The idea for this posting started when I read New approaches to dominate in embedded development article. Then I found some ther related articles and here is the result: long article.
Embedded devices, or embedded systems, are specialized computer systems that constitute components of larger electromechanical systems with which they interface. The advent of low-cost wireless connectivity is altering many things in embedded development: With a connection to the Internet, an embedded device can gain access to essentially unlimited processing power and memory in cloud service – and at the same time you need to worry about communication issues like breaks connections, latency and security issues.
Historically, a typical embedded system has been designed as a control-dominated system using only a state-oriented model, such as FSMs. However, the trend in embedded systems design in recent years has been towards highly distributed architectures with support for concurrency, data and control flow, and scalable distributed computations. For example computer networks, modern industrial control systems, electronics in modern car,Internet of Things system fall to this category. This implies that a different approach is necessary.
Companies are also marketing to embedded developers in new ways. Ultra-low cost development boards to woo makers, hobbyists, students, and entrepreneurs on a shoestring budget to a processor architecture for prototyping and experimentation have already become common.If you look under the hood of any connected embedded consumer or mobile device, in addition to the OS you will find a variety of middleware applications. As hardware becomes powerful and cheap enough that the inefficiencies of platform-based products become moot. Leaders with Embedded systems development lifecycle management solutions speak out on new approaches available today in developing advanced products and systems.
Tradionally embedded developers have been living and breathing C/C++. For a variety of reasons, the vast majority of embedded toolchains are designed to support C as the primary language. If you want to write embedded software for more than just a few hobbyist platforms, your going to need to learn C. Very many embedded systems operating systems, including Linux Kernel, are written using C language. C can be translated very easily and literally to assembly, which allows programmers to do low level things without the restrictions of assembly. When you need to optimize for cost, code size, and performance the typical choice of language is C. Still C is today used for maximum efficiency instead of C++.
C++ is very much alike C, with more features, and lots of good stuff, while not having many drawbacks, except fror it complexity. The had been for years suspicion C++ is somehow unsuitable for use in small embedded systems. At some time many 8- and 16-bit processors were lacking a C++ compiler, that may be a concern, but there are now 32-bit microcontrollers available for under a dollar supported by mature C++ compilers.Today C++ is used a lot more in embedded systems. There are many factors that may contribute to this, including more powerful processors, more challenging applications, and more familiarity with object-oriented languages.
And if you use suitable C++ subset for coding, you can make applications that work even on quite tiny processors, let the Arduino system be an example of that: You’re writing in C/C++, using a library of functions with a fairly consistent API. There is no “Arduino language” and your “.ino” files are three lines away from being standard C++.
Today C++ has not displaced C. Both of the languages are widely used, sometimes even within one system – for example in embedded Linux system that runs C++ application. When you write a C or C++ programs for modern Embedded Linux you typically use GCC compiler toolchain to do compilation and make file to manage compilation process.
Most organization put considerable focus on software quality, but software security is different. When the security is very much talked about topic todays embedded systems, the security of the programs written using C/C++ becomes sometimes a debated subject. Embedded development presents the challenge of coding in a language that’s inherently insecure; and quality assurance does little to ensure security. The truth is that majority of today’s Internet connected systems have their networking fuctionality written using C even of the actual application layer is written using some other methods.
Java is a general-purpose computer programming language that is concurrent, class-based and object-oriented.The language derives much of its syntax from C and C++, but it has fewer low-level facilities than either of them. Java is intended to let application developers “write once, run anywhere” (WORA), meaning that compiled Java code can run on all platforms that support Java without the need for recompilation.Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of computer architecture. Java is one of the most popular programming languages in use, particularly for client-server web applications. In addition to those it is widely used in mobile phones (Java apps in feature phones, ) and some embedded applications. Some common examples include SIM cards, VOIP phones, Blu-ray Disc players, televisions, utility meters, healthcare gateways, industrial controls, and countless other devices.
Some experts point out that Java is still a viable option for IoT programming. Think of the industrial Internet as the merger of embedded software development and the enterprise. In that area, Java has a number of key advantages: first is skills – there are lots of Java developers out there, and that is an important factor when selecting technology. Second is maturity and stability – when you have devices which are going to be remotely managed and provisioned for a decade, Java’s stability and care about backwards compatibility become very important. Third is the scale of the Java ecosystem – thousands of companies already base their business on Java, ranging from Gemalto using JavaCard on their SIM cards to the largest of the enterprise software vendors.
