Download Trusted embedded System Operating System (TeSOS)

provides a HAL, oering further implementations to easily support additional power management
functionalities of the underlying hardware. A function or power management policy that forces
the system to enter any low-power modes is also not available, however, the provided package
builds a base framework to implement these features by your own. Power modes dened in the
power management packages are:
•
Active: The system is running at maximum speed and fully operational. It can be expected
that power consumption is at the maximum.
•
Idle: If there is almost no or only a little activity over a predened short period of time, the
system would be in the idle state. This causes a reduction of the CPU speed or disabling
some of the input- or output devices. It has to be mentioned that due to the fact the idle
thread is always running, it has to be dened when to enter the idle state.
After some
interrupt occurs, the idle mode can easily be left again.
•
Sleep: Also to be dened by some power management rules, if the system is in idle mode
for a predened period of time, the system will go into the sleep mode. In this state it is
expected to shut down almost all power-consuming devices of the hardware.
•
O:
Shutting down the system means that the power consumption is minimized.
All
attached hardware is disabled. Possibly it is necessary to do additional actions to wake up
the system again.
The main function of the power management package is to control all available power controllers of the hardware platform. These power controllers could be controllers for LCD displays
or CPUs. It often happens that a hardware platform implements its own power controllers as
part of the relevant device driver package, it also can happen that there is no hardware support
for any power management at all. The eCos documentation gives some short exampled how to
implement a basic power controller.
7.2.4 External Factors
eCosCentric Limited, a 2002 founded commercial provider of eCos products and services located
in the United Kingdom, arms that in the fragmented embedded operating systems market eCos
is one of the major players, with global market usage of around 5-6 percent according to multiple
surveys including CMP's Embedded Study 2007, and EDC's Embedded Development Survey
3
2007 . Famous products using eCos are e.g., Playstation 3 (used to provide the Playstation's
Wi-Fi support based on the Marvell 88W8580 WLAN chip) or Samsung's LCD HDTVs, including the latest M and F top-of-the-line ranges of 32-70 inch sets. The TVs feature multi-media
playback via USB2 from cameras, mp3 players, and ash drives. A detailed list of products/projects using eCos can be found at
http://www.ecoscentric.com/ecos/examples.shtml.
The
used programming language for eCos applications is C/C++.
Beginning around the year 1997, eCos continually receives updates on supported hardware
or additional packages, such as the PPP stack in April 2004. The current eCos version 3.0 was
released in March 2009. However, a lot of contributions to the project were implemented from
single persons, while the big releases are contributed by eCosCentric. Parts of the system also
are contributed by RedHat, a leading open source provider located in USA and Canada. Except
of a small number of packages, the copyright of the eCos public source repository is owned by
the Free Software Foundation (FSF), thus the origin country of eCos is the same as the FSF.
The Free Software Foundation Inc. is located in Bosten, USA.
At the moment, no certication of eCos is available.
3
http://www.researchandmarkets.com/reports/c90477
117