1.2 Software and software development Flashcards

Question

What are the 5 types of OS?

Answer 1

- Distributed - Multi-User - Real-Time - Embedded - Multi-tasking

Answer 2

- An OS that handles many processes at the same time

Answer 3

- An OS that allows more than one person to access a single computer at the same time - The computer will manage the user's various permissions and access rights when they log on - Server operating system software will handle the requests of multiple people using different computers on a network at the same time

Answer 4

- An OS which can combine the processing power of multiple computers across a network for a single task

Answer 5

- The operating system controls and coordinates system controls and coordinates the computers, presenting them to the user as if they were a single system

Answer 6

- They run on dedicated hardware so they run with maximum efficiency, using low powered processor and very little memory

Answer 7

- An OS that executes processes within a known time frame - Plenty of redundancy is built into these systems so they can handle sudden increases in input - As such, processors in real-time OS rarely run at capacity

Answer 8

- Responsible for loading the OS when the computer first turns on - It first checks that the hardware it needs is connected and working using a POST

Answer 9

- Used to load the OS kernel into memory

Answer 10

- Stored in flash memory - So that they can be changed and retained when the power if switched off

Answer 11

- Software that tells the OS how to communicate with a peripheral device

Answer 12

- The device driver translates the OS' instructions into a series of instructions that a specific piece of hardware will understand

Answer 13

- A program that has the same functionality as a physical computer

Answer 14

-Trick a program into thinking it's running on its native hardware when it's running on an entirely different machine

Answer 15

- If one server stops working, the others can pick up the load and continue working as if nothing happened

Answer 16

- Because other programming languages would either have to use a specific language of each device or use a suitable compiler. - Java gets around this by compiling its code into a half-way code known as bytecode or intermediate code - This code is then translated by a Java Virtual Machine (JVM) running on a target device which then translates it into specific machine code

Answer 17

- Makes the code highly portable between devices.

Answer 18

- System software - Application software

Answer 19

- Operating Systems - Utility software

Answer 20

- Windows - Linux - Windows - macOS - iOS

Answer 21

- Antivirus - Defragmentation - Backup - Compression - Firewalls

Answer 22

- Presentation - Word processor - Web browser - Games - Email

Answer 23

- A word processor is an example of one. It does not have a specific or narrow purpose - You can use it to carry out different tasks and meet multiple needs

Answer 24

- Database software is an example of one. - Being highly specific and bespoke, however, makes it almost essential for creating serious database application

Answer 25

- On systems where there is a direct need

Answer 26

- Software designed to: - Keep your computer safe - Keep it running efficiently - Provide you with useful tools to manage your files and applications

Answer 27

- Files can become corrupt or damaged for a number of reasons - File repair attempts to correct these issues and restore the file to its original working state

Answer 28

- Backups can be set up to be manual, automatic or scheduled - There are 2 types: Full backups or incremental backup - Backup software often comes with your OS but an also be purchased separately

Answer 29

- To reduce the size of a file so it takes up less space and downloads faster over the internet - Compressed files must be extracted before they can be read - Depending on the algorithm used data is either lost, reducing the quality of an image or audio file, or represented in a different way using binary, retaining the original data in a new, compressed format (e.g. ZIP)

Answer 30

- To re-organise files on a hard disk, putting fragments of files and free space back together - The process reduces the movement of the read/write head across the surface of the disk, which speeds up file access

Answer 31

- Unnecessary as it has no moving parts - Reduces the drive's lifespan

Answer 32

- Helps keep your computer and files safe from many types of malware including: - Viruses - Trojans - Worms

Answer 33

- Users can modify and distribute the software - Can be installed on any number of computers - Support provided by the community - Users have access to the source code - May not be fully tested

Answer 34

Benefits: - Software is free - Wide community modification Drawbacks: - Can be poorly supported - Some features might not be well tested

Answer 35

Benefits: - Gets their software out there to a wider community Drawbacks: - Little-to-no financial gain

Answer 36

- Protected by the Copyright Design and Patents Act - Users cannot modify the software - Usually paid for and licensed per user or per computer - Supported by developers who do not release source code - Tested by developer prior to release, although it may run beta programs

Answer 37

Benefits: - Well supported, tested and professional built product Drawbacks: - Cost or ongoing subscription fee

