ARX (operating system)
Encyclopedia
ARX was a Mach-like operating system
written in Modula-2+
developed by Acorn Computers Ltd in the UK
and the Acorn Research Centre (ARC) and Software Technology Laboratory and later Olivetti Research Center (ORC, when Olivetti bought out Acorn) at Palo Alto for their new ARM
RISC processors
based Archimedes
computers range. According to the project Application Manager during the project, Acorn was developing for it, Compiler for Acorn Modula-2 Extended Language (CAMEL in Modula-2+
) bootstrapping from an Acorn Extended Modula-2 (AEM2) compiler, though never released externally, it was ported to use it in SUN
Unix machines, in an effort to port Sun's workstations Sun NeWS
to the Archimedes, and when Olivetti bought out Acorn, developed a compiler based on CAMEL for the Modula-3
programming Language.
ARX was a pre-emptive 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 (WORM)
disks file system and featured a window system, a window toolkit (and a direct manipulation User Interface
editor) and an InterScript-based text editor, for enriched documents written in InterPress
(an HTML
precursor). The OS had to be fitted in a 512KB ROM image
. This suggests that ARX had a microkernel
-type design.
It was not finished in time to be fitted to the Acorn Archimedes range of computers, which shipped in 1987 with the Arthur operating system, derived from the earlier MOS
operating system from Acorn's earlier 8-bit
BBC Micro
range. Arthur was later superseded by RISC OS
.
The Acorn Research Centre was bought out by Olivetti
.
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
written in Modula-2+
Modula-2+
Modula-2+ is a programming language descended from the Modula-2 language. It was developed at DEC Systems Research Center and Acorn Computers Ltd Research Centre in Palo Alto, California. Modula-2+ is Modula-2 with exceptions and threads. The group who developed the language was led by P...
developed by Acorn Computers Ltd in the UK
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
and the Acorn Research Centre (ARC) and Software Technology Laboratory and later Olivetti Research Center (ORC, when Olivetti bought out Acorn) at Palo Alto for their new ARM
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
RISC processors
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
based Archimedes
Acorn Archimedes
The Acorn Archimedes was Acorn Computers Ltd's first general purpose home computer to be based on their own ARM architecture.Using a RISC design with a 32-bit CPU, at its launch in June 1987, the Archimedes was stated as running at 4 MIPS, with a claim of 18 MIPS during tests.The name is commonly...
computers range. According to the project Application Manager during the project, Acorn was developing for it, Compiler for Acorn Modula-2 Extended Language (CAMEL in Modula-2+
Modula-2+
Modula-2+ is a programming language descended from the Modula-2 language. It was developed at DEC Systems Research Center and Acorn Computers Ltd Research Centre in Palo Alto, California. Modula-2+ is Modula-2 with exceptions and threads. The group who developed the language was led by P...
) bootstrapping from an Acorn Extended Modula-2 (AEM2) compiler, though never released externally, it was ported to use it in SUN
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
Unix machines, in an effort to port Sun's workstations Sun NeWS
NeWS
NeWS was a windowing system developed by Sun Microsystems in the mid 1980s. Originally known as "SunDew", its primary authors were James Gosling and David S. H. Rosenthal...
to the Archimedes, and when Olivetti bought out Acorn, developed a compiler based on CAMEL for the Modula-3
Modula-3
In computer science, Modula-3 is a programming language conceived as a successor to an upgraded version of Modula-2 known as Modula-2+. While it has been influential in research circles it has not been adopted widely in industry...
programming Language.
ARX was a pre-emptive multitasking
Computer multitasking
In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...
, multithreading
Thread (computer science)
In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...
, 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 (WORM)
Write Once Read Many
A Write Once Read Many or WORM drive is a data storage device where information, once written, cannot be modified. On ordinary data storage devices, the number of times data can be modified is not limited, except by the rated lifespan of the device, as modification involves physical changes that...
disks file system and featured a window system, a window toolkit (and a direct manipulation User Interface
User interface
The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...
editor) and an InterScript-based text editor, for enriched documents written in InterPress
InterPress
InterPress is a page description language developed at Xerox PARC, based on the Forth programming language and an earlier graphics language called JaM...
(an HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
precursor). The OS had to be fitted in a 512KB ROM image
ROM image
A ROM image, or ROM file, is a computer file which contains a copy of the data from a read-only memory chip, often from a video game cartridge, a computer's firmware, or from an arcade game's main board...
. This suggests that ARX had a microkernel
Microkernel
In computer science, a microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system . These mechanisms include low-level address space management, thread management, and inter-process communication...
-type design.
It was not finished in time to be fitted to the Acorn Archimedes range of computers, which shipped in 1987 with the Arthur operating system, derived from the earlier MOS
Acorn MOS
Acorn's Machine Operating System or OS was a computer operating system used in the Acorn BBC computer range. It included support for four-channel sound and graphics, file system abstraction, and digital and analogue I/O including a daisy-chained fast expansion bus...
operating system from Acorn's earlier 8-bit
8-bit
The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...
BBC Micro
BBC Micro
The BBC Microcomputer System, or BBC Micro, was a series of microcomputers and associated peripherals designed and built by Acorn Computers for the BBC Computer Literacy Project, operated by the British Broadcasting Corporation...
range. Arthur was later superseded by RISC OS
RISC OS
RISC OS is a computer operating system originally developed by Acorn Computers Ltd in Cambridge, England for their range of desktop computers, based on their own ARM architecture. First released in 1987, under the name Arthur, the subsequent iteration was renamed as in 1988...
.
The Acorn Research Centre was bought out by Olivetti
Olivetti
Olivetti S.p.A. is an Italian manufacturer of computers, printers and other business machines.- Founding :The company was founded as a typewriter manufacturer in 1908 in Ivrea, near Turin, by Camillo Olivetti. The firm was mainly developed by his son Adriano Olivetti...
.