Information systems store data in the following major types of media: human brains, paper, microforms, computer media, and audio and video tapes and CDs.
(i) Human brain
The human brain was used to store data and information long before paper was invented. However, the human brain provides a store not only for data, but also knowledge.
You will recall from Unit l that knowledge is the extent of familiarity possessed by a person with certain facts, truths, principles or subjects.
Knowledge consists of facts, truths and ideas that fit together to form a coherent and meaningful whole. A person's overall knowledge influences how he perceives the world around him. In other words, knowledge is used by people to interpret and evaluate new information. Knowledge serves as a pool from which people can extract specific truths, facts, ideas for informing or instructing other people. Data are stored in human brains as part of knowledge. Data are also created from a person's knowledge when the person uses symbols to express information extracted from the knowledge.
Nobody knows for sure how data and knowledge are organized and stored in the human brain. Psychologists claim however that human beings store data in either short-term or long-term memory. Data in short term memories are stored for a short time, and are lost unless committed to long term memory. Among the strategies used by people to store data in long term memory is to say, read or write the data repeatedly. Is this not how you commit data to memory? If not, how do you do it? There are of course many other methods which we cannot explain here.
(ii) Paper
Paper became a media for storing data when papyrus was invented.
Data were initially stored on paper by writing long hand until printing was invented. Data are still mostly recorded on paper in the form of published or unpublished, as well as printed, typed and hand-written documents. Among the well known paper-based data and information sources are books, newspapers, journals, technical reports, correspondence, etc.
(iii) Microforms
Microforms is the general word used to describe all miniature but non-computerized storage media such as film rolls, film slides, microfiche, etc. Data are stored in these media as miniature or microscopic images, hence, the name microforms. The data are stored
on such media by photographing or scanning pages of paper or computer documents, and then transferring the images unto film rolls, film slides or microfiche. The major advantage of microforms is that they require much less space to store than paper. However, special equipment such as reading glasses or lens, film projectors, microfiche readers, etc, are required to access the data in these media.
(iv) Computer media
Data are increasingly being stored on computer media. Computer media include tapes, disks, diskettes, compact disks (CDs), smart cards, mobile phone recharge cards, etc. Data are stored on computer media as data files. A data file on a computer media is any collection of data stored under a single name. The data might comprise alphabetical, numerical or special characters, or digitized images.
(You may review Unit 5 for explanation on how computers store digitized images). The data in the file may also be subdivided into data records and fields, as you learned in Units 7 and 8.
(v) Audio and video media
The gramophone record was a popular media for storing sound data before the arrival of audio and video tapes and CDs. Tapes and CDs are now used for storing sound, image and voice data. You most probably had listened to a Michael Jackson tape or CD before, but tapes and CDs are now used as media for publishing books, dictionaries and encyclopedias. Indeed, some of the study materials in some of your NOU courses might be provided on audio or video tapes or CDs.
Exercise 12.1
Use an audio tape recorder to record the content, of this unit (up to and including this exercise) into a cassette tape. Read aloud, making sure that you pause appropriately at commas, semi-colons and full stops. Separate the sections and the paragraphs with appropriate pauses, as you read along.
Get one of your friends to read the data that you have recorded, and, then also listen to your recording. Which does he/she like more?
The above exercise illustrates how data are recorded unto, and stored on audio and video tapes. We will now explain some of the usual strategies used for effective data storage on two other very common types of storage media:
paper and computer media.