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TheIBMStorage and Information Retrieval System, better known by the acronymSTAIRS, was a program providing storage and onlinefree-text search of text data. STAIRS ran under theOS/360 operating system under theCICS orIMS transaction monitors, and supportedIBM 3270 display terminals.[1]
STAIRS was introduced as a product in 1973, but had previously been developed in-house by IBM in support of itsantitrust lawsuit in 1969. Originally the product was called simply STAIRS but, with the advent of IBM's "/Virtual Storage" operating systems (such asOS/VS1), the non-CMS versions were later renamed to STAIRS/VS.
STAIRS was initially released as an application running underIMS andCICS, but aVM/CMS implementation was developed by IBM Canada in the late 1970s and marketed mostly in Europe, called STAIRS/CMS.[2]
STAIRS was succeeded by IBM SearchManager/370 and SearchManager/2 in 1991, and was discontinued in 1992, with support ceasing in 1994.[3]
STAIRS queries were formulated asboolean expressions of desired terms. In addition to the normal boolean functions of AND, OR, and NOT, STAIRS recognized such modifiers asadjacent to orin the same paragraph as. Plain text documents could also contain so-calledformatted fields, which could be used for additional selection. These might contain fixed information such as a date or state name.
A powerful feature was that queries could be saved and re-executed. Queries could also be extended; for example, by specifying the result of previous query five AND an additional search term.
When search results were displayed for the user, 3270 highlighting was used to emphasize occurrences of search terms.
STAIRS was used in-house by organizations such as large corporations and government agencies[4] with large collections of unstructured documents. It was also bundled by database providers as a subscription service.[5]
STAIRS provided good search performance by indexing every word in a document except user-selectablestop words, usually common words such as "and" or "the."
Two levels of index were used, adictionary containing one occurrence of each word, and aninverted text file storing document identification and position information for each occurrence of each word. The actual document text was stored in a thirdtext file.
STAIRS document databases could only be updatedoff-line. The data (in the non-CMS implementations) was stored inbasic direct access method (BDAM) files, which caused upgrade and portability problems later in its life-cycle.