input
to enter data into a computer
process
to change the meaning or format of some data
output
to display or output data that has been processed
sequential
following instructions in an algorithm step by step in order from start to finish
parallel
process is distributed between two or more processors installed
multi agent
separate tasks are processed by different agents
RAM
can be read from and written to
fast access
the operating system
software in use
the data the software is using
virtual memory
a part of the hard drive and used as an extension of ram
von neumann architecture
computer system designed in which the program is stored in memory with the data
cache
memory used to make up for the difference in speeds between two internal components
the cpu
executes programs and manages the rest of the hardware
control unit
controls the execution of instructions in the correct sequence
it decodes instructions
it regulates and controls processor timing using regular pulses from the system clock
it sends and receives control signals to and from other devices within the computer
ALU
performs arithmetic operations and logical operations
fetch decode execute
fetch - causes the next instruction and any data involved to be fetched from main memory
decode - decodes the instruction
execute - carries out the instruction
program counter
contains the address of the next instruction tot be fetched
address bus
unidirectional and carries the address to a desired location in the main memory
data bus
the data in the location is returned to the CPU
control bus
control signals are transported
clock speed
faster clock speed, faster rate of processing
however, the processor generates a large amount of heat which increases as the clock speed increases
factors that affect cpu performance
clock speed
number of processor cores
size of cache
magnetic
mechanical parts move over the disks surface to read and write data magnetically
optical
data is stored as pits and lands and a laser beam passes over the pits and lands
solid state
data is recorded onto solid memory chips without any moving parts
magnetic advantages
cheap
cast storage capability
fast write speed
magnetic disadvantages
lots of mechanical parts
durability is an issue
not very portable
optical advantages
cheap
very portable
takes up little space physically
optical disadvantages
less storage capacity compared to other types
easily damaged
requires a reader
slow write speeds
ssd advantages
highly durable
no moving parts
very fat read/write speeds
no noisy fan
faster start up times
ssd disadvantages
expensive at present
less storage capacity than traditional hsrd disk
cloud storage
saving data in an offsite storage system maintained by a third party
cloud computing advantages
able to access data and applications anytime from anywhere
no need for a powerful computer with a huge hard drive
backing up data is no longer needed
cloud computing disadvantages
handing over important data to other companies may worry people
sensitive data can be more vulnerable to hacking
truth table
a table showing all possible combinations of the inputs and outputs of an operator
functions of an operating system
provides user interface
manages memory, multitasking, peripherals, files and user access rights
different UIs
GUI
menu driven
CLI
voice activated
interrupts
signals sent to the cpu by external devices to indicate and event that needs immediate attention
embedded systems
a dedicated computer system designed to perform a few specific functions
security utilities
anti virus
spyware protection
firewalls
backup and recovery
firewall
prevents unauthorised access to a computer or network from the internet
disk defrag
moves separate parts of the files around so that they can be stored together