Component 2 Flashcards
(181 cards)
Describe the storage of data in indexed sequential files. [4]
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.
Identify 3 uses of RFID [3] p
Inventory and assets tracking
Contactless payment systems
Livestock or pet identification
Explain the term data mining. [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.
Explain how data can be manipulated to provide the user with useful information. [11] e
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
Identify 3 advantages of OMR [3] p
Fast data input from multiple-choice forms
Low error rate when filled correctly
Reduces manual data entry workload
Identify 3 uses of OCR [3] p
Digitising printed documents for archiving
Automatic number plate recognition
Processing scanned application forms
Explain why there may be objections to the use and storage of biometric data. [4]
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).
Describe integer and its storage requirements [2] p
- A whole number (positive, negative or zero)
- Storage depends on bit length
Explain what is meant by data consistency. [2]
- 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.
Explain how a program instruction is decoded. [2] p
*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
Describe fixed-length string data and its storage requirements. [2]
- 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.
Describe the organisation and process of using a random access file to store data. [6]
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.
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]
- 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.
Describe networks and how they communicate. [1] e
Networks consist of two or more computer systems that are connected to allow them to share resources and exchange information.
Explain the predictive analytics. [4]
- 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
Describe three disadvantages of off-the-shelf software. [6] p
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
Describe the most suitable mode of operation for traffic lights. [2]
Traffic Lights Real time control processing.
Traffic lights have timed intervals, and may also react
to the arrivals of traffic.
Describe three disadvantages of bespoke software. [6] p
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
Describe the function of the Program Counter in the Von Neumann fetch-execute cycle. [2]
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.
Compare representing numbers in integer and floating point forms. [5] e
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
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]
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
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]
- 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.
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]
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.
Identify 3 uses of MICR [3] p
Processing bank cheques
Document validation
Secure identification