Comparative trade route analysis

List of contents of this article:

• 1. In the database, what is the difference between the "mutual exclusion condition" and the "non-deprivation condition" in the deadlock generation condition...
• 2, in the operating systemDeadlock appears means
• 3, What does computer deadlock mean?
• 4, What should I do if the computer is seriously dead and the system is dead?
• 5, What are the preventive measures for system process deadlock
• 6, 4 necessary conditions for deadlock

In the database, what is the difference between the "mutual exclusion condition" and the "no deprivation condition" in the deadlock generation condition?..

1. Secondly, the order and speed of the process operation are different, which may also cause deadlock. Four necessary conditions to generate deadlocks: (1) Mutual exclusion conditions: A resource can only be used by one process at a time. ( 2) Request and retention conditions: When a process is blocked due to the request for resources, the obtained resources are not released.

2. The four necessary conditions for deadlock are mutually exclusive conditions, request and maintenance conditions, non-deprivation conditions, and circular waiting conditions, as follows: mutually exclusive conditions: a resource can only be used by one process at a time. Request and maintenance conditions: When a process is blocked due to the request for resources, the obtained resources are not released.

3. Mutual exclusion: A resource only allows one process to access at a time, that is, once the resource is assigned to a process, other processes cannot access it again until the process access ends.Possession and waiting: A process itself occupies resources, and at the same time, the resources are not satisfied and waiting for other processes to release the resources.

4. Deadlock means that in a concurrent system, multiple processes are waiting for each other due to competition for limited resources. The occurrence of deadlock requires four conditions: mutually exclusive conditions, request and retention conditions, non-deprivation conditions and loop waiting conditions. Deadlock will only occur when these four conditions are met at the same time.

5. The necessary conditions generated by the dead chain are as follows: (1) Mutual exclusion conditions: a resource can only be used by one process at a time. ( 2) Request and retention conditions: When a process is blocked by requesting resources, it does not release the obtained resources.

6. Four necessary conditions for deadlock Mutual exclusion conditions(Mutual exclusion): Resources cannot be shared and can only be used by one process. Hold and wait: The process that has obtained the resource can apply for a new resource again.

The appearance of deadlock in the operating system means

1. In the resource allocation diagram, if there is a loop, it means that there is a process deadlock in the system. When a process in the system requires multiple resources to run, and it has obtained some resources, but the request for other resources is not met, a deadlock will also occur.

2. The so-called deadlock of the computer operating system refers to a stalemate caused by the competition for resources of multiple processes during operation. ProduceThe reason for deadlock: competitive resources: When multiple processes in the system use shared resources and the resources are insufficient to meet the needs, it will cause the process to compete for resources and cause a deadlock.

3. Deadlock refers to a blocking phenomenon caused by two or more processes in the execution process due to competition for resources or communication with each other. Without external forces, they will not be able to advance. At this time, it is said that the system is in a deadlock state or the system has a deadlock. These processes that are always waiting for each other are called deadlock processes.

4. Deadlock in the operating system means that if each process in a process set is waiting for an event that can only be caused by other processes in the set, the situation of indefinite stalemate is called deadlock. The factors that cause deadlock are the amount of resources owned by the system.Resource allocation strategy.

5. Deadlock: refers to a blocking phenomenon caused by two or more processes in the process of execution due to competition for resources or communication with each other. Without external forces, they will not be able to advance. At this time, it is said that the system is in a deadlock state or the system has a deadlock. These processes that are always waiting for each other are called deadlock processes.

What does computer deadlock mean?

1. Deadlock is to access the same mutually exclusive resource in the computer, causing two or more processes to not get this resource and are all in a waiting state. In concurrent programming, deadlock is a very common logical error. By adopting the correct programming method, the occurrence of deadlock is not difficult to avoid.

2. Deadlock means that the system is still running, but the loop waiting has occurred, resulting in the inability to perform the function normally. ( Deadlock definition: When multiple processes make resource applications, they fall into an infinite waiting phenomenon without the action of external forces.) Crash means that the system crashes and cannot run (down definition: the system is destroyed and crashes.

3. Deadlock is a common computer.System problems occur when multiple processes or threads are waiting for each other to release resources. Simply put, when two or more processes hold each other's required resources, they cannot move forward and enter a permanent waiting state, which is deadlock.

4. What does computer deadlock mean? (1) In a group of processes, each process waits infinitely for the resources possessed by another process in the group of processes, so the resources that can never be obtained. This phenomenon is called process deadlock, and this group of processes is called deadlock processes. ( 2) The root cause is: limited resources and improper operation.

5. Deadlock: A situation in which two or more processes in the execution program are permanently blocked (waiting), and each process is waiting for the resources occupied and blocked by other processes.

6. Deadlock refers to a blocking phenomenon caused by two or more processes in the process of execution due to competition for resources or communication with each other. Without external forces, they will not be able to advance. At this time, it is said that the system is in a deadlock state or the system has a deadlock. These processes that are always waiting for each other are called deadlock processes.

What should I do if the computer is seriously dead and the system is dead?

In addition, multi-factor authentication methods, such as SMS verification codes, smart cards, etc., can also be used to increase the security of authentication. In addition, it is also necessary to regularly check system security vulnerabilities and update security patches.

If the computer is urgently used, it is recommended to use other normal electricity.Make a USB disk PE and see if the boot password can be solved in the PE. If not, you can consider backing up the system disk data and reinstalling the system to solve the problem.

Restart the computer. If you can enter the system normally, it means that the last abnormality was just an occasional program or system operation error, which is irrelevant.

What are the preventive measures for system process deadlock

Using the deprivation control method can destroy the condition, which makes a process that has maintained certain resources, because the new resource requirements are not currently met Enough, it must first temporarily release all the resources maintained (a kind of deprivation), then wait, and then submit a request to the system together, which can also prevent deadlock.

Abandon the "request and maintain" condition. When adopting this method, the system stipulates that all processes must apply for all the resources required for the entire operation process at one time before starting to run.

The necessary conditions for deadlock are: mutually exclusive conditions, maintenance and waiting conditions, inalienable conditions and loop waiting conditions. Deadlock can be prevented by breaking the necessary conditions for deadlock. If the static resource allocation strategy is adopted, the loop waiting condition can be broken.

4 necessary conditions for deadlock

1. Mutual exclusion: Resources cannot be shared and can only be used by one process. Hold and wait: The process that has obtained the resource can apply for a new resource again.

2. Conditions for not deprivation: The resources obtained by the process cannot be forcibly deprived before they are used up. Loop waiting conditions: Several processes form a head-to-tail loop waiting resource relationship.

3. [Answer]: Answer: B Analysis: Four necessary conditions for deadlock: mutual exclusion, possession and request, non-deprivation and circular waiting.

4. The four necessary conditions for deadlock are: mutual exclusion conditions, request and maintenance conditions, non-deprivation conditions, and loop waiting conditions. Only when these four conditions are met will the phenomenon of deadlock occur. As long as one of them is broken, the occurrence of deadlocks can be effectively prevented.

5. The four necessary conditions for deadlock are as follows: mutually exclusive use, a resource can only be used by one process at a time, and multiple processes are not allowed to use one resource at the same time.It cannot be forcibly occupied. The resource applicant cannot forcibly seize resources from the resource possessor. Resources can only be voluntarily released by the possessor and obtained by the applicant.