
  Operating Systems
• Word Processing
• Spreadsheets
• Database Management Systems
• Web design software
• Internet Access E-mail
• Graphics Packages

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What software you need will affect you decision
of what hardware to buyFor example how much hard
drive space will you need with the following
requirements?

• Windows XP Professional Operating System - 1.5
  GB
• Full install of MS Office 2003 - 450 MB
• Dream Weaver - 800 MB
• Adobes Photoshop - 280MB
• Have room to store my photo album with 150
  pictures - .. Average of 500KB each

In GB 1.5.45.8.28150.0053.78
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What doesnt this ad tell us?

• Is any application software included?
• What about a monitor, mouse, speakers etc.
• What about getting on the internet?

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The mouse
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• Most standard systems come complete with a
  standard 2 button mouse
• Frequently one can upgrade the mouse
• 2 button with wheels
• Optical Mouse.. no trackballs!
• Wireless Mouse no tail!

200
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When buying peripherals such as a mouse consider
the type of connections available on your
system.. And the price!
PS2 Connection Newer Technology faster than a
Serial
Serial Connection Oldest Technology - slow
USB Connection Newest Technology - fastest
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The monitor
200 - 2000

• Most systems do not come standard with a monitor
  unless buying a complete package. Consider the
  following when selecting a computer
• Size 17", 19" or 21" screen sizes
• Monitor type
• CRT bigger but cheaper,
• LCD Display - Smaller but more expensive
• Dot/Stripe Pitch - The smaller the Dot Pitch the
  sharper the image
• Resolution number of pixels that can be
  displayed usually higher resolution gives a
  clearer image

To go with your fancy new monitor youll need a
video card that is compatible
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Speakers
20 - 200

• Your new computer system may or may not come with
  other peripheral devices including
• Speakers and sound cards
• Speakers vary based on Appearance, Subwoofer,
  3D-sound
• Sound Cards provide interface between the
  speakers computer

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Black White
Color
Printers
50 - 10,000

• Unless your purchasing a complete package your
  system will probably not come with a printer.
  The two most common printer types are
• Laser Jet - faster, quieter. Can be single or
  duplex (print both sides), different sizes,
  multiple trays etc.
• Inkjet - cheaper

Its not always with printer that gets you.. Its
the price of the ink supplies!
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A desktop, a laptop, a tablet PC?

• Desktop
• Easy to use at a desk larger keyboard
• Least expensive and available with greatest
  speeds memory

• Laptop
• Portable
• More expensive than a desktop
• Keyboard, mouse -not quite as easy to use

• Tablet
• Great for taking notes keeping ad-hoc records
• Portable able to take it with you
• Most expensive slower than std. computers

300 incl. monitor
500
1800
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Getting On-line

• To get on-line you will need several items
• An Internet Service Provider (ISP)
• Method of connecting
• Telephone with modem (56K)
• DSL existing phone line but faster
• ISDN digital phone line
• Cable co-axial cable
• Hardware
• Modem translate computer data to a signal
• Communications/Network Card
• Port
• Ethernet Jack use with cable modems
• Phone Jack use with telephone modems

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• The simplest communication is transmission of
  data over a communication channel between two
  computers

• A modem (modulator/demodulator) connects your
  computer to the Internet by modulating the
  digital signal from the computer to a carrier
  signal

Computer lt--gt Modem
Transmission Media
lt--gt Modem lt--gt Computer
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Networking - connecting a group of computers
together
LAN - local area network WAN - wide area
network Internet network of networks
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And what about security?

• Virus Protection get Anti-virus software and
  keep it up to date
• Firewall Software/Hardware that denies entry to
  all incoming traffic except those specifically
  requested or allowed
• Spam Filters
• Available on most email packages or by providers
  and can be customized

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