Component 2

Question 1

Describe the storage of data in indexed sequential files. [4]

Answer 1

 Save records in data blocks on disk, with records sorted into sequential order within each data block.
 Locating records through use of index block pointers.
 Explanation of multiple levels of index.
 Fast searching using indexes will find the data block containing the required record.
 Could be faster than searching the overflow area of the random access file.
 Easy to add any amount of further records by adding extra data blocks, then setting index pointers.

Question 2

Identify 3 uses of RFID [3] p

Answer 2

Inventory and assets tracking
Contactless payment systems
Livestock or pet identification

Question 3

Explain the term data mining. [3]

Answer 3

*The process of analysing a large batch of information to discern trends; by identifying patterns and connections in data based on what information users request or provide.
*Statistical and data mining tools are applied to large data sets: to build models to predict what might happen in the future.

Question 4

Explain how data can be manipulated to provide the user with useful information. [11] e

Answer 4

Sorting - Arranging data into a specific order
Filtering - Selecting only the data that meets certain criteria
Aggregating - Summarising data
Grouping - Organising data into categories
In order to:
Generate visualisations / Identify trends / Spot anomalies

Question 5

Identify 3 advantages of OMR [3] p

Answer 5

Fast data input from multiple-choice forms
Low error rate when filled correctly
Reduces manual data entry workload

Question 6

Identify 3 uses of OCR [3] p

Answer 6

Digitising printed documents for archiving
Automatic number plate recognition
Processing scanned application forms

Question 7

Explain why there may be objections to the use and storage of biometric data. [4]

Answer 7

Inconvenience and intrusion of privacy in having to be photographed/ fingerprinted.
Cost of the system, e.g. in increasing the fee that has to be paid by individuals for a biometric passport.
The facial recognition database could allow officials to carry out unauthorised surveillance by monitoring CCTV pictures.
Possible errors in the system, (e.g. through misidentifying persons in poorly lit street following a crime).

Question 8

Describe integer and its storage requirements [2] p

Answer 8

• A whole number (positive, negative or zero)
• Storage depends on bit length

Question 9

Explain what is meant by data consistency. [2]

Answer 9

• Changes made to different occurrences of data is controlled and managed in such a way that all the occurrences of a specific data item
• This refers to the separation of information from the applications and programs that use it.
• So that modifications to source code are not required every time changes to the data characteristics / properties are made have the same value.
• Ensuring searches produce consistent results.

Question 10

Explain how a program instruction is decoded. [2] p

Answer 10

*Instruction in the CIR is sent to the control unit
*The control unit decodes the instruction by interpreting the opcode and identifying any required operands

Question 11

Describe fixed-length string data and its storage requirements. [2]

Answer 11

• A series of characters where the number of characters is fixed by the programmer when declaring the string as a variable.
• The storage requirement of a fixed length string is a factor of the character set used e.g. 8 Bit ASCII. Storage requirement = 8 x maximum number of characters.

Question 12

Describe the organisation and process of using a random access file to store data. [6]

Answer 12

File organisation, records are stored in random order in the file with no sequencing.
The file is organised using a pre-defined relationship between the key of the record and its location within the file.
The value of the record key is mapped by a function to its address within the file, enabling direct access.
Access times should be consistent as the location of the record within the file is not a factor in the access time of the record.

Hashing – The usual method for mapping, is to employ a hash function to calculate the address.
A hash function generates the record address by performing some simple operations on the key or parts of the key.
A good hashing function should be quick to calculate, cover the full range of the address space, give an even distribution and avoid frequent collisions.

Question 13

Describe two uses of QR codes other than to input a URL, which when scanned could be used by the device’s browser to open a webpage. [4]

Answer 13

• Calendar data. Including appointment details that may be saved directly to a digital diary.
• Location data. That can be scanned and processed to give directions.
• Email address. That can be used to open a blank email / locator form with pre-defined recipient and subject.

Question 14

Describe networks and how they communicate. [1] e

Answer 14

Networks consist of two or more computer systems that are connected to allow them to share resources and exchange information.

Question 15

Explain the predictive analytics. [4]

Answer 15

• The use of data, statistical algorithms / machine learning / modelling techniques.
• to identify the likelihood of future outcomes / trends.
• Based on historical data.
• Provides an assessment of what will happen in the future.
• Produce data visualisations
• Data cleansing and transformation

Question 16

Describe three disadvantages of off-the-shelf software. [6] p

Answer 16

May not full meet needs - Designed for a wide audience, so may lack specific features a user or business requires
Unnecessary features - Can be bloated with functions that are not needed, potentially making it more complex and resource-heavy
Limited flexibility - Users cannot easily modify the software to suit changing requirements

Question 17

Describe the most suitable mode of operation for traffic lights. [2]

Answer 17

Traffic Lights Real time control processing.
Traffic lights have timed intervals, and may also react
to the arrivals of traffic.

Question 18

Describe three disadvantages of bespoke software. [6] p

Answer 18

High cost - Development can be expensive due to customisation, testing, and ongoing maintenance
Longer development time - It may take months or even years to fully develop and test the software
Risk of developer dependency - Future updates or fixes may require the original developers, leading to potential delays or higher costs

Question 19

Describe the function of the Program Counter in the Von Neumann fetch-execute cycle. [2]

Answer 19

The Program Counter (PC) will hold the address of the next instruction to be fetched from main memory.
As soon as the address is read the Program Counter (PC) increments
to hold the address of the next instruction to be executed.

Question 20

Compare representing numbers in integer and floating point forms. [5] e

Answer 20

Integers are fast processing however floating point isn’t
Integers are stored exactly however floating point can give rounding errors
Integers usually require fewer bits than floating point for similar-sized values

Floating point supports very large and small values
Floating point represents fractional values

Question 21

When an email is sent using TCP, a connection is established, a 3-way handshake is made, and the email is transmitted. Describe this communication process. [4]

Answer 21

Source sends SYN ‘initial request’ packet to the target server in order to start the dialogue.
Target server responds with a SYN-ACK packet to agree to the process.
Source sends an ACK packet to the target to confirm the process.
The email message is broken down into packets, sent via the Internet / traverses a series of gateways before arriving at the target device where the group of packets are reassembled by TCP

Question 22

Partitioning of main memory is a responsibility of the operating system’s memory management function.
Explain the need for partitioning of main memory, the different methods that can be used for partitioning and possible consequences associated with these methods. [9]

Answer 22

• Partitioning allows for separate processes to be allocated to the partitioned areas of main memory.
• Without partitioning every process would have to be loaded into memory separately once the proceeding process had been executed significantly slowing down the overall process.
• An operating system’s memory management function keeps track of the status of each memory location, either allocated or free to ensure its effective and efficient use.

Two memory management techniques:
* Contiguous, where each executing process must be loaded entirely into one partition of main memory.
* Non-contiguous, where processes can be divided into different parts and fill the space in main memory. This has the advantage of reducing memory wastage, but slows execution because time is consumed in address translation.

The consequences of partitioning will vary according to the partition method used, either fixed, variable or dynamic.

Fixed partitioning.
* The simplest method used to put more than one process into main memory.
* The partitions are made before execution or during system configuration.

Possible consequences include:
* Internal Fragmentation: Main memory use is inefficient. Any program, no matter how small, occupies an entire partition. This can cause internal fragmentation.
* External Fragmentation: The total unused space of various partitions cannot be used to load processes
* Limited process size: Processes of size greater than the size of the largest partition in main memory cannot be accommodated.
* Limitation on degree of multiprogramming: Partitions in main memory are made before execution. The number of processes cannot be greater than the number of partitions in memory.

Variable partitioning is a system for dividing memory into non-overlapping but variable sizes. The number of partitions is fixed but the size of each partition may vary. More flexible as small processes are allocated to small partitions and large processes allocated to larger partitions.

Dynamic Partitioning.
* Partitions are not made before execution but during run-time according to processes’ needs, with the size of partition equal to the size of incoming process.
* The number of partitions is not fixed but depends on the number of incoming processes and size of main memory.

