Mark scheme Flashcards
(117 cards)
1
Q
Outline one problem of maintaining legacy systems.
A
- Maintaining previous/outdated computer system, which uses old technology and old application programs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;
2
Q
Explain what is meant by user acceptance testing.
A
A system or a partially functional prototype;
Given to users to test for functionality or to gain feedback on functions or the user interface;
3
Q
Discuss one advantage and one disadvantage of printed material, when compared to online support, as a method to provide user documentation.
A
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;
4
Q
Outline the use of a failover system.
A
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;
5
Q
Describe the function of the control unit (CU) in the central processing unit (CPU).
A
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.
6
Q
Describe how the cache memory can speed up the functioning of a processor.
A
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;
7
Q
Outline one feature of the operating system that needs to be considered when running a game application.
A
- 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;
8
Q
Discuss two possible problems that may occur during data migration.
A
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;
9
Q
Outline one economic aspect that the examination office needs to take into account to support parallel running.
A
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;
10
Q
In the given context, distinguish between Ethernet and wireless in terms of reliability of transmission.
A
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;
11
Q
Describe two features of a VPN that make it secure.
A
- 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)
12
Q
State one technology that is necessary for a VPN
A
SSL 3.0 (Secure socket layer 3)
TLS (with encryption) (Transport Layer Security) IPsec with encryption;
13
Q
Define the term usability
A
Usability means making the computer systems easy to use, matching them more closely to user needs and requirements
14
Q
Identify two methods that could be used to improve the accessibility of a computer system.
A
Voice recognition
Text to speech
Use of touch screen
Braille keyboard
15
Q
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.
A
- 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
16
Q
Describe two types of documentation that should be provided with the software package.
A
- 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;
17
Q
State two methods of delivering user training.
A
Formal classes
Self-instruction
Online training
18
Q
Define the term server
A
A computer system that serves as a central repository of data and programs and is shared by clients
19
Q
Outline what is meant by parallel running
A
Simultaneous operation
Of the new and old system
20
Q
Outline one reason for choosing parallel running as opposed to a direct changeover.
A
As the old system is still running; The new system could be evaluated/used; Without any consequences if the new system fails;
21
Q
Outline the function of the MAR
A
MAR is a register in the CPU
Loaded with the address of the next instruction/data
To be taken from the RAM
22
Q
Outline the function of the MDR
A
MDR is a register in the CPU
Holding the data which is most recently
Taken from RAM
23
Q
Identify two functions of the operating system.
A
Resource allocation Memory management Interrupt handling
24
Q
State where the operating system is held when the computer is turned off
A
Hard disk
ROM
Solid state disk (SSD)
25
Identify the part of the CPU which performs decoding
Control unit
26
Identify the part of the CPU which executes the instruction
Arithmetic and logic unit;
27
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]
28
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;
29
State the purpose of cache memory
Is used to save time in accessing RAM
30
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
31
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;
32
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
33
examples of peripheral devices
Keyboard
Magnetic card reader; Microphone
Monitor
Visual display
Speakers
34
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).
35
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
36
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
37
State one method of providing user documentation.
Help files; Online support;
38
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;
39
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;
40
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
41
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
42
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
43
Identify two reasons for releasing a software update.
1. To patch any vulnerabilities/bugs/cyberspace threats
2. To provide improved functionality/new functions/usability/maximize efficiencies
3. To generate income for the software company/to innovate and stay ahead of other software companies
4. To ensure compatibility with other (updated) technologies;
44
Explain why cache memory can speed up the processing within a computer.
1. Cache memory can be accessed/is faster than RAM
2. It is used to hold common/expected/frequently used data/operations
3. Closer to CPU than RAM/situated between RAM and CPU/on same board as CPU/ with faster read/write speed
4. Cache memory is static RAM and this memory doesn't need to be constantly refreshed;
45
Functions of OS
46
How does memory management prevent program from crashing?
