Arrangements – Computer Systems

Data representation

Representation of positive numbers in binary including place values and range up to and including 32 bits
Conversion from binary to decimal and vice versa
Description of the representation of negative numbers using two’s complement using examples of up to 8 bit numbers
Description of the relationship between the number of bits assigned to the mantissa/exponent and the range and precision of floating point numbers
Conversion to and from bit, byte, Kilobyte, Megabyte, Gigabyte, Terabyte. (Kb, Mb, Gb, T b )
Description of Unicode and its advantages over ASCII
Description of the bit map method of graphic representation using examples of colour/grey scale bit maps
Description of the relationship of bit depth to the number of colours using exam ples up to and including 24 bit depth (true colour)
Description of the vector graphics method of graphic representation
Description of the relative advantages and disadvantages of bit mapped and vector graphics
Description of the relationship between the bit depth and file size
Explanation of the need for data compression using the storage of bitmap graphic files, as examples

Detailed description of the purpose of the ALU and control unit
Description of the purposes of registers:
- to hold data being processed
- instructions being executed
- addresses to be accessed
Description of the function of the data bus and the address bus
Description of the read, write and timing functions of the control lines
Identification of other control lines, including reset and interrupt lines
Simple description, referring to the appropriate buses and control lines, of the steps in the fetch-execute cycle
Description of the following elements of computer memory : registers, cache, main memory, backing storage
Distinction between the above elements of memory according to function and speed of access
The concept of addressability
Description and evaluation of the following measures of performance:
- clock speed
- MIPS
- FLOPS
- application based tests
Description of the effect the following factors have on system performance:
- data bus width
- use of cache memory
- rate of data transfer to and from peripherals
Description of current trends in computer hardware, including
- increasing clock speeds
- increasing memory
- backing storage capacity

Description of the use and advantages of buffers and spooling
Description of a suitable selection of hardware, including peripherals, to support typical tasks including
- production of a multimedia catalogue
- setting up a LAN in a school
- development of a school website
Justification of the hardware selected in terms of appropriate characteristics including
- resolution
- capacity
- speed
- cost
- compatibility
Description of the features, uses and advantages of solid state storage devices including flash cards
Description of the development trends in backing storage devices
Description of the following functions of an interface:
- buffering
- data format conversion (serial to parallel)
- data format conversion (analogue to digital)
- voltage conversion
- protocol conversion
- handling of status signals
Distinction between parallel and serial interfaces
Description and explanation of the current trends towards increasing interface speeds and wireless communication between peripherals and CPU

Comparison of LANs, WANs, Intranet and Internet work in terms of
- transmission media
- bandwidth
- geographical spread
- functions
Distinction between a main frame with terminals and a network of computers
Descriptive comparison of peer-to-peer networks and client server networks
Description of the functions of file, print and web servers
Description of a node and a channel
Description of bus, star, ring and mesh topologies using the terms node and channel
Description of the consequences for each of the above topologies of node and channel failure
Simple description of the functions and uses of a hub, switch and router
Identification of the need for a network interface card (NIC)
Description and explanation of the trends towards higher bandwidth and wireless communications
Description of the following technical reasons for the increasingly widespread use of networks:
- advances in computer hardware
- including processors
- main memory capacity
- backing storage
- data transfer rates
- improved network related software, including
  - browsers
  - network operating systems
Description of the misuse of networks for the following illegal purposes:
- breaching copyright
- hacking
- planting viruses
Description of the application of the following to the misuse of networks
- the Computer Misuse Act
- the Copy right Designs and Patents Act
- the Data Protection Act

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