Precursor graph: A directed acyclic graph, which can be recorded as DAG ( Directed Acyclic Graph ), is used to describe the sequence of execution between processes.
The concurrent execution of programs includes two meanings:
● For multiple programs (processes), all processes are interleaved. (external concurrency)
● For a program, all its instructions are executed sequentially. (internal sequentiality)
The transition of the three basic states of the process:
In process management, a process changes from blocked state to ready state when (waited event has occurred)
The state when the necessary resources are allocated and the processor is obtained is the execution state
The three basic states of the process can be transformed into each other under certain conditions. The condition for the process to change from the ready state to the running state is (selected by the process scheduler)
The three basic states of the process can be transformed into each other under certain conditions. The condition for the process to change from the running state to the blocked state is (waiting for an event to occur)
The operating system manages the process through (process control block)
Usually, after the user process is created (as the job runs normally or terminates abnormally)
Whether it is a hardware-critical resource or a software-critical resource, multiple processes must mutually exclusive access to them.
1. In the following description about the critical section, the correct one is ___C_____ .
A. The critical section can allow a specified number of processes to execute simultaneously
B. The critical section contains only one program segment
C. A critical section is a program segment that must be executed mutually exclusive
D. The execution of the critical section cannot be interrupted
2. Two processes cooperate to complete a task. In concurrent execution, a process waits for a message from its partner, or establishes a certain condition before proceeding. This restrictive cooperative relationship is called the ___A_____ of the process .
A. Synchronization B. Mutex C. Scheduling D. Execution
3. If there are five concurrent processes in the system involving the same variable A , then the relevant critical sections of variable A are at least composed of _____D___ critical sections.
A. 2 B. 3 C. 4 D. 5
4. There are two user processes A and B , both of which use a printer in the system to output calculation results during the running process, then there is an ____ indirect ______ constraint relationship between the two processes A and B.