Consequences arising from dynamic partitioning.
* No Internal fragmentation.
* No restriction on degree of multiprogramming
* No restriction of process size.

Disadvantages
* More difficult to implement as it requires allocation of memory during run-time.
* External fragmentation may still arise as e.g., partitions initially allocated to a 2 MB and a 1MB process cannot be re-allocated to a 3 MB process after execution as each process must be accommodated within one partition.

Question 23

An engineering firm has decided to replace the 32-bit computer system it uses for Computer Aided Design (CAD) work with a new 64-bit system, with multi-core processors and increased memory.

Explain the advantages the new system should provide for the engineering firm. [6]

Answer 23

Memory utilisation
CAD requires a lot of memory to accommodate the large drawing files. A 32-bit system can access 232 memory addresses, i.e. 4 GB of RAM or physical memory. A 64-bit system can access 2^64 memory addresses and is required to handle any amount of memory greater than 4 GB.

Improved productivity due to speed of calculations.
CAD software calculates the relative sizes and positions of the various screen entities. The number of calculations per second affects the speed at which the system can complete tasks. 64-bit multi core processors allow an increased number of calculations per second which will make the system run faster and operate more efficiently, improving the productivity of the CAD work.

Multitasking
Using 64-bit helps with multi-tasking, where users can easily switch between applications, or CAD tasks, without noticeable delays.

Question 24

Identify 3 uses of MICR [3] p

Answer 24

Processing bank cheques
Document validation
Secure identification

Question 25

Describe a range of conditions or events that would generate an interrupt and explain how they would be dealt with. Give examples to illustrate your answer. [7]

Answer 25

Interrupts are signals to the operating system / CPU requesting attention. The operating system / CPU will suspend the current program(s) in order to deal with the interrupt (then resume the program(s) from the point reached). * Mouse click or mouse move * Keyboard key press * Printer ready for further data * Printer out of paper/ink… * Disk drive data transfer completed * Power failure * Mathematical error in program, such as 'division by zero'. * File handling error in program such as file not 'found'. * Execution of program completed. * User termination of program by CTRL/ALT/DEL or ESC. interrupts may have different priorities.

Question 26

Describe the need for multiplexing.  [2]

Answer 26

In computer networks, multiplexing is needed to combine multiple digital signals into one signal so the multiple messages can be transmitted along a single data link / channel at the same time.

Question 27

Describe how time-slicing operates in a system. [2] p

Answer 27

Divides the CPU’s processing time into small units called time slices Each active process is given a turn to run for a short time splice before control passes to the next process, allowing for multitasking (and fair CPU usage)

Question 28

What are the disadvantages of vocabulary dictation input [3] p

Answer 28

Can struggle with strong accents and speech impediments Background noise can affect accuracy May misinterpret homophones

Question 29

Describe the main features of batch processing. [2]

Answer 29

* Uses a transaction file to record events, then the master file is updated at the end of each period (day/week…) * Is a simpler/faster system to operate. Transactions can simply be stored in the order received, with all processing carried out later. * Can be carried out automatically at times when the computer system is not otherwise in use (e.g. at night).

Question 30

Describe typical contents of TCP/IP packet. [5] e

Answer 30

Source address Destination address Packet number (and total number of packets) The data itself A checksum

Question 31

State why input and output buffers are necessary in a spooling system. [1]

Answer 31

There is a difference in device speed between the spooling system disk and the mainframe processor, printer, or user terminals.

Question 32

Describe the main features of real time control processing. [2] p

Answer 32

Immediate response to inputs - the system processes data and reacts instantly or within a strict time limit Used in automated systems where timing is critical, such as industrial control, robotics, or flight systems

Question 33

Explain what is meant by database normalisation. [4]

Answer 33

 is a way of structuring data according to theoretical rules  normalising data usually reduces data duplication/redundancy  avoids danger of inconsistency / maintains integrity  avoids danger of data being lost during update  avoids wasting processing time  probably enables easier maintenance of the database  allows different views of the data.

Question 34

Compare the operation of USB and Bluetooth as methods of connecting peripheral devices. [4]

Answer 34

Universal Serial Bus is a (fast) interface for connecting peripherals to computers using serial data transmission / wired connection.  USB cables transmit data and also provide a power supply for peripheral devices.  Many devices can be linked to the serial bus, chained together through hubs.  Devices on a serial bus can be allocated different levels of priority: continuous operation (e.g. web cam) or only by generating an interrupt (e.g. keyboard). Bluetooth is a wireless interface for connecting peripherals to computers.  avoids need for cables, which might be more convenient on small desk, or for using headphones.  devices would need their own power supply  Devices generally require pairing

Question 35

Describe the process of handshaking between two devices. [4]

Answer 35

 Handshaking is the process by which two devices establish their readiness to communicate  Device 1 will send a signal (SYN) to device 2  Device 2 will acknowledge the signal (SYN-ACK)  Device 1 sends another signal of acknowledgement  Device 1 begins transmission.

Question 36

Describe the role of the computer in CAD. [2]

Answer 36

*To run specialised graphics software able to carry out the geometric calculations necessary to produce accurate 2D and 3D screen representations / models; that can be viewed and manipulated from all angles. *To improve the efficiency / productivity of the design process; by enabling early visualisation of design proposals, improve record keeping through better documentation and version control and promote team working through better communications.

Question 37

Describe file attributes. [2] e

Answer 37

Metadata that define the properties or status of a file Helps with file protection, organisation, and system management

Question 38

Describe two other advantages of using open source software other than it (often) being free to use. [4]

Answer 38

* Reliability - Software continually analysed and improved by a large community resulting in secure and stable code. * Independence from the original authors. - Code continues to be developed by its users. * Open standards - Removes the problem of incompatible formats that exists with proprietary software.

Question 39

Describe the most suitable mode of operation for gas billing. [2]

Answer 39

Batch processing. Bills are issued regularly in response to meter readings.

Question 40

Identify 3 advantages of touch screen [3] p

Answer 40

Intuitive and easy to use No need for separate input devices And so saves space

Question 41

Explain the basic state of a process: running. [3] p

Answer 41

The process is actively being executed by the CPU Only one process per CPU core can be in the this state at a time It has full access to the processor until its time splice ends or it’s interrupted

Question 42

Explain the basic state of a process: blocked. [3] p

Answer 42

The process cannot continue until a specific event occurs, such as receiving input or access to a locked resource
For example, if a process requests data from a disk, it will be blocked until that data is available Once the event is completed, its moved to the ready queue

Question 43

Describe the role of crawling. [2]

Answer 43

* The discovery process in which search engines send out a team of robots (crawlers or spiders) to find new and updated content, such as a webpage, an image, a video, etc. * The content is discovered by following links on webpages to find new URLs and then adding them to a the index of discovered URLs — to later be retrieved when a searcher is seeking information that the content on that URL is a good match for.

Question 44

Describe the process of symmetric encryption. [4]

Answer 44

Symmetric encryption is a type of encryption where only one key is used to both encrypt and decrypt electronic data. The parties communicating via symmetric encryption must exchange the key so that it can be used in the decryption process. Using symmetric encryption algorithms, data is "scrambled" so that it cannot be understood by anyone who does not possess the secret key to decrypt it. Once the intended recipient who possesses the key has the message, the algorithm reverses its action so that the message is returned to its original readable form. The secret key that the sender and recipient both use could be a specific password/code, or a random string of letters or numbers generated by a secure random number generator (RNG).

Question 45

Describe three disadvantages of open-source software. [6] p

Answer 45

Limited support - May rely on community forums rather than professional help, which can be reliable / slow Security risks - Code is publicly available, which could be exploited by attackers if not properly maintained Complexity and usability issues - Some open-source tools are less user-friendly or harder to install and configure compared to commercial alternatives

Question 46

Explain the use of multi-level indexes. [3] e

Answer 46

First-level index points to blocks of second-level indexes The second-level indexed then point to the actual data blocks Helps manage very large datasets efficiently

Question 47

Describe the most suitable mode of operation for theatre booking. [2]

Answer 47

Theatre Booking Real time transaction processing. To avoid double bookings, the ticketing database is updated immediately payment is made.

