instructions on how to perform specific tasks when running various programs
how to execute the program
describe how the input data is to be entered
system documentation
file security measures
data flow diagrams/structure diagrams
list of files and record structures and the database design
A manual system is being replaced by a computerized system, state how staff will be affected
staff must be trained to new hardware and software
some staff may no longer be needed
working patterns change
Outline the need for periodic reviews in a system life cycle
a caparison of the systemâs actual and original performance can be made, and errors made during design can be detected
can highlight any unexpected problems/benefits the system has yielded can necessary adjustments/enhancements/additions can be made
State examples of utility software [2]
File manager
Data compressor
Antivirus software
Defragmentation software
Outline how validation and verification can be used to ensure data is as accurate as possible [4]
Verification is method of checking/ensuring that data at source is the same as inputted data
Usually the user is involved, for example, asked to retype data
Validation is performed by the software
Checking the range, whether the type of data is correct
Explain, in terms of resources, how Voice over IP provides a collaborative working environment for a company with multiple locations nationwide
VoiP is audio and video stream transmitted over the internet, for which broadband internet connection is needed
That can be integrated in an office desktop computer
With collaboration desk endpoints/webcams/desktop computer/widgets
Discuss the issues that should be considered before making decisions on access to the data stored on this system, and storing the data locally or through the use of a cloud service [6]
Official access to the data
Sensitive data access must be restricted through user authentication
Only those directly concerned can be able to access
Less people should be able to edit
Access levels should be set up with strong authentication
Physical access to servers should be controlled if a local system is used
Data security
Cloud service providers are professionals and usually have stronger security
If patient data is sold, patient and hospital could suffer serious consequences
Is cloud governed by appropriate privacy laws?
Is it located internationally or is it governed by laws of country?
Data could be intercepted in transmission so it must be protected with encryption
Explain problems that occur when transferring data from the old system to the new system [4]
Data records in DBs would have different structures
Files could be incompatible from different hardware systems
Customer records could have the same keys/IDs so cannot be uniquely identified
Explain how cache memory can speed up the processing within a computer [3]
It is accessed faster than RAM
Used to hold common/frequently used data
Closer to CPU than RAM with faster read/write speeds
Cache memory is static RAM, doesnât need to be constantly refreshed
Longer questions
This question is about the system life cycle model
Outline its purpose [2]
The process of replacing the old computer system by the new one/creating the new computer system
Identify the state in which a feasibility report is generated [1]
Analysis
Explain why software production is normally cyclical
software will be used for several years and will require some modification
there will be obscure bugs that are not apparent until the program has come to use
modifications will be required due to changes in computer hardware and system software
program can be modified to improve performance, or add new features
system reviewed regularly to determine whether it meets userâs, and old programs can be modified and additional hardware can be added
This question is about word processing and data migration
State the advantages of autosave
if power goes off, only the text typed after the last (automatic) save is lost
State additional features of a word processor
apply styles/effects
insert tables/pictures/formulae
mail merge
macros
Print documents
Outline security measure that should be taken to prevent data loss
off site data storage
make backups regularly (hard copies)
Printed copies of transactions
Transaction log file: so that in case of loss, transactions can be restored
prevent physical damage to computers/protection from natural disasters
Outline problems arising from installation of new hardware and software in office
data migration problems: different file formats so conversion must be performed
employee efficiency may drop as they learn to use the new system
issue of compatibility with legacy software/hardware
Discuss possible problems that may occur during data migration [3]
Data loss/corruption: when moving data from one storage device to another (could be lost, or not useful because corrupted)
Incompatibility of data formats: necessary to translate from one format to another, to be able to use the data in the new system, which causes delays/performance issues
Outline problems with maintaining legacy systems [2]
Database contains inconsistencies/redundancies
Typically large and complex systems/mainframes
Hard to understand/change/evolve because programs might be disorganized and documentation might be missing
Compatibility issues with old programming languages and database technologies
Maintaining outdated computer systems
Outline the use of a failover system [2]
A standby/redundant system
Used to eliminate/reduce the impact on users/owners
By automatically taking over if the primary system suddenly becomes unavailable
A computer system is being developed
Outline two types of possible errors [4]
Syntax errors: mistyping, omitting symbols
Run-time errors: division by 0, out of bounds, attempts to read missing file
Logic errors: incorrect formula to calculate something
Describe examples of software that assist in the development of computer programs [6]
Editor: enables programs to enter/modify source code
