Pick (operating system)

The operating system Pick (of the name of its inventor, Dick Pick) is a Operating system Multiutilisateur, in Temps divided and with virtual Memory based on a system of “multivaluée” database (SGBDR MV).

It is used mainly for the business applications. Initially an operating system with SGBDR MV intended for the minicomputers, it was diffused on the microcomputers and the great systems, and remains still of use today. The operating system part having disappeared from almost all the implementations only the SGBDR MV persists.

Principles

A Pick database follows a hierarchical decomposition in accounts, with files, recordings, fields, under-fields and under-under-fields. Historically in Pick, the recordings are called “items”, the fields “attributes”, the under-fields “values” or “multivaleurs” (from where the current name of “multivaluée database”) and the under-under-fields “under-values”. The fields, under-fields and under-under-fields are all length variable and located by special delimitors (codes ASCII 254,253 and 252). Any file, recording or field can thus contain several entities of the lower level. A source program BASIC for example is under Pick anything else only one recording whose each attribute constitutes a line.

Each file can contain one or more parts “dated” (given) and a part “dict” (dictionary), which specifies how to interpret the data. Each account has a “Master dictionary” (“Mandelevium”), which counts and defines all the files, but also all the orders, elements of the query language, etc, accessible since this account. A system of “synonyms” in particular makes it possible to reach since an account given to elements of another account.

Addressing inside a file is done by means of a Fonction of chopping ( hash coding ), based on primary education space and the Modulo usually allotted to the file, with application of a algorithm to the key of the recording, and management of chainings of partitions (memory pages) when necessary.

Today still the Pick databases function on the principle of virtual machine. Many a applicatifs functioning under this database appuye on the use of a emulator of terminal.

Solutions owners, such Onware, make it possible to use the basic principle of data multivaluées while storing the data in database like Oracle or SQL Server; this " migration" is not always possible (that at impossible summer in 2002 in a large company: charge with calculation too important after migration) and when it is possible a strong increase in the power of the material requires to keep the same performances (an application which turned under Pick-universe on a 486DX66 after its migration under Oracle was to use 16processeurs IBM being worth 1Meuro to keep the same response time)

History

Pick was implemented under the name Generalized Information Retrieval Language System (GIRLS) on an IBM System/360 in 1965 by Don Nelson and Dick Pick at TRW bound for the American army, to manage the inventory of parts of helicopters. It was then marketed in 1973 by Microdata (and their British distributer CMC) under the name of “Reality Operating System”.

On the Microdata implementation, the principal language for the development of applications was Databasic, a kind of BASIC with many extensions for the operations on the databases written by Charles Bachman (turing award 1973). A system “PROC” was used to carry out the command files. ENGLISH, a language having a type taken again by SQL, allowed the search and the “reporting” for data, but not the updates. It did not allow all handling of data multivaluées 3 dimensions, nor to carry out the traditional operations of relational databases like the joints, because sophisticated redefinitions of fields in the data dictionary made it possible to carry out joints by the execution of a research in another file. The system included a spoulor. A simple text editor was provided, but was usable only for maintenance, not being able to lock the recordings. The majority of the applications were thus written with other tools like Batch, RPL, or the Compilateur BASIC to make sure of the validation of the data and to guarantee the locking of the recordings.

Dick Pick founded “Pick & Associates”, famous then “Pick Systems”, currently “Raining Data”. It what is called granted licenses of now “Pick” to many manufacturers and salesmen who produced alternatives different from “Pick”. The true name being SGBDR MV, Pick being the mark of the first SGBDR MV. The patents and principles of the SGBDR MV having fallen into the public domain there are several implementations in free software under the public license general GNU (Maverick, OpenQM, Winter)

The database sold by Raining Data is known like “D3”, and that sold by IBM under the name “U2” is also known like UniData and Universe. Dick Pick is deceased in October 1994 of an brain attack.

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