Differences between parallel and concurrent processes and threads

parallel : At the same time, multiple instructions are executed concurrently on multiple processors.

concurrency : At the same time, only one instruction can be executed, but multiple process instructions are executed quickly, making it possible to have multiple processes concurrently executing on the macro.

The process generally has the following 4 major elements:

1. There is a procedure for its execution (the program can be shared by multiple processes).

2, there is a dedicated system stack space.

3, there is a corresponding process control block in the kernel.

4, has the independent storage space, means has the exclusive user space.

Line threads for the process, only the previous 3, and the lack of fourth.

In particular:

If there is no user space at all, it is called a kernel thread .

If a user space is shared, it is called a user thread .

Differences between parallel and concurrent processes and threads