This question already has answers here:
Closed 12 years ago.
Possible Duplicate:
in which area is c++ mostly used?
I started off with C in school, went to Java and now I primarily use the P's(Php, Perl, Python) so my exposure to the lower level languages have all but disappeared. I would like to get back into it but I can never justify using C over Perl or Python. What real-world apps are being built with these languages? Any suggestions if I want to dive back in, what can I do with C/C++ that I can't easily do with Perl/Python?
To borrow some text from the answer I had for another related question:
Device drivers in native code.
High performance floating point number crunching (i.e. SIMD).
Easy ability to interface with assembly language routines.
Manage memory manually for extended execution runs.
Most of my work has been C and C++. I studied computer engineering in school and worked with embedded devices. My Master's degree had an emphasis in graphics and visualization. One of our visualization apps was written in Python, but for the most part, graphics demands C/C++ for the speed. I now work with embedded devices running Windows Mobile and Windows CE - all C++, though you can do a lot with C#. I previously worked in simulations, which was all C++ code on the backend. C++ is still king for time-sensitive IO, embedded applications, graphics and simulations.
Basically, if you need tight control of timing, you go lower level. Or if you need light-weight (ie, small program size, small memory footprint)
Somewhat unscientifically I took a look on Sourceforge and the top twenty projects/language break-down is currently thus:
Java(43,199)
C++(34,313)
PHP(28,333)
C(26,711)
C#(12,298)
Python(12,222)
JavaScript(10,307)
Perl(8,931)
Unix Shell(3,618)
Delphi/Kylix(3,353)
Visual Basic(3,044)
Visual Basic .NET(2,513)
Assembly(2,283)
JSP(1,891)
Ruby(1,731)
PL/SQL(1,669)
Objective C(1,424)
ASP.NET(1,344)
Tcl(1,241)
ActionScript(1,164)
Perl + Python together still total less than C alone. I have no idea why Java is so high, I know of no single Java developer and have not seen a single Java project, but I am sure someone is using it! For probably the same reason, you are not seeing much C/C++, you are just not working in a domain where it figures highly. I work in embedded systems where C and C++ are ubiquitous and Python comes nowhere. Different languages are encountered to different extents in different worlds.
You ask what you can do with C/C++ that you cannot do easily with Perl/Python; well the answer is plenty, real-time embedded systems for one; but if that is not what you want/need to do, then there is no reason to. On the other hand I might ask the reverse; I'd use C++ for things you might use Python for, simply because for me it would be easier and quicker (than learning a new language and getting the tools working)
C/C++ can be, and is, used for nearly all "types" of programs.
There are some major advantages to C and C++:
Potentially better performance
Easier to build interoperable libraries, especially if working with libraries usable from multiple languages.
well the interpreters for your "P's" languages are most certainly written in c/c++. Most OS code is written in C/C++. On the application side, if you are into games, they are generally written in c/c++. Anything that needs high performance and or low memory is a good candidate.
I've used Gsoap, a c++ soap client implementation for a web service that got HUGE traffic.
Most desktop/console applications with a bias toward graphics rely heavily on C++. This includes CAD software and AAA video games, among other things.
Related
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 1 year ago.
Improve this question
I've been writing software in Java for many years now, but it was always for internal applications that would be deployed to a server. I'd like to get into writing desktop applications now but I don't know where to start. I've written a few Java/Swing applications but again they were for internal use.
My understanding is that Java and other semi-compiled and interpreted languages are too easy to reverse engineer, making them unsuitable for commercial software. I am aware that there are compilers for Java and some other interpreted language, but I've also heard that they are pricey and/or unreliable.
Assuming I start a microISV and wish to develop and sell applications to a broad audience, what's my best bet? I would prefer something that can be written close to once, and compiled for different operating systems but I am not opposed to .NET and a Windows-only audience if other languages would compromise the experience (installation ease & user experience) in Windows. My only issue there is that I don't have a large starting budget and paying out the wazoo for the required development tools is not really in the cards.
Why would people want to reverse engineer your software? They might pirate it, but you can't prevent pirating no matter what language you use. I doubt you have a top-secret algorithm that you're trying to hide either, in which case reverse-engineering might be an issue.
