30-04-2011, 02:00 PM
Presented by
Aaruni Giriraj
[attachment=13134]
Embedded Operating Systems and Linux
What is an Embedded OS?
An "embedded system" is any computer system or computing device that performs a dedicated function or is designed for use with a specific embedded software application.
Embedded systems may use a ROM-based operating system or they may use a disk-based system, like a PC. But an embedded system is not usable as a commercially viable substitute for general purpose computers or devices.
What makes a good Embedded OS?
Modular
Scalable
Configurable
Small footprint
CPU support
Device drivers
etc, etc, etc...
What is Real Time?
“Real time in operating systems: The ability of the operating system to provide a required level of service in a bounded response time.”
Hard vs. Soft Real Time
Hard
guaranteed worst-case response times
absolutely, positively, first time every time
Soft
Kinda, sorta, usually
What makes a good RTOS?
Multi-threaded and pre-emptible
Thread priority has to exist because no deadline driven OS exists
Must support predictable thread synchronization mechanisms
A system of priority inheritance must exist
Commercial Embedded Linux
Neoware NeoLinux
Red Hat derived for information appliances
PalmPalm Tynux
Internet appliuance and multimedia
Red Hat Embedded Linux
general purpose embedded solution
RedSonic Red-Ice Linux
runs from DiskonChip or CompactFlash
Open Source Embedded Linux
Embedded Debian Project
convert Debian to an embedded OS
ETLinux
for PC104 SBC’s
uCLinux
for microprocessors that don’t have MM
uLinux (muLinux)
distro fits on a single floppy
Commercial Linux RTOS
FSMLabs - Open RT Linux
Lineo - Embedix Realtime
LynuxWorks - BlueCat RT
MontaVista Software - Real Time Extensions
REDSonic - REDICE Linux
TimeSys - Linux/Real-Time
Open Source Linux RTOS
ART Linux - real time extension based on RTLinux
KURT - event schedules with 10us resolution
Linux-SRT - for soft real time apps like multimedia
Qlinux - provides Quality of Service guarantees
RTAI - “hard” Real Time Application Interface
RTLinux
A “hard real-time” mini operating system
runs Linux as it’s lowest priority execution thread
Linux thread completely preemptible
Real time threads and interrupt handlers never delayed by non-realtime operations
Supports user level programming
MiniRTL implementation fits on a floppy
What’s so special about Linux?
Multiple choices vs. sole source
Source code freely available
Robust and reliable
Modular, configurable, scalable
Superb support for networking and Internet
No runtime licenses
Large pool of skilled developers
What’s so special about Linux?
What’s special about Open Source?
Flies in the Ointment
Lack of hardware device drivers
Competing and/or lacking standards
No formalized qualification testing
No single source for marketing
GPL license issues
Startup vendors with shaky futures
What CPU’s will it run on?
Intel X86
MIPS
ARM
StrongARM
PowerPC
Hitachi SuperH
C or C++ for Development?
In general C is a better choice
Advanced OOP features can cause code bloat
C++ compilers can generate many routines for a single function
Virtual methods and polymorphism slow program launch times significantly
Size really does matte
Aaruni Giriraj
[attachment=13134]
Embedded Operating Systems and Linux
What is an Embedded OS?
An "embedded system" is any computer system or computing device that performs a dedicated function or is designed for use with a specific embedded software application.
Embedded systems may use a ROM-based operating system or they may use a disk-based system, like a PC. But an embedded system is not usable as a commercially viable substitute for general purpose computers or devices.
What makes a good Embedded OS?
Modular
Scalable
Configurable
Small footprint
CPU support
Device drivers
etc, etc, etc...
What is Real Time?
“Real time in operating systems: The ability of the operating system to provide a required level of service in a bounded response time.”
Hard vs. Soft Real Time
Hard
guaranteed worst-case response times
absolutely, positively, first time every time
Soft
Kinda, sorta, usually
What makes a good RTOS?
Multi-threaded and pre-emptible
Thread priority has to exist because no deadline driven OS exists
Must support predictable thread synchronization mechanisms
A system of priority inheritance must exist
Commercial Embedded Linux
Neoware NeoLinux
Red Hat derived for information appliances
PalmPalm Tynux
Internet appliuance and multimedia
Red Hat Embedded Linux
general purpose embedded solution
RedSonic Red-Ice Linux
runs from DiskonChip or CompactFlash
Open Source Embedded Linux
Embedded Debian Project
convert Debian to an embedded OS
ETLinux
for PC104 SBC’s
uCLinux
for microprocessors that don’t have MM
uLinux (muLinux)
distro fits on a single floppy
Commercial Linux RTOS
FSMLabs - Open RT Linux
Lineo - Embedix Realtime
LynuxWorks - BlueCat RT
MontaVista Software - Real Time Extensions
REDSonic - REDICE Linux
TimeSys - Linux/Real-Time
Open Source Linux RTOS
ART Linux - real time extension based on RTLinux
KURT - event schedules with 10us resolution
Linux-SRT - for soft real time apps like multimedia
Qlinux - provides Quality of Service guarantees
RTAI - “hard” Real Time Application Interface
RTLinux
A “hard real-time” mini operating system
runs Linux as it’s lowest priority execution thread
Linux thread completely preemptible
Real time threads and interrupt handlers never delayed by non-realtime operations
Supports user level programming
MiniRTL implementation fits on a floppy
What’s so special about Linux?
Multiple choices vs. sole source
Source code freely available
Robust and reliable
Modular, configurable, scalable
Superb support for networking and Internet
No runtime licenses
Large pool of skilled developers
What’s so special about Linux?
What’s special about Open Source?
Flies in the Ointment
Lack of hardware device drivers
Competing and/or lacking standards
No formalized qualification testing
No single source for marketing
GPL license issues
Startup vendors with shaky futures
What CPU’s will it run on?
Intel X86
MIPS
ARM
StrongARM
PowerPC
Hitachi SuperH
C or C++ for Development?
In general C is a better choice
Advanced OOP features can cause code bloat
C++ compilers can generate many routines for a single function
Virtual methods and polymorphism slow program launch times significantly
Size really does matte
