the operating system Flashcards
paper 2
what is an operating system?
software that manages and controls the computer hardware + acts as an interface between user and the hardware
eg windows, macOS
OS services (name 3)
- provides user interface
- runs software programs by loading code + data into RAM and activating CPU
- allows multiple programs active at same time by sharing processor time
- allows configuration of hardware eg screen resolution
- displays catalogue of programs and data files
- provides security to prevent unauthorised access
how does the OS manage peripherals?
manages peripherals (inputs/outputs) by communicating and sending data output to them using drivers
how does the OS manage memory?
OS loads data into RAM when needed and unloads it when it isn’t
partitioning
buffering
partitioning
dividing memory into multiple partitions and allocating each partition to instructions and data for one specific task
buffering
allocating part of memory to temporarily store data in transit between computer and a slower device eg webcam/printer
cannot be filled and emptied at same time so double buffer can be used so one can be filled while the other is emptied to speed up data transfer.
how does the OS manage the backing store?
allocate physical disk space as files are added, edited or deleted providing hierarchical, searchable structure for users.
utility software
software that performs tasks that support the operating system
analyses processes, optimises processes or maintains the system
categories of utility software (name 4)
anti-virus
compression
debuggers
screensavers
system monitors
encryption
defragmentation
anti-virus
checks the computer for malware and notifies the user of any is found
compression
allows a file/folder to be reduced in size for storage or transmission
debuggers
identify and help to resolve problems in software
screensavers
starts automatically after a pre-set interval to prevent screen burn and save power
system monitors
utilities allow the user to track memory and processor usage + network connection speed and more
name 3 uses of a user interface
- allows copying/ deleting/ moving/ sorting/ searching of file or folders
- allows access to system settings such as hardware
- allows users to have more than one window open
- provides graphical user interface
- provides user with error messages
modes of operation
different ways that operating systems have of working
batch processing
real time control processing
real time transaction processing
batch processing
a series of tasks completed at the same time (normally without intervention overnight when resources are available)
uses a transaction file to record events and updates the master file at the end of the period
eg running pay roll, gas billing ( as bills are issued regularly in response to meter readings)
simpler/faster with transactions being stored in order they are recieved