week 2 Flashcards
OS
manages computer hardware, and software resources, and provides common services for computer programs.
OS components
1_ the kernel
2_ the loader
3_ Device Manager
4file manager
5 command interpreter
6_ GUI (graphical user interface)
The kernal
core of computer’s Operating system
The loader
loaded at system boot time
Device manager
it’s allows user to view and control the hardware attached to the computer
File manager
manage all the files on th computer
command interpreter
understand and executes command
GUI (graphical user interface)
allows the user to interact with electronic devices through graphical icons and audio
types of OS
1_ Workstation OS (Microsoft windows, Mac OS, Linux)
2_ Server OS (windows server, linux, unix)
3_ Mobile Device OS( android, iOS)
3 types of Workstation OS
1_ Enterprise client: Client in business network
2_ network OS: run on servers in business network
3_ home client:
3 main types of SW licensees
1_ proprietary: windows PC
2freeware: linux PC
3 shareware
proprietary SW license
the user have to buy a license to allow the user to use the SW
doesn’t transfer the ownership to the user
(windows, Mac OS, Adobe)
Freeware SW license
the author retains the ownership
some author give away the machine code only or give away the High-level language source code
can be downloaded by various Web sites
(Linux, Android, unix)
shareware SW license
allow the user free use of the SW but if the user is satisfied they pay a small amount ($10-$50)
the author retains the ownership
can be downloaded from web sites
(win zip, download accelerator)
core tasks of an OS
1_ processor management
2_ memory management
3_ device management
4_ file management
5_ application interface
6_ user interface
processor management
the OS makes sure that each application gets it’s necessary attention required
Memory management types
1_ virtual memory: separate the memory address used by a process from actual physical address
2_ Garbage collections: automated allocation
Memory management
each application has enough Private memory, applications do not run into other applications
file management
the OS is responsible for maintaining the file system
device management
OS talks to and manages devices through device driver or software driver
Device driver
computer program allowing higher-level computer programs to interact with hardware device
application interface
application developers do not need to know much about the hardware
types of OS (according to type of computer and application they support)
1_ real-time operating system (RTOS)
2Single-user, single task
3 single-user, multi-tasking
4_ multi-user, multi-tasking
RTOS ( Real Time OS)
run computer embedded in machinery, manages the computer so that particular operation executes in precisely the same amount of time every time it occurs
(QXN, Real time linux)
