)Not synchronized; that is, not occurring at predetermined or regular intervals. The term asynchronous is usually used to describe communications in which data can be transmitted intermittently rather than in a steady stream. For example, a telephone conversation is asynchronous because both parties can talk whenever they like. If the communication were synchronous, each party would be required to wait a specified interval before speaking.
The difficulty with asynchronous communications is that the receiver must have a way to distinguish between valid data and noise. In computer communications, this is usually accomplished through a special start bit and stop bit at the beginning and end of each piece of data. For this reason, asynchronous communication is sometimes called start-stop transmission.
Most communications between computers and devicesare asynchronous.
- asynchronous groupware
Groupware that enables multiple participants to collaborate but not in real time, at the same time. Asynchronous groupware includes e-mail, version control systems, or collaborative writing systems. Contrast with synchronous groupware.
- asynchronous messaging
Asynchronous messaging describes communications that takes place between two applications or systems, where the system places a message in a message queue (called an Event Queue in enterprise messaging systems) and does not need to wait for a reply to continue processing. Contrast with synchronous messaging.
- asynchronous replication
A technology used in server and network storage. Once data has been written to the primary storage site, new writes to that site can be accepted, without having to wait for the secondary or remote storage site to also finish its writes. The downside to asynchronous replication is the possibility of data loss if the […]
- Atomic Operation
An operation during which a processor can simultaneously read a location and write it in the same bus operation. This prevents any other processor or I/O device from writing or reading memory until the operation is complete. Atomic implies indivisibility and irreducibility, so an atomic operation must be performed entirely or not performed at all.
A file attached to an e-mail message. Many e-mail systems only support sending text files as e-mail. If the attachment is a binary file or formatted text file (such as an MS-Word document), it must be encoded before it is sent and decoded once it is received. There are a number of encoding schemes, the […]