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2008-04-16 Joel Sherrill <joel.sherrill@OARcorp.com>

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* user/bsp.t, user/conf.t, user/init.t, user/intr.t, user/overview.t,
	user/timer.t: Correct default values. Make it clear that confdefs.h
	calculates the memory required for you.
This commit is contained in:
Joel Sherrill
2008-04-16 18:30:16 +00:00
parent 58b9db5877
commit 211cafba7f
7 changed files with 66 additions and 59 deletions
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41
doc/user/overview.t
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@@ -1,5 +1,5 @@
@c
@c COPYRIGHT (c) 1988-2002.
@c COPYRIGHT (c) 1988-2008.
@c On-Line Applications Research Corporation (OAR).
@c All rights reserved.
@c
@@ -329,33 +329,20 @@ microprocessor architecture.
@section Memory Requirements
Since memory is a critical resource in many real-time
embedded systems, RTEMS was specifically designed to allow
unused managers to be excluded from the run-time environment.
This allows the application designer the flexibility to tailor
RTEMS to most efficiently meet system requirements while still
satisfying even the most stringent memory constraints. As a
result, the size of the RTEMS executive is application
dependent. A worksheet is provided in the Memory Requirements
chapter of the Applications Supplement document for a specific
target processor. The worksheet is used to calculate the memory
requirements of a custom RTEMS run-time environment. The
following managers may be optionally excluded:
embedded systems, RTEMS was specifically designed to automatically
leave out all services that are not required from the run-time
environment. Features such as networking, various fileystems,
and many other features are completely optionsl. This allows
the application designer the flexibility to tailor RTEMS to most
efficiently meet system requirements while still satisfying even
the most stringent memory constraints. As a result, the size
of the RTEMS executive is application dependent.
@itemize @bullet
@item clock
@item timer
@item semaphore
@item message
@item event
@item signal
@item partition
@item region
@item dual ported memory
@item I/O
@item rate monotonic
@item fatal error
@item multiprocessing
@end itemize
RTEMS requires RAM to manage each instance of an RTEMS object
that is created. Thus the more RTEMS objects an application
needs, the more memory that must be reserved. See
@ref{Configuring a System Determining Memory Requirements} for
more details.
RTEMS utilizes memory for both code and data space.
Although RTEMS' data space must be in RAM, its code space can be