* A semaphore is basically an integer whose value is never allowed to be
* lower than 0. Two operations can be performed on it: increment the
* value by one, and decrement the value by one. If the value is currently
- * zero, then the decrement operation will blcok until the value becomes
+ * zero, then the decrement operation will block until the value becomes
* greater than zero.
*/
struct semaphore_t {