computer science 9-1

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computer systems: hardware
computer systems: hardware
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components a microposeser needs...
1) Input devices 2) Memory to store the instructions 3)permenant long term memory 4)Output devices 5)buses
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what do computers need to start?
system software (then application software like word)
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what is an embeded system?
A cmputer system built within a larger device to control its functions
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3 devices that contain an embeded system
Washing manchine , Camera , Car
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RAM-
Acts as a temporary form of program, information and storage. VOLATILE. CAN be wrote and read too.
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ROM-
Stores basic instructions like how he computer starts up. NON-VOLATILE. CANNOT be wrote too only read.
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what are the 4 main things the CPU consists of?
ALU (arathmetic logic unit), CU (control unit) , registers and chache
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what does the control unit do?
controls the activity of the CPU by sending out control signals
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What does the ALU do?
carries out arathmetic and logic operations
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what do registers do?
memory locations in the CPU
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what does the cache do?
very fast RAM
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what do buses do?
carry electrical signals
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F-D-E : FETCH?
an instruction is transfered from memory to CPU
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F-D-E : DECODE?
the CPU works out what the instruction means
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F-D-E : EXCUTE?
the control unit carried out the instruction using the ALU involving logical and mathmatical operations
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what does the program counter do in the fetch decode excute cycle? (FETCH)
Supplies the address of the location of the instruction to be fetched. The program counter is a register in the CPU.
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what is pipelining?
a technique modern procsessers use which allows them to procsess more than one instruction at a time
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what does increasing the clock speed do?
increases procsessing therefore increases the speed of your computer
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what are the effects of over-clocking?
increase in heat which can lead to instability and permenant damage to the computer.
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what does a heat sink do?
prevent things from melting and or malfunctioning as a cause of increasing clock speed
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microprocesers 9GHz require what too cool them?
liquid nirogen
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advantages of multi core procsessers
parralel procsessing - work together in the same program. Multitasking - work on more than one program at any one time
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disadvantages of multicore procsessers
it might only be able to be carried out sequentiol therefore it would be no use
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what is cache?
a high speed storage mechanis for frequently used data. I t can be part of memory or located on a storage device.
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where can cache size be found?
in the BIOS set up screen of a computer
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why cant clock speed be increased indefinetly?
it creates to much heat
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what does a computer need to be classed as multi core?
several CPU's
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what happens when RAM is full?
the operating system will store data on a hard drive disk (the virtual memory)
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what happens to the least used data?
items are swapped out of virtual memory and moved back when necessary
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magnetic media:
electromagnetics in read-write heads and write data on discs coated withmagnetic material. e.g a hard drive
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optical media:
light from lasers read-write data on specially prepared discs. e.g cd
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electrical or solid state:
data is stored electrically using flash memory e.g USB
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cloud storage:
off site sorage accsesed via the internet
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computer systems: system software
computer systems: system software
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what does system software include?
BIOS, operating system and system utilities
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what is memory management?
in charge of RAM, large programs use RAM more than small. Checks that all program requests for memory fit accordandly it will also de-allocate space and swap and swap out data to the swap file
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what is procsess management?
prioratise and allocate time to each process
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what is peripherial management?
manages all input and output through drivers
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what is file managment?
it controld permissions such as the users ability to read,write to a file etc
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what is an operating system?
a collection of software ans forms part of system soft ware
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what does the operating system do?what does it control?
manages all the other software applications and memory allocations. it controlshardware devices
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how does the operating system communicate
through a user interface
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what do utility programs do?
preformes specific functions to maintain and optamise the computer operationsand ensure the security of the system
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what does utility program include?
system clean up, disk fragmentation, anti-virus programs and file compression tools
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what does a computer network allow?
devices to share data and resources
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the 3 types of networks
LAN's (large area networks) WAN's (wide area networks) PAN's (persanol area networks)
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what are the 2 typer of computer in a client server network
servers and clients
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in peer to peer what are the computers like?
all equal.
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what is centralised in a client server network but distriputed in peer to peer
security, data storage and the backing up of data
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what do computers need to connect a network
network adaptor
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what are used to allow computers in a single network to message to be transmited
hubs and switches
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what are used to transmit messages on different networks?
routers
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what are cables and radio waves used for?
carry data
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what are the 2 most common ways for transmission
ethernet and WI-FI for wireless
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what is topology?
the arrangement of computers and other devices in the network connected together
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what do topologies include?
star and mesh networks
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what is the internet?
a huge network of networks
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what do you need to connect to the internet?
a modem and an adapter
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what are protocols?
rules computers use for communicating on networks
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what does an ISP provide?
acsess to the internet inferstructure for users
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what are domain names?
easier versions that stand for ip adresses IP address are needed they look like - 143.974.68.675
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what does DNS do?
domain name server - coverts the domain names back to an ip address
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what is TCP/IP?
a suite of 4 protocals 1.the application layer 2.the transport layer 3.the internet (network) layer 4. the data link (network accsess) layer
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what are virtual networks?
private secure netwoks within larger WAN's such as the internet
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system security
system security
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what does social engineering mean?
getting people to share private and persanol infomation by decepation
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what can stolen information be used for?
steal money and even more persanol data
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what are the methods of social engineering?
blagging, phishing and shouldering
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what is malware?
software intended to make a computer not function correctly, to corrupt or destroy data or to collect information without their knowledge
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what are the types of malware (6)
worms,viruses,trojan horses,spyware,pharming and adware
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how can you protect your computer from malware?
use software to destroy it
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what are the methods of attack (4)
brute force, denial of server (DOS), SQL injections and zero day attacks
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how can you keep networks secure?
1.accsess control, user security 3.firewalls 4.encryption
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what should organisations have?
network policies - to detect and withstand attacks and recover if their security is breached
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what is penetration testing?
carrying out controlled attacks to test the safeguards in place
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ethical cultural and legal impacts
ethical cultural and legal impacts
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what are the effects of computer science technologies?
1. use of electricity in farming and production 2.disposal in landfill sites 3. release of toxic chemicals when burnt
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what are the envirmental impacts of computer science technology?
1.monitering and modelling climate change 2. use in animal conservation 3.design and development of 'green energy' sources
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what does being 'ethical' mean?
behaving in a morally acceptable way by doing things that society recognises as good
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whats an example of something being legal but not ethical?
using devices to track movements and daily activities of people
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what is the digital divide?
the divide between people have the ability to accses IT and thoose who don't
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what acts do legislation include?
1. data protection act (1988) 2.computer missuse act (1990) 3.copyright designs and patents act (1988) 4.freedom of information act (2000)
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what does the creative commons licence allow?
creaters of work to give rights to the user
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who can modify the source code of proprietary software?
no-one exept the person team or organisation that created it and maintains exclusive control over it
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what is open source software?
softwar ewhos source code is available for use,modification or enhancments by anyone
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Card 2

Front

components a microposeser needs...

Back

1) Input devices 2) Memory to store the instructions 3)permenant long term memory 4)Output devices 5)buses

Card 3

Front

what do computers need to start?

Back

Preview of the front of card 3

Card 4

Front

what is an embeded system?

Back

Preview of the front of card 4

Card 5

Front

3 devices that contain an embeded system

Back

Preview of the front of card 5
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