Question 48

Describe the use of computer-generated animations in two areas not connected with entertainment. [4]

Answer 48

* A medical animation - a short educational film, usually based around a physiological or surgical topic, rendered using 3D computer graphics and most commonly used as an instructional tool for medical professionals or their patients. * Education and training. A popular tool in classroom teaching and learning and in work related training. Use of animation can increase interest & motivation in learning. * Forensic animation - The use of computer animation, stills, and other audio visual aids to recreate incidents to aid investigators and help solve cases.

Question 49

Identify 3 advantages of OCR [3] p

Answer 49

Converts printed text into editable digital format Reduces the need for manual data entry Speeds up document processing

Question 50

Explain the process for using biometric data to control access to a secure area or system. [4]

Answer 50

Data capture The data would be digitised and stored on a database. Access request - data would again be captured and compared to the reference record stored in the database. A decision made, based upon the comparison.

Question 51

Describe penetration testing. [2] e

Answer 51

A controlled simulation of a cyberattack carried out (to test a systems defences) Includes planning, testing, reporting vulnerabilities and suggesting improvements

Question 52

What are the advantages of optical disk [5] p

Answer 52

Low cost per disk So good for read-only distribution Portable and lightweight Resistant to magnetic fields Long shelf life

Question 53

Powerful computer systems are used in forecasting the weather. Explain why such systems are needed and any drawbacks of these systems. Your answer should also discuss how data is captured and processed. [10]

Answer 53

 Weather forecasts are made by collecting quantitative - numerical - data about the current state of the atmosphere  Data is captured by using a variety of sensors  In the case of weather models, data such as rain fall, temperature and wind speed are fed into a computer  Data is transmitted and collected centrally from thousands of sensors  This data is then put into a mathematical model  Predictions are made based on current conditions  A series of calculations is performed on the raw data on it to determine how it will change over time  Normally, mathematical modelling is done by powerful computers, which can carry out many calculations per second  The computer uses equations produced from the scientific understanding of atmospheric processes  Such as fluid dynamics and thermodynamic equations  The more sophisticated and up-to-date your model is, the more accurate your forecast should be  Parallel processing is generally used for complex calculations in mathematical weather models  Distributed processing enables many computers to share the load  Collaboration across countries  Weather predictions are not always 100% accurate  Equipment is extremely expensive  Weather predictions cannot account for freak weather patterns

Question 54

Explain why internet banking applications use TCP, whereas online games use UDP. [4]

Answer 54

TCP includes comprehensive error checking to prevent and correct errors. UDP uses only checksum to avoid errors and cannot correct errors. TCP data packets are sequenced UDP data packets arrive in no fixed order, but are re-assembled in the order they are received, resulting in possible inaccuracies. TCP is suitable for point to point transmission. UDP is suitable for broadcasting data packets to groups of endpoints. TCP is suitable for uses where data integrity is essential. UDP is used where transmission speed is such that a few dropped packets do not matter.

Question 55

Describe what is meant by an indexed sequential file and give the main advantage of using an indexed sequential file compared with a standard sequential file. [3]

Answer 55

 Records are stored in key sequence order (within each data block)  An index allows data to be accessed directly / index contains key field and disk address of record / the key field and index are used to locate the correct position  Advantage - faster access - can use index to access required data directly

Question 56

Explain how the control unit will fetch the next program instruction. [2]

Answer 56

* The program counter value is used to calculate the RAM address of the next program instruction. The address is transferred to the MAR. * The address is then sent out along the address bus. The program instruction returns along the data bus (and is stored in the CIR). * The program counter is updated.

Question 57

Identify 3 uses of OMR [3] p

Answer 57

Exam paper marking Surveys and questionnaires Voting forms or ballots

Question 58

Identify 3 advantages of MICR [3] p

Answer 58

High accuracy in reading characters Difficult to forge or alter Can be read even if obscured by marks or stamps

Question 59

Give two examples of interrupts which might be involved in controlling the processing of programs. [2]

Answer 59

 Clock sends interrupt at the end of the time slice  Disk controller sends interrupt when file transfer completed  Printer sends interrupts to spooling system  Processor sends interrupt if a software error occurs  Terminals send interrupts if key pressed/mouse clicked

Question 60

Describe a disadvantage of priority based scheduling and explain how this may be overcome. [4]

Answer 60

If new higher priority processes keep coming into the ready queue, then the processes waiting in the ready queue with lower priority may have to wait for long durations before execution. Possibly leading to indefinite blocking or starvation. The concept of aging can be used to prevent starvation of any process. Where the priority of a low-priority job is incremented as waiting time increases.

Question 61

Describe the role of three special CPU registers in the fetch-execute cycle, other than the program counter. [6]

Answer 61

Current Instruction Register (CIR). Holds the instructions that is currently being processed / executed. Memory Address Register (MAR). Holds the address found of the current instruction that is to be fetched from memory. / Holds the memory address to which data is to be transferred. Memory Data Register (MDR) Holds the contents found at the address held in the MAR./ Holds data that is to be transferred to RAM. Accumulator. Acts as temporary storage location which holds an intermediate value in arithmetic and logical operations. / Holds intermediate results which overwrite results of previous steps in a calculation.

Question 62

Explain the term multiprogramming. [2]

Answer 62

*A multi-programming operating system allows multiple processes to reside in main memory where only one program is running. *The aim is to optimise CPU use by reducing CPU idle time. *Concept of context switching - The switching is done when the currently executing process halts, such as when waiting for I/O, and the CPU is allocated to some other process

Question 63

Describe the main features of real time transaction processing. [2]

Answer 63

* Involves direct updating of the master file immediately an event occurs. * Can avoid double booking * Gives an accurate current view of the data * Involve more complex algorithms

Question 64

Describe the purpose of an operating system in a personal computer. [9]

Answer 64

* Providing a user interface, typically using windows, icons, menus and pointers (WIMP). * Providing an interface to peripheral devices such as keyboard, mouse, speakers, printer... * Running software programs, by loading program code and data into RAM then activating the CPU to execute the program. * Allowing multiple programs to be active at the same time, by sharing processor time. * Providing an interface for local or wide area networking. * Allowing the configuration of hardware, such as screen resolution, mouse movement response. * Providing device drivers to allow new peripherals to be installed. * Controlling the storage of files in secondary storage, and displaying a catalogue of programs and data files. * Providing security to prevent unauthorised access or alteration of data. * Allowing multiple users to have personal secure access through a password system. * Responding to system errors in a way which minimises data loss. * Displaying previews of common file types, such as: images, video, sound, text. * Handling on-line updates to the operating system.

Question 65

Describe black hat hacking. [2] e

Answer 65

Illegal hacking performed with malicious intent Often for personal / financial gain, political aims or to cause harm

Question 66

Describe the advantages of different users having different views of the data in a database. [4] e

Answer 66

Improved security and privacy Simpler UI Improved data integrity Easier maintenance and scalability

Question 67

Explain how collisions might occur in a bus network and how these collisions are dealt with. [4]

Answer 67

* Bus networks are bi-directional. * Messages might be transmitted simultaneously from two computers and come into collision. * Computers will detect that a collision has occurred due to the interference pattern produced. * All computers stop transmitting, then wait for a random time interval before attempting to retransmit.

