OCR gcse computer science

Jodie  Awthinre
Flashcards by , created over 3 years ago

Flashcards on OCR gcse computer science , created by Jodie Awthinre on 10/21/2015.

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Jodie  Awthinre
Created by Jodie Awthinre over 3 years ago
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Question Answer
what is a computer? an electronic, programmable data processing machine
what is a computer system? is a collection of hardware and software working tougher to achieve some data processing task
what does the computer system do? input, process, store and output
what is a user interface? a boundary between the end user and the system
examples of a computer system? and what are the inputs/outputs/processing system-holiday booking inputs-dates/destination processors-check availability output- tickets/hotel info
what is an embedded system? systems that are part of a larger system, they are usually also control system. they include portable devices such as: digital watches/satnavs/cameras/mp3
what is a control system ? systems that controls machinery rather than produces outputs
what is meant in reliability in a computer system ? - that they are working - without any glitches - data is secure
what is one thing that if it not reliable that may cause death? life support machine
what are the 5 different standards? de facto de jure proprietary industry open
what is de jure? means by law. they have become so universally used they have to be used in all computers e.g ASCII
what is de facto? not by law but are open to everyone and are commonly used. e.g Microsoft word
what is proprietary? owned by a company and Ensure compatibility between the companys products E.g apple
What are industry standards? standards set up by a recognised non-comericial organisation
What is open soure? open standards are publicaly available, produced collaboratively,free of charge ir small cost.
What does cpu stand for? central processing unit
What does the cpu do? carries out all processing in a computer
What is the fetch execute cycle? 1) fetch the instruction from memory 2)decode the instructions 3) executes the process
What does alu stand for? Arithmetic logic unit (carries out the 'maths' operations)
What does the control unit do? uses electrical signals to control the flow of data within the cpu
What is clock speed? the number of cucles per second mesured in Hz
What is cache memory? a way of storing data quickly however it is very expensive
What is meant by mutiple processor cores ? more than one core so the computer can do more than one task at a time
Explain ram Random access memory Volatile Can be accessed and changed Stores data being used by the computer Contains the operating system Large
Explain rom Non volatile Programed during a computers manifactuon Stores instructions and data required to start up the computer Contains boot program Small
What is the boot program? its a sequence of processes that contains all the information and instructions to get the comouter up and running
What is virtual memory? is part of the hardrive and is used when the computer does not have enough ram. It is slower than ram so by adding more ram it imoroves the speed of the computer
What is flash memory? its a thpe of rom that can be rewritten. Used in portsble medium such as sd cards and usb
What is the operationg systerm? Set of programs that controlls the hardware and lets users and aplications work with the computer
Why is using files good? makes it easier for end user to locate
What is meant by the file types doc,pdf and html? doc-word document Pdf-portable document format(used to store documents in exactly defined format it cant be changed by anyone else) Html-hypertext makeup lamguage (web pages)
What is meant by the file types Xls-microsoft excel spreadsheet Mdb-microsfot access database Exe-executable(- program that can run) Jog-joint photgraphic experts group(compreessed image) Mp3-(music file ussing lossy compression)
What is a utility program? software tools that help make maintaing the system easier
What is anti virus software? detects and removes viruses
What is spyware? checks and removes programs that record the websites you vistit and passwrods you use
What Are firewals? monitor traffic entering and leaving systems in oder to block unauthorised material
Advantages of custom written software advantages-customised to needs of customer Extacly the right feature Developer made provide training Devleoper can be contacted if something is wrong
Disadvantages of custom written may not be as extensively tested May be expensive May take a long tome to develop
advantages of off the shelf its is ready to use been tested well has less problems user guides low cost
disadvantages of off the shelf wont be exactly what the customer needs may need to be customised customer may have to search for training providers
advantages of open source it may be free of charge can be altered because the source code is available very reliable
disadvantages of open source no maintenance contracts no contact if there is any problems may be a different platform the company already uses
advantages of proprietary someone to go to if there is a problem tested regular updates
disadvantages of proprietary expensive users may get "locked into" the software may be inflexible for the users needs
what is the importance of a database? -key for a business to work -must be accurate -makes it easy to find data -need to protect the data
what is validation? process of checking data when it is inputted
what are validation methods and meaning? length check-must have a certain number of characters type check-must be a certain data type range check-must fall between certain limits presence check-must be filled in lookup check-must match what is held on the file format check-must conform to a certain pattern check digit- must be exactly the same as data previously entered
what are diagnostics? diagnoses what is wrong with the computer
what is meant by verification? checking data entered is correct it can be a visual check
what is the structure of a database? table field record row Column
what is a database management system? The software that looks after a database at a fundamental level.
What are the 5 data types Integer Real Character String Boolean
What is the data type integer and give an example of use? whole number values E.g 26 Used to store data such as quantities
What is the data type real and give an example of use ? numbers with a decim
What is the data type character and give an example of use? Single character E.g a,H,6 or & used to store signle characters
What is the data type string and give an example of use? A string of characters E.g phone numbers or postcode
What is the data type boolean and give an example of use? one of two value E.g true or false
What is a form? provides a friendly user interface so the user can input data onto a database
What is a report? outputted from a database. Set up to sumarise a group pf data
What is query? its used to extract a subset of data in a data base
What is a network? a collection of connected computers plus their peripherals
Advantages of Lan (local area network) central storage so data sharining is easy Central storage makes back ups easy Easy to update Easlily monitored Security pollicy can be centrally admitted Users can communicate with each other Peripherals can be shared
Disadvantages of lan maintances is expensive Network problems might effect all users Security may be a problem because data is accessible from many locations
What is wan? wide area network It covers large are. The ultimate an is the internet. -often connect lan tougher -they make use of publicly available telecome facilities -allow bussiness to function from any location
What is compression? its often used to speed up the transmissions of data such as images it changes the data into a form that uses fewer bits of data than the original data
What is lossy? lossy compression reduces the file by permently deleating certain information.
What is lossless? every bit of data remains after the file has been uncompressed
What is ip adressing? Ip adress tells you where to go or send data, you can give a computer an ip adress. Each website is stored on a computer and these have an ip adress like a postcode and adress so you know where to send a letter to.
What is mac adressing? A mac adress is given to the hardware and cannot be changed, a computer might have several mac adresses for wireless, for wired for blue tooth etc.
What are topologies? topologies refers to the layout of a network.
What is an algorithim? algorithims provide a computer with a set of instruction or rules that are followed to complete a task
What is a expert system? Systems designed to behave like a human
What is managment information system? Nrings information from all parts of an organisation so that managers can make sensible decisions
What is data integraty? Data being accurate and consitant
Explain magnetic storage Stores: os,programs and user data They are realiable Low cost High capacity
Explain optical storage Eg a cd Good for transfering files Good capacity Low cost Light weight
What is resoloution? Number of pixles per unit
what is proprietary software? is software where you only get given the program and cannot see the source code and you are given licence on how to use it.
name two types of interface graphical interface command line interface
what is meant by multi tasking it enable several programs to run at once.