Questions and Answers of Cambridge International AS & A Level Computer Science

a) Three processes, A, B and C, are presently in logical memory.Process A is 600 MiB, process B is 800 MiB and process C is 200 MiB.The starting address in physical memory for process A is 1000.Each
a) When designing and writing program code, explain what is meant by:– An exception– Exception handling.b) A program is to be written to read a list of exam marks from an existing text file into
A college has two types of student: full-time and part-time.All students have their name and date of birth recorded.A full-time student has their address and telephone number recorded.A part-time
A declarative programming language is used to represent the following facts and rules:These clauses have the following meaning:a) More facts are to be included.Ali and Meena are the parents of
A Queue Abstract Data type (ADT) has these associated operations:– Create queue– Add item to queue– Remove item from queueThe queue ADT is to be implemented as a linked list of nodes.Each node
Data is stored in the array NameList [1:10]. This data is to be sorted.a) i) Copy and complete this pseudocode algorithm for an insertion sort.ii) A special case is when NameList is already in order.
The following graph shows the routes connecting buildings on a university campus. The numbers represent the time taken (in minutes) to cycle from one building to another.a) i) Use Dijkstra’s
Tom is using a GPS device to navigate from point B to point E.Tom’s GPS uses the A* algorithm to find the shortest route:B → C → M → J → K → EThis route is shown in orange on the
The following graph is made up of a (9 × 8) matrix.Use the A* algorithm to show the shortest route from A to B. 1 2 3 4 5 6 7 8 9 starting point 'A' 3 4 5 6 7 finishing point 'B' 8
a) Explain the difference between the A* algorithm and Dijkstra’s algorithm.b) The following graph (network) shows how long it takes (in seconds) to walk between ten hotels in a city.i) Using
Copy and complete the text, using words from the box. Words may be used once, more than once, or not at all. actual output machine learning reinforcement learning back propagation minimised removed
a) Describe three features you would associate with:i) Reinforcement learningii) Supervised learning.b) Explain why these applications are regarded as artificial intelligence.i) Chat botsii) Search
a) Answer these multiple choice questions.i) Identify the statement that best describes artificial intelligence.A. Putting human intelligence into a computer systemB. Programming a computer using a
A user keys a URL into their browser and hits the key.a) Re-order the following stages, 1-6, to show how an SSL digital certificate is used to set up a secure connection between client (user) and
a) Explain the terms SSL and TLS.b) Explain the following terms used in TLS.i) Record protocolii) Handshake protocoliii) Session cachingc) Give two differences between SSL and TLS.
a) Explain what is meant by QKD.b) The following eleven statements refer to the transmission of an encryption key using quantum key distribution protocols.Put each statement into its correct
There are four stages in the compilation of a program written in a high-level language.a) Four statements and four compilation stages are shown below. Copy the diagram below and connect each
The following syntax diagrams for a particular programming language show the syntax of:– An assignment statement– A variable– An unsigned integer– A letter– An operator– A digit.a) The
In this question, you are shown pseudocode in place of a real high-level language.A compiler uses a keyword table and a symbol table.Part of the keyword table is shown below.– Tokens for keywords
a) Explain how programs can access data from memory when using virtual memoryb) Describe the following page replacement algorithms.i) First in first out (FIFO)ii) Optimal page replacement (OPR)iii)
A number of processes are being executed in a computer. A process can be in one of these states: running, ready or blocked.a) For each of the following, the process is moved from the first state to
State the ten computer terms being described below.a) A fixed time slice allotted to a process.b) When a process switches from running state to steady state or from waiting state to steady state.c)
A computer operating system (OS) uses paging for memory management.In paging:– Main memory is divided into equal-size blocks, called page frames– Each process that is executed is divided into
This table shows the burst time and arrival time for four processes:This is a list of average waiting times, in ms:6.0 6.25 6.5 8.0 8.25 10.0 11.25
A logic circuit is shown.a) Write the Boolean expression corresponding to this logic circuit.b) Copy and complete the truth table for this logic circuit.c) i) Copy and complete the Karnaugh map
a) Four descriptions and four types of computer architecture are shown below.Draw a line to connect each description to the appropriate type of computer architecture.b) In a massively parallel
a) Describe four types of processors used in parallel processing.b) A hardware designer decided to look into the use of parallel processing.Describe three features of parallel processing she needs to
a) An SR flip-f lop is constructed from NOR gates:i) Complete the truth table for the SR flip-f lop. ii) One of the S, R combinations in the truth table should not be
a) Consider the following truth table.i) Draw a Karnaugh map from this truth table.ii) Use your Karnaugh map from part a) i) to produce a Boolean expression.b) Use the laws of Boolean algebra to
