A/ROSE

Last updated
A/ROSE
Developer Apple Computer
OS family
Working stateHistoric
Initial releaseFebruary 1988;36 years ago (1988-02)
PlatformsMacintosh Coprocessor Platform for Macintosh (Motorola 68000)

A/ROSE (Apple Real-time Operating System Environment) is a small embedded operating system that runs on Apple Computer's "Macintosh Coprocessor Platform", an expansion card for the Macintosh.

Contents

The idea was to offer a single "overdesigned" hardware platform on which third-party vendors could build practically any product, reducing the otherwise heavy workload of developing a NuBus-based expansion card. However, the MCP cards were expensive, limiting the appeal of the concept. A/ROSE had very little use, apparently limited solely to Apple's own networking cards for serial I/O, Ethernet, Token Ring, and Twinax. [1] GreenSpring Computers developed the RM1260, which is an IndustryPack (IP) carrier card with a 68000 CPU running A/ROSE and is intended for the data acquisition market.

History

Apple released this A/ROSE-based Ethernet NuBus card with a Motorola 68000 processor. Apple ethernet nb.jpg
Apple released this A/ROSE-based Ethernet NuBus card with a Motorola 68000 processor.

A/ROSE and the MCP originated in August 1987 during the development of the Macintosh II. While working on various networking products for the new system, the developers realized that the existing classic Mac OS would make any "serious" card difficult to create, due to large latencies and the difficulty of writing complex device drivers. Their solution was to make an "intelligent" NuBus card that was essentially an entire computer on a card, containing its own Motorola 68000 processor, working space in RAM mirrored in the main system, and its own basic operating system. The first version of the system was ready for use in February 1988.

A/ROSE was internally called MR-DOS (Multitasking Realtime Distributed Operating System), but Microsoft (the developer of MS-DOS) did not appreciate the name and put pressure on Apple to change it.[ citation needed ] Eric M. Trehus, a QA engineer on the Token Ring card running A/ROSE reportedly said "A/ROSE by any other name is still MR-DOS."[ citation needed ]

A/ROSE is infamous for its esoteric purpose, which is generally not understood by Mac end users, and for causing many Mac emulators, such as Basilisk II, to produce a system error at boot time.

Overview

A/ROSE is very small at 28 KB, with a 6 KB kernel. A/ROSE supports pre-emptive multitasking with round-robin scheduling of tasks, with a 110 microsecond context switch time and only 20 microseconds of latency (guaranteed interrupt response time). The system's task is primarily to move data around and start and stop tasks on the cards, and the entire API contains only ten calls.

A/ROSE is a message passing system, and the main calls made its programs are Send() and Receive(). Messages are short, including only 24 bytes of user data, and sent asynchronously. To find the appropriate endpoint, its name server allows the applications to bind their names to their task IDs, allowing them to move in the system and be found dynamically. The OS has several routines for finding, starting, and stopping tasks on other cards, one of which is a virtual card representing the host computer.

To coordinate communications and provide a mechanism for talking with the host's CPU, a cut-down copy of A/ROSE also runs inside the Mac OS in the form of a system extension, or "INIT", known as "Prep". Device drivers for A/ROSE cards are INITs and started up automatically. After starting, they find the Prep stub and use the normal A/ROSE communications channel it provides to communicate with the cards.

For instance, the Apple TokenTalk NB card installs its driver as an INIT, and optionally installs the Prep stub, assuming it had not been installed before. On startup the driver finds the Prep stub and asks it to enumerate the TokenTalk cards installed in the machine, and optionally uploads code or settings to them. From that point on, Prep handles the communications with the card, handing off the results to the TokenTalk driver.

