Computer Basics Which computer should I buy? What do I get for an extra $775 and do I even need it ? Desktop 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 do I get for an extra $775 and do I even need it?
Tower Box: Central Processing Unit - CPU (motherboard), power supply, Main Memory (RAM), Auxiliary Memory devices: Hard drive, CD, DVD, etc.
A Laptop – with CPU, monitor, keyboard, touch pad & speakers
Hard Drive Bus
the ‘2’ key then
2 + The
Y = X+2
Y = 4
Output 4 on
the screenCPU – 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
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 won’t necessarily speed up your processing if the bus speed is too slow!
GHz - a unit of frequency equal to one billion cycles per second
All data is represented by a string of 0’s and 1’s.
All information is translated by a set of instructions into this format and then processed
Static Random Access Memory
doesn’t need to be “refreshed” - but like all RAM, is erased when the power is OFF
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
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.
Programs to control computer operations are called Operating Systems (OS)
..and promised soon…. VISTA
Computer programs written to perform specified tasks. They work in tandem with specific Operating Systems
What software you need will affect you decision of what hardware to buy…For example how much hard drive space will you need with the following requirements?
In GB: 1.5+.45+.8+.28+150*.005=3.78
PS2 Connection Newer Technology – faster than a Serial
Serial Connection Oldest Technology - slow
USB Connection Newest Technology - fastest
$200 - $2000+
Most systems do not come standard with a monitor unless buying a “complete package”. Consider the following when selecting a computer:
To go with your fancy new monitor you’ll need a video card that is compatible
$20 - $200+
Your new computer system may or may not come with other peripheral devices including
Speakers and sound cards
$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:
Its not always with printer that gets you.. It’s the price of the ink supplies!
Easy to use at a desk – larger keyboard
Least expensive and available with greatest speeds & memory
More expensive than a desktop
Keyboard, mouse -not quite as easy to useA desktop, a laptop, a tablet PC?
$300+ incl. monitor
Computer <--> Modem
<--> Modem <--> Computer
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”