Computer Systems A Programmer‘s Perspective Second Edition
The general phenomenon of multiple flows executing concurrently is known
as
concurrency
. The notion of a process taking turns with other processes is also
known as
multitasking
. Each time period that a process executes a portion of its
flow is called a
time slice
. Thus, multitasking is also referred to as
time slicing
.For
example, in Figure 8.12, the flow for Process A consists of two time slices.
Notice that the idea of concurrent flows is independent of the number of
processor cores or computers that the flows are running on. If two flows overlap
in time, then they are concurrent, even if they are running on the same processor.
However, we will sometimes find it useful to identify a proper subset of concurrent
flows known as
parallel flows
. If two flows are running concurrently on different
processor cores or computers, then we say that they are
parallel flows
, that they
are
running in parallel
, and have
parallel execution
.
concurrency parallel 并发 并行
原文：http://www.cnblogs.com/yuanjiangw/p/6182842.html
