Computer Systems

Computer Systems

1. Computer structure

   • Control Unit
   • Arithmetic/logic unit (ALU)
   • Registers

2. Types of computer

   • Embedded
     • a small processor (computer) that is inside a large piece of equipment
   • Palmtop
     • small enough to be held in one hand while it is being used. For this reason a palmtop computer
   • Laptops and notebooks
     • use an LCD/TFT screen, a keyboard and all other input and output devices in the base.
   • Desktop
     • This type of computer tends to be in one location
   • Mainframe
     • This type of computer is very large and very powerful.

3. Networking

   • LAN - Local Area Network
     • Transmission Media LANs can make use of both cable and wireless media. Wireless gives the convenience of not having to have cables attached to the computer and the freedom to access the network while the device is in range. Using cables in a LAN means you can transfer data faster and more reliably.
   • WAN - Wide Area Network
     • Transmission Media Wide Area Networks often use telecommunication links, telephone lines, leased lines or satellite links.

4. Computer software

   • Standard File Formats
     • Standard file format is a different way of storing documents or data so that it may be recognised by different computer programs on different operating systems.

5. Data representation

   • Each individual 1 or 0 is called a binary digit or bit and it is the smallest piece of data that a computer system can work with.
   • Representation of positive whole numbers We can represent any number, however large, in binary. Remember we can only store numbers between 0 and 255 in one byte. This is obviously rather restrictive since it's not dealing with large integers, negative numbers or decimal numbers.

6. Interface

   • Computer peripherals such as CD-ROM drives, scanners, keyboards all have different characteristics. For example, they may: Have different data transfer rates Use a wide variety of codes and control signals Transmit data in serial or in parallel form Even work at higher voltages than the CPU All operate at much slower speeds than the CPU

7. Computer misuse act

   • Hacking is where an unauthorised person uses a network, Internet or modem connection to gain access past security passwords or other security to see data stored on another computer. Viruses are relatively simple programs written by people and designed to cause nuisance or damage to computers or their files

8. Copyright Designs and Patents Act

   • This makes it illegal to copy music, movies, software and text without the permission of the person who invented them.