Real-time Multitasking eXecutive (iRMX) is a

real-time operating system A real-time operating system (RTOS) is an operating system (OS) for real-time computing applications that processes data and events that have critically defined time constraints. A RTOS is distinct from a time-sharing operating system, such as Unix ...

designed for use with the

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

8080 The Intel 8080 is Intel's second 8-bit microprocessor. Introduced in April 1974, the 8080 was an enhanced successor to the earlier Intel 8008 microprocessor, although without binary compatibility.'' Electronic News'' was a weekly trade newspa ...

and

8086 The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit data bus (allo ...

family of processors.

Overview

Intel developed iRMX in the 1970s and originally released RMX/80 in 1976 and RMX/86 in 1980 to support and create demand for their processors and Multibus system platforms. The functional specification for RMX/86 was authored by Bruce Schafer and Miles Lewitt and was completed in the summer of 1978 soon after Intel relocated the entire Multibus business from

Santa Clara, California Santa Clara ( ; Spanish language, Spanish for "Clare of Assisi, Saint Clare") is a city in Santa Clara County, California. The city's population was 127,647 at the 2020 United States census, 2020 census, making it the List of cities and towns i ...

to Aloha, Oregon. Schafer and Lewitt went on to each manage one of the two teams that developed the RMX/86 product for release on schedule in 1980. Effective 2000 iRMX is supported, maintained, and licensed worldwide by TenAsys Corporation, under an exclusive licensing arrangement with Intel. iRMX is a layered design: containing a kernel, nucleus, basic I/O system, extended I/O system and human interface. An installation need include only the components required: intertask synchronization, communication subsystems, a filesystem, extended memory management, command shell, etc. The native filesystem is specific to iRMX, but has many similarities to the original

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

(V6) filesystem, such as 14 character path name components, file nodes, sector lists, application readable directories, etc. iRMX supports multiple processes (known as jobs in RMX parlance) and multiple threads are supported within each process (task). In addition, interrupt handlers and threads exist to run in response to hardware interrupts. Thus, iRMX is a

multi-processing Multiprocessing (MP) is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. Ther ...

multi-threaded In computer architecture, multithreading is the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution. Overview The multithreading paradigm has become more popular a ...

, pre-emptive,

(RTOS).

Commands

The following list of

command Command may refer to: Computing * Command (computing), a statement in a computer language * command (Unix), a Unix command * COMMAND.COM, the default operating system shell and command-line interpreter for DOS * Command key, a modifier key on A ...

s are supported by iRMX 86. * ATTACHDEVICE * ATTACHFILE *

BACKUP In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "wikt:back ...

* COPY * CREATEDIR * DATE *

DEBUG In engineering, debugging is the process of finding the root cause, workarounds, and possible fixes for bugs. For software, debugging tactics can involve interactive debugging, control flow analysis, log file analysis, monitoring at the ap ...

* DELETE * DETACHDEVICE * DETACHFILE * DIR * DISKVERIFY * DOWNCOPY * FORMAT * INITSTATUS * JOBDELETE * LOCDATA * LOCK * LOGICALNAMES * MEMORY *

PATH A path is a route for physical travel – see Trail. Path or PATH may also refer to: Physical paths of different types * Bicycle path * Bridle path, used by people on horseback * Course (navigation), the intended path of a vehicle * Desir ...

* PERMIT * RENAME * RESTORE * SUBMIT * SUPER *

TIME Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...

* UPCOPY * VERSION * WHOAMI

Historical uses

iRMX III on Intel Multibus hardware is used in the majority core systems on CLSCS the

London Underground The London Underground (also known simply as the Underground or as the Tube) is a rapid transit system serving Greater London and some parts of the adjacent home counties of Buckinghamshire, Essex and Hertfordshire in England. The Undergro ...