Translator (interpreter/compiler): software that translates source code to machine code
Linker: software that puts appropriate machine addresses in all external files, links all modules
Loader: software that takes appropriate machine code and loads instructions into their specific locations
Debugger: software that helps programmers find errors
A criminal justice agency is being computerized
Identify disadvantages of computerizing a large system
capital expenditure of a large computer system is enormous
more staff will have to be employed and trained to use the computer, which is time-consuming/costly
computer may be down when information is needed quickly
regular activities may be suspended/disrupted when a change is being made
Explain advantages for the criminal agency if the system is computerized
common features of crimes can be quickly cross-referenced to find similarities
computer can search database of crime details and past convictions to draw a suspect list faster than manual
separate agencies can pool information, which cannot be done manually
Discuss concerns the public might have
fear that civil liberties could be infringed in that a computer may store any data about people, not just crimes
which so much information, fear of of it being misused
more staff using computers, less police on streets, leading to lack of public confidence
A business wants to computerize operations. First task is to clearly define the problem
Outline the benefits of methods of data collection to help define the problem [4]
Observation: allows analyst to see exactly how processes are carried out
Questionnaires: can cover every aspect; can reach every employee
Research: allows analysts to see how other similar businesses solve the problem; relatively cheap to administer
Interviews: interaction allows all aspects to be thoroughly investigated
Outline the documentation that would be presented to the business and design team
Business: feasibility report containing a brief description of the proposed system, estimated costs, technical and legal responsibility
Design team: requirements specification containing a definition of the problem, definition of inputs and outputs, and a list of tools, facilities, people available for developing solution
Outline additional pieces of documentation that would be produced after the analysis stage
User guide: for personal to use the system
flowcharts/code: to aid programmers in future modifications
Technical documentation: help future teams to alter/improve the system
Interactive prototypes: consistency must be ensured in re-designing
Discuss advantages and disadvantages of printed material vs online support for documentations [4]
Advantages:
Portability: the printed material is easily transportable
Availability: always available, no power cut or Internet problems
Disadvantages:
Readability: font size can only be changed online
Aging: online is more frequently updated than paper
Environmental: waste of paper vs energy consumption
This question is about user testing
Explaining what is user acceptance testing [2]
A system or a particularly functioning prototype
Given to users to test for functionality or to gain feedback on functions or the user interface
Describe the purpose of a prototype [3]
Used to ensure all essential functions of the system meets needs of user
To speed up development process
Userâs feedback helps in refining the acceptable prototype in order to develop the complete system, or a further prototype should be created in order to develop the satisfactory
New computerized system is being planned in a library
Describe a method in which system requirements can be obtained from stakeholders [2]
interviews could be held with the stakeholder
To establish the functions required by the site, direct observation could be made of the users of the current system
To gain an insight on how the library is being used
Outline one reason for providing a prototype for this new execution cycle [2]
Allow stakeholders to gain an idea of how the system would work
So they can provide feedback and suggest improvements
This question is about usability
Define the term usability [1]
Making the computer systems more easy to use
Matching them more closely to user needs and requirements
Identify methods of inputting data that can improve the accessibility [2]
text to speech
voice recognition
braille keyboards
touch screen
input from scanner
State potential usability issues with cell phones [3]
Small screen
Uses batteries for power
No hard drive/small memory
Reliability/network coverage issues
Too many steps to access a particular feature
This question is about a new system
Explain the role of users in the process of developing a new computer system [3]
Role of users is important because inadequate user involvement leads to project failure
All users must participate and explain what how they use the system and what they think is wrong with the system
All users are involved in testing of the system and training
Explain why it is important to produce more than one prototype of the new system
More than one allows the manager to choose that one that is the most suitable
Which give more flexibility and improves final system
This is about accessing the computer system
Explain how two or more customers are able to access the computer system at the same time [2]
Central computer is a multi-user environment
Which shares its time among customers
Explain how each customerâs data is secure when two customers access the system at the same time [2]
OS protects user data in RAM
To prevent overwriting or accidental changes
This question is about data migration
Define data migration
The transfer of data from one system/storage device to another
Identify problems that may arise [2]
Data loss, due to transmission faults/lack of adequate storage
Incompatible file formats, which could lead to incomplete or incorrect data transfer
Different file structures, which will result in a mismatch of data, for example in customer records
