SAS (software) 1 SAS (software) SAS SAS 9 on Microsoft Windows Developer(s) SAS Institute Stable release 9.3 / July 12, 2011 Written in C Operating system Windows, IBM mainframe, Unix/Linux, OpenVMS Alpha Type numerical analysis License proprietary SAS (pronounced "sass", originally Statistical Analysis System) is an integrated system of software products provided by SAS Institute Inc. which enables programmers to perform: • retrieval, management, and mining • report writing and graphics • statistical analysis • business planning, forecasting, and decision support • operations research and project management • quality improvement • applications development • data warehousing (extract, transform, load) • platform independent and remote computing In addition, SAS has many business solutions that enable large-scale software solutions for areas such as IT management, human resource management, financial management, business intelligence, customer relationship management and more. Description SAS is driven by SAS programs, which define a sequence of operations to be performed on data stored as tables. Although non-programmer graphical user interfaces to SAS exist (such as the SAS Enterprise Guide), these GUIs are most often merely a front-end that automates or facilitates the generation of SAS programs. The functionalities of SAS components are intended to be accessed via application programming interfaces, in the form of statements and procedures. A SAS program has three major parts: 1. the DATA step 2. procedure steps (effectively, everything that is not enclosed in a DATA step) 3. a macro language, a metaprogramming language SAS Library Engines and Remote Library Services allow access to data stored in external data structures and on remote computer platforms. The DATA step section of a SAS program,[1] like other database-oriented fourth-generation programming languages such as SQL or Focus, assumes a default file structure, and automates the process of identifying files to the operating system, opening the input file, reading the next record, opening the output file, writing the next record, and closing SAS (software) 2 the files. This allows the user/programmer to concentrate on the details of working with the data within each record, in effect working almost entirely within an implicit program loop that runs for each record. All other tasks are accomplished by procedures that operate on the data set (SAS' terminology for "table") as a whole. Typical tasks include printing or performing statistical analysis, and may just require the user/programmer to identify the data set. Procedures are not restricted to only one behavior and thus allow extensive customization, controlled by mini-languages defined within the procedures. SAS also has an extensive SQL procedure, allowing SQL programmers to use the system with little additional knowledge. There are macro programming extensions, that allow for rationalization of repetitive sections of the program. Proper imperative and procedural programming constructs can be simulated by use of the "open code" macros or the Interactive Matrix Language SAS/IML component. Macro code in a SAS program, if any, undergoes preprocessing. At run time, DATA steps are compiled and procedures are interpreted and run in the sequence they appear in the SAS program. A SAS program requires the SAS software to run. Compared to general-purpose programming languages, this structure allows the user/programmer to concentrate less on the technical details of the data and how it is stored, and more on the information contained in the data. This blurs the line between user and programmer, appealing to individuals who fall more into the 'business' or 'research' area and less in the 'information technology' area, since SAS does not enforce (although it recommends) a structured, centralized approach to data and infrastructure management. SAS runs on IBM mainframes, Unix, Linux, OpenVMS Alpha, and Microsoft Windows. Code is "almost" transparently moved between these environments. Older versions have supported PC-DOS, the Apple Macintosh, VMS, VM/CMS, PrimeOS, Data General AOS and OS/2. History SAS was conceived by Anthony J. Barr in 1966.[2] As a North Carolina State University graduate student from 1962 to 1964, Barr had created an analysis of variance modeling language inspired by the notation of statistician Maurice Kendall, followed by a multiple regression program that generated machine code for performing algebraic transformations of the raw data. Drawing on those programs and his experience with structured data files,[3] he created SAS, placing statistical procedures into a formatted file framework. From 1966 to 1968, Barr developed the fundamental structure and language of SAS. In January 1968, Barr and Jim Goodnight collaborated, integrating new multiple regression and analysis of variance routines developed by Goodnight into Barr's framework.