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Q&A-KCSE Computer Studies Paper 1

A company has decided to use a computer for stock control. Describe the process of systems development from the time the decision was made to proceed with computerisation until final testing.

specify output requirements
design documents/screen displays
data for input/storage
form design
storage devices
file structures/access/design
data security/back up files
systems flowchart etc.
implementation i.e. pilot/intermediate/parallel running
testing strategy
training
hardware/software
programming/algorithms
validation
user manual
technical documentation
entering data into system

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Explain the difference between main memory and secondary storage.

  • 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 
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Outline a factor that can influence the performance of a network.

  • The different factors that can influence the performance of a network include: bandwidth, network design, data collisions, and excess broadcast traffic.
  • The bandwidth can influence through the method of transmission and medium used
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What is a primary key?

  • an attribute/combination of attributes chosen to ensure that the records in a table are unique
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State what is meant by each of the following modes of data  processing

(i) Batch processing.
(ii) Real-time processing.
(iii) Online processing.
(iv) Off-line processing.

(i) Jobs collected together for processing at a later time
(ii) Output produced quickly enough to affect the next input
(iii) User has direct contact with the processor
(iv) User cannot communicate directly with the processor

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Describe what is meant by shareware.

 the trial version of software for a limited time/number of uses with limited features  free of charge

If a full version is required need to pay a fee/sign up

When the trial is over user is asked to pay/sign up

Protected by copyright

Type of software licence
 

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The Acme company stores data for a private scientific research group. It has recently upgraded its storage capacity and needs to dispose of its existing hard drives securely. Outline two methods for the secure disposal of the data on the hard drives.

Acme company needs to ensure that if they are reselling the drives they wipe the drive (this should be done regardless of the destruction of the drive) to the DoD standard.

  • Disassemble the drive by pulling it apart the drive so that the data would not be accessed
  • Destroy the metal disk either by drilling holes so it cannot be read
  •  Encrypt drives with passwords that are not accessible
  • Degaussing the hard drives
  • Use specialized overwriting software

This would ensure that any software cannot be used to locate files.

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Describe what is meant by a MAC address.

  • used to identify a device
  • it is a unique (address)
  • it is a static address // it does not change
  • it is set by the manufacturer
  • the first part is the manufacturer ID/number / identifies the manufacturer
  • the second part is the serial number / ID.

 

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One characteristic of a robot is its mechanical structure.
State two other characteristics of a robot

  • It has electrical components.
  • It is programmable.

 

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1 (a) Computer networks are valuable to many businesses and individuals.
(i) State the purpose of network protocols

Any one of:
• To allow connected machines to communicate
• To provide the rules of communication between two networked devices

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State two effects of a computer virus

  • memory used up/slows down computer/alters setting/systems failure
  • erases files/erases data/corrupts data/data needs restoring
  • infects other computers on the network
  • production loss/financial loss
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State the seven layers of the OSI model

  1. Application
  2. Presentation
  3. Session
  4. Transport
  5. Network
  6. Data link
  7. Physical

Suggest one disadvantage to the programmer of using a high-level language instead of a low-level language.

  • not able to directly manipulate the hardware
  • may need to wait for translation before running
  • the program may be less efficient.

 

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Describe two desirable features to look for in a laptop rather than a desktop computer.

– lightweight
– long battery life
– cool running processor
– touch pad
– internal webcam

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Define what is meant by a ‘network protocol

  • An agreement / set of rules / standard for how computers should communicate or how data is sent/received/transmitted on a network
  • Example of what could be agreed in the protocol (e.g. speed / error checking / etc.)
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Distinguish between a PAN and a LAN

A PAN exist around a single person whereas a LAN covers a larger area

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 Describe four features of the operating system when providing a graphical user interface on a personal computer. Give a suitable example of each feature.

Windows for example a word processing application and a spreadsheet
 
Menus, for example, allow the user to perform operations or run applications such as right-click to create a new folder  
 
Icons for example a picture of linked computers for networking
 
Pointers(mouse or touchscreen)  for example to select items/trigger events  
 
Shortcuts for example to frequently used applications for example having a shortcut to your mail client on your desktop
 
File navigation for example when searching the hard disc for a file/folder using a browser
 
copying / deleting / moving/sorting/naming/searching of files or folders for example copying of a file from the hard drive to a USB pen drive (File handling)
 
Desktop customisation for example changing the colours and background image
 
Copy and paste for example between applications e.g. copying a graph from a spreadsheet to a word processor
 
Error messages for example provide users with error/warning/help messages for example ‘printer out of paper’ 

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Describe each of the following storage devices

DVD - optical media which use one spiral track; red lasers are used to read and write data on the media surface; makes use of dual-layering technology to increase the storage capacity

ROM - non-volatile memory chip; contents of the chip cannot be altered; it is often used to store the start-up routines in a computer (e.g. the BIOS)

SSD/ Solid State Drive/memory (SSD)

non-volatile memory device that uses NAND flash memories (which consist of millions of transistors wired in series on single circuit boards)

Blue Ray -  optical media that uses blue laser technology to read and write data on the media surface; it uses a single 1.1 mm polycarbonate disc

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Define the following modes of electronic data processing:

  1. Multitasking
  2. Real time processing
  3. Timesharing
  4. Online Processing

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

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Distinguish between one to one and one to many relationships as used in relational databases

One to one  - Each record in the parent table has exactly one related record in the child table, and vice versa.

One to Many -  Each record in the parent table can have multiple related records in the child table, but each record in the child table is related to only one record in the parent table

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