1. 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
3. Uses secondary/virtual memory to allow more processes to run simultaneously
47
Identify any two of the layers of the OSI model
1. Physical layer
2. Data link layer
3. Network layer
4. Transport layer
5. Session layer
6. Presentation layer
7. Application layer
48
Explain how compression of data may lead to negative consequences.
1. Some compression methods (lossy) discard data
2. Decompression will not return the complete file/some detail will have been removed
3. Which in some cases e.g. audio/video may be unacceptable
4. If original not saved/lost there is no way to recover it
49
Explain how the use of media access control (MAC) addresses can improve security
1. The MAC address identifies a specific device (network card/controller)
2. MAC address checked against list of approved addresses/whitelist If not on list access to network is denied
3. Prevents unauthorized access/makes access more difficult/(unless the NIC is cloned)/providing an extra layer to authentication process
4. Data sent to a specific MAC address can only be accessed on that device;
50
Outline the main steps involved in a selection sort
1. The list is searched for the next element in order
2. And placed in its correct position in the new list deleting original OR in the same list by swapping with the element that was there
3. This is repeated for all elements
51
Other than the use of different keywords, outline two ways in which two higher level languages might differ from one another.
1. Method of translation
-> Whether by compiler or interpreter (or both)
2. Loosely/strongly typed
-> Refers to whether data types are specified
3. Different programming paradigms
-> Procedural or object oriented etc
4. Purpose of the language
-> Specific (eg scientific/AI) or general
5. Compatibility with different environments
-> Java with virtual machine can run on all O/S / some languages are O/S specific
6. Syntax differences; Structure of statements etc;
52
Define the term data migration
Data migration is the transfer of data from one system/storage device to another;
53
Describe two problems, concerning data migration, which the company may have to overcome.
1. Data Loss
-> due to transmisson faults/lack of adequate storage
2. Incompatible file formats
-> which could lead to incomplete or indirect file transfer
3. Different file structures
-> mismatch of data
4. Validation rules differ between companies
-> Which could lead to inconsistent/incorrect results
5. Different character sets might be used
-> Which could lead to inconsistent/incorrect results
6. Different languages might be used
-> Leading to translation issues
7. Data corrupted when transferring (data) files
-> And not usable at destination
54
Aspects of change management
1. Workforce issues
-> Such as redundancy/retraining
2. The time frame involved
-> In merging the two systems
3. Testing
-> Of the combined systems/new data
4. Data entry; If migration not possible
-> Costs involved; In the aligning of the two systems
5. Changeover decisions
-> Such as parallel running etc
55
Security characteristics for WAN/GAN
1. A secure authentication process
2. That involves login, passwords and security questions
3. One-time pads
4. Encryption;
56
Security characteristics for VPN
1. Authentication
2. Tunnelling
-> Which is a packet within a packet
3.(Each layer) encrypted; -> Location and IP of user masked;
57
Discuss the importance of protocols in ensuring the successful preparation, transmission and delivery of data using packet switching.
Packet switching involves splitting data into packets to transmit to a specific destination; Protocols are rules/standards used to compile and transmit each packet in a standard format; Essential that all packets are constructed exactly the same; So that the receiver knows automatically how to decode the contents/does not need further instructions for decoding the packets; Error checking methods included to verify that data arrives in same state as it was sent; Protocols include destination information that means that at each node the packet passes through it is sent to the next node towards the correct destination; Packet number essential to be included for reassembling at the other end as not all packets will arrive in order;
58
Describe two advantages to society of the increased availability of WiFi outside the home.
1. Social
-> Keeping up to date when away from home/abroad/travelling/in hospital
-> Can gain access to information such as email/social sites/sports results/ facetime family and friends from long distance/get your homework to do in cafe;
2. Business
-> Working away from home (if you work from home)
-> Avoids missing important meetings if not present or travelling and not able to attend a meeting/ makes possible to work on documents
3. Immediate information: -> Access to public facilities; Make immediate payments/check local transport timetables/taxi (uber)/book restaurants
4. Cost saving: -> Convenience of mobile accessibility
-> Without the cost incurring using a mobile network such as 3G/4G;
59
Identify two essential features of a computer language.
