Operating systems Flashcards
what is an operating system
the software that controls the overall operation of a computer
example of operating systems
windows, macOS, UNIX, Linux, Solaris
example of smart phone operating systems
apple iOS, google android, windows phone, Blackberry OS, Nokia Symbian OS
Software classification
Software consists of application and system
system consists of utility and operating system
operating system consists of user interface and kernel
what is application software
not a part of the oeprating system, sit on top of it?
includes browsers, word, youtube, email, notes, calculator etc.
System software comprises
utility software and the operating system, is inbetween application software and hardware
utilty software extends capabilities of the operating system
user interfaces
text based (shell)
graphical user interface(GUI)
kernel
performs required functions and contains components
- file manager (looks after file storage/retrieval)
- device drivers (software for comms with devices)
- memory manager (handles memory allocation/deallocation)
scheduler and dispatcher (handles CPU task scheduling)
what does the file manager do
maintains records of all files stored in mass storage
- where each file is located
- which users are permitted access to various files
- which portions of mass storage are available
directory
Directory (or folder): a user created bundle of files and other directories
directory path: a sequence of directories and subdirectories from the root
user interface types
Text based (Shell)
Graphical User interface (GUI)
Components of kernel and their functions
File manager (looks after file storage/retrieval)
Device drivers (software for comms with devices)
Memory manager (handles memory allocation/deallocation)
Schedular - determines which activities are to be considered for execution
dispatcher - controls allocation of time to the activities
device drivers
programs that communicate with controllers to carry out operatins on the peripheral devices attached to the machine
- each device driver is uniquely designed for the type of device
- devices include disk driver, printer, graphics card ets
Memory manager
Allocates space in memory #go back to this.
Schedular and dispatcher
Schedular - determines which activities are to be considered for execution
Dispatcher - contolrs the allocation of time to the activies
