Mark scheme Flashcards
Outline one problem of maintaining legacy systems.
- Maintaining previous/outdated computer system, which uses old technology and old application programs
-> That are hard to understand/expensive to change/evolve because programs might be disorganized/ documentation might be missing/incomplete/unreliable; - Compatibility issues (typically refer to old programming languages/old database technology);
- Maintaining but not updating the old system can lead to compatibility / security issues; It may be difficult to recruit staff/programmers familiar with old languages/operating systems;
- Database contains inconsistencies/redundancies (eg information systems and no DBMS);
- Usually pre-internet, needs interfaces; Typically large and complex systems/mainframes;
Explain what is meant by user acceptance testing.
A system or a partially functional prototype;
Given to users to test for functionality or to gain feedback on functions or the user interface;
Discuss one advantage and one disadvantage of printed material, when compared to online support, as a method to provide user documentation.
advantages:
Portability
Printed material is more easily transportable and can be moved around (eg for a scanner/printer) Extent of material Books/technical instructions for installation may have more details, and be more useful to provide deeper explanations
Availability
It is always available (no power cut problems);
Disadvantages:
Readability
Font size online can be (easily) magnified
Trouble-shooting/cross-reference/usability; Online is faster and usually has links to other pages whereas paper is a thick manual
Aging
Online is more frequently updated than paper manuals
Environmental
Waste of paper versus energy consumption;
Outline the use of a failover system.
A failover system is a standby/redundant system;
Which is used to eliminate/reduce the impact on users/owners;
By automatically taking over if the primary system suddenly becomes unavailable;
Describe the function of the control unit (CU) in the central processing unit (CPU).
Obtains the data/instructions from the memory
Interprets/decodes them into commands/steps/signals
Controls transfer of data and instructions among other units of a CPU (for example, command to ALU for execution)
Manages/coordinates all the units of the computer; etc.
Describe how the cache memory can speed up the functioning of a processor.
Cache memory is closer to CPU/faster to access than main memory/incorporated on the chip
By holding recently/frequently used data and instructions in cache
Execution of program/fetching instructions and data is faster;
Outline one feature of the operating system that needs to be considered when running a game application.
- Memory management; -> Game applications use a lot of memory and require constant refreshing; 2.Processor loading of OS functions (efficiency)
-> Graphics handling of OS (as distinct from graphics card), - GUI; O/S needs to handle input from appropriate devices;
Discuss two possible problems that may occur during data migration.
Data loss/corruption
-> when moving data from one storage device to another
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 in business/office operation;
Outline one economic aspect that the examination office needs to take into account to support parallel running.
Two systems are running simultaneously so that operations are not disrupted; This is a costly operation; [4] Because both systems and all their resources should be maintained / More staff should be hired;
In the given context, distinguish between Ethernet and wireless in terms of reliability of transmission.
WIRELESS The reliability of wireless depends on the strength of the wireless signal/distance from router; on the topology/shape of the surroundings; on interference/number of simultaneous connections on an access point; ETHERNET Ethernet is more reliable as the strength of the signal is independent from the distance from the router (within the college); There is no issue with the topology/shape of the surrounding, as long as the user has a connection; connection depends on condition of cables – no loose or broken cable connections;
Describe two features of a VPN that make it secure.
- Authentication
-> Nobody outside the VPN should be able to affect the security property of the VPN - Encryption
-> Data intercepted will not be readable - Tunnelling software
-> Security properties of each tunnel should be agreed by the administrators of the two endpoints of the tunnel - Multiple exit nodes
-> Makes it hard to distinguish where the data was generated thus more secure (less prone to phishing)
State one technology that is necessary for a VPN
SSL 3.0 (Secure socket layer 3)
TLS (with encryption) (Transport Layer Security) IPsec with encryption;
Define the term usability
Usability means making the computer systems easy to use, matching them more closely to user needs and requirements
Identify two methods that could be used to improve the accessibility of a computer system.
Voice recognition
Text to speech
Use of touch screen
Braille keyboard
By making direct reference to the technologies used, explain how a virtual private network (VPN) allows a travelling salesperson to connect securely to their company’s network.
- Tunnelling protocols
-> Allows the data to be encapsulated/hidden whilst travelling across the internet; - Encryption protocols (IPSEC)
-> If hacked it will not be understandable - The use of gateways
-> Allows the salesperson to connect with the company’s server
Describe two types of documentation that should be provided with the software package.
- Technical documentation
-> Describes how to install software
-> Describes the hardware configuration needed - User documentation
-> Describes various functions of the software
-> Helps users to learn how to use the software;
State two methods of delivering user training.
Formal classes
Self-instruction
Online training
Define the term server
A computer system that serves as a central repository of data and programs and is shared by clients
Outline what is meant by parallel running
Simultaneous operation
Of the new and old system
Outline one reason for choosing parallel running as opposed to a direct changeover.
