OLTP On-Line Transaction Processing
To immediately deal with user input, and immediately respond to the computer system to produce results.

On-Board Hardware
Peripheral devices directly into the motherboard design, or separated from the original installation made with the computer expansion card into the computer's expansion slots to increase the added value of the motherboard or to reduce the use of slots and joints.

On-demand computing
In order to combine the network hardware and software approach to the provision for cross-enterprise distributed network computing power, so companies need large computing resources, can be opened in other parts of idle processor computing system.
At present IT industry including IBM, CA have been initiated on-demand computing concept. According to IBM definition, On demand computing is a kind of by a wide range of hardware and software platform consisting of information technology systems, visual ever-changing business needs to change, with system security, reliability advantages, and do not have a response to the occasional surge the peak demand for the machine and install an excess of information technology system architecture.
The science and technology from the concept of the electricity supply grid, grid computing is a kind of devices on a network share through the coordination of all the CPU, data storage and network resources to decentralized way of operating together to accomplish a work of technology.
CA believes that on-demand computing infrastructure can be static to dynamic, the use of resource allocation and automation software provider, so that IT resources, like in power plants to supply energy-like dynamics.
To implement the on-demand operations management, and does not need to replace the server, nor is it a new generation of hardware products, which is a platform neutral computing, allowing enterprises more effective and efficient use of existing IT environments.

On Now Hardware
By Microsoft (MICROSOFT) made by the power and system management structure, the purpose is to enable computers to home appliances like with like open-use, ONNOW system defines six kinds of power states: 1. S0: fully open. 2. S1: Processor (CPU) was suspended immediately reply operation. 3. S2: processor to stop electricity. 4. S3: Power in the supply into the power saving mode. 5. S4: shutdown, the memory (MEMORY) content into hard disk (HDD), the next boot back to pre-shutdown state. 6. S5: shut down completely.