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Explain what is meant by non-composite and composite data types
non-composite data types can be defined without referencing another type.
composite data types refer to other data types in their definition
Identify one type of cryptography.
asymmetric, symmetric, quantum
Describe the purpose of both the A* algorithm and Dijkstra’s algorithm.
to find the optimal route between two nodes based on distance/cost/time
State two functions of SSL/TLS
Ensure security/privacy when using the internet
Data encryption
Identification / authentication of client and server
Describe what is meant by the OOP feature inheritance.
Inheritance is where a derived class takes properties / behaviours attributes / methods of a parent / super class / base class
Explain why user-defined types are necessary
used to create new data types that help to extend the flexibility of a programming language as the programmer can create data types based on the application’s requirements.
Explain what is meant by supervised learning
enables learning by mapping an input to an output based on example input– output pairs
Explain what is meant by Deep learning
It simulates the data-processing capabilities of the human brain to make decisions
Describe what is meant by multi-tasking and how it benefits process management.
Running multiple processes concurrently which benefits process management by allowing more tasks to complete than would be the case if they had to run one task after another.
Describe the sequential method of file access.
sequential access method searches for records one after the other from the physical start of the file until the record is found/the end of file.
Identify and describe two communication protocols that are used when sending or receiving emails.
SMTP, IMAP, POP3
Identify three process states.
running, ready, blocked
Explain why protocols are essential for communication between computer systems. [2]
Protocols establish a standard set of rules for communication.
Protocols enable compatibility between devices from different manufacturers/platforms.
Two devices wouldn’t be able to communicate/send messages to each other if they were using different protocols.
Give two examples of situations where the use of SSL/TLS would be appropriate.
When transmitting authentication data e.g. passwords, session cookies
When transmitting data that must be protected from modification on its way to or from a server e.g. user input, or results from the server
State 3 features of RISC processors.
Uses hard-wired code/control units
Uses relatively few instructions / simple instructions
Uses relatively few addressing modes
Makes use of a single-cycle for each instruction
Makes use of fixed length / fixed format instructions
Makes use of general-purpose registers
Pipelining is straightforward to apply
The design emphasis is on the software
Processor chips require few transistor
State the purpose of the optimisation stage in the compilation of a program. [3]
to improve the code so it minimises program storage, CPU time, memory use, program execution time
Describe the function of the shortest job first scheduling routine and give a benefit of this routine.
The process with the shortest time to complete/burst time is selected first and executed. The process will continue until complete or put in a waiting state once execution has begun // it is non-pre-emptive. The scheduler will continue to choose shorter processes over longer processes if they continue to be added to the queue can cause starvation for longer jobs.
Benefits:
Shorter jobs don’t have to wait for longer jobs to complete before processing // Significantly reduces the average overall waiting time for processes // Ensures starvation doesn’t occur for process with shorter burst times
Higher throughput of processes
Define these Object-Oriented Programming (OOP) terms:
Encapsulation
Getter
Setter
Polymorphism
Encapsulation – putting properties and methods inside a class // ensures sensitive data is hidden from users by hiding values of a structured data object inside a class.
Getter – method that is used to return the value of a property.
Setter – method that is used to update the value of a property.
Polymorphism - when methods with the same name are redefined / behave differently in derived / inherited classes / subclasses
Explain the process of syntax analysis during program compilation.
It takes input from the lexical analyser in the form of token streams.
The source code is analysed / parsed against the rules of the language to detect any errors in the code.
The output from this phase is a parse tree.
Syntax errors are reported.
Explain what is meant by disk thrashing.
Disk thrashing is a problem that may occur when virtual memory is being used.
As the main memory fills up, more and more pages need to be swapped in and out of virtual memory.
This swapping leads to a very high rate of hard disk access / excessive disk head movements.
Moving a hard disk read/write head takes a relatively long time / long latency time.
Eventually, more time is spent swapping pages than processing data which can cause the program to freeze or not run.
Describe two ways in which packet switching ensures a complete message is received when passing messages across a network.
Packets checked at receiving end / on arrival [1] … if packets arrive damaged or don’t arrive at all, a re-send request is sent [1]
Packets routed through different paths / sent individually [1] … if a route is blocked, the packet is sent through a different route to ensure it arrives [1]
If the packet’s hop count is exceeded [1] … the packet will be retired, which can generate a re-send request [1]
Outline the process followed to acquire a digital certificate.
the company requests a digital certificate from a Certificate Authority (CA)
the CA responds with its public key and digital certificate, … signed with its private key
the company gathers authentication information e.g. its public key … and sends it to the CA signed with the company’s private key and encrypted with the CA’s public key
the CA verifies the received information and generates/issues the digital certificate.
Describe the function of a router in packet switching. [4]
The router reads the IP address of the destination from the packet header.
A router uses a routing table to find information … about e.g., available hops / netmask / gateway used / adjacent routers / the status of the routers along the route.
The router determines the next hop / optimum route. // The router sends the packet on its next hop.
The router manages the hop counter // The hop counter is reduced by 1 every time the packet passes a router
BONUSSSS
BONUSSSS
State the purpose of each layer in the TCP/IP protocol suite.
*answer*