Although in the past some differences existed between embedded Java and traditional PC based Java solutions, the only difference now is that embedded Java code in these embedded systems is mainly contained in constrained memory, such as flash memory. A complete convergence has taken place since 2010, and now Java software components running on large systems can run directly with no recompilation at all on design-to-cost mass-production devices (consumers, industrial, white goods, healthcare, metering, smart markets in general,…) Java for embedded devices (Java Embedded) is generally integrated by the device manufacturers. It is NOT available for download or installation by consumers. Originally Java was tightly controlled by Sun (now Oracle), but in 2007 Sun relicensed most of its Java technologies under the GNU General Public License. Others have also developed alternative implementations of these Sun technologies, such as the GNU Compiler for Java (bytecode compiler), GNU Classpath (standard libraries), and IcedTea-Web (browser plugin for applets).
My feelings with Java is that if your embedded systems platform supports Java and you know hot to code Java, then it could be a good tool. If your platform does not have ready Java support, adding it could be quite a bit of work.
Embedded databases are coming more and more to the embedded devices. If you look under the hood of any connected embedded consumer or mobile device, in addition to the OS you will find a variety of middleware applications. One of the most important and most ubiquitous of these is the embedded database. An embedded database system is a database management system (DBMS) which is tightly integrated with an application software that requires access to stored data, such that the database system is “hidden” from the application’s end-user and requires little or no ongoing maintenance.
There are many possible databases. First choice is what kind of database you need. The main choices are SQL databases and simpler key-storage databases (also called NoSQL).
SQLite is the Database chosen by virtually all mobile operating systems. For example Android and iOS ship with SQLite. It is also built into for example Firefox web browser. It is also often used with PHP. So SQLite is probably a pretty safe bet if you need relational database for an embedded system that needs to support SQL commands and does not need to store huge amounts of data (no need to modify database with millions of lines of data).
If you do not need relational database and you need very high performance, you need probably to look somewhere else.Berkeley DB (BDB) is a software library intended to provide a high-performance embedded database for key/value data. Berkeley DB is written in Cwith API bindings for many languages. BDB stores arbitrary key/data pairs as byte arrays. There also many other key/value database systems.
RTA (Run Time Access) gives easy runtime access to your program’s internal structures, arrays, and linked-lists as tables in a database. When using RTA, your UI programs think they are talking to a PostgreSQL database (PostgreSQL bindings for C and PHP work, as does command line tool psql), but instead of normal database file you are actually accessing internals of your software.
Building quality into embedded software doesn’t happen by accident. Quality must be built-in from the beginning. Software startup checklist gives quality a head start article is a checklist for embedded software developers to make sure they kick-off their embedded software implementation phase the right way, with quality in mind
Traditional methods for achieving safety properties mostly originate from hardware-dominated systems. Nowdays more and more functionality is built using software – including safety critical functions. Software-intensive embedded systems require new approaches for safety. Embedded Software Can Kill But Are We Designing Safely?
IEC, FDA, FAA, NHTSA, SAE, IEEE, MISRA, and other professional agencies and societies work to create safety standards for engineering design. But are we following them? A survey of embedded design practices leads to some disturbing inferences about safety.Barr Group’s recent annual Embedded Systems Safety & Security Survey indicate that we all need to be concerned: Only 67 percent are designing to relevant safety standards, while 22 percent stated that they are not—and 11 percent did not even know if they were designing to a standard or not.
If you were the user of a safety-critical embedded device and learned that the designers had not followed best practices and safety standards in the design of the device, how worried would you be? I know I would be anxious, and quite frankly. This is quite disturbing.
The advent of low-cost wireless connectivity is altering many things in embedded development – it has added to your list of worries need to worry about communication issues like breaks connections, latency and security issues. Understanding security is one thing; applying that understanding in a complete and consistent fashion to meet security goals is quite another. Embedded development presents the challenge of coding in a language that’s inherently insecure; and quality assurance does little to ensure security.
