1.5 Operating Systems Flashcards
Software
The applications and programming instructions that tell computer what to do
Operating system
Core software that controls how a computer operates
E.g. windows, linux, iOS
-provides interface, memory management, device drivers, file management
User interface
Allows a person to interact with a computer. Standard way of interact with a computer - mouse, keyboard, finger pad
Types: Command line interface, Menu interface, Graphical User Interface
Command Line Interface
Allows user to interact directly with the computer system by typing command (instructions) into a screen
Menu Interface
Gives user a list of possible actions that the system can carry out. If the action is not on the menu, the user cannot do it
GUI
Graphical User Interface. Most commonly used today. ‘Friendly’ way for people to interact with the computer as it uses pictures, graphics, ions
Memory management
Memory is a limited resource and needs to be managed.
-A program has to be loaded into RAM before they can run. To run more than one program, they have to all be in memory
-memory manager gives each program a private memory area so programs cannot interfere with each other
-responsible for moving programs between RAM and virtual memory
-multitasking/ fragmenting
Multitasking
-operating system of computer can have many programs running simultaneously in memory
-scheduling - processor allocates small amounts of time to each process and cycles between them
Fragmentation
-Program A is loaded into RAM
-Smaller program B gets loaded
-Program A closes
-larger program C loads into available space and is split
–memory doesn’t shift around as that would be slow and intensive, instead stays where it is and programs fit around it
Device driver
Software programs designed to work closely with a particular piece of hardware. Enables the operating system to control and communicate with the device.
-every piece of hardware that communicates with the OS will require a device driver (OS–> Device driver –> Hardware)
-Internal devices: hard disk, DVD drive, sound card
-External devices: printer, mouse, monitor
User management
A single computer may be used by more than one person. Each person has an ‘account’ on that computer
-OS creates a private desktop and folders only they can access when logged in with user access rights
User access rights
OS keeps data secure and private with user access rights through usernames and passwords
-Read - ability to view/ open file but not change them
-Write - allows file to be modified
-Execute - gives user rights to execute or run an executable application
File management
-Organize/ keep track of files
-e.g. hierarchical file system (root, node)