Question 68

Explain the purpose of files in data processing. [3] e

Answer 68

A file is a collection of related data, organised in records and fields They are saved permanently They provide organisation and structure

Question 69

Describe the main features of an effective expert system. [5]

Answer 69

* An expert system uses an inference engine, knowledge base of facts and rules for decision making. * Facts and rules should be produced by a specialist with relevant expertise, using the best available information. * The user is asked a series of questions. Subsequent questions may vary according to the answers given. * Question sequences should be designed so as to gather the necessary information needed for decision making for all valid sets of input values. * The user interface should be user-friendly, with adequate help and error trapping during data entry. * The system should generate results on screen or on paper in a format which is clearly understandable to the user. * The system should list its results in order of suitability, or indicate a relative value or score for each. * The system should explain its reasoning in reaching its decisions, so that the accuracy of the results can be evaluated.

Question 70

Describe simplex, half duplex and full duplex transmission methods. [3] e

Answer 70

Simplex - One way Half-Duplex - Two way Full Duplex - Two way and simultaneous

Question 71

Compare the use of fixed and variable length records. [4]

Answer 71

Fixed length records. The length of the fields in each record is set to be a certain maximum number of characters / bytes. If all the fields in the record have a fixed length, then each record is the same length. If each field does not contain the maximum number of characters allowed, storage space will be needlessly set aside and wasted. Data may be lost if it is too large to fit inside the allowed space in a field. Make file processing much easier because the start and end of each record is fixed, making it simple to locate both individual records and fields. Variable length records. The length of a field can change to allow data of any size to fit. Space is not wasted, only the space needed is ever used. More complex to program / difficult to locate the start and end of individual records and fields. Each field needs an end-of-field marker. When records need to be located the end-of-field markers are used to locate individual records and fields

Question 72

Describe the role of indexing. [2]

Answer 72

* Search engines process and store the information they find in an index * The index is a large database of all the content they’ve discovered that is deemed suitable to serve to searchers.

Question 73

What are the advantages of Magnetic Tape [5] p

Answer 73

Very high storage capacity (good for large data archives) Low cost per GB (economical for long-term storage) Durable and long lifespan (if stored properly) And so ideal for backup Low power consumption compared to active storage devices

Question 74

Describe the distinguishing characteristics of VoIP. [3]

Answer 74

* Voice over Internet Protocol is a type of internet telephony in which the Internet is used to make phone calls or send messages. * Messages are either one on one or for audio conferencing. * VOIP programs allow employees and clients to make voice and video calls. * Converting analogue voice signals to digital for transmission through the network, and then back to analogue, is accomplished by a codec.

Question 75

Describe measures that can be taken to prevent cyber-attacks attacks. [3]

Answer 75

* Turn on firewalls, use anti-virus / anti- malware software * Password rules. Strong passwords are one of the first lines of defence. Make regular password updates mandatory and use strong passwords. * Update regularly. Any connection to the Internet is vulnerable. Keep every connection, operating system, and application up to date with patches and enhancements. * Implement VPNs for all connections. Networks that are protected only by generic security measures are more vulnerable to attack. Implement virtual private network (VPN) connections and make their use easy and mandatory when using public Wi-Fi services. * Retire unused services When systems are no longer needed, delete the applications, logins, and user credentials associated with them. Turn off unused software features such as a video chat function to limit potential for unauthorised access.

Question 76

Explain what is meant by distributed data. [5] p

Answer 76

Data that is stored across multiple locations or systems (rather than a single central database) These locations may be different serves, networks or geographical locations Data is usually managed by a distributed database system, which ensures consistency and accessibility across all nodes Improves reliability and availability, since if one site fails, other can still provide access Allows for faster local access and better performance by placing data closer to where it is needed

Question 77

Describe variable-length string and its storage requirements [2] p

Answer 77

Only uses memory for the characters actually stored Requires extra storage for metadata

Question 78

Identify 3 advantages of RFID [3] p

Answer 78

Tags can be read without line of sight Fast and automated scanning Can store more data than barcodes

Question 79

Expert systems are widely used by organisations for a variety of purposes. Describe the benefits and possible disadvantages to an organisation of using an expert system. [8]

Answer 79

Can store more knowledge than one person that can easily be kept up to date. Helps to give a more accurate decision. Does not get ill, retire, go on holiday, etc. available 24/7and allows access to an expert where not available locally. Increases competitive advantage / Improves company efficiency and profitability. Used to centralise decision making (more consistency) and allow lower management levels to make decisions making better use of management time. Allow broader distribution of expertise throughout the company. A good expert system explains its decision so that a user can decide whether to accept the decision. Expert systems can learn from experience and allow employees to learn from the system. No common sense used in making decision. Lack of creative responses that human experts are capable of Lack of ability to adapt to changing environments and to recognize when there is no answer.

Question 80

What are the disadvantages of voice print recognition [3] p

Answer 80

Can be affected by cold or emotional state Background noise can interfere with recognition Requires high quality microphones and audio processing for reliability

Question 81

Explain the different tasks carried out by IMAP and SMTP. [2]

Answer 81

IMAP is used to upload/download e-mail between the user's computer and an internet server. SMTP transfers e-mail between internet servers.

Question 82

Advise on processes that protect the security and integrity of data for a organisation that receives bookings via the Internet and stores data about guests and staff. Explain why it is important to carry out these steps. [11]

Answer 82

* The organisation should consider physical security. Keep the computer in a locked area when staff are not present. CCTV might be used to monitor the reception area. * Individual members of staff should have user names and passwords. * Access to the network by different users should be recorded in a log file. * Staff should receive training and sign a code of conduct regarding computer use and confidentiality of data. * Staff may be given different levels of access to the computer system, according to their job roles. * Some staff may have read-only access to booking data. * Sensitive data such as bank account details should be held on the computer system in encrypted format. * All client data transmitted by e-mail should be sent in an encrypted format. * If the organisation accepts bookings and payments from its web site, then customers should be able to submit their data through a secure encrypted system. * The organisation should introduce an efficient backup system, with copies of data made daily. Backup data should be stored off-site, either on a portable storage device or using the 'cloud'. * A transaction file should be kept, to help in restoring data in the event of loss. * The hotel must implement improved security in order to conform with the Data Protection Act.

Question 83

Describe the term master file. [2]

Answer 83

 Holds descriptive data; the actual data that is supposed to be processed and holds the resultant data after the process is completed i.e. long term data records which contain data which does not change or data which is periodically updated  Data is held sequentially, in key field order.

Question 84

Explain the hierarchical structure of a directory. [4] e

Answer 84

System is organised in a tree-like structure The root director is at the top (from where all other folders branch out) Each subdirectory consists of subdirectories and files Makes file management efficient and allows access control and searching through paths

Question 85

Explain why powerful computers are required to produce CGI for films. [2]

Answer 85

* Many frames are required to produce a short section of film. * Each frame requires many calculations to generate the graphics – a justification is needed, e.g. calculating positions of moving/rotating objects, calculating positions of shadows. * Realistic textures must be applied to surfaces, e.g. hair, fabric, metal, water.

Question 86

Describe malicious damage to data. [2] e

Answer 86

Deliberate actions intended to corrupt, steal, delete or manipulate data Often done by a hacker or a disgruntled employee

Question 87

Explain data warehousing. [4] p

Answer 87

Large, centralised repository that stores data collected from multiple sources Typically structured and historical, used for analysis rather than day-to-day operations Allows organisations to perform complex queries to generate business intelligence reports Data is often cleaned, organised and optimised for retrieval decision-making

Question 88

What are the advantages of HDD [5] p

Answer 88

Large storage capacity at a relatively low cost Faster access than sequential storage media Reliable for long-term (if well maintained) Suitable for frequent read/write operations Widely available and compatible in most systems

Question 89

Describe the functions of router. [3]

Answer 89

* A router is used to forward data packets between networks. * Routers control traffic on wide area networks such as the Internet. * The router determines the destination of a data packet from the IP address in the packet protocol, then selects an appropriate route for onwards transmission. * Routers may hold information about current transmission speeds to adjacent nodes, so that the fastest path for onward transmission can be selected.

Question 90

Explain the purpose of a hashing algorithm. [2]

Answer 90

A hashing algorithm is a process that includes a mathematical hashing function. It that converts input data of arbitrary length into a compressed numerical hash value of fixed length.