a) Write down the Boolean expression to represent the logic circuit below. b) Produce the Karnaugh map to represent the above logic circuit and hence write down a simplified Boolean
a) This table shows some statements about circuit switching and packet switching.Copy the table and indicate which statements are true () and which are false ().b) Explain the following terms
a) Explain what is meant by circuit switching.b) There are many applications in which digital data are transferred across a network. Video conferencing is one of these.For this application, circuit
a) An Ethernet frame contains a section called Ethernet data.Copy and complete this diagram to show the other four items missing from the Ethernet data section.b) State what is meant by the term
a) Copy the diagram below and connect each peer-to-peer term to its correct description.b) Copy and complete the diagram to show the layers in a TCP/IP protocol. c) Describe the protocols used
a) Three file organisation methods and two file access methods are shown below. Copy the diagram below and connect each file organisation method to its appropriate file access method(s).b) An energy
a) Using the pseudocode declarations below, identifyi) An enumerated data typeii) A composite data typeiii) A non-composite data typeiv) A user-defined data type.Write pseudocode to declare a
In a particular computer system, real numbers are stored using floating-point representation with:– 8 Bits for the mantissa– 8 Bits for the exponent– Two’s complement form for both mantissa
A computer uses 12 bits for the mantissa and 6 bits for the exponent.a) Convert these binary floating-point numbers into denary.b) Convert these denary numbers into binary floating-point numbers.i)
A computer holds binary floating-point numbers in two’s complement form with the binary point immediately after the left-most bit.A 24-bit word is used as follows:a) Three words are held in
A company creates two new websites, Site X and Site Y, for selling bicycles.Various programs are to be written to process the sales data.These programs will use data about daily sales made from Site
A 1D array, Product, of type STRING is used to store information about a range of products in a shop. There are 100 elements in the array. Each element stores one data item.The format of each data
When the guarantee on a computer runs out, the owner can take out insurance to cover breakdown and repairs.The price of the insurance is calculated from:– The model of the computer− The age of
A driver buys a new car.The value of the car reduces each year by a percentage of its current value.The percentage reduction is:– In the first year, 40%– In each following year, 20%The driver
Explain the difference betweena) A procedure and a functionb) Passing parameters by value and by referencec) Defining a procedure and calling a procedure.
Procedures and functions are subroutines.Explain what is meant bya) A procedureb) A functionc) A parameterd) A procedure or function header.
Explain what is meant by the term library routine.Give two examples of uses of library routines.
a) For this question, you will need to use this function, which returns the real value of the square root of anyPosVal:Extend your algorithm for Question 2 toi) Calculate the hypotenuseii) Calculate
Write a pseudocode algorithm to input the height and width of a right-angled triangle and check that these values are positive and less than the maximum values given in question 1.
Use pseudocode to declare these variables and constants.You will need to decide which identifiers are variables and which are constants. Identifier name Description height Stores value input for
A queue Abstract Data Type (ADT) has these associated operations:– Create queue– Add item to queue– Remove item from queueThe queue ADT is to be implemented as a linked list of nodes.Each node
Data is stored in the array NameList [1:10]. This data is to be sorted using a bubble sort:a) A special case is when NameList is already in order. The algorithm above is applied to this special
a) Write pseudocode to set up a text file to store records like this, with one record on every line.b) Write pseudocode to append a record.c) Write pseudocode to find and delete a record.d) Write
Explain, using diagrams, the process of reversing a queue using a stack.
Explain, using an example, what is meant by a composite data type.
Abstract data types (ADTs) are collections of data and the operations used on that data.Explain what is meant bya) Stackb) Queuec) Linked list.
Study the pseudocode and answer the following questions. Line numbers have been added to help you.a) Give the line number of:i) An assignment statementii) A selectioniii) An iteration.b) Complete an
Computer programs have to evaluate expressions.– Study the sequence of pseudocode statements.– Write down the value assigned to each variable.a) Perimeterb) Areac) Zd) A DECLARE h, w, r,
Describe, using an example, the process of stepwise refinement.
Several techniques are used in computational thinking.Explain what is meant bya) Abstractionb) Decompositionc) Pattern recognition.
An air conditioning unit in a car is being controlled by a microprocessor and a number of sensors.a) Describe the main differences between control and monitoring of a process.b) Describe how the
a) Many mobile phone and tablet manufacturers are moving to OLED screen technology.Give three reasons why this is happening.b) A television manufacturer makes the following advertising claim:‘Our
Algorithms can be shown as structured English, flowcharts and pseudocode.Explain what is meant bya) Structured Englishb) A flowchart c) pseudocode.
