你可以通过以下方法清楚地记住不同之处:

互斥锁:用于保护关键区域， 互斥锁不能跨进程使用，只能在单个进程中使用 信号量:用于信号资源的可用性。 信号量既可以跨进程使用，也可以跨进程使用。

Mutex is used to protect the sensitive code and data, semaphore is used to synchronization.You also can have practical use with protect the sensitive code, but there might be a risk that release the protection by the other thread by operation V.So The main difference between bi-semaphore and mutex is the ownership.For instance by toilet , Mutex is like that one can enter the toilet and lock the door, no one else can enter until the man get out, bi-semaphore is like that one can enter the toilet and lock the door, but someone else could enter by asking the administrator to open the door, it's ridiculous.

http://www.geeksforgeeks.org/archives/9102将详细讨论。

互斥是一种锁机制，用于同步对资源的访问。 信号量是一种信号机制。

如果他/她想使用二进制信号量来代替互斥量，这取决于程序员。

除了互斥对象有一个所有者之外，这两个对象还可以针对不同的用途进行优化。互斥锁被设计为只保留很短的时间;违反这一点会导致糟糕的性能和不公平的调度。例如，一个正在运行的线程可能被允许获取一个互斥量，即使另一个线程已经被阻塞在这个线程上。信号量可以提供更多的公平性，或者可以使用几个条件变量强制实现公平性。

Mutex uses a locking mechanism i.e. if a process wants to use a resource then it locks the resource, uses it and then release it. But on the other hand, semaphore uses a signalling mechanism where wait() and signal() methods are used to show if a process is releasing a resource or taking a resource. A mutex is an object but semaphore is an integer variable. In semaphore, we have wait() and signal() functions. But in mutex, there is no such function. A mutex object allows multiple process threads to access a single shared resource but only one at a time. On the other hand, semaphore allows multiple process threads to access the finite instance of the resource until available. In mutex, the lock can be acquired and released by the same process at a time. But the value of the semaphore variable can be modified by any process that needs some resource but only one process can change the value at a time.

一本有用的书，我从这里学习和复制

互斥锁用于“锁定机制”。每次只有一个进程可以使用共享资源

而

信号量用于“信号机制” 比如“我完成了，现在可以继续了”