Central line signals control system was supplied by Westinghouse (now Invensys) and commissioned in the late 1990s. The Central line is an automatic train operation line. Automatic train protection is by trackside and train borne equipment that does not use iRMX. It is the automatic train supervision elements that use a mix of iRMX on Multibus, and

Solaris Solaris is the Latin word for sun. It may refer to: Arts and entertainment Literature, television and film * ''Solaris'' (novel), a 1961 science fiction novel by Stanisław Lem ** ''Solaris'' (1968 film), directed by Boris Nirenburg ** ''Sol ...

on SPARC computers. 16 iRMX local site computers are distributed along the Central line together with 6 central iRMX computers at the control centre. All 22 iRMX computers are dual redundant. iRMX CLSCS continues in full operation.

Oslo Metro The Oslo Metro ( or or simply ) is the rapid transit system of Oslo, Norway, operated by Sporveien T-banen on contract from the transit authority Ruter. The network consists of five lines that all run through the city centre, with a total leng ...

uses a similar, although less complex, Westinghouse-supplied iRMX control system through the central

Common Tunnel The Common Tunnel (), sometimes called the Common Line (), is a long tunnel of the Oslo Metro which runs through the Sentrum, Oslo, city center of Oslo, Norway. The name derives from the fact that all five lines of the metro use the tunnel, whi ...

tracks. This was expected to be decommissioned in 2011.

Variants

Several variations of iRMX have been developed since its original introduction on the Intel 8080: iRMX I, II and III, iRMX-86, iRMX-286, DOS-RMX, iRMX for Windows, and, most recently, INtime. While many of the original variants of iRMX are still in use, only iRMX III, iRMX for Windows, and INtime are currently supported for the development of new real-time applications. Each of these three supported variants of iRMX require an

Intel 80386 The Intel 386, originally released as the 80386 and later renamed i386, is the third-generation x86 architecture microprocessor from Intel. It was the first 32-bit computing, 32-bit processor in the line, making it a significant evolution in ...

equivalent or higher processor to run. A significant architectural difference between the INtime RTOS and all other iRMX variants is the support for address segments (see

x86 memory segmentation x86 memory segmentation is a term for the kind of memory segmentation characteristic of the Intel x86 computer instruction set architecture. The x86 architecture has supported memory segmentation since the original Intel 8086 (1978), but ''x86 ...

). The original 8086 family of processors relied heavily on segment registers to overcome limitations associated with addressing ''large'' amounts of memory via 16-bit registers. The iRMX operating system and the compilers developed for iRMX include features to exploit the segmented addressing features of the original

x86 architecture x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel, based on the 8086 microprocessor and its 8-bit-external-bus variant, the 8088. T ...

. The INtime variant of iRMX does not include explicit support for segmentation, opting instead to support only the simpler and more common 32-bit flat addressing scheme. Despite the fact that native processes written for INtime can only operate using unsegmented flat-mode addressing, it is possible to port and run some older iRMX applications that use segmented addressing to the INtime kernel. When Intel introduced the Intel 80386 processor, in addition to expanding the iRMX RTOS to support 32-bit registers, iRMX III also included support for the four distinct protection rings (named rings 0 through 3) which ''describe'' the protected-mode mechanism of the Intel 32-bit architecture. In practice very few systems have ever used more than rings 0 and 3 to implement protection schemes.

iRMX

The I, II, III, -286 and -86 variants are intended as standalone real-time operating systems. A number of development utilities and applications were made for iRMX, such as compilers ( PL/M, Fortran, C), an editor (Aedit), process and data acquisition applications and so on. Cross compilers hosted on the VAX/VMS system were also made available by Intel. iRMX III is still supported today and has been used as the core technology for newer real-time virtualization RTOS products including iRMX for Windows and INtime.