Answer 38

Benefits: - They receive an income for their product Drawbacks: - Constant demand from community for more features and improvements - Piracy issues

Answer 39

- The process of converting source code to machine code

Answer 40

- Assemblers - Interpreters - Compilers

Answer 41

- Translates assembly code into machine code - Takes basic commands and operations from assembly code and converts them into binary code that can be recognised by a specific type of processor

Answer 42

- Translates source code into machine code - Takes one line, translates it, then executes it - Once it discovers an error, it will output it, but it will keep running

Answer 43

- Translates source code into object code and then machine code - Takes the whole source code and converts it into machine code - Won't run unless all errors are corrected first

Answer 44

Advantages: - Memory efficient - Speed of execution is faster - Hardware-oriented Disadvantages: - Long programs written in such languages cannot be executed on small computers - Difficult to remember the syntax

Answer 45

Advantages: - No need for translation at run-time - Speed of execution is faster - Code is usually optimised Disadvantages: - Code needs to be re- compiled when the code is changed. - Designed for a specific type of processor

Answer 46

Advantages: - Easy to write source code, as the programs will always run, stopping when it finds a syntax error - Code does not need to be recompiled when code is changed Disadvantages: - Translation software is required at run-time - Speed of execution is slower - Code is not optimised - Source code is required

Answer 47

- A compiler runs through a series of parses - With each parse, the compiler performs different actions on the source code - Each parse is designed to carry out set tasks and prepare the code for the next stage of compilation

Answer 48

- A sequence of steps designed to perform a task

Answer 49

Assembly language is a programming language where mnemonics are used to represent instructions

Answer 50

- Paging - Segmentation

Answer 51

- Pages are fixed size - Pages are made to fit sections of memory - Pages are physical divisions - Programs are split to fit into a given number of pages - Paging takes no account of how it splits the program, only that it splits it into fixed-sized pages - It could separate the instructions inside a looping condition so they are in different pages, but that wouldn't be efficient

Answer 52

- Segments are different sizes - Segments are complete sections of programs - Segments are logical divisions

Answer 53

- Using parts of the HDD to store programs that can't be stored in primary memory

Answer 54

- While the processor does the FDE cycle other devices and applications may require the processor's attention. - They need a way to signal to the processor that they require attention - this is what's called an interrupt

Answer 55

- Interrupt Service Routine - A program with a set of instructions that need to be fetched, decoded and executed to carry out the operations of the interrupt - That means that the contents of the PC need to be changed to point to the address for the first instruction of the interrupt

Answer 56

- The values held in the registers are copied into a data structure in memory known as the stack - These values are pushed onto the stack in a stack frame, effectively saving them for later retrieval - The interrupt can now be executed - Once the interrupt is complete, we pop the frame off the top of the stack.

Answer 57

- Retrieve the previous values for the original program - Load them back into the processor registers - Carry on executing the original program where we left off

Answer 58

- The stack system handles it by: - Suspending ISR A - Pushes register contents onto the top of the stack - Starts executing ISR B - Once ISR B has completed executing, we pop the frame off the top of the stack to retrieve the value for ISR A, load them back into the processor registers and carry on executing ISR A

Answer 59

- Power supply failure - Power/reset button pressed

Answer 60

- Moving the mouse - Keyboard presses

Answer 61

- Illegal instructions encountered - Arithmetic overflow - New log on request

Answer 62

- Screen recording application - Data-logging program reading an input-sensor every second

Answer 63

- Buffer nearly empty - Printer ink supply notification - Signal the completion of a data transfer to/from a device

Answer 64

- Manages which process to execute next - Manages the length of time the next process can execute for

Answer 65

- Process A is a new process - The number indicates the length of time before it finishes - It enters the ready queue - When the currently executing process finishes or is blocked or suspended, process A can move into a running state - From here it will either: - Finishing executing completely and leave the system - Get blocked as it requires an input or output commands, meaning it can't continue until more data is received - Run out of time - each process is allocated a certain amount of time after which it is suspended and moved to the back of the ready queue

Answer 66

- First come First Served - Processes are executed in the order they arrive - If a process takes a long time, the others behind it have to wait

Answer 67

- Shortest Job First - Picks the processes that take the shortest amount of time and runs them until they finish - The scheduler needs to know how long each process will take

