Process Concept(p60) 令 A program in execution ☆The“ animated spirit” of a program o The entity that can be assigned to and executed on a processor PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Process Concept（p60） ❖ A program in execution ❖ The “animated spirit” of a program ❖ The entity that can be assigned to and executed on a processor
rocess Characteristics(Supplement) Dynamic: create->dispatch->request 1o-> redispatch(重分派)>ext ☆ Concurrence Independence: Each process does not feel the existence of other processes Discontinuity: PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Process Characteristics（Supplement） ❖Dynamic: create->dispatch->request I/O-> redispatch(重分派)->exit ❖Concurrence： ❖Independence：Each process does not feel the existence of other processes. ❖Discontinuity:
Architecture of Process (p120) ☆ User data and progran ☆ System stack Pcb Process Control block PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Architecture of Process（p120） ❖User data and program ❖System stack ❖PCB，Process Control Block
Process States Concurrence execution of processes ☆ States of processes(2- states、5- states) PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Process States ❖Concurrence execution of processes ❖States of processes（2-states、5-states）
Example of Concurrence Execution(p102) An example Three processes are fully loaded in main memory. A small dispatcher program that moves the processor from one process to another The first 12 instruction executed in processes a and c s Process b executes four instructions and the fourth nstruction invokes(激发) an 1O operation for which the process must wait. PROCESSES AND SCHEDULING
PROCESSES AND SCHEDULING Example of Concurrence Execution(p102) An example: ٭ Three processes are fully loaded in main memory. ٭ A small dispatcher program that moves the processor from one process to another. ٭ The first 12 instruction executed in processes A and C. ٭ Process B executes four instructions and the fourth instruction invokes（激发） an I/O operation for which the process must wait