Lecture 12.Processes and ProcessesSynchronizationProcessTime-sharing systemCritical section problemSemaphoreProcess communicationPagelCS3369RealtimeControlComputerSoftware/WANGLushene
Page 1 Process Time-sharing system Critical section problem Semaphore Process communication Lecture 12. Processes and Processes Synchronization CS3369 Realtime Control Computer Software/WANG Lusheng
ProcessAprocess is a program in executionA computer can run several programssimultaneouslyA program can be executed several times bythe same computer simultaneouslyPage2CS3369Realtime ControlComputerSoftware/WANGLushene
Page 2 A process is a program in execution. A computer can run several programs simultaneously. A program can be executed several times by the same computer simultaneously. Process CS3369 Realtime Control Computer Software/WANG Lusheng
Time-sharing SystemMultiple jobs(processes)are executed bytheCPU switching between them, but the switchesoccur so freguently that the users may interactwith each program while it is runningThe switch among processes is done by OSPage3CS3369RealtimeControlComputerSoftware/WANGLushene
Page 3 Multiple jobs (processes) are executed by the CPU switching between them, but the switches occur so frequently that the users may interact with each program while it is running. The switch among processes is done by OS. Time-sharing System CS3369 Realtime Control Computer Software/WANG Lusheng
Data communication in embedded systemsChannels.directed transfer of informationPools:sharedinformationProcess SymbolinputoutputprocessingPage 4CS3369RealtimeControlComputerSoftware/WANGLushene
Page 4 Data communication in embedded systems. Channels: directed transfer of information. Pools: shared information. Process Symbol: input output processing CS3369 Realtime Control Computer Software/WANG Lusheng
ChannelsA channel provides the medium for items ofinformation to be passed between one process andanotherMore than one item of information can pass through achannel at any one time and they are usually orderedaccording to the rule of FIFO (first-in-first-out)Interrupt #Ox09 stores keys typed by users ina buffer whichis accessible byotherinterrupts.putch.1getgpPage5CS3369RealtimeControlComputerSoftware/WANGLushene
Page 5 A channel provides the medium for items of information to be passed between one process and another. More than one item of information can pass through a channel at any one time and they are usually ordered according to the rule of FIFO (first-in-first-out). Interrupt #0x09 stores keys typed by users in a buffer which is accessible by other interrupts. Channels put get p ch._1 g CS3369 Realtime Control Computer Software/WANG Lusheng