Category Archives: 1. Computer Systems

1. Computer Systems, Computing Higher

Computer software – Arrangements

  • Description of the function of a bootstrap loader
  • Description and exemplification of the main functions of a single user operating system :
    • interpreting users commands,
    • file management,
    • memory  management,
    • input/output management,
    • resource allocation,
    • managing processes
  • Definition of a utility  program
  • Description of utility  programs including:
    • virus checker
    • disk editor
    • defragmenter
  • Description of the standard file formats for graphics files:
    • jpeg
    • gif
    • TIFF
  • Description of  a suitable selection of software to support typical tasks including:
    • production of  a multimedia catalogue
    • setting up a LAN in a school
    • development of a school website
  • Description and exemplification of software compatibility  issues
    • including memory and storage requirements
    • OS compatibility
  • Classification of viruses by type of file infected:
    • file virus
    • boot  sector virus
    • macro virus
  • Description of  the following  virus code actions :
    • replication
    • camouflage
    • watching
    • delivery
  • Distinction between
    • a virus
    • a worm
    • a Trojan horse
  • Description of anti-virus software detection techniques:
    • use of checksum
    • searching for virus signature
    • heuristic detection
    • memory  resident monitoring
1. Computer Systems, Computing Higher

A day made of glass 2

2 Comments

[kml_flashembed movie="http://www.youtube.com/v/X-GXO_urMow" width="425" height="344" allowfullscreen="true" fvars="fs=1" /]

Now remember that this is an advert for a glass manufacturer. However the technology on display is pretty cool.

Think about the technology that would need to be embedded in the glass as well as the networking technology that is used.

As a counter point though I would like to offer another series of choices. What about projector technology?

[kml_flashembed movie="http://www.youtube.com/v/TUo3yFRxYSw" width="425" height="344" allowfullscreen="true" fvars="fs=1" /]

Or Augmented Reality Contact Lenses?

[kml_flashembed movie="http://www.youtube.com/v/XrLLddIppCU" width="425" height="344" allowfullscreen="true" fvars="fs=1" /]

All this technology is quite a way from everyday use, but 20 years ago (1992) students didn’t have mobile phones, no one had the Internet in their pocket and the World Wide Web was one year old.

1. Computer Systems, Revision

Calculations in computer systems

I was sure I had this here already but I can’t find it.

Here are the main formula we used in the computer systems unit

  • Largest number with n bits = 2n-1
  • No of memory locations/different colours = 2n
  • Coloumn heading in a binary number at n bit =2n-1
  • Size of bitmap = no. of Horizontal pixels X no. of Vertical pixels X Colour Depth
  • No. of pixels = DPI X size in inches
  • Total storage capacity = no. of memory locations X location size.

You should also be able to convert from bits, Bytes, Kilobytes, Megabytes, Gigabytes & Terabytes.

  • Bit= 1/0 (Binary digIT)
  • 1 Byte = 8 Bits
  • 1 Kilobytes= 1024 Bytes  (210)
  • 1 Megabytes= 1024 KB  (220)
  • 1 Gigabytes = 1024 MB  (230)
  • 1 Terabytes = 1024 GB  (240)

For colour depth

  • 8 bits = 256 colours (28)
  • 16 bits = High Colour 65,536 colours (216)
  • 24 bits = True Colour 16,777,216 colours (224)
1. Computer Systems, Revision

Control Unit

1 Comment

O was asked this question today and I can’t help but feel that the pupil wasn’t happy with the answer. So here I go again.

The Control Unit is a sub part of the processor (along with ALU & Registers). It is responsible for the sequencing, decoding and it also synchronizes the execution of the program instructions.

I am not sure that you will be happy with this description so I went to find some support notes and an animation ( I even found it in scratch) to help you to visualise it.

I did find this video though that covers a range of topics.

[kml_flashembed movie="http://www.youtube.com/v/HEjPop-aK_w" width="425" height="344" allowfullscreen="true" fvars="fs=1" /]

So to sum up, the Control Unit, controls all operations of the CPU, It also controls the flow of data along the buses.