Computer
Systems
Nat 4/5 Computing Science
Types of Computer and
Performance
Lesson Aims
By the end of this lesson:
 Pupils at Nat 4 level will be able to:
 Describe and use clock speed as an indicator of
performance
 Pupils aiming for Nat 5 will be able to
 Describe the uses of embedded, smartphone,
laptop, desktop and supercomputers.
 Compare features of embedded, smartphone,
laptop, desktop and mainframe computers:
 Discuss the type and speed of processors
Nat 4/5
Clock Speed
 Clock
speed is the simplest measure of
performance
 This
is the amount of operations that the
computer can perform in one second


Modern home CPU’s operate in the 2.4-3.2 GHz
range
This means at least 2,400,000,000 instructions per
second
Nat 4/5
Speed isn't everything
 Some

processors have 2, four or six cores
2,3,4,6, 8 or 16 cores are the usual options
 This
means that there are 2, 4 or 6 smaller
processors built into a single processor.

Each core can work on a single instruction
 The
faster the processor the more heat they
generate.
So which is better?
Dual core at 3.5Ghz or Quad core at 2.4Ghz?
Nat 4/5
Sometimes power is key
 Other
processors might need a very low
power usage

For example using in netbooks, mobile
phones or other portable devices.
Nat 4/5
Apples and Oranges
 When
comparing performance it helps if the
processors are of similar type etc.


For example you cannot compare the clock
speed of a Dual Core processor to that of a Quad
core processor.
The fastest supercomputer only has a clock speed
of 1.6 Ghz (but it does have1,572,864 of them!)
 1.6
Pb of RAM might help too!
Nat 4/5
Types of Computer
 As
technology improves the types of
computer produced change.
 Social factors also change types of popular
computers


For example laptop sales in the last few years
have surpassed desktops.
There are an increase in smart phones
 And
almost every piece of equipment will
have a computer ‘embedded’ inside it
Nat 4/5
Different Types of Computer
Desktop
Smartphone
Embedded
Laptop
Tablet
Mainframe
 For

each type of system you need to identify:
The features of the computer system, a purpose for
each system, advantages and disadvantages for
each system.
Nat 4/5
Moore's Law
 In
1965 the co-founder of Intel(Gordon Moore)
made a prediction that:

“The number of transistors incorporated in a chip
will approximately double every 24 months.”
 So
far this ‘law’ has held true but there are
physical limits that will be reached.


Current processors are manufactured using 32
nanometre transistors (switches)
Intel has developed transistors so small that
about 200 million of them could fit on the head of
a pin
Nat 4/5
Summary

You need to be familiar with the
following types of computers


Embedded, laptop, desktop,
supercomputer and smartphone
And compare them in terms of:




Type and speed of processor
Size of main memory
Backing storage
Input and output devices