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OS --Exam -- Topics, What happens, Os-startup-Code - Coggle Diagram
OS --Exam -- Topics
Process Control
Modes OF execution
user mode
kernel mode
Process Creation
Process Switching
A
50% completed (values registers )
Int
Store values
Kernel mode
B
25%
restore values from user Area Page
continue -execution
Process-States
Two-State Model
Five-State-Model
Fork & Exec
Fork
creates a child process
exact copy of parent process
Exec
replace parent with child process
Interrupts vs Sys.Call vs Trap
Trap - raised by user-program
int - raised by hardware
Basics
OS-Data-Structures
Process-Table
Entry
id
Space
User-Area-Page
used registers storage space
next instruction after INT (IP)
System-Status-Table
currently running process id
What happens
Interrupt (I/o)
Scheduler
Long-Term
no.of process in ready queue
Short-Term
picks the process
Round-Robin-Scheduler
Shortest-Job-TIme
Priority
Middle-Term
Blocked -State
Brings back to ready queue
Dispatcher
enter user process
i don't want other process to wait untill this I/o completes
Os-startup-Code
loads all required files into os
Set the Virtual Addrs for first process
calls first process
Process Runs
Boot-Module
VIrtual -spaces to all process