Developing Secure Embedded Software white paper explains why some commonly used approaches to security typically fail:
MISCONCEPTION 1: SECURITY BY OBSCURITY IS A VALID STRATEGY
MISCONCEPTION 2: SECURITY FEATURES EQUAL SECURE SOFTWARE
MISCONCEPTION 3: RELIABILITY AND SAFETY EQUAL SECURITY
MISCONCEPTION 4: DEFENSIVE PROGRAMMING GUARANTEES SECURITY
Some techniques for building security to embedded systems:
Use secure communications protocols and use VPN to secure communications
The use of Public Key Infrastructure (PKI) for boot-time and code authentication
Establishing a “chain of trust”
Process separation to partition critical code and memory spaces
Leveraging safety-certified code
Hardware enforced system partitioning with a trusted execution environment
Plan the system so that it can be easily and safely upgraded when needed
Flood of new languages
One workable solution, especially for embedded Linux systems is that part of the activities organized by totetuettu is a C program instead of scripting languages (Scripting). This enables editing operation simply script files by editing without the need to turn the whole system software again. Scripting languages are also tools that can be implemented, for example, a Web user interface more easily than with C / C ++ language. An empirical study found scripting languages (such as Python) more productive than conventional languages (such as C and Java) for a programming problem involving string manipulation and search in a dictionary.
Scripting languages have been around for a couple of decades Linux and Unix server world standard tools. the proliferation of embedded Linux and resources to merge systems (memory, processor power) growth has made them a very viable tool for many embedded systems – for example, industrial systems, telecommunications equipment, IoT gateway, etc . Some of the command language is suitable for up well even in quite small embedded environments.
There are some thing that needs to be considered when using scripting languages. Sometimes lack of static checking vs a regular compiler can cause problems to be thrown at run-time. But it is better off practicing “strong testing” than relying on strong typing. Other ownsides of these languages is that they tend to execute more slowly than static languages like C/C++, but for very many aplications they are more than adequate. Once you know your way around dynamic languages, as well the frameworks built in them, you get a sense of what runs quickly and what doesn’t.
Bash and other shell scipting
Shell commands are the native language of any Linux system. With the thousands of commands available for the command line user, how can you remember them all? The answer is, you don’t. The real power of the computer is its ability to do the work for you – the power of the shell script is the way to easily to automate things by writing scripts. Shell scripts are collections of Linux command line commands that are stored in a file. The shell can read this file and act on the commands as if they were typed at the keyboard.In addition to that shell also provides a variety of useful programming features that you are familar on other programming langauge (if, for, regex, etc..). Your scripts can be truly powerful. Creating a script extremely straight forward: It can be created by opening a separate editor such or you can do it through a terminal editor such as VI (or preferably some else more user friendly terminal editor). Many things on modern Linux systems rely on using scripts (for example starting and stopping different Linux services at right way).
One of the most useful tools when developing from within a Linux environment is the use of shell scripting. Scripting can help aid in setting up environment variables, performing repetitive and complex tasks and ensuring that errors are kept to a minimum. Since scripts are ran from within the terminal, any command or function that can be performed manually from a terminal can also be automated!
The most common type of shell script is a bash script. Bash is a commonly used scripting language for shell scripts. In BASH scripts (shell scripts written in BASH) users can use more than just BASH to write the script. There are commands that allow users to embed other scripting languages into a BASH script.
There are also other shells. For example many small embedded systems use BusyBox. BusyBox providesis software that provides several stripped-down Unix tools in a single executable file (more than 300 common command). It runs in a variety of POSIX environments such as Linux, Android and FreeeBSD. BusyBox become the de facto standard core user space toolset for embedded Linux devices and Linux distribution installers.
Shell scripting is a very powerful tool that I used a lot in Linux systems, both embedded systems and servers.
Lua is a lightweight cross-platform multi-paradigm programming language designed primarily for embedded systems and clients. Lua was originally designed in 1993 as a language for extending software applications to meet the increasing demand for customization at the time. It provided the basic facilities of most procedural programming languages. Lua is intended to be embedded into other applications, and provides a C API for this purpose.
Lua has found many uses in many fields. For example in video game development, Lua is widely used as a scripting language by game programmers. Wireshark network packet analyzer allows protocol dissectors and post-dissector taps to be written in Lua – this is a good way to analyze your custom protocols.
There are also many embedded applications. LuCI, the default web interface for OpenWrt, is written primarily in Lua. NodeMCU is an open source hardware platform, which can run Lua directly on the ESP8266 Wi-Fi SoC. I have tested NodeMcu and found it very nice system.