Validation rules differ between companies, which could lead to inconsistent/incorrect results
Other than data migration, describe two aspects of change management that may arise from this takeover [4]
Workforce issues, such as redundancy/retraining
The time frame involved, in merging the two systems
Testing, of the combined systems/new data
Data entry, if migration not possible
Costs involved, in the aligning of the two systems
Changeover decisions, such as parallel running
Computer organization
Short questions
Describe how checksum could ensure data integrity in the transmission of data
checksum is computed from the data
groups of bits are added before transmission and sum appended to the group
when the data is received the actual sum is compared with the checksum
if the two are the same, it is assumed that data has not been corrupted
otherwise a resend would be requested
Compare magnetic tape with flash memory as a media for backing
Flash memory is more portable between devices, but is small and can be stolen
Tape has a larger storage capacity, more than flash memory
Tape has sequential data access (slower) while flash has direct data access (faster)
Tape is cheaper but the hardware is required is expensive
Outline the need for interrupt priorities
interrupts can be generated by various devices or programs in a computer system; some doing more important jobs than others
some tasks require a faster response from the CPU than others because they are more important/operate faster
Longer questions
This question is about defragmentation softwares
Outline the function
in files, the free space on disk can be broken down into a number of smaller sized areas
only small parts of new files can be stored in these areas
a defragmentation software will recognise data on disk such that files are stored intact and free space is located in a single larger area for the storage of future files
Outline reasons for using one [2]
Defragmentation software places sections of the same file next to each other
To allow faster access (to that file)
This is a question about the OS
State two examples of a use of an interrupt
software application reports an error
power problem alert
IO interrupt
Malfunctioning hardware interrupts
Outline how the operating system processes an interrupt
OS is alerted that a service is needed
this also depends on the priority of the service required
the current processing is suspended â stack is used to store the current data
the service is dealt with and the processing is resumed
Outline a situation where multi-tasking is necessary
a computer user may want more than one application at the same time to copy something from one app to a document
user may want to work on a word processing document while a database program is searching for or sorting data
user may want to work on spreadsheets or databases at the same time as printing something
Outline features of the OS that need to be considered when running a game application [2]
Memory management: use a lot of memory and require constant refreshing
Processor loading and graphics handling of OS
GUI: needs to handle input from appropriate devices
State one application for each of the following methods of data input
OCR (optical character recognition)
scanning text into a computer readable form
so that it can be edited on a computer
example: bank processes without human involvement
touchscreen
screen allows you to select options/work through menus
example: ticket machine at airport; information kiosk systems in product information
This question is about the machine-instruction cycle
State where all instructions and data are stored
primary memory/RAM
Outline the function of a computer bus
a bus is a pathway through which the processor communicates with other parts of the system
data, addresses, or control signals are transmitted
Outline the role of the data bus and address bus in the process
buses are used as physical connections to carry information to the CPU
the data bus transports date to/from the CPU, whereas the address bus transports the memory address where the data is supposed to go/be
Outline the following functions of an operating system [2+2]
Memory management
Allocates an appropriate section/amount of memory
For each program (currently) running
Holds contents of memory
Which are to be transferred from memory to other CPU components
Allowing processor and memory to act independently (processor not affected by differences in speed of operation)
Security
Deals with passwords/access levels
So that only the appropriate people can work with particular files
Explain the role of the following [2+2+2+4]
Accumulator
Within the ALU
Temporarily stores the results of any calculation
Instruction register
Within the CU
Stores the instruction that is currently being processed
Program counter
Within the CU
Stores the address of the next instruction to be executed
Incremented each time an instruction is carried out
Buses
Address bus: provides a pathway from the memory to processing unit that carries the address in the memory to and from which data is transferred; address only passes from CPU to external memory/IO ports (one way)
Data bus: carries data to and from memory/registers within the CPU (bi-directional)
Control bus: carries read/write signals/interrupt request signal between different parts of the processor
This question is about the CPU
Describe the function of the control unit (CU) in the CPU
Obtains data/instructions from the memory
Decodes them into commands
Controls transfer of data and instructions among other units of a CPU
Coordinates all units of a computer
This question is about bits and floats
Define the term bit [1]
binary digit
(minimal) unit of storage that can be set to 0 or 1
State and define the problem that occurs when a (9 bit) data is stored in an 8-bit register [1]
Overflow error
The value to be stored in the memory location os too large/larger than the largest value that can be stored in this memory location
State one reason for using floating-point representation and one for using integer representation [1+1]
