ADABAS is a relational database system from Software AG, used for IBM mainframes, UNIX, VAX, and OS/2. As a high-performance database for large, mission-critical applications, ADABAS supports thousands of users in parallel while giving sub-second response times. Its key features include: Openness and interoperability with minimal resource usage; A single Web-based administration tool; Open SOA and SQL interfaces; Data management with no limits; Proven performance and reliability

Adaptiv Workforce, an application from Adaptiv Software, helps employers manage information about employees, shifts, and pay schedules, and build labor forecasts.

Adaptive Server Enterprise (ASE), relational database management system product of Sybase Corporation, is a direct descendant of Sybase SQL Server.

Ad-Aware is a program from Lavasoft that detects and removes spyware on a user's computer. It also detects dialers, trojans, malware, data-mining, aggressive advertising, Parasites, Scumware, Browser hijackers, and tracking components. There is a freeware version called Ad-Aware Personal, as well as two commercial products—Ad-Aware Plus and Ad-Aware Professional. The free download includes Ad-Aware SE Personal Edition, skins, help manuals, RegHance and the latest definition file. The freeware version of Ad-Aware is compatible with Microsoft Windows 98/Me/NT/2000/XP/2003. Since January 6, 2006, Ad-Aware SE Personal is a part of the Google Pack.

Add-in, also known as Add-on, is a mini program that runs in combination with the main application in order to extend and improve the functionality of that application. In the Windows environment, add-ins are becoming increasingly commonly-used Object Linking and Embedding (OLE) technologies.

Add-on, also known as Add-in, is a mini program that runs in combination with the main application in order to extend and improve the functionality of that application. For example, there are add-on report generation programs that are attached to popular database products such as dBASE, giving them additional report-generation and graphics capabilities.

AdeptXBBS was a BBS originally written explicitly for the OS/2 operating system. It was believed that the OS/2 operating system would propel this new BBS as a leader. While AdeptXBBS was completed with much of the functionality, features, and performance initially promised, the product never reached the popularity that the authors hoped and then faded away. In particular, as the world of Client/Server BBS systems took hold, the Internet came into wide use, and free operating systems such as Linux and FreeBSD could act as dialin/telnet servers gained popularity, most of BBS systems become obsolete.

Application Development Facility (ADF) is an application development package designed for IMS by IBM. Programmers define sets of “rules” and these are combined with a simple screen design to provide a rather basic application.

An Architecture Description Language (ADL) is a computer language used to describe software and/or system architectures, because the software architecture must be communicated to software developers and other stakeholders concerned about the architectrue. There are several ADLs, such as Acme (developed by CMU), AADL (standardized by SAE), C2 (developed by UCI), Darwin (developed by Imperial College London), and Wright (developed by CMU).

Acrobat, a document exchange software from Adobe Systems, provides a platform-independent means of creating, viewing, and printing documents. Acrobat can convert a DOS, Windows, UNIX or Macintosh documents into a Portable Document Format (PDF) which can be displayed on any computer with an Acrobat reader. The Acrobat reader can be downloaded free from the Adobe website.