As the old system is still running; The new system could be evaluated/used; Without any consequences if the new system fails;
Outline the function of the MAR
MAR is a register in the CPU
Loaded with the address of the next instruction/data
To be taken from the RAM
Outline the function of the MDR
MDR is a register in the CPU
Holding the data which is most recently
Taken from RAM
Identify two functions of the operating system.
Resource allocation Memory management Interrupt handling
State where the operating system is held when the computer is turned off
Hard disk
ROM
Solid state disk (SSD)
Identify the part of the CPU which performs decoding
Control unit
Identify the part of the CPU which executes the instruction
Arithmetic and logic unit;
Describe the purpose of this prototype.
Prototype is used to ensure all essential functions/operations of the system are present/meets the needs of the users
Prototype is used to speed up development process
Positive user’s feedback helps in refining the acceptable prototype in order to develop the complete system/product; Or else a further prototype should be created in order to develop the satisfactory system/product; etc. [3]
State three potential usability issues with cell phones
Has a small (touch-sensitive) screen; Uses batteries for power; No hard disk drive / small memory; Reliability / Network coverage issues; Over in warm weather; Too many steps to access a particular feature;
State the purpose of cache memory
Is used to save time in accessing RAM
Outline one advantage and one disadvantage of wireless networks.
- Ease of use for mobile users * Connectivity between different locations * Reliability * Cost * Security * Change in working patterns * Health issues
+ expansion
Outline two ethical issues concerning this use of the internet.
The data/information is deliberately incorrect; The data/information has not been validated; Intellectual property issues; Plagiarism;
Outline the features of a virtual private network (VPN).
VPN transmission is always encrypted / provides a secure connection
Establishes the tunnel between sender/receiver Sender/receiver is authenticated before sending/receiving
VPN users have access to all services available
examples of peripheral devices
Keyboard
Magnetic card reader; Microphone
Monitor
Visual display
Speakers
Outline the purpose of protocols in transferring this data
Protocols are sets of rules for transmitting data correctly; They ensure that data is sent from a customer’s computer and received by the shop’s computer; To create a secure transmission of data from the client to the server through the use of the Hypertext Transfer Protocol (HTTPS) ie the customer can pay for the books securely (using TLS or SSL).
Identify two reasons why consistent grammar and syntax should be essential features of a higher level programming language.
Easy to learn/use Otherwise time may be wasted learning the new language/writing programs in this HLL
There will be no/less compilation errors
There will be no/less logical errors
(Reduction of time to create software;)
Future maintenance/development is possible by other programmers
Identify two features of a user interface that will allow application programmers to interact more easily with the programming language.
GUI; Toolbars; Menus; Built in commands for inputting from touch screens; Predicted text so that typing a class name followed by a full stop will bring up a list of methods/attributes; Automatically use a colour to represent keywords/variables and improve readability
State one method of providing user documentation.
Help files; Online support;
Outline the need for an interpreter or a compiler.
Must be translated from a higher level language understandable by humans/not understood by machines; Must be translated into machine code; For the CPU to execute it;
Describe one advantage to application programmers of having both an interpreter and a compiler available.
Interpreter is faster/immediately warns about syntax errors/executes commands and they could use it instead of the compiler while coding and debugging their programs; Compiler is required when there is a need to produce an executable version of a program;
Outline the need for predefined sub-programs and collections
Reusability; Modularity; Reliability / All predefined sub-programs are tested and reliable;
reduces cost/saves time for the programmers
Describe the use of beta testing
It is when an application/program is tested/ to get feedback (for errors/improvements); By releasing it to the general public/users/stakeholders before final release
Identify two causes of data loss.
Natural disaster/power failure
Accidental deletion Malicious activities (hacking/theft/viruses); Hardware/software/system failure
Bad integration/migration of systems/data
Transmission error
Lossy compression when the original no longer available only the modified version
Identify two reasons for releasing a software update.
- To patch any vulnerabilities/bugs/cyberspace threats
- To provide improved functionality/new functions/usability/maximize efficiencies
- To generate income for the software company/to innovate and stay ahead of other software companies
- To ensure compatibility with other (updated) technologies;
Explain why cache memory can speed up the processing within a computer.
- Cache memory can be accessed/is faster than RAM
- It is used to hold common/expected/frequently used data/operations
- Closer to CPU than RAM/situated between RAM and CPU/on same board as CPU/ with faster read/write speed
- Cache memory is static RAM and this memory doesn’t need to be constantly refreshed;
Functions of OS
How does memory management prevent program from crashing?
- The OS allocates (and deallocates) specific sections of memory to each program/process/module 2. This ensures that the memory assigned to one program is not overwritten
- Uses secondary/virtual memory to allow more processes to run simultaneously