1. Fixed vocabulary
2.Unambiguous meaning
3. Consistent grammar
4.Consistent syntax
5. Provide a way to define basic data types and operations on those types (ability to write functions/procedures)
6. Provide ability of Input and output handling
7. Provide some kind of loop that can be stopped / conditional statement / branching (conditional and unconditional branching)
8. It should have variables that reference computer memory, syntax for basic arithmetic and logical
9. Operations on those memory locations
10. It has to run on/be able to be processed by a computer (ie it must have a compiler/interpreter)
60
fundamental operations of a computer
add
retrieve
compare
store
61
role of a client
A piece of computer hardware or software that accesses a service made available by a server / The role of a client is to access a service made available by a server by sending a request for service;
62
role of a server
A program/host computer that awaits and fulfills requests from client programs (in the same or other computers) / The role of a server is to fulfill requests from client programs (which can reside in the same or in other computers)
63
Identify one method of inputting data that can improve the accessibility of a computer system for some users.
1. Text-to-speech
2. Voice recognition
3. Braille keyboards
4. Touch screen
5. Input from scanner
64
Outline the role of the data bus and address bus in this process.
Buses are used as physical connections to carry information to the CPU; The data bus transports data from/to CPU, whereas the address bus the memory address where the data is supposed to go/be.
65
Define the term bit.
Binary digit; (Minimal) unit of storage that can be set to 0 or 1
66
Outline what is meant by beta testing.
Involves sending sample software to the intended audience; (Selected audience do not pay for this software); To try/use the software product; And give the feedback to the authors (which help in correcting bugs);
67
Describe how a spellchecker checks whether a word in a text file is correctly spelt or not.
Each word in the text file is compared with words in a dictionary (held in memory/online); If the word is found in the dictionary it is correctly spelt / if the word is not found in the dictionary, spellchecker will recognize that it is incorrectly spelt;
68
advantage of text file being automatically saved at regular intervals
If power goes off, only the text typed after last (automatic) save is lost;
69
Identify two additional features of a word processing package that could be useful for this office.
Apply styles, effects; Insert (tables/pictures/graphs/formulas/...); Mail merge; Macros; Print;
70
Outline the purpose of one application software package other than a word processing package that could be used in this office.
Example answers Spreadsheet; For graphically presenting various data; Database software; For holding employees/customers data; Web page creators/editors; To create/manage the office’s web pages;
71
Outline the security measures that should be taken to prevent data loss.
1. Off site data storage
-> Make backups regularly/periodically/frequently
2. Prevent physical damage to the computers / -> Keep equipment in safe and dustfree places / Protect equipment from static electricity that can erase data or damage components / Protection during lightning and electrical storms;
72
Outline one problem that may arise from the installation of new hardware and software in the office.
1. Data migration problems
-> different file formats so conversion must be performed
2. Employee efficiency may drop
-> As they learn to use the new system
3. Issue of compatibility with legacy software/hardware
-> So features of new software/hardware may not work correctly;
73
Compare direct changeover and phased conversion.
Direct changeover, the old software and hardware is completely replaced, in one move, by the new software and hardware
Phased conversion involves selecting one section in the office for the direct changeover and other sections will be switched when the first section selected is running satisfactorily.
Eventually the whole office has been changed
A phased conversion is less risky than a direct changeover as any problems that might arise will be isolated in only one section in the office
Direct changeover means everyone in the organization has same software/hardware and so there are no compatibility issues;
74
Identify one hardware component of the WLAN, other than computers.