Question 91

Describe the need for switching. [2] p

Answer 91

Needed to direct data to the correct destination within a network Ensures data packets are sent only to the intended device, improving efficiency and reducing network traffic

Question 92

Explain how the control unit will execute an instruction, which requires that the numerical value in register R is stored at main memory address 02B6. [3]

Answer 92

* The program command is accessed in the CIR. * The data to be saved is transferred from general purpose register R to the MDR. * The address 02B6 where the data is to be saved is transferred to the MAR. * The address is then sent out on the address bus. * The data value is sent out along the data bus.

Question 93

Describe the need for encryption. [2] e

Answer 93

Data is vulnerable during storage and transmission (across networks like the internet) Encryption ensures it cannot be read or tampered with by unauthorised users

Question 94

Describe the characteristics and use of cache memory used by the central processing unit. [4]

Answer 94

 Cache memory attempts to solve the “Von Neumann Bottleneck” where the processor runs much faster than the memory by acting as a middleman between main memory and the registers.  Cache is small, extremely fast memory  Placed near or on the processor.  Data and instructions that are used regularly are stored in cache and retrieved by the processor when necessary.  When the cache is full least recently used data is discarded.  Algorithms try to avoid a cache miss (when data has to be fetched from main memory rather than cache).

Question 95

Discuss the implications of cyber-attacks on society. [3]

Answer 95

* On domestic and international politics, integrating cyber-attacks with data that contain a mixture of real and false information to influence public opinion / election results. * Theft of business patents and processes cause detrimental impacts on businesses, with measurable financial and productivity implications. * Usernames, passwords, credit card data, health records – malicious use of this data by criminals can result in the organisations the data was stolen from suffering from loss of reputation, fines, falling sales, and legal proceedings. * Hackers gaining access to everyday public and utility services in order to cause havoc and disrupt society constitutes a genuine threat to UK national and infrastructure security. * Hackers gaining access national security and military systems to cause havoc and hold nations to ransom.

Question 96

Explain the role of DHCP protocol in relation to IP addresses. [3]

Answer 96

IP provides an address which identifies a computer device on a network. DHCP can (dynamically) allocate an IP address when a device connects to a network. This IP address will apply for a single session then may be reallocated.

Question 97

Explain why a FTP application should make use of TCP protocol to upload a web page to an Internet server. [2]

Answer 97

TCP has error checking facilities, which ensure that correct packets of data are received to construct the file. If packets are found to be corrupted, replacement copies can be requested.

Question 98

Identify the benefits of relational database systems. [4]

Answer 98

* Avoids data duplication * Avoids inconsistent records * Data can be readily edited and updated * Data can be added and deleted as required * Can support complex queries * Enables different access levels to different data

Question 99

What are the advantages of vocabulary dictation input [3] p

Answer 99

Faster than typing for many users Hands-free Can be more natural and intuitive for entering large amount of text

Question 100

Explain why a video streaming application should make use of UDP protocol. [2]

Answer 100

UDP does not have error checking facilities. For video streaming, it is better to accept occasional corruption of the picture or sound, rather than pausing the presentation while replacement data packets are downloaded.

Question 101

Identify two methods for dealing with collisions in a hash table. [2]

Answer 101

Placing the data in the next available free position in the hash table. Chaining / Storing the data as a linked list node and placing a pointer to the node in the hash table position. Use of an overflow area.

Question 102

Describe the terms transaction file. [2]

Answer 102

 Contains the transactions i.e. changes that are supposed to be made to the data in the master file  Data is held serially in temporal order i.e. in the order it was collected

Question 103

Explain the basic state of a process: ready. [3] p

Answer 103

The process is waiting in the ready queue for its turn to use the CPU It has everything it needs to execute but must wait for the scheduler to assign it a time slice Once selected it moves to the running state

Question 104

Discuss the implications of cyber-attacks on individuals. [3]

Answer 104

* Email accounts, social media sites, and other personal information have been compromised. * Cyber-attacks affect personal data and privacy, as well political, economic, and social systems. * The implications for the average person range from identity theft to financial losses to reputational damage resulting from non-consensual data broadcasts. * Many cyber-attacks are extremely personal. Hacked emails, social accounts, webcams, and mobile phones provide some of the numerous attack vectors for domestic assailants. * Due in large part to the proliferation and accessibility of digital weapons, spyware and other surveillance tools can be implanted, and have been used in cases ranging from cyber bullying to domestic abuse.

Question 105

Describe the process of asymmetric encryption. [4] p

Answer 105

Asymmetric encryption uses two keys: a public key (shared with others) and a private key (kept secret) The sender encrypts the data using recipient’s public key Only the recipient can decrypt the data using their private key This ensures confidentiality, as only the intended recipient can access the original message, even if the encrypted data is intercepted.

Question 106

Describe parallel transmission, giving an example of where its used. [2]

Answer 106

* Parallel transmission is the sending of each bit of a byte of data at the same time along separate channels * Parallel transmission is very fast, and is used when a large amount of data is being sent / when data needs to be sent quickly * communication between components on the motherboard of a computer. * Video streaming

Question 107

Describe three methods of file access. [6]

Answer 107

* Sequential access. Records in the file are read in order. * Direct or random access. The file is organised via an index that enables access to specific records * Indexed sequential access. A combination of sequential and direct access methods where indexes are located directly and then searched sequentially for the next level index or actual record.

Question 108

Describe three advantages of off-the-shelf software. [6] p

Answer 108

Lower cost - Development and maintenance costs are shared among many users, making it cheaper than bespoke options. Immediate availability - Can be purchased and used right away without long development times Well-tested and supported - Widely used software is often more stable, with extensive documentation and community or commercial support

Question 109

Describe the storage of data in random access files. [6]

Answer 109

 Using hashing to convert a key field value into a memory location/address.  Explanation of strategy to handle collisions.  Explanation of strategy to access records.  If the main file is large and there are few collisions, most records will be found immediately.  Separate overflow area where records are stored in the next available memory location  Overflow area can be serial file or linked list  Searching the separate overflow area is done linearly and may be slow if the area is large  Progressive overflow within the main file may be used, so records are found very close to their home locations even if overflow has occurred.  Could be a problem with the random access file if the overflow area becomes too large – main file may need to be restructured with a different hash function.  Could be faster than obtaining records from the sequential indexed file, where several index blocks must be searched and the required record found amongst other records in a data block.

Question 110

Explain, giving an example, the importance of networking standards. [3]

Answer 110

* Networking standards such as Wi-Fi protocols and Ethernet ensure the interoperability of networking technologies. * The standards define the rules of communication among networked devices. * Standards exist to help ensure products of different vendors are able to work together in a network without risk of incompatibility. * Examples include Wi-Fi protocols and Ethernet.

Question 111

Discuss the advantages of a voice input interface on a hand held device. [4]

Answer 111

* Speech is a very natural way to interact, and it is not necessary to use a keyboard or work with a remote control * No training required for users * Voice is hands-free making it suitable for use in a variety of environments e.g. driving * Suitable for the disabled (qualified) * Can be used to drive several apps in a sequence e.g. Find John Smith and give me directions to him. * Faster than typing on a keyboard (must be qualified not just faster).