PHP is a server-side HTML embedded scripting language. It provides web developers with a full suite of tools for building dynamic websites but can also be used as a general-purpose programming language. Nowadays it is common to find embedded hardware devices, based on Raspberry Pi for instance, that are accessible via a network, run Linux and come with Apache and PHP installed on the device. So on such enviroment is a good idea to take advantage of those built-in features for the applications they are good – for building web user interface. PHP is often embedded into HTML code, or it can be used in combination with various web template systems, web content management system and web frameworks. PHP code is usually processed by a PHP interpreter implemented as a module in the web server or as a Common Gateway Interface (CGI) executable.
Python is a widely used high-level, general-purpose, interpreted, dynamic programming language. Its design philosophy emphasizes code readability. Python interpreters are available for installation on many operating systems, allowing Python code execution on a wide variety of systems. Many operating systems include Python as a standard component; the language ships for example with most Linux distributions.
Python is a multi-paradigm programming language: object-oriented programming and structured programming are fully supported, and there are a number of language features which support functional programming and aspect-oriented programming, Many other paradigms are supported using extensions, including design by contract and logic programming.
Python is a remarkably powerful dynamic programming language that is used in a wide variety of application domains. Since 2003, Python has consistently ranked in the top ten most popular programming languages as measured by the TIOBE Programming Community Index. Large organizations that make use of Python include Google, Yahoo!, CERN, NASA. Python is used successfully in thousands of real world business applications around globally, including many large and mission-critical systems such as YouTube.com and Google.com.
Python was designed to be highly extensible. Libraries like NumPy, SciPy and Matplotlib allow the effective use of Python in scientific computing. Python is intended to be a highly readable language. Python can also be embedded in existing applications and hasbeen successfully embedded in a number of software products as a scripting language. Python can serve as a scripting language for web applications, e.g., via mod_wsgi for the Apache web server.
Python can be used in embedded, small or minimal hardware devices. Some modern embedded devices have enough memory and a fast enough CPU to run a typical Linux-based environment, for example, and running CPython on such devices is mostly a matter of compilation (or cross-compilation) and tuning. Various efforts have been made to make CPython more usable for embedded applications.
For more limited embedded devices, a re-engineered or adapted version of CPython, might be appropriate. Examples of such implementations include the following: PyMite, Tiny Python, Viper. Sometimes the embedded environment is just too restrictive to support a Python virtual machine. In such cases, various Python tools can be employed for prototyping, with the eventual application or system code being generated and deployed on the device. Also MicroPython and tinypy have been ported Python to various small microcontrollers and architectures. Real world applications include Telit GSM/GPRS modules that allow writing the controlling application directly in a high-level open-sourced language: Python.
Python on embedded platforms? It is quick to develop apps, quick to debug – really easy to make custom code quickly. Sometimes lack of static checking vs a regular compiler can cause problems to be thrown at run-time. To avoid those try to have 100% test coverage. pychecker is a very useful too also which will catch quite a lot of common errors. The only downsides for embedded work is that sometimes python can be slow and sometimes it uses a lot of memory (relatively speaking). An empirical study found scripting languages (such as Python) more productive than conventional languages (such as C and Java) for a programming problem involving string manipulation and search in a dictionary. Memory consumption was often “better than Java and not much worse than C or C++”.
Its event-driven architecture fits perfectly with how the world operates – we live in an event-driven world. This event-driven modality is also efficient when it comes to sensors.
It doesn’t require a complicated IDE; all you really need is a terminal.
GET method specific URLs to your software function calls. If your embedded platform has ready made Node.js support available, you should definately consider using it.
According to New approaches to dominate in embedded development article there will be several camps of embedded development in the future:
One camp will be the traditional embedded developer, working as always to craft designs for specific applications that require the fine tuning. These are most likely to be high-performance, low-volume systems or else fixed-function, high-volume systems where cost is everything.
Another camp might be the embedded developer who is creating a platform on which other developers will build applications. These platforms might be general-purpose designs like the Arduino, or specialty designs such as a virtual PLC system.
Transition will take time. The enviroment is different than computer and mobile world. There are too many application areas with too widely varying requirements for a one-size-fits-all platform to arise.
Most important information sources: