Karteikarten
OCR gcse computer science
Karten in diesem Stapel (80)
- 1what is a computer?an electronic, programmable data processing machine
- 2what is a computer system?is a collection of hardware and software working tougher to achieve some data processing task
- 3what does the computer system do?input, process, store and output
- 4what is a user interface?a boundary between the end user and the system
- 5examples of a computer system? and what are the inputs/outputs/processingsystem-holiday booking
inputs-dates/destination
processors-check availability
output- tickets/hotel info - 6what 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
- 7what is a control system ?systems that controls machinery rather than produces outputs
- 8what is meant in reliability in a computer system ?- that they are working
- without any glitches
- data is secure - 9what is one thing that if it not reliable that may cause death?life support machine
- 10what are the 5 different standards?de facto
de jure
proprietary
industry
open - 11what is de jure?means by law. they have become so universally used they have to be used in all computers
e.g ASCII - 12what is de facto?not by law but are open to everyone and are commonly used.
e.g Microsoft word - 13what is proprietary?owned by a company and Ensure compatibility between the companys products
E.g apple - 14What are industry standards?standards set up by a recognised non-comericial organisation
- 15What is open soure?open standards are publicaly available, produced collaboratively,free of charge ir small cost.
- 16What does cpu stand for?central processing unit
- 17What does the cpu do?carries out all processing in a computer
- 18What is the fetch execute cycle?1) fetch the instruction from memory
2)decode the instructions
3) executes the process - 19What does alu stand for?Arithmetic logic unit (carries out the 'maths' operations)
- 20What does the control unit do?uses electrical signals to control the flow of data within the cpu
- 21What is clock speed?the number of cucles per second mesured in Hz
- 22What is cache memory?a way of storing data quickly however it is very expensive
- 23What is meant by mutiple processor cores ?more than one core so the computer can do more than one task at a time
- 24Explain ramRandom access memory
Volatile
Can be accessed and changed
Stores data being used by the computer
Contains the operating system
Large - 25Explain romNon volatile
Programed during a computers manifactuon
Stores instructions and data required to start up the computer
Contains boot program
Small - 26What is the boot program?its a sequence of processes that contains all the information and instructions to get the comouter up and running
- 27What 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
- 28What is flash memory?its a thpe of rom that can be rewritten. Used in portsble medium such as sd cards and usb
- 29What is the operationg systerm?Set of programs that controlls the hardware and lets users and aplications work with the computer
- 30Why is using files good?makes it easier for end user to locate
- 31What 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) - 32What is meant by the file typesXls-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) - 33What is a utility program?software tools that help make maintaing the system easier
- 34What is anti virus software?detects and removes viruses
- 35What is spyware?checks and removes programs that record the websites you vistit and passwrods you use
- 36What Are firewals?monitor traffic entering and leaving systems in oder to block unauthorised material
- 37Advantages of custom written softwareadvantages-customised to needs of customer
Extacly the right feature
Developer made provide training
Devleoper can be contacted if something is wrong - 38Disadvantages of custom writtenmay not be as extensively tested
May be expensive
May take a long tome to develop - 39advantages of off the shelfits is ready to use
been tested well
has less problems
user guides
low cost - 40disadvantages of off the shelfwont be exactly what the customer needs
may need to be customised
customer may have to search for training providers - 41advantages of open sourceit may be free of charge
can be altered because the source code is available
very reliable - 42disadvantages of open sourceno maintenance contracts
no contact if there is any problems
may be a different platform the company already uses - 43advantages of proprietarysomeone to go to if there is a problem
tested
regular updates - 44disadvantages of proprietaryexpensive
users may get "locked into" the software
may be inflexible for the users needs - 45what 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 - 46what is validation?process of checking data when it is inputted
- 47what 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 - 48what are diagnostics?diagnoses what is wrong with the computer
- 49what is meant by verification?checking data entered is correct it can be a visual check
- 50what is the structure of a database?table
field
record
row
Column - 51what is a database management system?The software that looks after a database at a fundamental level.
- 52What are the 5 data typesInteger
Real
Character
String
Boolean - 53What is the data type integer and give an example of use?whole number values
E.g 26
Used to store data such as quantities - 54What is the data type real and give an example of use ?numbers with a decim
- 55What is the data type character and give an example of use?Single character
E.g a,H,6 or &
used to store signle characters - 56What is the data type string and give an example of use?A string of characters
E.g phone numbers or postcode - 57What is the data type boolean and give an example of use?one of two value
E.g true or false - 58What is a form?provides a friendly user interface so the user can input data onto a database
- 59What is a report?outputted from a database. Set up to sumarise a group pf data
- 60What is query?its used to extract a subset of data in a data base
- 61What is a network?a collection of connected computers plus their peripherals
- 62Advantages 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 - 63Disadvantages of lanmaintances is expensive
Network problems might effect all users
Security may be a problem because data is accessible from many locations - 64What 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 - 65What 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
- 66What is lossy?lossy compression reduces the file by permently deleating certain information.
- 67What is lossless?every bit of data remains after the file has been uncompressed
- 68What 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.
- 69What 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.
- 70What are topologies?topologies refers to the layout of a network.
- 71What is an algorithim?algorithims provide a computer with a set of instruction or rules that are followed to complete a task
- 72What is a expert system?Systems designed to behave like a human
- 73What is managment information system?Nrings information from all parts of an organisation so that managers can make sensible decisions
- 74What is data integraty?Data being accurate and consitant
- 75Explain magnetic storageStores: os,programs and user data
They are realiable
Low cost
High capacity - 76Explain optical storageEg a cd
Good for transfering files
Good capacity
Low cost
Light weight - 77What is resoloution?Number of pixles per unit
- 78what 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.
- 79name two types of interfacegraphical interface
command line interface - 80what is meant by multi taskingit enable several programs to run at once.
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- Karteikarten am OCR gcse computer science , erstellt von Jodie Awthinre am 21/10/2015.
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