Question 112

Describe the principles of high-level scheduling making reference to the three basic states of a process and the role of time-slicing and polling. [7]

Answer 112

* Processing is controlled by a scheduler. * The currently active programs will be held in a job queue (runnable state). * Each program will receive a slice of processing time when it reaches the front of the queue (running state). * If a program requires slow input or output, it will temporarily leave the job queue (blocked state). * Input/output will be handled by the spooling system while the processor continues to process other jobs. * The scheduler will poll the blocked jobs, to check when input/output is completed and the job can re-join the job queue. * Efficiency can be improved by providing multiple job queues, so that users experience minimum delays. * Description of a queue strategy, e.g. Smaller jobs enter a fast queue. Larger jobs are held in a main queue and only receive processor time when the fast queue is empty * Polling to check the state of input / output devices

Question 113

Many contemporary desktop computers use a hybrid storage combination of Solid State Drive (SSD) and Hard Disk Drive (HDD). Explain the advantages of this approach. [6]

Answer 113

SSDs are more durable: SSDs are faster: SSDs have faster data access SSD Performance is unaffected by fragmentation: SSDs consume less power: SSDs are lighter: SSDs run cooler: Hard Disk Drives are cheaper than SSDs, which generally gives a more cost effective storage capacity. However, SSDs are cost-efficient

Question 114

Describe a situation in which a programmer may choose to use variable length records in a program. [2]

Answer 114

* Variable length records are preferred when the records in a file are of very different lengths. * So as to avoid wasting memory / storage / disk space. * Variable length records are suitable for situations where no searching or updating is necessary

Question 115

Describe the functions of multiplexor. [3]

Answer 115

* A multiplexor allows multiple messages to be combined, so that they can be sent over a data link simultaneously, then separated again at the end of the link. * Time division multiplexing allocates small time slices alternately for data from each of the input message streams. * Frequency division multiplexing sends the different messages simultaneously, but using different transmission frequencies. * On a mainframe (multi-user) computer, a multiplexor allows input to the system from different terminals, then routes system output to the correct terminal. * On a wide area network (e.g. Internet), multiplexing may be used to combine messages for transmission over the very fast high-capacity backbone of the network.

Question 116

Describe the importance of HTTP. [2] p

Answer 116

Used for transferring webpages over the internet Defines how requests from a client and repossess from a web server are formatted and transmitted

Question 117

Explain the terms bit, byte and word. [3] e

Answer 117

Bit - value of 0 or 1, representing a single binary state Byte - 8 bits Word - Group of bits handled as a unit, depending on CPU architecture

Question 118

Describe the special security and integrity problems which can arise during online updating of files. [3] e

Answer 118

If internet connection is lost during synchronisation then the file stored on the cloud will be incomplete If data is corrupted when the user is working on the client machine, then the corrupted file may be synchronised by the cloud If a file is used across many devices, there may be mismatches in data stored across the devices and that stored online

Question 119

Explain why collisions are not a problem in ring networks. [2]

Answer 119

* Ring networks operate in a single direction. * Token ring networks carry a single circulating token, to which a message must be attached for transmission. Only one message can be transmitted at a time. * Larger ring networks are divided into sectors, separated by nodes. Only one message may be present in each sector. Messages will not be transmitted onwards until the next sector is clear.

Question 120

Explain the purpose of a DBMS. [5] e

Answer 120

A software that provides an interface between the user/application and the database It allows users to query and manipulate the data using a high-level language (like SQL) Its responsible for: -Managing data storage, retrieval and updates -Ensuring data integrity, security and consistency
-Providing back-up and recovery functions

Question 121

Describe serial transmission, giving an example of where its used. [2]

Answer 121

* Serial transmission involves sending a series of bits one after another along a single communication channel. *Serial transmission operates reliably over long distances *Network communications

Question 122

Discuss the advantages to users of products produced by robotic methods. [2]

Answer 122

* Lower prices due to reduced manufacturing costs. * Consistent quality due to accurate manufacturing. * Faster delivery times. * Quicker innovation for new products.

Question 123

Explain a single-user system. [2] p

Answer 123

* Only one user can operate the system at a time * The OS manages resources for just that single active session

Question 124

Compare packet switching with circuit switching. [5] e

Answer 124

Circuit switching - dedicated communication path is established between the sender and receiver before data is transmitted Has a constant transmission rate Packet switching - data is split into packets which are sent taking different paths Efficient use of network resources Robust as if one route fails, packets can be rerouted

Question 125

Describe buffering and explain why double buffering is used. [4] e

Answer 125

The process of temporarily storing data in a memory area whilst its being moved between devices or processes It help compensate for the speed differences between a fast sender and a slower receiver (allowing them both to operate more efficiently) Double buffering uses two buffers instead of one. One buffer is being read / written whilst the other is being filled / emptied This allows continuous data flow with no interruption, reducing latency (and prevents flickering in video playback)

Question 126

Describe the role of ranking. [2]

Answer 126

* During a search, search engines look through their index for highly relevant content and then orders that content by relevance to solve the searcher's query. * The higher a website is ranked, the more relevant the search engine believes that site is to the query.

Question 127

Identify three advantages offered by QR codes over traditional barcodes. [3]

Answer 127

* Higher capacity / Require less space / the same data can be stored over a smaller surface area. * Readable from any direction. * Damage resistant when printed / built in error correction * Allow for structured appending / data split over multiple codes * Scanning software or application is supplied with smartphones

Question 128

Explain the purpose of random access main memory and cache memory. Comment on the advantages of installing a large amount of main memory and cache memory. [6]

Answer 128

 RAM holds programs and / or associated data when an application is running.  RAM holds the operating system.  RAM composed of cheap semiconductor devices.  Cache holds intermediate data whilst processing is carried out.  Cache located between the RAM and the processor.  Cache faster to access than RAM main memory.  Cache made from logic devices, so is more expensive than main memory.  Large RAM main memory allows more data and larger sections of program to be held in electronic memory. This reduces the number of slow disk operations./ Virtual memory  A large cache size reduces the need for slower access to RAM main memory.

Question 129

Describe three advantages of bespoke software. [6] p

Answer 129

Tailored to specific needs - designed to meet the exact requirements of a business or user, improving efficiency and usability Competitive advantage - Unique features not available in commercial software can give businesses an edge over competitors Greater control and flexibility - The client owns the software, allowing them to make changes and updates whenever necessary

Question 130

Describe a data processing system which makes use of a master file and transaction file to produce utility bills. [8]

Answer 130

Inputs: * Updated meter reading * New customer / amended customer details Processes: * Sorting of transaction file in key field order to match master file. * Merging of data to update master file * Calculation of electricity used and cost Outputs: * Updated master file * Customer bills * Error log

Question 131

What are the advantages of cloud storage [5] p

Answer 131

Accessible from anywhere Scalable storage Data backup No physical hardware needed by the user Collaboration-friendly

Question 132

Describe the importance and use of TCP/IP protocols. [2]

Answer 132

The Internet Protocol (IP) is the address system of the Internet / has the core function of delivering packets of information from a source device to a target device. TCP is used in conjunction with IP in order to maintain a connection between the sender and the target / to ensure packet order and for error checking.

Question 133

Describe the functions of switch. [3]

Answer 133

* A switch is used to connect computers in a local area network. * The switch is programmed / maintains a table with the IP addresses/machine addresses of connected devices, so can send data to the required device. * When a packet of data is received by the switch, it is checked to determine the destination address.

Question 134

Explain how the registers work together when executing an instruction in the fetch-decode-execute cycle [7]

Answer 134

PC shows the address of the next instruction that needs to be processed in RAM The program counter then increments by 1 The MAR is updated to the next RAM address to be processed The instruction at the address in RAM is transferred to the MDR Instruction is copied to the CIR Instruction in CIR is decoded and executed Any result from the execution is stored in the accumulator

Question 135

Identify the drawbacks of relational database systems. [4]

Answer 135

Complex to design High resource usage Requires skilled staff Scalability limitations (for unstructured data)

Question 136

Describe how polling operates in a spooling system. [2]

Answer 136

Operating system periodically checks the progress of jobs suspended in the spooling system, / availability of I/O devices Allows jobs to re-join the runnable queue when input/output is completed.

