Galileo was an unreleased

32-bit In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32- bit units. Compared to smaller bit widths, 32-bit computers can perform large calcula ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

that was under development by

Acorn Computers Acorn Computers Ltd. was a British computer company established in Cambridge, England, in 1978. The company produced a number of computers which were especially popular in the United Kingdom, UK, including the Acorn Electron and the Acorn Archi ...

as a long-term project to produce "an ultra-modern scalable, portable, multi-tasking, multi-threading, object-oriented, microkernel operating system", reportedly significant enough to Acorn's strategy to warrant a statement to the financial markets. Announced in early 1997 as targeting "the next generation of smart appliances", running initially on

ARM architecture ARM (stylised in lowercase as arm, formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a family of reduced instruction set computer (RISC) instruction set architectures for computer processors, configure ...

devices but intended to be easily portable to "other RISC processors" (or even "a range of RISC and CISC processors"), emphasis was made on its

quality of service Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...

features that would guarantee system resources to critical tasks, as well as its reliability, its sophistication relative to

RISC OS RISC OS is a computer operating system originally designed by Acorn Computers Ltd in Cambridge, England. First released in 1987, it was designed to run on the ARM chipset, which Acorn had designed concurrently for use in its new line of Archi ...

(which was described as "too primitive to succeed as a 21st century operating system"), and its small footprint that would "enable Acorn to compete in the semi-embedded systems market". However, the system's "modular object-oriented" architecture gave it the scalability to potentially be deployed in devices ranging from "multimedia cellular phones" and network computers to desktop workstations and server platforms.

Features

The operating system was to offer an "innovative modular real time kernel", also described as a microkernel with a hardware abstraction layer, having a footprint of only 15 KB. The kernel itself supported

preemptive multitasking In computing, preemption is the act of temporarily interrupting an executing task, with the intention of resuming it at a later time. This interrupt is done by an external scheduler with no assistance or cooperation from the task. This preemp ...

, being "multi-threaded and fully pre-emptive", and was portable through extensive high-level language use (an estimated 95% of the code) in conjunction with the hardware abstraction layer. Kernel responsibilities included memory allocation, interrupt handling,

direct memory access Direct memory access (DMA) is a feature of computer systems and allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU). Without DMA, when the CPU is using programmed input/output, it is ...

services, scheduling, and the resource allocation required by the quality of service functionality. Systems using Galileo were to be able to leverage the modularity of the software architecture to deliver a "complete customisable software stack" that could be deployed in

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

, with system modules and applications being executed in-place to reduce

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requirements. The architecture was also meant to allow additional components, such as multimedia codecs or network stacks, to be downloaded and deployed without the need to restart the system. It was noted that "virtually all Galileo tasks run in user mode", with "complete memory and CPU usage protection" enforced to uphold the quality of service regime. The inclusion of quality of service features was intended to "eliminate the need for dedicated multimedia chips" in consumer-level Internet appliances, particularly those chips concerned with video compression and decompression that might instead be implemented in software, thus helping manufacturers to reduce system costs below an anticipated target given of $100 by 1998. Such objectives were to be achieved through collaboration with system-on-chip manufacturers, with a specific collaboration in progress mentioned in early 1997, and with "companies such as Hitachi" expected to release suitable hardware in 1998.

Fate

The operating system was scheduled to be the successor of

, although Acorn envisaged RISC OS remaining relevant for "high functionality ARM based devices" in the short to medium term, with Galileo being aimed at "portable and networked interactive media devices". Early versions for existing Acorn customers were anticipated by the second half of 1997, and the Galileo kernel was stated as having been "up and running" as a prototype, but the project was cancelled when the workstation division closed as part of Acorn's restructuring in 1998. The commercial potential of Galileo had been put into some doubt by the announcement of the

Symbian Symbian is a discontinued mobile operating system (OS) and computing platform designed for smartphones. It was originally developed as a proprietary software OS for personal digital assistants in 1998 by the Symbian Ltd. consortium. Symbian ...

alliance which established Psion's

EPOC EPOC may be: * Excess post-exercise oxygen consumption * Emotiv EPOC, consumer brain–computer interface devices for PC. * EPOC (operating system), the precursor OS to the Symbian operating system * Efficient Probabilistic Public-Key Encryption ...

operating system as the basis of a mobile communications platform to be adopted by

Nokia Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational telecommunications, information technology, and consumer electronics corporation, established in 1865. Nokia's main headquarters are in Espoo, Finlan ...

and

Ericsson (lit. "Telephone Stock Company of LM Ericsson"), commonly known as Ericsson, is a Sweden, Swedish multinational networking and telecommunications company headquartered in Stockholm. The company sells infrastructure, software, and services in ...

, with

Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorola ...

having also announced a commitment to the initiative. Despite Galileo promising to be "technically better" than EPOC, the comparative readiness of the two offerings was summarised in one publication's remark that "EPOC has started the race while Galileo is still in the pits with its engine in bits". Nevertheless, at that time, hopes were expressed for opportunities for the product in set-top boxes and network computers.

References

Acorn operating systems ARM operating systems {{operating-system-stub