– when transferring large files/attachments with emails
– when streaming music/video files/bit streaming
– when using VoIP/video conferencing
– software updates
– online transactions
– Using VLE (Virtual Learning Environment)

CLI

• Commands have to be typed in full with no mistakes
• Requires memorization of commands
• Uses less memory

GUI

• Due to graphics, GUI uses a lot of memory
• GUI is more user friendly
• Cannot operate properly if memory is low

Comparison

• Both carry out file management
• Both are operating systems
• Both control software and hardware

Explain the purpose of each of the following features of a spreadsheet chart (KCSE 2021, Q19 (a))

Legend

• Legends are a small visual representation of the chart's data series to understand each without confusion.

A data series

• is a row or column of numbers that are entered in a worksheet and plotted in your chart, such as a list of quarterly business profits
• A group of related data points or markers that are plotted in charts and graphs

Data Marker

• A symbol on the chart that represents a single value in the worksheet.
• A column, dot, pie slice, or another symbol in the chart representing a data value

https://www.lifewire.com/data-series-data-points-data-labels-3123411

Advantages

– immediate response to questions/queries
– can see each other watch body language etc.
– easier to have several participants (would be difficult using instant messaging if
several people involved)

Disadvantages

– need for expensive equipment/high set up costs
– sometimes synchronisation problems make it difficult for delegates
– need to train people to use the new technology
– greater use of bandwidth

Multi-tasking - It is a data processing modes where a single CPU processing more than one task or program apparently at the same time

Time-sharing - a processing mode where a single CPU processes tasks from more than one user apparently at the same time

Time-sharing - this is a processing mode in which the CPU serves two or more users with different processing requirements ( tasks)

On-line processing - is a mode of processing where the result of data processing transaction is available immediately

Real-time processing - is a mode of data processing in which the time interval required to process and respond to inputs is so small that the response itself is useful for controlling the physical activity of a process

Trojan (horse); a program which misleads the user into thinking it is another

piece of software which, when run, executes another program;

Spyware; a program which records data such as usernames and passwords on

a host system and forwards the information to a third party;

Adware; code embedded or attached to program files which will persistently

show adverts (that attempt to generate revenue);

Worm; code which will run autonomously and replicates itself on a host system;

Ransomware; a program that encrypts user’s data to make it unreadable until

they pay for the key;

Remote Access Tool (RAT); allows access to control and monitor a computer

from a remote network location;

Rootkit; malware that has managed to gain ‘root’ admin privileges;

Bots/Zombies; a program installed on a computer that performs a job for the

remote owner of the bot/zombie such as sending spam or sending web requests

to perform a DOS or attacking a computer system;

Scareware; malware that tells you something is wrong with your system in an

attempt to get you to make a purchase;

Keylogger; a program that monitors/records a user’s keystrokes in order to steal

passwords/confidential details;

• Computer viruses
• Unstable power supply
• Hard disk crash
• Theft of data/programs

• a repeater is a two-port device that amplifies a signal from one port to another
• a switch is a multiport device that uses a table of addresses to send a signal through the correct port

• when designing a database a data dictionary provides the description and purpose of the fields/attributes of the database table(s). For example the field name (i.e. “phone number”), the data type (text); the size of the field (10) etc.

• Real time  E.g. turning the wheel must turn the car immediately
• On line - Otherwise system cannot be real time

Phased:
Advantages:

• only a small part of the operation affected if new system fails
•  no need to pay for two sets of wages

Disadvantages:

•  time consuming (each part needs testing fully before expanding system)

Pilot:
Advantages:

• if new system fails, only that part will be affected
• possible to gradually train staff on pilot before whole system changes over

Disadvantages:

•  time consuming (waiting to see how pilot works before rolling out to rest of the organisation)

Direct:
Advantages:

•  less likely to malfunction since fully tested
• immediate benefits/less time wasted
•  reduced costs (only one system so no need to duplicate staff)

Disadvantages:

• disastrous if the new systems does fail

Parallel:
Advantages:

•  if new system goes down, there is a backup system in place
• possible to gradually train staff/staff have time to get used to the new system

• Main memory is transitory/temporary/volatile, secondary storage is (semi-)permanent
• The processor can only use data/instructions that are in the main memory
• Main memory is directly accessible to the processor, secondary storage is not directly accessible to the processor