Wireless router/modem; Access points; Switch; Wireless repeater/extender/booster
75
The advantages of this WLAN are user-mobility and economical access points. Outline two disadvantages of this WLAN.
Data transfer will decrease (compared with a wired LAN); Because the number of computers using the network increases; (and because) WLAN has lower bandwidth than a wired LAN; Less data security; As devices from outside the school can access the network/intercept transmissions; More easily open to misuse; As teacher/administrator cannot directly monitor a specific student/teacher/ machine; Intermittent connectivity due to physical barriers (walls); Results in low transfer/speed and may hinder operations
76
Identify three ways in which the network administrator can reduce the risk of unauthorized access to confidential data.
1. Give each user appropriate login details/passwords
2. Different access rights for students, teachers, school administrators (file-level and share-level security)
3. All passwords and files should be encrypted
4. Use the latest WiFi protocol/WPA2
5. Require MAC address authentication
6. Password protect the documents;
77
Define the term protocol.
Set of rules for data transmission;
78
explain how data is transferred by packet switching.
Data is organized in specially formatted units (data packets) which are routed from source to destination using network switches and routers
Network switches and routers determine how best to transfer the packet between a number of intermediate devices (routers and switches) on the path to its destination (rather than flowing directly over a single wire on the path to its destination); Data packets are reassembled at the destination
79
Describe one method by which systems requirements can be obtained from the stakeholders.
1. Interviews
-> to establish the functions required by the system
2. Direct observation
-> to gain insight into how the system is being used
80
Outline one reason for a prototype
Stakeholders can gain idea an idea on how it would look/work/be used
so they can give feedback/suggest improvements
81
Outline the role of the memory data register in the machine execution cycle
1. holds a copy of contents in memory
3. Which are to be transferred from/to memory to/from other CPU components
3. Allowing the processor and memory to act independently/processor not affected by differences in the speed of operation;
82
Calculate how many different colours can be represented using two hexadecimal characters
2 hex = 4 + 4 = 8 bits; hence 2^8/16^2/256 colours
83
Explain the importance of the memory management function of an operating system.
1. Allocates and de-allocates memory/ assignes blocks of memory to programs
2. Ensures a program has sufficient memory to run/manages virtual memory if needed
3. To avoid overwriting /clashing of programs/optimise system performance/maximise memory usage
84
Identify two characteristics of a data packet.
1. It contains a set amount of data
2. It contains a fixed structure (or identify elements of the structure other than data)
3. It contains data that is to be sent via a communications channel
4. It contains specific details for transmission e.g. address of sender and receiver, error codes
85
Explain why protocols are used in network communications
1. Protocols are a set of rules
2. (That are used) so that both sender and receiver are using/expecting the same formats/methods
3. To allow data to be transmitted successfully / without errors
86
For an identified application, explain why a binary search would be preferred to a linear search.
1. Searching through a database of names
That contains a large amount of data
2. That is already sorted
And needs to be searched in the least amount of time
3. Is faster because binary search divides and searches smaller blocks of data/does not have to compare each element in the list
87
Describe two different methods that the medical centre could use that would allow data to be restored should it be lost for any reason.
1. Backup
-> Data files on a regular basis
2. Printed copies
-> Printouts can be kept of transactions
3. Transaction Log file
-> Written for each transaction can be used to restore;
88
data security issues
Official access to the data [3 max]:
1. Access to this sensitive data must be restricted. 2. Only those directly concerned can be able to access it.
3. Even less people should be able to edit it. Therefore access levels should be set up, with strong levels of authentication.
4. Physical access to servers should be controlled if using the local system
Data security [3 max]:
1. Is the data safer stored locally or on the cloud? 2. Cloud service providers are professionals – they should have stronger security than a hospital system.
3. What track record / reputation does the cloud service provider have?
4. If patient data could be sold/inspected, then both the patient and hospital could suffer serious consequences.
5. Is the cloud governed by appropriate privacy laws?
6. Is it located internationally or is it governed by the laws of the country in question?
7. Could be intercepted in transmission
89
Define the term concurrent processing
Processes/task are carried out simultaneously/at the same time
90
Outline two advantages, to this company, of installing a WLAN.
1. Use on the move
-> More versatile staff encouraged to collaborate etc
2. Allows BYOD
-> Which could lead to greater productivity (as familiarity with device)
3. No extra equipment is needed for expansion after initial set-up
-> Which will save the company time and money
4. Reduces wiring
-> Therefore improved safety for employees;
91
security issues of a WLAN and how they can be resolved
1. The data can be intercepted as it goes through “the air”
a) Can be resolved by strong encryption/protocols; WPA-2 / a description of WPA-2
b) Use of trusted MAC addresses; Regular changes of router password
2. BYOD issues leading to insecure devices
a) Clear company policy regarding use
b)Use of sand-box
c) Only approved devices allowed
d) MAC addresses – only adding clean and tested devices brought in by staff
e)Installation of MDM services
f) Authentication (user ID + password on all devices including BYOD)
g) Security features added by company;
92
Explain how setting up a virtual private network (VPN) would provide a suitable solution
1. A VPN/tunneling allows the employee’s device to appear to be part of / a node of the internal company network
-> Thus affording him/her full access to the network resources;
2. Data that passes through a VPN can be encrypted
-> So any unauthorized access will not be able to understand the data
3. Tunnelling allows the company’s own protocols to be used/IPsec/TSL ensure security
-> Even though the data is passing over an outside network
4. Multiple exit nodes / hidden IP addresses/encrypted connections
-> Make it hard to distinguish where the data was generated;
93
Outline what is meant by the term computer network.
1. A group of computers and other computing hardware devices that are linked together through communication channels/cables/wirelessly
2. To enable communication (sharing files, sharing information) between systems/among a wide range of users
94
Outline what is meant by a database management system.
1. Database management system is an application software
2. that allows users to define/create/maintain a database / provides (controlled) access to the data
3. Examples of database applications are computerized library, inventory, flight reservation, etc;
95
Outline one advantage of using beta testing prior to the release of a new product.
1. Beta testing is done from the user/client perspective
-> So, requirement mismatches can be easily identified
2. The real users have an opportunity to test a new product before it is (publicly) released
-> So, user acceptance is assured
3. Any bugs identified could be (easily) fixed before the public release of the product
-> So, quality of the product is enhanced
96
Advantages of direct observation
1. Direct observation is systematic/structured process
2. Direct observation allows that current computer system can be studied in its natural setting
3. Direct observation provides a better understanding of the way computer system is used
97
Disadvantages of direct observation
1. Direct observation is susceptible to observer bias
2. Direct observation also can affect the behavior of users/process being observed
3. Direct observation is time consuming
98
Identify two possible compatibility issues as a part of data migration.
1. Language differences/different character set
2. Different conventions of representing various data/currencies, dates, etc
3. Incompatible software/incompatible hardware;
99
Describe how data is transmitted by packet switching
1. data being separated into specifically formatted units (packets)
2. each packet contains data and information such as packet number, address that identifies recipient comptuer etc
3. Packets are routed from source to destination using (different) network switches and routers
4. Using these addresses, network switches and routers determine how best to transfer the packet on the path to its destination
5. Packets are reassembled at the destination (using packet numbers)
6. If any of packets is missing it should be retransmitted
100
Distinguish between random access memory (RAM) and read only memory (ROM).
RAM acts as temporary storage of data, instructions and programs currently running (for the operating system and for the running applications) whilst ROM is permanent memory (stores the instructions and data that won't change/stores the instructions that the computer needs in order to boot up
Memory access, both read and write operations are performed on RAM whilst ROM works with read only operation
If power failures happened during access to RAM then all data will be permanently lost/RAM is volatile memory/whilst if power failure happened during the ROM access no data will be lost/ROM is non-volatile memory;
101
Outline the function of an operating system in managing primary memory.