[4][5] Goodnight's routines made the handling of basic statistical analysis more robust, and his later implementation (in SAS 76) of the general linear model increased the analytical power of the system. By 1971, SAS was gaining popularity within the academic community. One strength of the system was analyzing experiments with missing data, which was useful to the pharmaceutical and agricultural industries, among others. In 1973, John Sall joined the project, making extensive programming contributions in econometrics, time series, and matrix algebra. Other participants in the early years included Caroll G. Perkins, Jolayne W. Service, and Jane T. Helwig. Perkins made programming contributions. Service and Helwig created the early documentation.[4] In 1976, SAS Institute, Inc. was incorporated by Barr, Goodnight, Sall, and Helwig. SAS sued World Programming, the developers of a competing implementation, World Programming System, alleging that they had infringed SAS's copyright in part by implementing the same functionality. This case was referred from the United Kingdom's High Court of Justice to the European Court of Justice on 11 August, 2010.[6] In May 2012, the European Court of Justice ruled in favor of World Programming, finding that "the functionality of a computer program and the programming language cannot be protected by copyright."[7] SAS (software) 3 Versions SAS 71 SAS 71 represents the first limited release of the system. The first manual for SAS was printed at this time, approximately 60 pages long.[8] The DATA step was implemented. Regression and analysis of variance were the main uses of the program. SAS 72 This more robust release was the first to achieve wide distribution. It included a substantial user's guide, 260 pages in length.[9] The MERGE statement was introduced in this release, adding the ability to perform a database JOIN on two data sets.[10] This release also introduced the comprehensive handling of missing data.[11] SAS 76 SAS 76 was a complete system level rewrite, featuring an open architecture for adding and extending procedures, and for extending the compiler.[12] The INPUT and INFILE statements were significantly enhanced to read virtually all data formats in use on the IBM mainframe.[13] Report generation was added through the PUT and FILE statements.[14] The capacity to analyze general linear models was added.[15] 79.3–82.4 1980 saw the addition of SAS/GRAPH, a graphing component; and SAS/ETS for econometric and time-series analysis. In 1981 SAS/FSP followed, providing full-screen interactive data entry, editing, browsing, retrieval, and letter writing. In 1983 full-screen spreadsheet capabilities were introduced (PROC FSCALC). For IBM mainframes, SAS 82 no longer required SAS databases to have direct access organization ( (DSORG=DAU), because SAS 82 removed location-dependent information from databases. This permitted SAS to work with datasets on tape and other media besides disk. Version 4 series In the early 1980s, SAS Institute released Version 4, the first version for non-IBM computers. It was written mostly in a subset of the PL/I language, to run on several minicomputer manufacturers' operating systems and hardware: Data General's AOS/VS, Digital Equipment's VAX/VMS, and Prime Computer's PRIMOS. The version was colloquially called "Portable SAS" because most of the code was portable, i.e., the same code would run under different operating systems. Version 6 series Version 6 represented a major milestone for SAS. While it appeared superficially similar to the user, major changes occurred "under the hood": the software was rewritten. From its FORTRAN origins, followed by PL/I and mainframe assembly language; in version 6 SAS was rewritten in C, to provide enhanced portability between operating systems, as well as access to an increasing pool of C programmers compared to the shrinking pool of PL/I programmers. This was the first version to run on UNIX, MS-DOS and Windows platforms. The DOS versions were incomplete implementations of the Version 6 spec: some functions and formats were unavailable, as were SQL and related items such as indexing and WHERE subsetting. DOS memory limitations restricted the size of some user-defined items. The mainframe version of SAS 6 changed the physical format of SAS databases from "direct files" (DSORG=DA) to standard blocked physical sequential files (DSORG=PS,RECFM=FS) with a customized EXCP macro instead of BSAM, QSAM or previously BDAM which was used through version 5 until the complete rewrite of version 6. The practical benefit of this change is that a SAS 6 database can be copied from any media with any copying tool including IEBGENER — which uses BSAM. In 1984 a project management component was added (SAS/PROJECT). In 1985 SAS/AF software, econometrics and time series analysis (SAS/ETS) component, and interactive matrix programming (SAS/IML) software was introduced. MS-DOS SAS (version 6.02) was introduced, along with a link to mainframe SAS. In 1986 Statistical quality improvement component is added (SAS/QC software); SAS (software) 4 SAS/IML and SAS/STAT software is released for personal computers. 1987 saw concurrent update access provided for SAS data sets with SAS/SHARE software. Database interfaces are introduced for DB2 and SQL-DS.