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139 lines
4.3 KiB
Perl
139 lines
4.3 KiB
Perl
@c
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@c COPYRIGHT (c) 1988-1998.
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@c On-Line Applications Research Corporation (OAR).
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@c All rights reserved.
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@c
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@c $Id$
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@c
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@chapter Basic Information
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The questions in this category are basic questions about RTEMS. Where
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did it come from, why is it, what is it, when should you use it, etc.?
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@section What does RTEMS stand for?
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RTEMS is an anacronym for the Real-Time Executive for Multiprocessor
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Systems.
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Initially RTEMS stood for the Real-Time Executive for Missile Systems
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but as it became clear that the application domains that could use
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RTEMS extended far beyond missiles, the "M" changed to mean Military.
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At one point, there were both Ada and C implementations of RTEMS. The
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C version changed the "M" to mean Multiprocessor while the Ada version
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remained with the "M" meaning Military.
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@section What is RTEMS?
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RTEMS is a real-time executive which provides a high performance
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environment for embedded military applications including the
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following features:
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@itemize @bullet
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@item multitasking capabilities
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@item homogeneous and heterogeneous multiprocessor systems
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@item event-driven, priority-based, preemptive scheduling
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@item optional rate monotonic scheduling
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@item intertask communication and synchronization
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@item priority inheritance
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@item responsive interrupt management
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@item dynamic memory allocation
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@item high level of user configurability
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@end itemize
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XXX This feature list is weak these days. :)
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@section What standards does RTEMS support?
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The original "Classic" RTEMS API is based on the Real-Time Executive
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Interface Definition (RTEID) and the Open Real-Time Kernel Interface
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Definition (ORKID). RTEMS also includes support for POSIX threads
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and real-time extensions.
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With the addition of file system infrastructure, RTEMS supports
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about 70% of the POSIX 1003.1b-1996 standard. This standard
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defines the programming interfaces of standard UNIX. This means
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that much source code that works on UNIX, also works on RTEMS.
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@section What processors is RTEMS available for?
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RTEMS is available for the following processor families:
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@itemize @bullet
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@item Motorola MC68xxx
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@item Motorola MC683xx
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@item Motorola ColdFire
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@item Hitachi SH
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@item Intel i386
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@item Intel i960
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@item MIPS
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@item PowerPC
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@item SPARC
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@item AMD A29K
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@item Hewlett-Packard PA-RISC
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@end itemize
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In addition, there is a port to UNIX which can be used as a prototyping
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and simulation environment.
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@section Executive vs. Kernel vs. Operating System (RTOS)
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The developers of RTEMS developers use the terms executive and kernel
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interchangeably. In the embedded system community, the terms executive
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or kernel are generally used to refer to small operating systems.
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So we consider it proper to refer to RTEMS as an executive, a kernel,
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or an operating system.
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@section Where/why was it developed?
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RTEMS was developed by On-Line Applications Research Corporation (OAR)
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for the U.S. Army Missile Command. The original goal of RTEMS was
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to provide a portable, standards-based real-time executive for which
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source code was available and royalties were paid.
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In other words, RTEMS was open source before open source was cool.
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@section Are there no similar commercial products?
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Yes, but not all are based on standards and the open source philosophy.
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@section How can I get RTEMS?
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RTEMS is distributed by OAR Corporation via the Internet. Point your
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favorite browser at the following URL and following the link:
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@set OAR-URL http://www.OARcorp.com
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@ifset use-html
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@href{@value{OAR-URL},,@value{OAR-URL}}
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@end ifset
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@ifclear use-html
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@value{OAR-URL}
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@end ifclear
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@section What about support?
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OAR Corporation provides numerous services for RTEMS including support,
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training, and custom development.
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@section Are there any mailing lists?
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The primary RTEMS mailing list is @code{rtems-list@@oarcorp.com}. You
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can subscribe by sending a message with the word @b{subscribe} as the
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body to @code{rtems-list-request@@oarcorp.com}.
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@section Are there any license restrictions?
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RTEMS is licensed under a modified version of the GNU General Public License
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(GPL). The modification places no restrictions on the applications which
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use RTEMS but protects the interests of those who work on RTEMS.
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The TCP/IP network stack included with RTEMS is a port of the FreeBSD
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network stack and is licensed under different terms that also do not
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place restrictions on the application.
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@section Are there any export restrictions?
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No.
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