ARX (operating system)


ARX was an unreleased Mach-like operating system written in Modula-2+ developed by Acorn Computers Ltd in the Acorn Research Centre United Kingdom and later Olivetti Research Center and later on Software Technology Laboratory at Palo Alto, California for their new ARM architecture reduced instruction set computer central processing unit based Archimedes personal computers.

Overview

According to the project Application Manager during the project, while Acorn was developing the kernel, it used C and Acorn Modula Execution Library in Acorn Extended Modula-2 compiler, though never released externally, CAMEL was ported to use it in Sun Microsystems Unix computer, in an effort to port Sun's workstations Sun NeWS to the Archimedes, and after Olivetti acquired Acorn, developed a compiler based on AEM2 for the programming language Modula-3.
ARX was a preemptive multitasking, multithreading, multi-user operating system. Much of the OS ran in user mode and as a result suffered performance problems due to switches into kernel mode to perform mutexes, which led to the introduction of the SWP instruction to the instruction set of the ARM3 version of the ARM processor. It had support of optical disks file system and featured a window system, a window toolkit and an Interscript-based text editor, for enriched documents written in Interpress. The OS had to be fitted in a 512 kibibyte read-only memory ROM image. This suggests that ARX had a microkernel-type design.
It was not finished in time to be used in the Acorn Archimedes range of computers, which shipped in 1987 with an operating system named Arthur, later renamed RISC OS, derived from the earlier Machine Operating System from Acorn's earlier 8-bit BBC Micro range.
The Acorn Research Centre was acquired by Olivetti.