Question 137

Describe types of malicious software and their vectors. [15] e

Answer 137

Virus Malicious code that attaches itself to legitimate files or programs It executes when the host program runs and can replicate by infecting other files Often spread via infected email attachments, downloads, or USB drives Worm A self-replicating program that spreads without needing to attach to other files Exploits security flaws to copy itself across networks and systems Spreads via network vulnerabilities, email or file-sharing services Trojan Horse Malware disguised as legitimate software Once installed, it can open backdoors, steal data, or install more malware Typically spread via phasing emails, malicious links or remote desktop exploits Spyware Secretly gathers user information Runs in the background and send data to an attacker Often bundled with freeware, email attachments, or malvertising Adware Displays unwanted ads, often tracking user behaviour Injects ads into browsers or pop-ups Often installed with free software or browser extensions

Question 138

Discuss the contingency planning that businesses should carry out to enable them to recover from computer system disasters. [9]

Answer 138

Scope Contingency planning should be developed to anticipate the loss of one or more of the following system components: * Computer room environment (secure computer room with climate control, conditioned and backup power supply, etc.) * Hardware (networks, servers, desktop and laptop computers, wireless devices and peripherals) * Connectivity to a service provider (fibre, cable, wireless, etc.) * Software applications (electronic data interchange, electronic mail, enterprise resource management, office productivity, etc.) * Data and restoration. Inventory Identify critical software applications and data and the hardware required to run them. Using standardised hardware will help to replicate and reimage new hardware. Ensure that copies of program software are available to enable re- installation on replacement equipment. Backup Provide for effective backup measures, ideally off site.’ and anticipate that backup software can fail, or the person responsible for backing up can fail therefore advantageous to use a cloud provider. The backup plan should cover; * What data is important / worth backing up * Frequency of backup required * Can backups be automated * Can operations be moved into the Cloud? Restore. The plan must identify recovery strategies to successfully restore data in the event the backup is needed, such as assembling the right recovery environment (operating systems and servers and storage) and the right people, applications and processes to bring back the data. Strategies The recovery plan might involve either dual centre, internal or external recovery.

Question 139

Describe how threading operates in a system. [2] p

Answer 139

Threading allows a single process to be divided into multiple independent tasks (threads) that can run concurrently Threads share the same memory space but can be scheduled separately, improving efficiency and performance in multitasking systems

Question 140

Compare symmetric and asymmetric cryptography. [6]

Answer 140

 Asymmetric algorithms have two keys - a private and a public key  Symmetric algorithms have one key that has to be at both ends of a transmission  With asymmetric algorithms a shared secret key does not have to be exchanged over an insecure medium such as the Internet as it does with symmetric algorithms  Asymmetric keys are far slower to use and not feasible for use in transmitting large amounts of data because of the increase in transmission times  Symmetric is best used for data on your own disks as it’s fast  Asymmetric is best used for keys, digital signatures, data sent over the web  In many cases, the public and private key pairs in an asymmetric system can remain intact for many years without compromising the security of the system.  Asymmetric keys are harder to generate.

Question 141

Describe direct (random) access files in terms of hashing algorithms, overflow areas and the need for files to be re-organised on occasions. [6]

Answer 141

 The physical location of the record is calculated using a hashing algorithm  This calculation is carried out on data in the key field  A data collision occurs when two data items are hashed to the same location  In this case there needs to be overflow areas where the latest data is stored  When there are many items in the overflow area, access may become slow  In which case a new hashing algorithm is required and a larger file may be needed.

Question 142

Explain, giving an example, what is meant by the concept Big Data. [3]

Answer 142

Very large datasets (volume) that are so complex (variety of datatypes) that traditional databases are unable to manage and process them within acceptable time frames. (velocity) e.g. Transactional data from e commerce, Machine data from GPS / RFID readers, Social media interactions

Question 143

Describe accidental damage to data. [2] e

Answer 143

Unintentional actions that lead to the loss or corruption of data Often caused by user-error of hardware failure

Question 144

Explain why some computer applications are considered safety-critical and why the development of such systems requires a high level of dependability. [3] e

Answer 144

A system where failure could result in loss of life, injury or significant damage These must be highly reliable as a small failure has catastrophic consequences Requires rigorous development methods such as formal verification, extensive testing, and validation

Question 145

Explain the term predictive analytics. [3]

Answer 145

*A way to predict future events based on past behaviour. It’s a combination of statistics and data mining *Predictive analytics assigns a probability (predictive score) for the likelihood that something such as a customer, will behave a certain way. It is used to predict behaviour and assess risk over a wide variety of disciplines.

Question 146

Explain a multi-user system. [2] p

Answer 146

Multiple users access the system simultaneously, often over a network The operating system uses time-sharing to allocate resources to keep session separate

Question 147

What are the advantages of voice print recognition [3] p

Answer 147

Provides a secure and unique method of authentication Convenient and non-invasive for the user Can be done remotely (like over the phone)

Question 148

Describe boolean data and its storage requirements. [2]

Answer 148

* A data type that may have one of two possible values, intended to represent the values of logic and Boolean algebra as true or false * May be stored in a single Bit as 1 if true and 0 if false.

Question 149

Explain, giving an example, reasons for using symmetric encryption. [3]

Answer 149

Due to the faster speed of symmetric encryption (compared to asymmetric), it is typically used for bulk encryption, e.g. for database encryption.

Question 150

Identify problems which can arise for a company using robotic production methods. [2]

Answer 150

* Need for retraining of the workforce to operate new technology * Cost of specialist technicians and programmers * Risk of breakdown of a complex system affecting production * Cost of adapting factory premises for automation / Initial setup costs * Risk of malicious damage by hackers

Question 151

Identify 3 uses of touch screen [3] p

Answer 151

Smartphones and tablets Self-service kiosks *Point-of-sale systems

Question 152

Describe the purpose and process of CPU scheduling. [4]

Answer 152

CPU scheduling is a process that allows one process to use the CPU while the execution of another process is on hold (waiting state) due to unavailability of any resource like I/O etc, thereby making full use of CPU.) Whenever the CPU becomes idle, the operating system must select one of the processes / jobs in the ready queue to be executed. The selection process is carried out by the CPU scheduler. The schedule selects from among the processes in memory that are ready to execute, according to set priorities, and allocates the CPU to one of them.

Question 153

Explain, using an example, what is meant by the term biometric data. [4]

Answer 153

Biometric data refers to measurement and recording of some physical characteristic of a person which can be used to uniquely identify that person.

Question 154

Describe the use of priorities and the factors involved in allocating differing priorities. [5] e

Answer 154

(In multitasking operating systems) priorities are used to determine the order in which processes are executed The scheduler assigns more CPU time to higher-priority tasks This priority depends on: -Type of task -Time sensitivity -Resource needs

Question 155

Explain what is meant by distributed processing, giving an example to illustrate its operation. [6]

Answer 155

Distributed processing is the technique of carrying out a large computing task by sharing the processing between computers in different locations. Each computer will run its own programs and have its own store of data but will share data with other computers in the distributed processing network as necessary. A specific record keeping system Computers in various locations. will be linked in a wide area network. Each computer will have the software necessary to carry out database operations on records, and to display any included associated information / images. Records will generally be held locally but additional records may also be held centrally when needed. Staff / users may access and update information at any of the locations by means of the network. The overall system may provide summary management data. The system will be able to inform users of updates and any actions needed.

Question 156

Explain how file fragmentation can occur on a secondary storage device and describe what occurs during defragmentation. [4]

Answer 156

 Over time, the file system fills up then file changes may result in blocks no longer being contiguous as they won’t fit back into the space vacated  Files are then split and physically stored on different parts of the disk  Defragmentation consolidates data on a disk  By moving all parts of files to an empty contiguous area.

Question 157

Compare, in terms of range and accuracy, fixed-point and floating-point representations. [3]

Answer 157

Floating point * has set number of bits for mantissa and exponent * trade-off between accuracy v range * larger mantissa leading to greater accuracy * larger exponent leading to greater range of numbers being represented * not possible to represent zero. Fixed point * not flexible and has a set range and level of accuracy, * is less complex.