Related Research Articles

<span class="mw-page-title-main">Amiga</span> Family of personal computers sold by Commodore

Amiga is a family of personal computers introduced by Commodore in 1985. The original model is one of a number of mid-1980s computers with 16- or 16/32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphics and audio compared to previous 8-bit systems. These systems include the Atari ST—released earlier the same year—as well as the Macintosh and Acorn Archimedes. Based on the Motorola 68000 microprocessor, the Amiga differs from its contemporaries through the inclusion of custom hardware to accelerate graphics and sound, including sprites and a blitter, and a pre-emptive multitasking operating system called AmigaOS.

<span class="mw-page-title-main">Macintosh II</span> First model of the second generation of the Apple Macintosh computer line

The Macintosh II is a personal computer designed, manufactured, and sold by Apple Computer from March 1987 to January 1990. Based on the Motorola 68020 32-bit CPU, it is the first Macintosh supporting color graphics. When introduced, a basic system with monitor and 20 MB hard drive cost US$5,498. With a 13-inch color monitor and 8-bit display card the price was about US$7,145. This placed it in competition with workstations from Silicon Graphics, Sun Microsystems, and Hewlett-Packard.

<span class="mw-page-title-main">Power Macintosh G3</span> Series of personal computers by Apple

The Power Macintosh G3 is a series of personal computers designed, manufactured, and sold by Apple Computer from November 1997 to August 1999. It represented Apple's first step towards eliminating redundancy and complexity in the product line by replacing eight Power Macintosh models with three: Desktop and Mini Tower models for professional and home use, and an all-in-one model for education. The introduction of the Desktop and Mini Tower models coincided with Apple starting to sell build-to-order Macs directly from its web site in an online store, which was unusual for the time as Dell was the only major computer manufacturer doing this. Apple's move to build-to-order sales of the Power Macintosh G3 also coincided with the acquisition of Power Computing Corporation, which had been providing telephone sales of Macintosh clones for more than two years.

<span class="mw-page-title-main">Apple IIGS</span> Apple II series 16-bit computer

The Apple IIGS is a 16-bit personal computer produced by Apple Computer. It is the fifth and most powerful of the Apple II family. It is compatible with earlier Apple II models but has a Macintosh look and feel, and resolution and color similar to the Amiga and Atari ST. The "GS" in the name stands for "Graphics and Sound", referring to its enhanced multimedia hardware, especially its state-of-the-art audio.

<span class="mw-page-title-main">System 7</span> Seventh major release of the classic Mac OS (1991)

System 7 is the seventh major release of the classic Mac OS operating system for Macintosh computers, made by Apple Computer. It was launched on May 13, 1991, to succeed System 6 with virtual memory, personal file sharing, QuickTime, TrueType fonts, the Force Quit dialog, and an improved user interface.

A desk accessory (DA) or desklet in computing is a small transient or auxiliary application that can be run concurrently in a desktop environment with any other application on the system. Early examples, such as Sidekick and Macintosh desk accessories, used special programming models to provide a small degree of multitasking on systems that initially did not have any other multitasking ability.

<span class="mw-page-title-main">Coprocessor</span> Type of computer processor

A coprocessor is a computer processor used to supplement the functions of the primary processor. Operations performed by the coprocessor may be floating-point arithmetic, graphics, signal processing, string processing, cryptography or I/O interfacing with peripheral devices. By offloading processor-intensive tasks from the main processor, coprocessors can accelerate system performance. Coprocessors allow a line of computers to be customized, so that customers who do not need the extra performance do not need to pay for it.

<span class="mw-page-title-main">MacsBug</span> Low-level debugger, originally for Motorola 68000

MacsBug is a low-level debugger for the classic Mac OS operating system. MacsBug is an acronym for Motorola Advanced Computer Systems Debugger, as opposed to Macintosh debugger. The original version was developed by Motorola as a general debugger for its 68000 systems. — it was ported to the Mac as a programmer's tool early in the project's development.