Float: greater range of numbers and better accuracy
Integer: no rounding/truncation errors and faster processing
This question is about the processor and cache
State the purpose of cache memory [1]
Used to save time in accessing the RAM
Describe how the cache memory can speed up the functioning of a processor [2]
Cache memory is closer to CPU
By holding frequently used data and instructions in cache, execution of program and fetching instructions and data is faster
State features considered when comparing the speed of different processors
Word length
Bus size
Frequency
Number of cores
Cache size
This question is on the operating system
Outline the function of the MAR [2]
Register in the CPU that is loaded with the address of the next instructions/data to be taken from the RAM
Outline the function of the MDR [2]
Register in the CPU that is holding the data which has been most recently taken from the RAM
Identify functions of the OS [2]
Resource allocation
Memory management
Interrupt handling
State where the OS is held when the computer is turned off
Hard disk
FROM
Solid state drive
Construct a diagram to illustrate the structure of the CPU clearly showing the flow of data [4]
Identify the part of the CPU which performs decoding and which executes the instructions [2]
Control unit performs decoding
Arithmetic and logic unit executes instructions
Networks
Short questions
Outline the role of a gateway in wide area network
a gateway provides a link between systems
by providing appropriate conversions/adding to the appropriate data
it is a network point that leads to another network, may be with different protocols
Define handshaking
the exchange of (predetermined) signals when a connection is established between modems/devices
a protocol used when communication with (peripheral devices) is taking place
the process by which both the sending and receiving devices in a computer network maintain and coordinate data communications
Explain two ways of reducing the time required to transmit data in a computer network [4]
Data could be compressed before sending; which means less data to send
High speed lines/fiber optics/dedicated lines could be used; which allow faster transmission than traditional lines
OR greater bandwidth of a communication channel; higher data transfer rate
Outline advantages and disadvantages of wireless networks [4]
Ease of use for mobile users: they can work from many different locations
Connectivity between different locations
Cost
Security: as wireless transmissions are easily intercepted
Positive change in working patterns (employees can work at home)
Health issues
Outline ethical concerns of using the Internet [4]
Data/information is deliberately incorrect: data integrity
Data /information has not been validated
Intellectual property issues
Plagiarism
Explain how compression of data may lead to negative consequences [3]
Some compression methods (lossy) discard data
Decompression will not return the completed file as some detail will have been removed
Which isnât some cases may be unacceptable
If original not saved, there is not way to recover it
Explain how the use of MAC addresses can improve security [3]
MAC address identifies a specific device
MAC address checked against list of approved addresses (if not on list, access to network denied)
Prevents unauthorized access with (it is an extra layer of protection)
Data sent to specific MAC address can only be accessed on that device
Longer questions
This question is about data loss. Sate examples of how data can be lost by
human error
forgetting to save newly created file
overwriting file/giving a file same name as an already stored file
accidentally erasing a file
hackers
hard-disk failure
disgruntled employees
server stolen
not human error
viruses
lightning/storms
operation environment, like dust on disk
Describe how data can be recovered
data from the disk is not physically erased
it is just removed from the index
so the software can be used to recreate links and place them back to idea
regularly create backups
so if data is lost, it can be recovered using the backup
Describe why data loss is a more serious problem than software or hardware loss for a sales company
loss of a hardware not major because it is not too expensive for company; hardware substitute can be purchased
loss of software is not a critical problem if backups have been made
it is difficult/impossible to replace data
Identify methods of protecting data
password
cryptography
internal controls/separating of employees/ secured waste
antivirus programs
backup systems
strengthen physical security
This question is about WLAN
Identify hardware components of WLAN (other than computer)
wireless router/modem
access points
switch
wireless repeater/extender
Outline disadvantages of WLAN
datatransfer rate less than LAN
WLAN has lower bandwidth than wired LAN
less data security as devices from outside can access network/intercept transmission
Identify ways the network administrator can reduce risk of unauthorized access to confidential data
give each user appropriate login details
different access rights for students
all passwords to be encrypted
use latest WiFi protocols/WPA2
require MAC address authentication
password protected documents
State the role of
a client
a piece of computer hardware/software that accesses a service made available by a server OR
the role of the client is to access a service made available by a server by sending a request for service
a server
a program/host computer that awaits and fulfils requests from client program (in the same or other computers) OR
the role of a server is to fulfil requests from client programs
Packet switching over the internet makes use of standard protocols during its operations
Define the term standard protocol
they are rules/procedures
governing the transmission of data
that allow data to be correctly received
Outline the purpose of using protocols [2]
Set of rules for transmitting data correctly
