43747
3.1 - The Function of
Operating Systems
- The main features of operating systems
- An OS must:
- Provide and manage hardware resources
- Provide an interface between the user and the machine
- Provide an interface between applications software and the machine
- Provide security for the data on the system
- Provide utility software to allow maintenance to be done
- Provide and manage hardware resources
- Original purpose was to prevent
duplication of code by providing
input and output resources
- Prevents each individual program
from having code to control input
and output (duplication of code)
- Input-Output Control System (IOCS)
- Prevents each individual program
from having code to control input
and output (duplication of code)
- Development of
assembly/high level
languages means that OS
needed:
- A translator
program to turn
human friendly code
into computer
friendly code
- Assembler - Handles translation from assembly
language
- Compiler - Translates high level code into object
code
- Interpreter - Translates a line of high level code
and runs the result before translating the next
line
- Assembler - Handles translation from assembly
language
- A translator
program to turn
human friendly code
into computer
friendly code
- Memory management
- More than one program
should be stored in memory
and the processor should give
time to each of the programs
- Processor should give time to each of the
programs and process higher priority
processes first of all
- Processor should give time to each of the
programs and process higher priority
processes first of all
- OS needs to keep all
programs separate
along with any data
they use
- Spooling
- Memory used to store data that has
been inputted by user or that is
about to be outputted until the
processor deals with it
- Memory used to store data that has
been inputted by user or that is
about to be outputted until the
processor deals with it
- Loader
- Remembers memory
locations of each
instruction or each piece of
data
- Remembers memory
locations of each
instruction or each piece of
data
- More than one program
should be stored in memory
and the processor should give
time to each of the programs
- An OS must:
- How Interrupts are Used to Obtain
Processor Time and how Processing
of Interrupted Jobs may Later be
Resumes
Want to create your own Mind Maps for free with GoConqr? Learn more.