You should go with whatever you know best, and Java can work just fine.
If you are intent on switching to another language, I recommend taking a look at Qt. Qt is a free and open-source cross-platform toolkit for C++ that allows you to write applications in that will compile and run on Windows, Mac, and Linux with minimal effort. You CAN write commercial software for free with Qt with its LGPL license.
Edit: GCJ compiles Java to native code, but only supports Java 1.4.
Well, if you're trying to be an Independent Service Vendor -- and not a Software Vendor -- then in a sense it doesn't matter if you use a language like Java which can be decompiled. Because you'd be selling yourself as the best person to integrate and customize the software for your clients. The software is the delivery mechanism for the thing that will actually make you the money: you and your skills. Plenty of companies make a profit by giving away their software for free and contracting their services to set it up for their clients. You can mitigate the Java decompiling issue somewhat by using an obfuscator, but it's kind of fighting the wrong battle.
If you intent to make your money selling software and not service, then Java would be a relatively risky route to take.
It all depends on your business plan.
If you are starting a one-man company, then you are selling your personal expertise. So the language you use must be the one (or maybe two) that you are most familiar with and expert in. I'm surprised you felt it necessary to ask this.
Any code can be decompiled to some degree. I think you can obfuscate Java to a degree that will deter the casual user... but I think the other people hit the nail on the head. Of all the reasons not to use Java, the ease of decompiling should be very very low on your list. If that is all that is stopping you, go for it! Google Java obfuscater and you will find something.
I'm skeptical about the risk of reverse engineering a complex piece of software written in Java, but for purposes of your question I'm willing to stipulate it. I assume the same issues rule out any other language that is implemented only on the JVM.
The most salient aspects of Java are
Static type system
Class-based object system
Automatic memory management
No freestanding functions or modules outside the class/interface system
Generics
This combination could be replicated in a language like C#, but I assume the same objections you have about distributing JVM bytecode also apply to MSIL bytecodes.
I'm having a hard time coming up with a language that has all these features. Here are some nearby languages:
C++ has everything except automatic memory management, plus it allows freestanding functions. However the C++ generic mechanism (templates) is not for the faint of heart, and it doesn't (yet) support modular typechecking. Lots more flexibility than Java but also lots more ways to shoot your foot off. Use with caution.
Modula-3 has all of the above but it's essentially a dead language, plus like C++ there's no modular type checking for the generics.
I'm not familiar enough with Eiffel to be able to make good comparisons, but I think it's worth looking into.
Delphi may also be worth looking into. It seems to have everything above except generics. It's primarily a proprietary Windows environment (formerly known as Object Pascal), but there seems to exist an open-source 'Free Pascal' compiler that supports Delphi.
There are many object-oriented languages with automatic memory management and dynamic typing, among which one might highlight ruby, Python, and Smalltalk. None of these really compiles well and reliably to standalone native machine code, although all push toward some form of experimental compilation. And they are all dynamically typed, which is quite different from what you're used to.
If I were in your position I would probably go ahead an use Java and accept some risk of reverse engineering. Decompilers aren't as wonderful as you might think, and they don't produce wildly maintainable code, either. But if you really want to be able to produce native machine code, I would investigate Delphi and Eiffel. (I myself would use Modula-3, but that's because I once invested substantial effort in learning it. It's a very well designed language for its niche, but the user community is about gone and I think it's a dead letter. Pity.)
I'm a Python programmer who knows a bit of Ruby and PHP as well. I don't really know enough about Java to do anything meaningful, and I certainly don't know C, C++, or other low-level languages. I've heard all the "Who cares about speed because hardware is cheap, but coders are expensive" arguments, and I'm not trying to raise a debate here. I want to understand 2 things about the community of lower level programming languages (whether it's C or even assembly):
What is the main reason you choose to still use it (job requirements, speed, desktop vs web, etc)?
Is it still worth me taking the time to learn C++ (monetarily speaking) or others this late in the game, or will I benefit?
Also, consider the benefits / disadvantages of dynamic vs static typing, when choosing your reasons. I primarily program for the web, but don't take that fully into consideration because it's partly due to the fact that the web is all I know.