Answer 68

- Round Robin - Each process is allocated a fixed amount of time, known as a time slice or quantum - If the process isn't complete by the end of its time slice, it returns to the back of the ready queue

Answer 69

- Shortest Remaining Time - Similar to SJF - Pre-emptive algorithm, meaning processes can be suspended if a higher priority process joins the queue

Answer 70

- Multi Level Feedback Queue - This algorithm builds upon these standard algorithms with the following design principles: - Separates processes into multiple ready queues based on their processing needs. - Gives preference to processes with high I/O bursts - I/O bound processes will sleep in a wait queue to give other processes CPU time - This algorithm allows for processes to be shifted between queues - If a process has too much CPU time, it will be moved to a lower priority queue - If a process is I/O bound or an interactive process, it will be moved to a higher priority queue - If a process is waiting too long in a low-priority queue, it will be moved to a higher priority queue

Answer 71

- Distributed - Multi-User - Real-Time - Embedded - Multi-tasking

Answer 72

- An OS that handles many processes at the same time

Answer 73

- An OS that allows more than one person to access a single computer at the same time - The computer will manage the user's various permissions and access rights when they log on - Server operating system software will handle the requests of multiple people using different computers on a network at the same time

Answer 74

- An OS which can combine the processing power of multiple computers across a network for a single task

Answer 75

- The operating system controls and coordinates system controls and coordinates the computers, presenting them to the user as if they were a single system

Answer 76

- They run on dedicated hardware so they run with maximum efficiency, using low powered processor and very little memory

Answer 77

- An OS that executes processes within a known time frame - Plenty of redundancy is built into these systems so they can handle sudden increases in input - As such, processors in real-time OS rarely run at capacity

Answer 78

- Responsible for loading the OS when the computer first turns on - It first checks that the hardware it needs is connected and working using a POST

Answer 79

- A language that focuses on telling a computer exactly what to do by way of step-by-step instructions - It's laid out as a series of statements such as: Iteration, Sequence and Selection

Answer 80

- Sequence - Selection - Iteration

Answer 81

- Executing one instruction after another

Answer 82

- Allows a program to branch and follow a different direction depending on the outcome of a condition

Answer 83

- Repeating sections of code

Answer 84

- The process of putting one statement inside another - which can be achieved through both iteration and selection statements

Answer 85

- A pointer to a memory address that we are able to give a user-friendly label/name

Answer 86

- A value which remains fixed and doesn't change while the program is running, it must be set when the program is first written

Answer 87

- Converting one data type to another

Answer 88

- A block of code given an unique identifiable name within a program

Answer 89

- To break down a larger problem into a series of smaller, more manageable problems, making them easier to code, debug and reuse.

Answer 90

- Procedures - Functions

Answer 91

- Blocks of code that carry out a set task

Answer 92

- Blocks of code that carry out a set task and return a value

Answer 93

- Programs are easier to write - Programs are easier to debug - Creates reusable components - Functions can be grouped in a library for easy reuse across multiple programs

Answer 94

procedure Game(Value1, Value 2) Statements... endprocedure

Answer 95

function Game(Value1, Value2) Statements return Value3 endfunction

Answer 96

- The / operator will return a float value (e.g. 7/2 = 3.5) - The DIV operator will return a whole number (e.g 7 // 2 = 3)

Answer 97

- The act of manipulating, extracting or changing the characters in a string variable

Answer 98

- By using the .length function

Answer 99

By using the substring function

Answer 100

print(variablename.upper())

Answer 101

print(variablename.lower())

Answer 102

print(variable.isupper()) print(variable.islower())

Answer 103

ascii = ord('character')

Answer 104

char = chr(charactervalue)

Answer 105

- Open the file for creating/overwriting or appending - Write the data to a file - Close the file

Answer 106

- Open the file for reading data - Assign a Boolean variable to false to indicate the end of file is not reached. - While the end of file is false and the search item is not found - Read the data from the file - If the data matches what is being searched for, assign the data to variables or output - Check if the end of file has been reached and assign the Boolean variable to true - Close the file

Answer 107

- When the program requires the items from the text file to be in a specific order

Answer 108

f = open('filename.txt', 'r') r stands for what e want to do with the file (e.g. r = read)

Answer 109

variablename = f.readLine().strip()

Answer 110

f.write(variablename)