On-the-fly

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In computer technology, on-the-fly (literally " on the fly ", mutatis mutandis including "in passing", "spontaneously") denotes a process that dispenses with the permanent or temporary storage of data , especially output data , in the permanent data memory . It makes sense to only generate outputs in volatile memory if they can be efficiently reproduced from source data at any time.

Examples of on-the-fly operations

Content on the World Wide Web

Internet pages with dynamic content that can be implemented using scripting languages such as PHP ( web server side ) or JavaScript ( web browser side ), without exception, comply with the on-the-fly principle, as the content shown is displayed directly during the display or shortly before it (with server-side script languages) is generated from original data in a different structure / form. The opposite of this are static HTML pages that only have constant and previously saved content.

Copy from optical media

When copying an optical medium to a second optical medium, "on-the-fly" refers to the direct reading and immediate burning of source data onto the target medium. Burning of the data to the target medium begins before the source medium is completely read; There is no need to create a temporary buffer, for example in the form of a file in the data memory . An error that occurs when reading in the source medium - caused by dirt, scratches or the like - may lead to the burn process being aborted or data on the target medium being damaged. When copying multiple times, the source medium must remain in the drive during the entire copying process.

Encoding of audio / video media

During the ripping of audio / video media, with "on-the-fly" encoding, there is no need to create a temporary buffer (1: 1 copy of the data to be encoded). This is only possible if the format can be encoded using an online algorithm . The process ends faster and the maximum memory consumption that occurs is reduced. However, the source medium must remain permanently in the removable medium . It should be mentioned here that encoding usually takes many times longer than reading in the data.

Online analytical processing

With online analytical processing (OLAP), special storage algorithms prepare evaluations for source data so that the numerous different variants for using the source data for high-performance access do not need to be compiled individually in advance, but rather are made possible for the user through aggregations at the time of the query ( Calculation on the fly ).

Providing software as a service

On-The-Fly Computing (OTF Computing) is about automatically making software individually tailored to the needs of a user available together and as a service . According to a requirement specification, this software is compiled from basic components, so-called basic services, and a user-specific setting of these basic components is made. Accordingly, the requested services are only compiled at the request of the user and then carried out in a computer center specially provided for this purpose in order to make the functions of the (on-the-fly) created service accessible to the user .

Individual evidence

1. ↑ M. Happe, F. Meyer auf der Heide, P. Kling, M. Platzner, C. Plessl: On-The-Fly Computing: A novel paradigm for individualized IT services . In: 16th IEEE International Symposium on Object / component / service-oriented Real-time distributed Computing (ISORC 2013) . June 2013, p. 1-10 , doi : 10.1109 / isorc.2013.6913232 ( ieee.org [accessed October 19, 2017]).