ECos
Encyclopedia
eCos is an open source
, royalty-free, real-time operating system
intended for embedded system
s and applications which need only one process
with multiple threads
. It is designed to be customizable to precise application requirements of run-time performance and hardware needs. It is implemented in C
/C++
and has compatibility
layers and API
s for POSIX
and µITRON
.
s, or with real-time requirements. It can be used on hardware with too little RAM to support embedded Linux
, which currently needs a minimum of about 2 MB of RAM, not including application and service needs.
eCos runs on a wide variety of hardware platforms, including ARM
, CalmRISC, FR-V
, Hitachi H8, IA-32
, Motorola 68000
, Matsushita AM3x, MIPS
, NEC V8xx, Nios II
, PowerPC
, SPARC
, and SuperH
.
Included with the eCos distribution is RedBoot
, an open source
application
that uses the eCos Hardware Abstraction Layer to provide bootstrap
firmware
for embedded system
s.
which was later bought by Red Hat
. In early 2002, Red Hat ceased development of eCos and laid off the staff that were working on the project. Many of the laid-off staff continued to work on eCos, and some formed their own companies providing services for the software. In January 2004, at the request of the eCos developers, Red Hat agreed to transfer its eCos copyrights to the Free Software Foundation
. The transfer was executed in October 2005 and finally implemented in May 2008.
is a commercial fork
of eCos created by eCosCentric
which
incorporates proprietary software
components. It is claimed as a "stable, fully tested, certified and supported version", however, some of the additional features have not been released as free software.
TCP/IP network stack port included with eCos is out of date—circa 2001—and exposes systems using such to numerous security and stability vulnerabilities (FreeBSD RELENG 4 4 0 RELEASE for IPv4 and FreeBSD's origin KAME
for IPv6), despite being claimed as "recent" in eCos documentation. Official eCos maintainers do not appear to monitor FreeBSD or KAME for security or stability updates, but rather rely on minimal and insufficient bug reports from users of eCos.
The SNMP package is rudimentary at best, once again, apparently due to its age.
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
, royalty-free, real-time operating system
Real-time operating system
A real-time operating system is an operating system intended to serve real-time application requests.A key characteristic of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter...
intended for embedded system
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
s and applications which need only one process
Process (computing)
In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system , a process may be made up of multiple threads of execution that execute instructions concurrently.A computer program is a...
with multiple threads
Thread (computer science)
In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...
. It is designed to be customizable to precise application requirements of run-time performance and hardware needs. It is implemented in C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
/C++
C++
C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
and has compatibility
Emulator
In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...
layers and API
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
s for POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
and µITRON
TRON Project
TRON is an open real-time operating system kernel design, and is an acronym for "The Real-time Operating system Nucleus". The project was started by Prof. Dr. Ken Sakamura of the University of Tokyo in 1984...
.
Design
eCos was designed for devices with memory size in the tens to hundreds of kilobyteKilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
s, or with real-time requirements. It can be used on hardware with too little RAM to support embedded Linux
Embedded Linux
Embedded Linux is the use of Linux in embedded computer systems such as mobile phones, personal digital assistants, media players, set-top boxes, and other consumer electronics devices, networking equipment, machine control, industrial automation, navigation equipment and medical instruments...
, which currently needs a minimum of about 2 MB of RAM, not including application and service needs.
eCos runs on a wide variety of hardware platforms, including ARM
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
, CalmRISC, FR-V
FR-V
The Fujitsu FR-V is a VLIW-based RISC microprocessor, including FR-400 and FR-450 which runs Linux, and are also supported by the GNU Compiler Collection. Some processors include support with an MMU while others do not....
, Hitachi H8, IA-32
IA-32
IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
, Motorola 68000
Motorola 68000
The Motorola 68000 is a 16/32-bit CISC microprocessor core designed and marketed by Freescale Semiconductor...
, Matsushita AM3x, MIPS
MIPS architecture
MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies . The early MIPS architectures were 32-bit, and later versions were 64-bit...
, NEC V8xx, Nios II
Nios II
Nios II is a 32-bit embedded-processor architecture designed specifically for the Altera family of FPGAs. Nios II incorporates many enhancements over the original Nios architecture, making it more suitable for a wider range of embedded computing applications, from DSP to system-control.Nios II is...
, PowerPC
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...
, SPARC
SPARC
SPARC is a RISC instruction set architecture developed by Sun Microsystems and introduced in mid-1987....
, and SuperH
SuperH
SuperH is a 32-bit reduced instruction set computer instruction set architecture developed by Hitachi. It is implemented by microcontrollers and microprocessors for embedded systems....
.
Included with the eCos distribution is RedBoot
RedBoot
RedBoot is an open source application that uses the eCos real-time operating system Hardware Abstraction Layer to provide bootstrap firmware for embedded systems...
, an open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
application
Application software
Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...
that uses the eCos Hardware Abstraction Layer to provide bootstrap
Booting
In computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...
firmware
Firmware
In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...
for embedded system
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
s.
History
eCos was initially developed by Cygnus SolutionsCygnus Solutions
Cygnus Solutions, originally Cygnus Support, was founded in 1989 by John Gilmore, Michael Tiemann and David Henkel-Wallace to provide commercial support for free software...
which was later bought by Red Hat
Red Hat
Red Hat, Inc. is an S&P 500 company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide....
. In early 2002, Red Hat ceased development of eCos and laid off the staff that were working on the project. Many of the laid-off staff continued to work on eCos, and some formed their own companies providing services for the software. In January 2004, at the request of the eCos developers, Red Hat agreed to transfer its eCos copyrights to the Free Software Foundation
Free Software Foundation
The Free Software Foundation is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software...
. The transfer was executed in October 2005 and finally implemented in May 2008.
Non-free versions
The eCosPro real-time operating systemReal-time operating system
A real-time operating system is an operating system intended to serve real-time application requests.A key characteristic of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter...
is a commercial fork
Fork (software development)
In software engineering, a project fork happens when developers take a legal copy of source code from one software package and start independent development on it, creating a distinct piece of software...
of eCos created by eCosCentric
ECosCentric
eCosCentric Limited is a privately held company dedicated to open source software, with a distinct focus on eCos. Founded in 2002 by the original eCos developers , it has headquarters in Cambridge in England from where it continues to support, develop and provide commercial services for eCos and...
which
incorporates proprietary software
Proprietary software
Proprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...
components. It is claimed as a "stable, fully tested, certified and supported version", however, some of the additional features have not been released as free software.
Criticisms
The FreeBSDFreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
TCP/IP network stack port included with eCos is out of date—circa 2001—and exposes systems using such to numerous security and stability vulnerabilities (FreeBSD RELENG 4 4 0 RELEASE for IPv4 and FreeBSD's origin KAME
KAME project
The KAME project was a joint effort of six organizations in Japan which aimed to provide a free IPv6 and IPsec protocol stack implementation for variants of the BSD Unix computer operating-system...
for IPv6), despite being claimed as "recent" in eCos documentation. Official eCos maintainers do not appear to monitor FreeBSD or KAME for security or stability updates, but rather rely on minimal and insufficient bug reports from users of eCos.
The SNMP package is rudimentary at best, once again, apparently due to its age.
External links
- eCos Homepage
- "eCos Porting Guide" article by Anthony J. Massa 2001-12-28
- "Embedded Software Development with eCos" book by Anthony J. Massa 2002-11-25, ISBN 0-13-035473-2
- eCosCentric web site