This document contains the syllabus and lecture notes for CS403PC: Operating System course. It provides an overview of the topics to be covered in Lecture 10, including process concepts and scheduling, context switching, and the information stored during context switches. It also lists the textbook and references for the course.

1. CS403PC: OPERATING SYSTEM
(R18 II(II Sem))
Department of computer science and engineering
(AI & ML)
LEC 10
by
Asst.Prof.M.Gokilavani
VITS
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2. Syllabus
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4. TEXTBOOK:
• Operating System Principles- Abraham Silberchatz, Peter B.
Galvin, Greg Gagne 7th Edition, John Wiley.
• Advanced programming in the UNIX environment, W.R. Stevens,
Pearson education.
REFERENCES:
• Operating Systems – Internals and Design Principles Stallings,
Fifth Edition–2005, Pearson Education/PHI.
• Operating System A Design Approach- Crowley, TMH.
• Modern Operating Systems, Andrew S. Tanenbaum 2nd edition,
Pearson/PHI.
• UNIX programming environment, Kernighan and Pike, PHI/
Pearson Education.
• UNIX Internals -The New Frontiers, U. Vahalia, Pearson
Education
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5. Topics covered in Lec 10
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UNIT – II: Process and CPU Scheduling - Process
concepts and scheduling, Operations on processes,
Cooperating Processes, Threads, and Interposes
Communication, Scheduling Criteria, Scheduling
Algorithms, Multiple -Processor Scheduling.
System call interface for process management-fork,
exit, wait, waitpid, exec

6. Context Switching
• A context switching is the mechanism to store
and restore the state or context of a CPU in
Process Control block so that a process
execution can be resumed from the same point
at a later time.
• Using this technique, a context switcher
enables multiple processes to share a single
CPU.
• Context switching is an essential part of a
multitasking operating system features.
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8. • When the scheduler switches the CPU from
executing one process to execute another, the
state from the current running process is stored
into the process control block.
• After this, the state for the process to run next
is loaded from its own PCB and used to set the
PC, registers, etc.
• At that point, the second process can start
executing.
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9. • Context switches are computationally intensive
since register and memory state must be saved
and restored.
• To avoid the amount of context switching time,
some hardware systems employ two or more
sets of processor registers.
• When the process is switched, the following
information is stored for later use.
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10. • Program Counter
• Scheduling information
• Base and limit register value
• Currently used register
• Changed State
• I/O State information
• Accounting information
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11. Topics to be covered in next Lec 11
• Operation of Process
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Thank you!!!