Antonio D'souza

Data operations

Data may be acquired from a variety of sources:

• humans via input devices (e.g. keyboard, mouse, touchpad, etc.);
• the environment via sensors (e.g. camera, microphone, etc.);
• storage devices connected directly (e.g. flash drive, SD card, etc.);
• other computers via a network (e.g. wifi, cellular, etc.).

Data may be analysed in sequence by a single computer or split up across thousands of computers and analysed in parallel. When data is modified, the new version may be used to replace the original version or every intermediate revision of the data may be stored in case somebody wants an older version someday (e.g. the census).

Data may be stored or transmitted in different forms from the original for various reasons such as these:

• compressed for efficiency/performance (e.g. zip, PNG, AAC, etc.);
• encrypted for security (e.g. SSL, FileVault, etc.);
• simplified/translated for archival/presentation (e.g. PDF, HTML, Unicode, etc.).

Data may be presented to humans using output devices (e.g. display screens, speakers, etc.). When presenting data to humans, it is important to be cognizant of differences between individuals in terms of sensory perception; vision and hearing impairments may reduce or eliminate the effect of data presentation that uses only a single medium.

Data may be deleted entirely after being used (e.g. SnapChat) or many copies of it may be transmitted to and stored in different places (e.g. Google Drive, BitTorrent, etc.). Storing multiple copies of data is usually done to reduce the chances of losing it (i.e. backups) or to have more convenient access to it in each place (i.e. caches).

Now read about the foundational types of data.