Software and Software Development

Algorithm: a ___ of ___________ used to _____ a _______

set, instructions, solve, problem

Waterfall methodology: A _______ series of stages, establishing __________ in early stages, focusing on the ___ ____ at the _____ and then they may be consulted in _____ stages.

linear, requirements, end user, start, later

Waterfall methodology advantages: clear __________ ensures all staff understand what they need to do and new staff can quickly be brought __ __ ____. ______ ______ make the project easier to ____ and make clear lines of ____________. _____ projects can be split into a set of smaller __________ and each can be approached using its own '_________'

documentation, up to date. Clearly defined stages, plan, responsibility. Large, subprojects, waterfall

Waterfall methodology disadvantages: If a change needs to be made at a _______ _____, all levels between that stage and the current stage must be _______, making the project ________ and unsuited to projects with _______ requirements. Users have little _____, as they are only involved at the ________ and _________ stages. The development process can take so long that the _______ ___________ no longer reflect what is _____

previous level, revisited, inflexible, changing, input, analysis, evaluation, original requirements, needed

Rapid Application Development: A __________ is created, evaluated and _______ is used to ______ the next ________. Any _______ are made and process is _______ until prototype becomes the _____ product

prototype, feedback, inform, iteration, changes, repeated, final

RAD advantages: Requirements don't need to be _____ from the ____. Caters to changing ____ __________, producing a highly _____ end product. The focus on only ____ features that the user wants reduces __________ ____

clear, start, user requirements, usable, core, development time

RAD disadvantages: poorer quality _____________, fast pace may reduce _______ of ____

documentation, quality code

Extreme programming (XP) methodology: An _____, ________ model that uses _____ programming alongside a representative ___ ____, with a heavy focus on the quality of the ____. The end user is ________ throughout development and new _________ can be _______ throughout

agile, iterative, paired, end user, code, integral, requirements, adopted

Alpha testing: Testing done by the _______ before ____ ______

programmer, beta testing

Black box testing: Tests the expected ______ based on the _____ without looking at the ____

output, input, code

Open source software: software that has its ______ ____ freely available to ____

source code, edit

Library: sections of ____ already _______ containing useful ________ e.g. _________

code, written, routines, encryption

Three advantages of libraries: Save ____ because no need to _______ code. Use _________ of other to _______ away complexity. Has already been _______, saving time ________

time, code, expertise, abstract, tested, debugging

Two disadvantages of libraries: May increase ____ of ________ file s library contains many _______ that aren't being ____. Not written by the _________ so they need to spend time __________ themselves with it

size, compiles, routines, used, programs, familarising

How linkers are used in the compilation process: Links the ____ ______ to _______ and can either _______ them in the _____ code or get the ________ code to point to the __________ libraries

main program, libraries, include, final, executable, external

Operating systems provide: memory __________, ________ management, ____ management, _________ management, ________

management, resource, file, interrupt, security

Distributed systems: A_____ which is ___ ______ _______ ______, allowing the ____ to be ______ across _______ _______ _________ using _________ __________

system run across multiple devices, load, spread multiple computer processors, parallel processing

Operating system: A ________ __ _______ that _____ _______ to ______ an _______ _____ ___ ___ ___ _______

collection of software, works together, provide, interface between the user and computer

Real-time system: ... ________ is _____ __ so the system can handle sudden _______ __ _____,so they rarely run at ______

A system that gives a response within a fixed time frame, redundancy, built in, increases in input, capacity

Embedded system: Software used to ____ the _____, built into the device itself and ________ to the _______. Stored in ___ so it cannot be _______

manage, device, specific, hardware, ROM, changed

Paging: ... causes _______ fragmentation. Non- _______ so every ____can be used.

Memory is split into fixed size, physical divisions, called pages, internal, contiguous page

Segmentation: ... causes _______ fragmentation

Memory is split into unevenly sized divisions, representative of structure and logical flow of a program, called segments, external

Why memory management is important (4 points)

Organises the use of main memory by converting logical addresses to physical addresses. Allows programs to share or allocate memory and protect processes and data from each other. Enables programs larger than main memory to run

Why scheduling is important (3 points):__ _______ __ ____ ____ __ _______ _______ ___ ______ and _______ ______ of __________ _____ with ____ ________ _____. _________ ___ __ _________

To process as many jobs as possible quickly and fairly, maximizes number, interactive users, fast response times. Efficient use of resources

Preemptive scheduling algorithm

jobs are actively made to start and stop

non preemptive scheduling algorithm

once a job is started, it is left alone until finished

first come, first served

a non preemptive scheduling algorithm where jobs are dealt with in the order they arrive (queue)

round robin scheduling

a preemptive scheduling algorithm where a time slice is given to each job and they are dealt with on a FIFO basis. If the job does not finish within a time slice it joins the end of the queue

shortest job first

a non preemptive scheduling algorithm where the queue is sorted/ordered by expected execution time, with shorter jobs at the front

Shortest remaining time: _ ________ ________ ________ where the _____ is _____ __ ________ ________ ________ ____, with _______ ____ at the _____. If as ___ ___ _______ ____ ____ than the ________ ______ ___, the _______ ______ ___ is _______ so the ___ ___ can ___

a preemptive scheduling algorithm, queue, sorted by expected remaining execution time, shorter jobs, front, new job requires less time, currently running job, currently running job, stacked, new, job, run

