1. CGS 3763 Operating Systems Concepts Spring 2013
Dan C. Marinescu
Office: HEC 304
Office hours: M-Wd 11: :30 AM

2. Lecture 8 – Friday, January 25, 2013
Last time:
Process; process state; a process in memory
Today:
Interrupts
Kernel data structures for process management
Week in review.
Problem solving – chapter 3
Next time
Creation and termination of processes
Inter-process communication
Shared memory
Message passing
Reading assignments
Chapters 3 and 4 of the textbook
Chapters 3 and 4 textbook slides
12/28/2018

3. The state of a process
12/28/2018

4. Interrupts  provide the means to react to internal and external events
12/28/2018

5. Interrupt handlers are a component of the kernel
12/28/2018

6. 12/28/2018

7. 12/28/2018

8. Kernel functions for program execution
Process management
Scheduling and resource allocation
Interrupt handling
Error handling
12/28/2018

9. System calls for process control
Load
Execute
Create, terminate a process
Block a process, abort
Get process attributes/set process attributes
Allocate/deallocate memory for a process
12/28/2018

10. Control data structure maintained by the kernel
To carry out its functions the kernel must maintain information about all objects in the system. For example:
Processes  Process Control Block (PCB)
Open files  File Control Block (FCB)
12/28/2018

11. Process Control Block (PCB)
The entry for a process contains the following information
Process state
Program counter
CPU registers
CPU scheduling information
Memory-management information
Accounting information
I/O status information

12. Process Control Block (PCB)

13. CPU Switch From Process to Process

14. Process Scheduling Queues
Job queue – set of all processes in the system
Ready queue – set of all processes residing in main memory, ready and waiting to execute
Device queues – set of processes waiting for an I/O device
Processes migrate among the various queues