A school stores a large amount of data. This includes student attendance, qualification, and contact details. The school’s software uses a file-based approach to store this data.a) The school is
A database has been designed to store data about programmers and the programs they have developed.These facts help to define the structure of the database:– Each programmer works in a particular
The IEEE Software Engineering Code of Ethics uses eight key principles shown in the right-hand column of the following diagram.Tom is employed as a tester with a software company. He is keen to
a) Computers over the years have been described as first to fifth generation.Identify the generation that is associated with AI.A. FirstB. SecondC. ThirdD. FourthE. Fifthb) AI is involved in
a) Name three types of software licensing.b) For each example, describe three features which identify the differences between them.c) Describe how copyright issues affect each type of named software
Nicolae has joined a software company as a new team manager. During his induction he was given a presentation on the company’s code of conduct and the company’s expected ethical behaviour. He was
The following block of data was received after transmission from a remote computer.Odd parity was being used by both sender and receiver.One of the bits has been changed during the transmission
a) Explain what antivirus software is and how it can be used to ensure data security.b) Explain how a firewall can be used to identify illegal attempts at accessing a computer system and how they can
A college is using a local area network (LAN) to access data from a database.a) Give two security measures to protect the data on the college’s computer system.b) Data regarding new students
State four features of an IDE that are helpful when coding a program.
Assemblers, compilers and interpreters are all used to translate programs.Discuss the different roles played by each translator.
File History and Time Machine are examples of back-up utilities offered as part of two different operating systems.a) Explain why it is important to back up files on a computer.b) One of the features
a) The operating system contains code for performing various management tasks. The appropriate code is run when the user performs actions.Copy the diagram below and connect each OS management task to
A programmer is writing a program that includes code from a program library.a) Describe two benefits to the programmer of using one or more library routines.b) The programmer decides to use a Dynamic
An intruder detection system for a large house has four sensors. An 8-bit memory location stores the output from each sensor in its own bit position.The bit value for each sensor shows:– 1 – The
a) i) Name three special registers used in a typical processor.ii) Explain the purpose of the three registers named in part i).b) Explain how interrupts are used when a processor sends a document to
A programmer is writing a program in assembly language. They need to use shift instructions.Describe, using examples, three types of shift instructions the programmer could use.
a) Three digital sensors, A, B and C, are used to monitor a process. The outputs from the sensors are used as the inputs to a logic circuit. A signal, X, is output from the logic circuit:Output, X,
a) Explain the main differences between HDMI, VGA and USB ports when sending data to peripherals.b) Describe how interrupts can be used to service a printer printing out a large 1000 page document.
a) Write these six stages of the Von Neumann fetch-execute cycle in the correct order.– Instruction is copied from the MDR and is placed in the CIR– The instruction is executed– The instruction
a) There are two types of RAM: dynamic RAM (DRAM) and static RAM (SRAM). Five statements about DRAM and RAM are shown below. Copy the diagram below and connect each statement to the appropriate type
The nine stages in printing a page using an inkjet printer are shown below.They are not in the correct order.Write the letters A to I so that the stages are in the correct order. The data is then
a) A company is developing a new games console. The game will be stored on a ROM chip once the program to run the new game has been fully tested and developed.i) Give two advantages of putting the
a) When data is transmitted over a LAN network there is the possible risk of data collision.i) Explain the term data collision.ii) Describe how CSMA/CD is able to detect collisions.iii) Explain how
A buffer is 2 MiB in size. The lower limit of the buffer is set at 200 KiB and the higher limit is set at 1.8 MiB.Data is being streamed at 1.5 Mbps and the media player is taking data at the rate
a) Explain the term bit streaming.b) A person watches a film streamed from a website on a tablet computer.i) Give two benefits of using bit streaming for this purpose.ii) State two potential problems
a) Conventional telephone calls are made using the public service telephone network (PSTN). The national network uses both copper cables and fibre optic cables.i) Explain the difference between
Star and mesh are two types of network topology that can be used to make a LAN.a) i) State one benefit and one drawback of the star network topology.ii) State one benefit and one drawback of the mesh
a) Convert the denary number 95 into binary coded decimal (BCD).b) Using two’s complement, carry out the binary subtraction:0 0 1 0 0 0 1 1 – 0 1 0 0 0 1 0 0And convert your answer into denary.c)
a) Carry out 0.52 + 0.83 using binary-coded decimal (BCD). Show all of your working.b) i) Define the term hexadecimal.ii) Give two uses of the hexadecimal system.iii) Convert the following binary
a) Write the denary numbers 60, 27 and −27 in 8-bit binary two’s complement form.b) Show the result of the addition 60 + 27 using 8-bit binary two’s complement form. Show all of your working.c)
The editor of a movie is finalising the music score. They will send the final version of the score to the movie producer by email attachment.a) Describe how sampling is used to record the music sound
A software developer is using a microphone and a sound editing app to collect and edit sounds for his new game.When collecting sounds, the software developer can decide on the sampling resolution he
a) The following bytes represent binary integers using the two’s complement form. State the equivalent denary values.i) 0 1 0 0 1 1 1 1ii) 1 0 0 1 1 0 1 0iii) Write the integer −53 in two’s