Question 158

Discuss the advantages and disadvantages of symmetric (single key) and asymmetric (double key) encryption methods and explain a situation where each encryption method would be the most suitable. [8]

Answer 158

* Single key encryption can be faster in use. Double key encryption takes longer to encrypt a document, and longer to decrypt, due to the large amount of calculations involved. * It can be faster to set up a single key encryption system than a double key system, as the programming involved may be simpler. * Single key encryption may not be secure if the key value has to be transferred over the internet and is intercepted by an unauthorised person. * Double key encryption avoids the security risk by only revealing the public encryption key to the sender. The private decryption key is held securely by the receiver and not revealed. * Single key encryption suitable for personal use in encrypting files on a single computer. No transfer of the key value to another user needed. * Single key encryption is suitable for use within an office or work group, where the key value can be transferred during personal meetings or over a secure local area network. * Double key encryption is more suitable for transfer of confidential data over the internet (such as credit card details), e.g. on-line hotel/airline bookings or shop purchases.

Question 159

Explain the need for and use of a range of utility software. [7] e

Answer 159

File indexing - allows easy random access
File conversion - converts files from one format to another (using compression)
Task management - allows the view of each of the tasks and overall performance of the computer
Disk scanning and repair

Question 160

Describe the cause of arithmetic underflow. [2]

Answer 160

* Occurs when the result of a floating point calculation is smaller than the computer can represent in memory * needs to be rounded or truncated.

Question 161

Explain the purpose of Data Dictionaries. [7] e

Answer 161

Centralised store of metadata that describes the structure of the database Contains: -Name and data types of fields -Table structures (including primary/foreign keys)
-Validation rules
-Default values -Constraints It ensures consistency

Question 162

Explain what is meant by data independence. [2]

Answer 162

* This refers to the separation of information from the applications and programs that use it. * So that modifications to source code are not required every time changes to the data characteristics / properties are made.

Question 163

Describe the importance and use of the FTP. [2]

Answer 163

 Use: allows the transfer of files over a network.  Importance: the FTP protocol has in-built error checking / re-transmission request as necessary.

Question 164

Describe the distinguishing characteristics of email. [3]

Answer 164

* A method of exchanging digital messages from the advertising agency to one or more recipients using the Internet. * Based on a store-and-forward model. * Neither the end users nor their computers are required to be online simultaneously * Users need connect only briefly, typically to a email server, for as long as it takes to send or receive messages.

Question 165

Describe white hat hacking. [2] e

Answer 165

Ethical hacking done with permission to help identify and fix security vulnerabilities Done to improve system and prevent malicious attacks

Question 166

Describe the role of three file management utilities. [6]

Answer 166

* Archivers: To archive folders for future reference. * Output a single file when provided with a directory or a set of files for long term storage. * Data conversion utilities * Transform data from a source file to some other format * Data recovery * Used to rescue good data from corrupted files. * Revision / version control utilities * Recreate a coherent structure where multiple users simultaneously modify the same file to help several translators work on a common source document. * File managers. Provide a method of performing routine data management tasks * Assists in deleting, renaming, moving, copying, merging, setting write protection status, setting file access permissions, generating and modifying folders and data sets.

Question 167

Explain what is meant by data redundancy. [2]

Answer 167

* Occurs when duplicate data is available in different tables. * Resulting of wastage of storage and compromising data consistency.

Question 168

Describe three of the main roles performed by the kernel. [6]

Answer 168

Process management. * Process execution, including the allocation of processor time and termination is controlled by the kernel so the system makes efficient use of the CPU and functions properly. Memory management * The kernel keeps track of the sections of memory that are currently allocated, manages the release of memory once processes have been executed and allocates / re-allocated memory to new processes that are ready for execution. Device management / I/O communication. * Manages all the system’s devices via communication with device driver software. All user inputs and all process outputs are handled by the kernel. Interrupt handling. * Higher priority processes that are ready for execution will generate an interrupt signal, or request for CPU access. The kernel will handle the interruption of current processing, enable the CPU to process the higher priority event and then manage the return to the interrupted process

Question 169

Explain the purpose of query languages. [3] e

Answer 169

To interact with databases Including data retrieval and manipulation (and User Access Control)

Question 170

Describe the need for archiving files. [3] e

Answer 170

Frees up space Preserves data For legal and regulations compliance

Question 171

Explain why searching and updating records may be carried out more quickly with fixed length records than with variable length records. [4]

Answer 171

* If records have a fixed length, the position of any record in the file can be calculated by multiplying the record length in bytes by the record sequence number. * A fast binary search can be used to locate a fixed length record in a sequential file. * Variable length records can only be found using a slower linear search method. * Fixed length records can be quickly updated in-situ without affecting other records in the file. There should be empty space present in the record to allow for any increase in the size of the data * If a variable length record is updated, the size of the record will change. The file will need to be rebuilt and the updated record inserted at the correct point in the sequence.

Question 172

Explain the term multitasking. [2]

Answer 172

*A method of organising computer use that allows several tasks or applications to be available at the same time. *The operating system will allow users to have several tasks apparently running at the same time, with the user switching freely between tasks or applications. *Concept of time sharing - The switching occurs when the time slice of currently executing process ends

Question 173

Discuss the disadvantages of a voice input interface on a hand held device. [4]

Answer 173

* Even the best speech recognition systems sometimes make errors e.g. homophones * If there is noise or some other sound in the room (e.g. the television or a kettle boiling), the number of errors will increase * Regional accents can affect the outcome * Requires data connection to interpret speech and return results * Delivering sensitive information e.g. credit card details could be a security risk. * Only understands certain foreign languages

Question 174

Describe the main risks involved of adopting a BYOD policy. [6]

Answer 174

Data theft Company data stored on the devices may be at risk if used over an unsecured wi-fi network away from the office Malware infiltration Malware downloaded during private use of the device could be transferred to the company network. Potential legal issues Company could face blame and legal consequences if a security breach through an employee’s device results in the leaking of business data / customers’ details. Device loss or theft Loss or theft of an employee’s device could lead to data being compromised if the employee has not followed company security protocols. Poor mobile management. Risks connected with employees moving on to other employment and not deleting private company information. Lack of training. Company security requirements may not be fully understood or implemented. Formal training required or is document sign off adequate?

Question 175

Explain the benefits to the use and storage of biometric data. [4] p

Answer 175

High security Convenience Efficient identification Reduces fraud

Question 176

Describe the distinguishing characteristics of Internet forums. [3]

Answer 176

* Conversations are held in the form of posted messages. The messages are at least temporarily archived. * A posted message might need to be approved by a moderator before it becomes visible. * A forum is hierarchical in structure: a forum can contain a number of subforums, each of which may have several topics. * Within a forum's topic, each new discussion started is called a thread, and can be replied to by as many people as wish to.

Question 177

Describe the various potential threats to computer systems [14] e

Answer 177

Malware - malicious software Social engineering - tricking users into giving out sensitive information Brute Force Attacks - attacks password security by working through all possible alphanumeric combinations DoS - Make a website and serves unavailable by swamping it with fake requests IP Spoof - Changing the IP address of a legitimate host so that a visitor who types the URL is taken to a fraudulent website (to steal sensitive data) Data interception - Capturing information during transmission and either eavesdropping it or altering it
SQL injection - A code insertion technique where a SQL statement is used to compromise the security of information held in a database

Question 178

Describe character and its storage requirements [2] p

Answer 178

A single symbol such as a letter, digit, or punctuation mark Stored depending on ASCII (7 bit) or Unicode (32 or 16 bit)

Question 179

Describe the cause arithmetic overflow. [2] p

Answer 179

Occurs when the result of a calculation exceeds the maximum value that can be stored in the allocated number of bits This causes the most significant bits to be lost or wrapped around, leading to an incorrect result

Question 180

Describe, giving an example, a way in which robotics are used in manufacturing. [2]

Answer 180

* Accurate assembly, e.g. circuit boards. * Carrying out unhealthy or dangerous activities, e.g. car body welding or spray painting. * Repetitive operations, e.g. packing food items in boxes. * Warehouse functions, e.g. collecting selected items from shelves.