Software Testing and Automation - Testing Important definitions and Processes

Load testing :

Load testing is the process of subjecting a computer, peripheral, server, network or application to a work level approaching the limits of its specifications. Load testing can be done under controlled lab conditions to compare the capabilities of different systems or to accurately measure the capabilities of a single system. Load testing can also be done in the field to obtain a qualitative idea of how well a system functions in the "real world."

Load testing is a part of a more general process known as performance testing. Examples of load testing include:

Downloading a series of large files from the Internet.
Running multiple applications on a computer or server simultaneously.
Assigning many jobs to a printer in a queue.
Subjecting a server to a large amount of e-mail traffic.
Writing and reading data to and from a hard disk continuously.

Load testing can be conducted in two ways. Longevity testing, also called endurance testing, evaluates a system's ability to handle a constant, moderate work load for a long time. Volume testing, on the other hand, subjects a system to a heavy work load for a limited time. Either approach makes it possible to pinpoint bottlenecks, bugs and component limitations. For example, a computer may have a fast processor but a limited amount of RAM (random-access memory). Load testing can provide the user with a general idea of how many applications or processes can be run simultaneously while maintaining the rated level of performance.

Load testing differs from stress testing, which evaluates the extent to which a system keeps working when subjected to extreme work loads or when some of its hardware or software has been compromised. The primary goal of load testing is to define the maximum amount of work a system can handle without significant performance degradation.

Black Box :
A black box is any device, sometimes highly important, whose workings are not understood by or accessible to its user. According to Edward Tenner, writing in The Washington Post, the first black box was a gun sight carried on World War II Flying Fortresses, with hidden components that corrected for environmental variables, such as wind speed. The crew probably didn't know how the device worked, but they knew it might be crucial to their survival. Nowadays, there are two types of black box carried on aircraft, which may be combined into a single device: a flight data recorder (FDR), which logs information such as speed and altitude, and a cockpit voice recorder (CVR), which logs all voice communication in the cockpit. These black boxes also carry beacons to help find the aircraft in a rescue situation.

A sampling of other black boxes:

In telecommunications, a black box is a resistor connected to a phone line that makes it impossible for the telephone company's equipment to detect when a call has been answered.
In data mining, a black box is an algorithm or a technology that doesn't provide an explanation of how it works.
In software development, a black box is a testing method in which the tester has no knowledge of the inner workings of the program being tested. The tester might know what is input and what the expected outcome is, but not how the results are achieved. A black box component is a compiled program that is protected from alteration by ensuring that a programmer can only access it through an exposed interface.
In film-making, a black box is a dedicated hardware device: equipment that is specifically used for a particular function.
In the theatre and television, a black box is an unfurnished studio.
In the financial world, a black box is a computerized trading system that does not make its rules easily available.