Formation of a waterfall

Typically, a river flows over a large step in the rocks which may have been formed by a fault line. Over a period of years, the boundaries of this shelf will gradually break away and the waterfall will steadily retreat upstream, creating a gorge of depression. Often, the rock layer just below the more resistant shelf will be of a softer type, meaning undercutting, due to splashback, will occur here to form a thin cave-like formation known as a rock shelter under and behind the waterfall. Finally, the outcropping, more resistant cap rock will fall down under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are then broken down into smaller boulders by attrition as they crash with each other, and they also erode the base of the waterfall by abrasion, creating a deep plunge pool.

Locks

Locks are advisory locks, where each thread cooperates by acquiring the lock before accessing the equivalent data. Some systems also implement mandatory locks, where attempting unauthorized access to a locked resource will force exclusion in the entity attempting to make the access. In terms of access to the data, no difference is made between shared or exclusive modes. Other schemes provide for a shared mode, where several threads can obtain a shared lock for read-only access to the data. Other modes such as exclusive, intend-to-exclude and intend-to-upgrade are also widely implemented.
Independent of the type of lock chosen above, locks can be confidential by what happens when the lock strategy prevents progress of a thread. Most locking designs block the finishing of the process requesting the lock until it is allowed to access the locked resource. A spin lock is a lock where the thread simply waits until the lock becomes accessible. It is very efficient if threads are only likely to be uncreative for a short period of time, as it avoids the overhead of operating system process re-scheduling. It is wasteful if the padlock is held for a long period of time.

Computation

Computation is a common term for any type of information processing that can be represent mathematically. This includes phenomenon ranging from simple calculations to human idea. In a more narrow meaning, computation is a process following a well distinct model that is understood and can be expressed in an algorithm, protocol, network topology, etc.
These hypothetical computing equipment can be viewed as idealised analog computers which operate on real numbers and are differential, whereas digital computers are partial to computable numbers and are algebraic. Depending on the model select, this may enable real computers to solve problems that are inextricable on digital computers.