2. PROCESS. Operating System Concepts with Java 8th Edition Silberschatz, Galvin and Gagn

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2 2. PROCESS Operating System Concepts with Java 8th Edition Silberschatz, Galvin and Gagn

3 SPOILER petabytes ~ record 3 million hours of TV shows operating system - process 3

4 operating system - process 4

5 WHAT? Process is a program in execution process execution must progress in sequential fashion :a process includes: 1. program counter 2. stack 3. data section Process in Memory operating system - process 5

6 Process State (important) As a process executes, it changes state New : The process is being created Running : Instructions are being executed Waiting : The process is waiting for some event to occur Ready : The process is waiting to be assigned to a processor Terminated : The process has finished execution operating system - process 6

7 Diagram of Process State operating system - process 7

8 Process State (important) As a process executes, it changes state New : The process is being created Running : Instructions are being executed Waiting : The process is waiting for some event to occur Ready : The process is waiting to be assigned to a processor Terminated : The process has finished execution operating system - process 8

9 Process Control Block (PCB) Information associated with each process X Process state X Program counter X CPU registers X CPU scheduling information X Memory-management information X Accounting information X I/O status information Where is it? operating system - process 9

10 CPU Switch From Process to Process operating system - process 10

11 Process Scheduling Queues X Job queue set of all processes in the system X Ready queue set of all processes residing in main memory, ready and waiting to execute X Device queues set of processes waiting for an I/O device Processes migrate among the various queues operating system - process 11

12 Representation of Process Scheduling operating system - process 12

13 Schedulers x Long-term scheduler (or job scheduler) selects which processes should be brought into the ready queue X Short-term scheduler (or CPU scheduler) selects which process should be executed next and allocates CPU operating system - process 13

14 Addition of Medium Term Scheduling operating system - process 14

15 Scheduler Short-term scheduler is invoked very frequently (milliseconds) -> (must be fast) Long-term scheduler is invoked very infrequently (seconds, minutes) -> (may be slow) The long-term scheduler controls the degree of multiprogramming Processes can be described as either: X I/O-bound process spends more time doing I/O than computations, (many & short CPU bursts) X CPU-bound process spends more time doing computations; (few & very long CPU bursts) operating system - process 15

16 Context Switch (important) When CPU switches to another process, the system must save the state of the old process and load the saved state for the new process Context of a process represented in the PCB Context-switch time is overhead; the system does no useful work while switching Time dependent on hardware support operating system - process 16

17 Process Creation Parent process create children processes, which, in turn create other processes, forming a tree of processes Process identified and managed by a process identifier (pid) In Resource sharing X Parent and children share all resources x Children share subset of parent s resources x Parent and child share no resources In Execution In Address space X Child duplicate of parent x Child has a program loaded into it X Parent and children execute concurrently X Parent waits until children terminate operating system - process 17

18 UNIX examples (UNIX????) Process Creation (cont) X fork system call creates new process X exec system call used after a fork to replace the process memory space with a new program operating system - process 18

19 A tree of processes on a typical Solaris operating system - process 19

20 Process Termination Process executes last statement and asks the OS to delete it (exit) X Output data from child to parent X Process resources are deallocated by OS Parent may terminate execution of children processes (abort) x Child has exceeded allocated resources x Task assigned to child is no longer required x parent is exiting Some operating system do not allow child to continue if its parent terminates All children terminated - cascading termination operating system - process 20

21 Interprocess Communication Processes may be independent or cooperating (Can affect or be affected by other processes, including sharing data) Why cooperating? Information sharing, Computation speedup, Modularity, and Convenience Two models of IPC : Shared memory & Message passing operating system - process 21

22 Which one is message passing? Which one is Shared memory? IPC model operating system - process 22

23 Synchronization in Message Passing : Blocking as a synchronous Blocking send, the sender block until the message is received Blocking receive, the receiver block until a message is available Non-blocking as a asynchronous Non-blocking send, the sender send the message and continue Non-blocking receive, the receiver receive a valid message or null operating system - process 23

24 Communications in Client-Server Systems 1. Sockets 2. Remote Procedure Calls, 3. :Remote Method Invocation (Java) A socket is Concatenation of IP address and port as an endpoint for communication e.g. socket :1625 host port 1625 :Communication consists between a pair of sockets operating system - process 24

25 The END...

26 References 1. Abraham Silberschatz, Peter Baer Galvin, Greg Gagne, Operating System Concepts With Java, Wiley operating system - process 26

27 Make report about your experiment in dual boot Assignment 2A x Experiment 1 - Windows Linux x 1. Explain detail steps to install windows and then linux on the same machine/pc 2. Explain about GRUB, or LILO according to the installation x Experiment 2 - Linux windows x 1. Explain detail steps to install linux and then windows on the same machine/pc 2. Is there any difference installation steps between 1st experiment and 2nd 3. How about the GRUB or LILO, is it all right? or anything is missing? Explain how to overcome the missing thing (if there is something wrong) operating system - process 27

28 Assignment 2B Please record your both of your experiments, upload your video (less than 45 minutes) that contain essential/important part of your experiments on youtube. So may be this will be your first video tutorial. Submit it's link before due date Score level from lowest to highest : 1. just plain video tutorial 2. video tutorial with subtitle or narration 3. video tutorial with English subtitle or English narration 4. point number 4 plus interesting things like you add background sound, or embedding video capturing yourself explain experiments, (like this _ BXML7n1R-0, I am sure you can make better than that) or other creative tutorial that make youtube downloader entertained operating system - process 28

29 SUBMISSION Submit your report to elearning REPORT must contain : 1. Cover page : Student id, and bla bla bla, and youtube link (please put the link on cover page) 2. Explanation important step of those experiments 3. References Format : AS2-<NRP>.pdf (eg. AS pdf) operating system - process 29

30 Class Assignment Each student Write on paper instructions (in bahasa indonesia) about : a. How to cook (team 1, team 5) b. How to remove stubborn dirt (dish) (team 2, team 6) c. How to bathing baby (team 3, team 7) d. How to repair vehicle (team 4, team 8) Write the steps separated with line, not paragraph Count the words and put It on right top corner of your paper page operating system - process 30