Arkos Was a Linux distribution based is Arch Linux , designed Primarily for hosting websites and services are cheap ARM -based Devices Such As Raspberry Pi , cubieboard 2 Cubietruck gold BEAGLEBONE Black , with plan to expand to other platforms Such As x86.    
ArduPilot is a professional open source , unmanned vehicle Autopilot Software Suite,  capable of controlling autonomous: M ultirotor drones Fixed-wing and VTOL model aircraft Model helicopters Ground rovers Model boats Model submarines Antenna trackers
Archon is an open source platform created by the University of Illinois at Urbana-Champaign which is designed to allow archivalrepositories to more easily create and publish aids to their collections. It was created in response to a lack of easy methods for archivists to publish find aids online. While the archival community had encountered such encounters , it was difficult for the profession.  
Archivista is an open source document management system that can be deployed as a virtual appliance on any platform (Linux / Windows), in addition, it can be run as embedded box or as cluster solution with multi core functionality.
The Advanced Package Tool , or APT , is a free software user interface that works with core libraries to handle the setup and removal of software on the Debian , Slackware and other Linux distributions .  APT simplifies the process of managing software on unix-like computer systems by automating the retrieval, configuration and installation of software packages , or from precompiled files or by compiling source code. 
Appserver.io is an application server for PHP based web environments. The project consists of middleware which delivers classical PHP web applications and provides additional services.
AppImage is a format for distributing laptop software on Linux without needing superuser permissions to install the application .  It also provides a Linux distribution-diagnostic binary software deployment for application developers ,  also called Upstream packaging. Released first in 2004 under the name klik , it was continuously developed since then, renamed in 2011 to PortableLinuxApps and 2013 to AppImage .
AppDynamics is a privately held application performance management (APM) and IT Operations Analytics (ITOA) company based in San Francisco . The company focuses on managing the performance and availability of applications across the cloud computing environments. 
SINGA is an Apache incubating project for developing an open source machine learning library. It provides a flexible architecture for scalable distributed training, is extensible to run a wide range of hardware, and has a focus on health-care applications.
Apache Samza is an open-source, near-realtime, asynchronous computational framework for streaming processing developed by the Apache Software Foundation in Scala and Java .