Multilevel feedback queue: A __________ scheduling algorithm that uses _____ __ ____, where each queue has different levels of ______. Jobs are _______ _____ to a queue with a ______ _____ of priority. If a process uses ___ ____ ___ ___, it is moved to a _____ priority queue and if a process has been ____ for a long time, it is moved to a queue (this helps avoid _________). Processes that depend on ____/ _____ ______ require a lot of processing time, so are kept in ____ priority queues, and processes that are _____ __ _______ are served ____.

preemptive, queues of tasks, priority, initially added, certain level, too much CPU time, lower, idle, higher, starvation, input/ output devices, high, quick to complete, first

Interrupt Service Routine: ___ _______ __ _____ __ _______. If the _______ is a _____ _______ than the current task, the contents of ___ _______ are _____ __ _ _____. The _______ __ is then ______ by ______ ___ _______ of its _____ ______ into the ______ ______. When the ISR is ______ the _______ _______ of the registers are _____ from the _____ and loaded back into the ______

the current FDE cycle is completed, interrupt, higher priority, the registers, pushed to a stack, relevant ISR, loaded, loading the address, first instruction, program counter, complete, previous contents, popped, stack, registers

Multi-user system: _______ _____ can _____ the ____ _____. Uses a _______ _______ to ensure _______ ____ is shared _____ between jobs and to _______ the risk of _______ _______ so users can access the same system the the ____ ____ without _______ _______ the other users

multiple users, access, same system, scheduling algorithm, processor time, fairly, mitigate, processor starvation, same time, adversely affecting

Multi-tasking system: Enable the user to run more than one ______ at the ____ ____. This is done by ____ ______ to quickly ______ between programs and __________ in memory

program, same time, time slicing, switch, applications

Multi core processor. More than one _________ ____ in a ______ ________ which can __________ process instructions at the same time

processing unit, single processor independently

BIOS: Responsible for ______ ___ __ when the computer first _____ __

loading the OS, turns on

What the BIOS does when a computer turns on:1. ____-__-____-____: ensures ___ ______ (e.g. keyboards, disk drives) is correctly __________ and functional2. checks the ___ _____, memory and _______ are operational3. _____ for _______ _____ _____ connected to the computer4. loads the ______5. bootloader passes control to the _____ which _________ the __

Power-On-Self-Test, all hardware, connected, CPU clock, processor, test, external memory devices, bootloader, kernel, initialises, OS

Bootloader: ___ ______ that ______ the __ ______ from the ___ ____ to ____ ______

the program, loads, OS kernel, hard disk, main memory

BIOS settings: ______ in _____ ______ so they can be _______ and are _______ when _____ is ___

stored, flash memory, changes, retained, power, off

Device drivers: _______ ________ used by the __ to __________ with _________, specific to the computer's ________ and __

utility software, OS, communicate, peripherals, architecture, OS

Utility software: ________ that performs a _______ ____, usually related to the ______ __ ___ ______

software, specific task, upkeep of the system

Application software: Used by the ___-____ to perform ___ ________ ____. E.g. ____ processing, spreadsheets, ___ ________

end-user, one specific task, word, web browsers

Systems software: ___-_____ software responsible for ________ the computer ________ and maintaining consistently ____ ___________. E.g. ________ programs, _______ programs, device _______

low-level, managing, resources, high performance, library, utility, drivers

Open source advantages: can be ________ and ________ by anyone, technical support ______, can be modified and ____ __.

modified, improved, online, sold on

Open source disadvantages: support online may be _________, lower ________

incorrect, security

Closed source advantages: thorough and ____-______ updates, company provides _______, ____ levels of security

well-tested, manuals, high

Closed source disadvantages: users cannot ______ and _______ software themselves, _______ restricts how many people can use software at once

modify, improve, license

Translator: a program that ________ ___-_____ source code into ___-_____ ______ ____

converts high-level, low-level object code

Compilers translate high-level code into machine code ___ __ ____, it is ________ to a particular _________ ____ and __

all at once, specific, processor type, OS

Interpreters _________ and _______ code ____-__-____, they stop and produce an error if a line contains one, ______ than running compiled code. Code requires correct ___________ in order to run

translate, execute, line-by-line, slower, interpreter

Procedural programming uses a ________ of ____________

sequences, instructions

Object-oriented programming is built on _______ ______ from ________ which have __________ and _______

objects formed, classes, attributes, methods

Immediate addressing: The operand is the ______ _____ where the instruction is performed

actual value

Direct addressing: The operand _____ the _______ which holds the _____ where the instruction is to be performed

gives, address, value

Indirect addressing: The operand gives the address of a ________ which _____ _______ _______, where ____ is located

register, holds another address, data

Indexed addressing: Index ________ used, stores certain _____. Address of operand determined by ______ the _______ to the _____ _______

register, value, adding, operand, index register

Advantages of OOP: _____ level of ___________, classes used across ________ projects, ____________ make the code more ________ by protecting _________

high, reusability, multiple, encapsulation, reliable, attributes

Disadvantages of OOP: requires alternative style of ________, not suited to all types of ________ and can sometimes produce ______, more ___________ program, unsuitable for _______ problems

thinking, problems, longer, inefficient, smaller