What is SAS
SAS Institute Inc. (pronounced "sass"[1]), headquartered in Cary, North Carolina, USA, has been a major producer of software since it was founded in 1976 by Anthony Barr, James Goodnight, John Sall and Jane Helwig. SAS was originally an acronym for Statistical Analysis System but for many years has been used as an arbitrary tradename (for which the company has received trademark protection in the US and abroad) to refer to the company as a whole, its products having long since broadened beyond the statistical analysis sphere. SAS Institute is one of the largest privately-held corporations in North Carolina.
History
Its main and original product was the SAS software package used in statistical analysis, consisting of numerous modules which ran on IBM mainframe computers. In addition to the usual mainframe practice of writing and submitting programs in batch, SAS offered the option, somewhat novel at the time, of a windowed programming environment, where the program being written or edited appeared in one window, the program output appeared in another window, and the program log appeared in a third window.
As other types of computers became available and powerful enough, SAS was continuously developed to run in those environments as well, keeping the familiar user interface and compatible file structure so that SAS users could easily switch from one type of operating system and/or hardware to another. Eventually fully functional SAS could be run on personal computers, either standalone or networked. The widespread rise of Microsoft Windows, however, brought some philosophical difficulties to the product developers, faced with adapting the standard SAS programming interface familiar to SAS users to the standard Microsoft Windows interface familiar to PC users. In addition, even on the personal computer platform, SAS retained the mainframe pricing structure of substantial yearly licensing fees, rather than adopting the personal computer pricing standard of a one-time outright purchase.
Description of SAS
SAS is driven by SAS programs that 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), most of the time these GUIs are just a front-end to automate or facilitate generation of SAS programs. SAS components expose their functionalities via application programming interfaces, in the form of statements and procedures.
A SAS program is composed of three major parts, the DATA step, procedure steps (effectively, everything that is not enclosed in a DATA step), and a macro 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, 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 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 SAS/IML component.
Macro code in a SAS program, if any, undergoes preprocessing. At runtime, 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 be less familiar with the technical details of the data and how it is stored, and relatively more familiar with 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 SAS recommends) a structured, centralized approach to data and infrastructure management.
SAS runs on IBM mainframes, Unix machines, OpenVMS Alpha, and Microsoft Windows; and code is almost transparently moved between these environments. Older versions have supported PC-DOS, the Apple Macintosh, VMS, VM/CMS, Data General AOS and OS/2.
Early History of SAS
SAS was conceived by Anthony J. Barr in 1966.[1] 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[2], 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 James Goodnight collaborated, integrating new multiple regression and analysis of variance routines developed by Goodnight into Barr's framework.[3][4] Goodnight's routines made the handling of basic statistical analysis more robust, and his later implementation (in SAS 76) of the general linear model greatly increased the analytical power of the system. By 1971, SAS was gaining popularity within the academic community. And by 1972, industry was making use of SAS. 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.[3]
In 1976, SAS Institute, Inc. was incorporated by Barr, Goodnight, Sall, and Helwig.
Components
SAS consists of a number of components, which organizations separately license and install as required.
SAS Add-In for Microsoft Office
A component of the SAS Enterprise Business Intelligence Server, is designed to provide access to data, analysis, reporting and analytics for non-technical workers (such as business analysts, power users, domain experts and decision makers) via menus and toolbars integrated into Office applications.
Base SAS
The core of SAS is the so-called Base SAS Software, which is used to manage data. SAS procedures software analyzes and reports the data. The SQL procedure allows SQL programming in lieu of data step and procedure programming. Library Engines allow transparent access to common data structures such as Oracle, as well as pass-through of SQL to be executed by such data structures. The Macro facility is a tool for extending and customizing SAS software programs and reducing overall program verbosity. The DATA step debugger is a programming tool that helps find logic problems in DATA step programs. The Output Delivery System (ODS) is an extendable system that delivers output in a variety of formats, such as SAS data sets, listing files, RTF, PDF, XML, or HTML. The SAS windowing environment is an interactive, graphical user interface used to run and test SAS programs.
SAS Enterprise Business Intelligence Server
Includes both a suite of business intelligence (BI) tools and a platform to provide uniform access to data. The goal of this product is to compete with Business Objects and Cognos' offerings.
Enterprise Computing Offer (ECO)
Not to be confused with Enterprise Guide or Enterprise Miner, ECO is a product bundle.
Enterprise Guide
SAS Enterprise Guide is a Microsoft Windows client application that provides a guided mechanism to use SAS and publish dynamic results throughout an organization in a uniform way. It is marketed as the default interface to SAS for business analysts, statisticians, and programmers.
Enterprise Miner
A data mining tool.
ETL
Provides Extract, transform, load services.
SAS/ACCESS
Provides the ability for SAS to transparently share data with non-native datasources.
SAS/ACCESS for PC Files
Allows SAS to transparently share data with personal computer applications including MS Access and Microsoft Office Excel.
SAS/AF
Applications facility, a set of application development tools to create customized applications.
SAS/ASSIST
Early point-and-click interface to SAS, has since been superseded by SAS Enterprise Guide.
SAS/C
SAS/CONNECT
Provides ability for SAS sessions on different platforms to communicate with each other.
SAS/DMI
A programming interface between interactive SAS and ISPF/PDF applications. Obsolete since version 5.
SAS/EIS
A menu-driven system for developing, running, and maintaining an enterprise information systems.
SAS/ETS
Provides Econometrics and Time Series Analysis
SAS/FSP
Allows interaction with data using integrated tools for data entry, computation, query, editing, validation, display, and retrieval.
SAS/GIS
An interactive desktop Geographic Information System for mapping applications.
SAS/GRAPH
Although base SAS includes primitive graphing capabilities, SAS/GRAPH is needed for charting on graphical media.
SAS/IML
Matrix-handling SAS script extensions.
SAS/INSIGHT
Dynamic tool for data mining. Allows examination of univariate distributions, visualization of multivariate data, and model fitting using regression, analysis of variance, and the generalized linear model.
SAS/IntrNet
Extends SAS’ data retrieval and analysis functionality to the Web with a suite of CGI and Java tools
SAS/LAB
Superseded by SAS Enterprise Guide.
SAS/OR
Operations Research
SAS/PH-Clinical
Defunct product
SAS/QC
Quality Control provides quality improvement tools.
SAS/SHARE
Is a data server that allows multiple users to gain simultaneous access to SAS files
SAS/STAT
Statistical Analysis with a number of procedures, providing statistical information such as analysis of variance, regression, multivariate analysis, and categorical data analysis.
SAS/TOOLKIT
SAS/Warehouse Administrator
Superseded in SAS 9 by SAS ETL Server.
SAS Web Report Studio
Part of the SAS Enterprise Business Intelligence Server, provides access to query and reporting capabilities on the Web. Aimed at non-technical users.