<span class="mw-page-title-main">Macintosh 512K</span> Revised version of the Macintosh 128K by Apple Computer

The Macintosh 512K is a personal computer that was designed, manufactured and sold by Apple Computer from September 1984 to April 1986. It is the first update to the original Macintosh 128K. It was virtually identical to the previous Macintosh, differing primarily in the amount of built-in random-access memory. The increased memory turned the Macintosh into a more business-capable computer and gained the ability to run more software. It is the earliest Macintosh model that can be used as an AppleShare server and, with a bridge Mac, communicate with modern devices.

Star Trek is the code name that was given to a secret prototype project, running a port of Macintosh System 7 and its applications on Intel-compatible x86 personal computers. The project, starting in February 1992, was conceived in collaboration between Apple Computer, who provided the majority of engineers, and Novell, who at the time was one of the leaders of cross-platform file-servers. The plan was that Novell would market the resulting OS as a challenge to Microsoft Windows, but the project was discontinued in 1993 and never released, although components were reused in other projects. The project was named after the Star Trek science fiction franchise with the slogan "To boldly go where no Mac has gone before".

<span class="mw-page-title-main">Macintosh XL</span> Modified version of the Apple Lisa

Macintosh XL is a modified version of the Apple Lisa personal computer made by Apple Computer. In the Macintosh XL configuration, the computer shipped with MacWorks XL, a Lisa program that allowed 64 K Macintosh ROM emulation. An identical machine was previously sold as Lisa 2/10 with the Lisa OS only.

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 preemptive scheduler usually runs in the most privileged protection ring, meaning that interruption and then resumption are considered highly secure actions. Such changes to the currently executing task of a processor are known as context switching.

<span class="mw-page-title-main">PowerBook 500 series</span> Range of Apple Macintosh PowerBook portable computers

The PowerBook 500 series is a range of Apple Macintosh PowerBook portable computers first introduced by Apple Computer with the 540c model on May 16, 1994. It was the first to have stereo speakers, a trackpad, and Ethernet networking built-in.

The Amiga computer can be used to emulate several other computer platforms, including legacy platforms such as the Commodore 64, and its contemporary rivals such as the IBM PC and the Macintosh.

The Mac286 was an Intel 80286-based MS-DOS coprocessor expansion card for one of Apple Computer's first expandable Macintosh computers, the 1987 Macintosh II. It was developed by Phoenix Technologies under contract to Apple Computer and sold by AST Research in an effort to close the gap between the Macintosh and IBM PC computing worlds. AST also introduced the related Mac86 card for the Macintosh SE.

The Mac OS nanokernel is an operating system kernel that serves as the basis of most PowerPC based system software versions 7 through 9 of the classic Mac OS, predating Mac OS X.

MagiC is a third party and now open-sourced multitasking-capable TOS-compatible operating system for Atari computers, including some newer clone systems manufactured later. There are also variants that run as part of Mac and PC emulation environments, as well as on macOS Intel-Mac computers.

<span class="mw-page-title-main">Compatibility card</span> Computer expansion card

A compatibility card is an expansion card for computers that allows it to have hardware emulation with another device. While compatibility cards date back at least to the Apple II family, the majority of them were made for 16-bit computers, often to maintain compatibility with the IBM PC. The most popular of these were for Macintosh systems that allowed them to emulate Windows PCs via NuBus or PCI; Apple had released several such cards themselves.

Mac operating systems were developed by Apple Inc. in a succession of two major series.

<span class="mw-page-title-main">Classic Mac OS</span> Original operating system of Apple Mac (1984–2001)

Mac OS is the series of operating systems developed for the Macintosh family of personal computers by Apple Computer, Inc. from 1984 to 2001, starting with System 1 and ending with Mac OS 9. The Macintosh operating system is credited with having popularized the graphical user interface concept. It was included with every Macintosh that was sold during the era in which it was developed, and many updates to the system software were done in conjunction with the introduction of new Macintosh systems.

References

  1. Maurer, Joseph. "Inside the Macintosh Coprocessor Platform and A/ROSE". MacTech . Retrieved November 25, 2023.