DOS-RMX

DOS-RMX is a variant of the standalone iRMX operating system designed to allow two operating systems to share a single hardware platform. In simplest terms,

DOS DOS (, ) is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft's MS-DOS, both of which were introduced in 1981. Later compatible syste ...

and iRMX operate concurrently on a single

IBM PC compatible An IBM PC compatible is any personal computer that is hardware- and software-compatible with the IBM Personal Computer (IBM PC) and its subsequent models. Like the original IBM PC, an IBM PC–compatible computer uses an x86-based central p ...

computer, where iRMX tasks (processes) have scheduling priority over the DOS kernel, interrupts, and applications. iRMX events (e.g., hardware interrupts) pre-empt the DOS kernel to ensure that tasks can respond to real-time events in a time-deterministic manner. In a functional sense, DOS-RMX is the predecessor to iRMX for Windows and INtime. In practice, DOS-RMX appears as a

Terminate-and-stay-resident A terminate-and-stay-resident program (commonly TSR) is a computer program running under DOS that uses a system call to return control to DOS as though it has finished, but remains in computer memory so it can be reactivated later. This technique ...

(TSR) program to the DOS kernel. Once loaded as a TSR, iRMX takes over the CPU, changing to

protected mode In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units (CPUs). It allows system software to use features such as Memory_segmentation, segmentation, virtual mem ...

and running DOS in a

virtual machine In computing, a virtual machine (VM) is the virtualization or emulator, emulation of a computer system. Virtual machines are based on computer architectures and provide the functionality of a physical computer. Their implementations may involve ...

within an RMX task. This combination provides RMX real-time functionality as well as full DOS services.

iRMX for Windows

Like DOS-RMX, this system provides a hybrid mixture of services and capabilities defined by DOS, Windows, and iRMX. Inter-application communication via an enhanced Windows DDE capability allows RMX tasks to communicate with Windows processes. iRMX for Windows was originally intended for use in combination with the 16-bit version of Windows. In 2002 iRMX for Windows was reintroduced by adding these RMX personalities to the INtime RTOS for Windows, allowing it to be used in conjunction with the 32-bit protected-mode versions of Windows (Windows NT, Windows 2000, etc.).

INtime

Like its iRMX predecessors, INtime is a real-time operating system. And, like DOS-RMX and iRMX for Windows, it runs concurrently with a general-purpose operating system on a single hardware platform. INtime 1.0 was originally introduced in 1997 in conjunction with the

Windows NT Windows NT is a Proprietary software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...

operating system. Since then it has been upgraded to include support for all subsequent protected-mode Microsoft Windows platforms, including Windows Vista and Windows 7. INtime can also be used as a stand-alone RTOS. INtime binaries are able to run unchanged when running on a ''stand-alone'' node of the INtime RTOS. Unlike Windows, INtime can run on an Intel 80386 or equivalent processor. Current versions of the Windows operating system generally require at least a

Pentium Pentium is a series of x86 architecture-compatible microprocessors produced by Intel from 1993 to 2023. The Pentium (original), original Pentium was Intel's fifth generation processor, succeeding the i486; Pentium was Intel's flagship proce ...

level processor in order to boot and execute. The introduction of INtime 3.0 included several important enhancements. Among them, support for multi-core processors and the ability to debug real-time processes on the INtime kernel using Microsoft

Visual Studio Visual Studio is an integrated development environment (IDE) developed by Microsoft. It is used to develop computer programs including web site, websites, web apps, web services and mobile apps. Visual Studio uses Microsoft software development ...

. INtime is not an SMP operating system, thus support for multi-core processors is restricted to a special form of

asymmetric multiprocessing An asymmetric multiprocessing (AMP or ASMP) system is a multiprocessor computer system where not all of the multiple interconnected central processing units (CPUs) are treated equally. For example, a system might allow (either at the hardware or op ...

. When used on a multi-core processor INtime can be configured to run on one CPU core while Windows runs on the remaining processor core(s).

BOS

Named BOS (BOS1810, BOS1820), the operating system was cloned by the East-German VEB Robotron-Projekt in Dresden in the 1980s.

Uses

Use cases can be viewed on the TenAsysTenAsys
/ref> website.

References

External links

* , iRMX {{Real-time operating systems Intel software Real-time operating systems