Ensure that data is send from customerâs computer and received by shopâs computer
To create secure transmission of data from the client to the server through the use of HTTPS, so the customer can pay securely
Outline the main differences between data security and data integrity
data security:
deals with preventing the data being intercepted by a third party
ensures that the people who must have access to the data are the only ones who have access to it
data integrity:
concerned with the data not being altered during transmission
making sure that the data is complete and not corrupted
This question is about a high-speed network
Distinguish between Ethernet and wireless in terms of reliability [4]
Wireless: reliability depends on
Strength of wireless network
topology/shape of surroundings
Interference of simultaneous contacts
Ethernet:
More reliable as strength of signal independent from distance from router
No issue with topology of surroundings
But connection depends on condition of cables (canât be loose or broken)
State technology necessary for a VPN [1]
SSL 3.0
TLS (transport layer security) with encryption
IPsec with encryption
Explain how a VPN allows a person to connect securely to their companyâs network [4]
Tunnelling protocols: allows the data to be encapsulated/hidden whilst travelling across the internet
Encryption protocols (IPSEC): so if hacked will not be understandable
Use of gateways: which allow the person to connect with the companyâs server
This question is about the OSI layer
Outline the concept of the Open Systems Interconnection (OSI) model in communication across a network [3]
The OSI is a standardized system/model for network connection
Which consists of 7 layers
Each dealing with a specific part of network communication
For example, the physical layer which defines the physical connection
Outline, with an example, the function of protocols [3]
Protocols are a set of roles to facilitate a process being carried out correctly
For example, in the physical layer, the protocols would define the methods for opening and closing communication
This question is about packet switching
Outline why packet switching helps provide better security and is less likely to be affected by network failure
Better security
Data is not sent all together
But is divided/sent in separate packets
Each packet is formatted, addressed, and routed
Packets sent by different routes
Making the complete message more difficult to intercept
Less likely to be affected by network failure
Individual packets can be sent by different routes
So if one route is down, others can be used
Describe how to packets are correctly reassembled by the receiving computer
As each packet contains control data/packet sequence number
Receiving computer can combine packets in correct order
This question is about personal information and shops
State measures the book skop can take to address risks [2]
All private information must be encrypted
Transmission channel must be protected by encryption
Logging on to the system must be secured
Dual data backup system in case of accidental deletion
Outline consequences to the customer if their data is not adequately protected [2]
Details stolen; used for fraudulent purposes
Contact details could be shared; used for fraud/junk mail
Personal details stolen; for identity theft
This is a hospital question
Identify two ways in which security of network within hospital can be ensured [2]
Each user should have a password that is changed regularly
Each computer should have access rights depending on location
Computers should not be unattended
Describe how data could be recovered in case of corruption [4]
All data should be backed up daily/weekly
So most recent backup of master file is loaded during corruption
Outline how the network administrator can reduce the risk that sensitive data is only seen by a doctor [4]
Each user should have appropriate access rights
Passwords should be encrypted
File systems should be encrypted
Administrator should record who has logged on from which computer and for how long
This is a question in wires
Outline advantages of WLAN over LAN [4]
Use on the move: more versatile staff, encouraged to collaborate
Allows employees to use their own devices: leads to greater productivity as familiarity with device
No extra equipment is needed for expansion after initial setup, therefore improved safety for employees
Discuss issues and how to resolve [4]
Data can be intercepted
Resolved using strong encryption, WPA2, trusted MAC address, regular hanches of router password
BYOD (bring your own device) issues leading to insecure devices: solve by only allowing approved devices, with added security features
Explain how a VPN is suitable in this solution [4]
Allows employeeâs device to appear to be part of internal company network
Allowing them full access to network resources
Allows companyâs own protocols to be used to ensure security
Even though data is passing over outside network
Programming concepts
Short questions
Sate the BigO efficient of sequential and binary search
O(n)
O(log n)
Define syntax and semantics in relation to programming languages
syntax: the rules of the structure (creation) of a programming language
semantics: the interpretation or meaning of the statements in a programming language
State tasks performed by a compiler
translates HLL to machine code
generates error messages
accesses built-in routines provided by HLL used
creates a separate machine language program
performs lexical analysis
performs syntactical analysis
Explain why subroutines are easier [1]
Can be written independently
Can be tested independently
Can be used many times
Compare internal and external sorting
internal sorting methods allow a set of data to be sorted by loading data into primary memory and applying sorting algorithm there
external sorting is needed when the data is too large for the available primary memory space
sorting takes place by loading subsets of the data into primary memory to be sorted
Outline differences between a compiler and an interpreter