Award [1] for the answer saying that the function of OS in primary memory management is allocation of specific memory blocks to individual programs and [1] for reallocation up to 2 marks max
"1. A part of the OS (memory manager) assigns that block of memory to the program when a running program requests a block of memory;
2. When the program no longer needs the data in previously allocated memory blocks, they become available for reassignment"
102
Outline the need for higher level languages.
1. High-level language(HLL) provides statements (for example, high level if(…), while(…) , etc) which are not dependent on the specific machine / and ability to create various data structures
a) Which saves the programmer’s time
2. Higher level languages are closer to human language
a) So programmers find them easier to understand/work with than lower level languages
3. HLL saves programmer from knowing details of computer architecture (and using all the specific (machine) instructions)
a) So giving more time to creating/developing the best way of coding a problem/process of coding is simpler and more understandable
103
Explain two benefits of using sub-procedures within a computer program.
Program organization; Program coding; Program testing; Maintenance;
1. Problem could be divided into smaller/easier parts
a) Which means solving easier/smaller parts of the problem for one programmer Or for a team of programmers, each programmer could work on different smaller parts
Simpler testing
b) each part of the program could be separately tested By the programmer who created the code or someone else in the team of programmers
3. Reusable code
a) Sub-procedures already written/tested could be used in various programs
4. Simpler maintenance and changes
a) Could be done only on required sub-programs;
104
Identify three characteristics of a collection.
Award [1] for data structure implementation/objects/elements of collections.
Award [1] for algorithms/methods/callback functions.
Award [1] for showing that collection reduces programming effort / increases performance (by providing efficient implementations of data structures and algorithms).
105
Define the term peripheral.
A piece of hardware / a hardware device that is externally connected or attached / remotely connected or attached (to the computer system)
106
Identify two features of a graphical user interface (GUI)
Menus; Dialogue boxes; Windows; Icons; Pointers; Buttons;
107
Outline one method of collecting information from stakeholders concerning the requirements for a new system
1. Surveys
a) (General) questions distributed to many stakeholders as a written or online document
2. Interviews
a) (Specific) questions asked of nominated stakeholders in an individual setting
3. Direct observations
a) Observer watches stakeholders performing their current tasks;
108
Features that need to be considered when planning a new computer system
1. Roles/Activities of users
2. Resources(hw+sw equipment) for the organisation
3. costs/budget limits
4. delivery time
5. compatibility with old system
6.
109
How is a colour represented in a computer
A colour will be split into three components (RGB)
Each component will be assigned a certain number of bytes
110
Features of a P2P network
1. no central server
2. resources are made more widely available (storage, bandwidth, computing power)
3. redundancy/recovery
4. supports file sharing for collaborative work
111
define the term data packet
a unit of data for transmission
with a format (eg. containgin address and data)
112
Explain why the speed of data transmission across a network can vary
1. Different parts of network use different media
2. network congestion
3. packets may take different routes
4. the receiver may be busy
5. physical size of network
6. fibre is faster than coax
7. some packets are made faster by congestion
8. may be longer transmission lines over large distances
113
Describe the features of SaaS
1. Data is in the cloud/computing infrastructure
2. SW necessary for activities in the cloud
3.
114
Security limitatinos of SaaS
1. Data is stored in the server of the service provider
a) so company has no control over its security
2. Legislation in provider's country may be weaker than in user's country
3. Security in transmission: applications running in site may require data in SaaS
hence longer transmission times and higher risk of failure/attack/interception
115
Extranet
1. external extension to a company's local network
2. limited access
3. uses internet protocosl
116
difference between a VPN and an extranet
VPN authentices sender (establishing tunnel)
VPN access os always encrypted, extranet has limited encryption
VPN transmission is always encrypted
VPN users have access to everything wheras extranet users only have access to specific devices
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