an interpreter converts a single instruction to machine code before execution takes place
a compiler creates a separate machine code version of the entire program while an interpreter does not
to execute a compiled program, the compiler does not need to be in the primary memory while the execution of an interpreted program requires the interpreter to be located in the primary memory at all times
with a compiler, a program only needs to be translated once, whereas with an interpreter it needs to translate every time used
Identify features of a computer language
fixed vocabulary
unambiguous meaning
consistent grammar and syntax
provide a way to define basic data types and operations on those types (ability to write functions/procedures)
provide the ability to to I/O handling
has to be able to be run/processed on computer
State two fundamental operations other than add and retrieve
compare
Store
Explain why x is never zero in (y/x)
To prevent a possible division by zero/run-time error/execution error/program from crashing
Longer questions
This question is about HLLs
Identify why consistent grammar and syntax are essential features [2]
Easy to learn/use
No compilation errors
Less logical errors
Further maintenance and development possible by other programmers
Describe an advantage to application programmers having both interpreter and compiler [2]
Interpreter is faster and immediately warns about syntax errors/executes commands and they could use it instead of compiler while coding and debugging their programs
Compiler required when there is need to produce an executable version of the program
Outline the need for predefined sub-programs and collections [2]
Reusability
Modularity
Reliability (reduces cost and time needed to develop large programs)
Abstract data structures
Short questions
Define recursion [2]
Function that calls itself
Describe the characteristics of a
Queue
FIFO data structure
Items can be added only to rear/tail and removed from front/head
Compare the use of a linked list with an array to store an process the daily sales in a business [3]
size/length of a static array is predetermined/fixed, and the size of a linked list can be changed, it depends on the memory available
Linked list can be expanded to suite the daily sales
Each item in a static array can be directly accessed whilst access to the items in linked list is sequential
And searching for a given item in linked list is slower, as it cannot be searches for using binary search
Explain benefits of using BST compared to stack when searching for a specific item [3]
Time efficiency
Data in BST is ordered
Such that as each node is checked for the item, half the remaining nodes are ignored
While all the elements in the stack have to be checked
So for large data sets, stacks may be inefficient as compared to BST
Memory efficiency
Each element on the stack has to be removed to be checked
When item is found, the stackâs contents will be changed
But when the element is found in the BST, the contents are not removed from the BST
So there is no need to create an additional copy of the BST, but a copy of a stack needs to be created
Explain how elements in the stack may be reversed using a quee [4]
Create an empty queue
While stack is not empty
Pop an element from the stack
Enqueue the popped element
While queue is not empty
Dequeue
Push dequeued element back on the stack
Compare a binary tree to a linked list in terms of searching and storage required [4]
A binary tree is faster and more efficient at searching as it can make use of binary search
A singly linked list is slower and less efficient as it is a linear/sequential data structure
More storage is required in a binary tree as it requires two pointers, and less storage is required for a singly linked list as it requires only one pointer
Outline why recursive solutions can be memory intensive [2]
Recursive call involves use of stacks
For storing/pushing data
If many recursive calls are made, memory usage can be very large
Explain why a stack was used in the game [2]
LIFO structure
In game, allows âundoâ function so movements can be retraced
Outline one advantage of making the queue dynamic [2]
Dynamic queue would not have fixed size
Memory is allocated as required/there is always sufficient memory to accommodate the queue
Resource management
Short questions
Outline why a virtual machine is an example of abstraction that is particularly useful when testing software on different platforms [3]
Provide software emulation/virtualization of other OSs
While hiding/abstracting physical environment/OS/execution environment of host machine
Do not directly correspond to any real platform so software may be tested/executed on any platform=
Software to be tested is compiled into the language of the virtual machine, and this is interpreted into the language of the host machine
Explain two functions that an operating system needs to perform in relation to multitasking [4]
Memory management:
OS allows more than one process to share memory
By allocating separate memory to each program
Provides memory isolation for each process
Processor management
To allow appearance of more than one program running at the same time
By allocation of time slices
Decides which process runs at a certain point in time
Arranges the execution of applications so that you believe that there are several things happening at once
Prioritizes tasks by importance
Describe how memory management of an OS prevents the system from crashing when more than one program is run at the same time [2]
OS allocates and deallocates specific sections of memory to each program/module
Ensures that the memory assigned to one program is not overwritten
Uses secondary/virtual memory to allow more processes to run simultaneously
Outline the use of paging in relation to virtual memory [2]
Paging allows similar-sized sections of data
Identified by specific addresses
To be swapped between RAM and secondary memory/storage
Explain the consequences of 1GB RAM on a multimedia game laptop [3]