Unashamed Fortran programmer here. Speed speed speed. Oh, and all the scientists I work with are reasonably fluent in Fortran. But then I work in computational electromagnetics on large clusters and supercomputers and wouldn't recognise a web application if it leapt up and bit me on the nose.
I wouldn't regard Fortran as low-level or less-expressive, I think it's a DSL for linear-algebra and more general number-crunching. So why did I take the bait and respond to this question ?
Dynamic vs static typing ? Static please, everything tied down at compile time so the compiler can work its socks off optimising.
For a web programmer, C/C++ will offer you virtually no advantage. It is less expressive than Perl, Ruby, Python, etc. and requires more code and attention to detail of memory management. Unfortunately, choosing a language for its "features" is often second to choosing for its platform. C++ isn't as clean and elegant as C#, most of that comes from its C compatibility. Sadly, even though there are better languages for certain things, most aren't compiled and most aren't widely supported.
If you plan to develop a commercial product that the customer will download or receive on CD, then C/C++ offers you protection of your Intellectual Property (hard to reverse engineer), and a small runtime footprint, as well as ability to target older platforms like Windows XP.
It is not too late in the game to learn C/C++. C/C++ will be around as long as all the higher level languages are around, because those languages are implemented in C/C++. It is not as if we will all move to Python one day and C/C++ will be retired. High level, non-compiled languages are not self-hoisting, so they cannot exist without C++.
It is the tool to use if you are going to implement higher level things like languages, APIs, toolkits, drivers, IDEs, etc. But C++ is not the tool to use if you want the fastest way to develop an internal GUI app or a Web app.
Just learn the tool for the job. If the job changes, or you wish to change the job, then you may want to push yourself to learn C++ to see the other side of the Computer Science world, the side between the CPU and what you currently write your web apps in.
I'd think the big three reasons here are going to be Performance, Legacy System Support, and Embedded Development.
So mega subjective it renders any answer next to useless.
For the numerical calculations I do writing straight C++ is just faster than using e.g. straight Python. Sure, I can interface my C++ libraries to higher-level languages (and I do), but since most of my work is done on the low-level numerical side, I wouldn't gain too much.
Also consider that a lot of libraries especially in scientific computation are in FORTRAN, C or C++ and linking against them from C++ is much faster (especially if you just want to get done with it) that creating wrappers and interfaces all yourself.
If you would gain anything from learning a low-level language depends a lot on your problem domain.
There are several good reasons for lower-level languages.
First, there's a lot of applications where performance does matter. The main application I work on is slow enough as it is (it does a whole lot of things), and would be unusable in Python.
Second, there are applications that require standalone executables that aren't all that big.
Third, there's a tremendous amount of legacy code in C and C++, and it isn't going away any time soon.
Fourth, operating systems are normally written in C or C++ or similar languages, and expose APIs in them. If you need to get chummy with the OS, for whatever reason, you're better off using the OS language.
Dynamic typing is very clearly better for getting an application up and running fast, and my Lisp background pushed me to believe that static typing is normally just premature optimization. However, lots of people believe that static typing is much better for enforcing correctness in large projects, and C and C++ are well suited for large projects.
For your second question, I have no idea what you want to do in the future, so I don't know if it would be worthwhile for you to learn C++. For professional development, I'd strongly suggest learning a variety of languages, including C or a similar language. There are other questions on SO about what languages to learn.
Why aren't Python, Ruby and PHP written in itself?
Mission critical applications need best possible performance and algorithms and doesn't need things like metaprogramming.
C++ has some great ideas and libraries, which I then found in those modern languages, sometimes better sometimes worse (compare power of templates in C++ and generics in Java).
Low level languages will make you learn something more about lower level abstractions of the computer, operating systems or networks.
Static restricts you in programming and often makes you write out the types, however it also let's you better express your intent in a way, which is automatically provable by compiler and you can get support for tools. Dynamic gives you free hands, you can do more and maybe easier, however you have to test better.
I may be misunderstanding you here but it sounds like you're under the impression that C++ is the appropriate language for every kind of project. It isn't. You wouldn't use a Liebherr truck for a cross country road trip. Every popular language in existence got that way because it works well for some situations. There was a time when C++ was used to write web applications which quickly gave way to Perl scripts because the trade-off between production and performance. So in response to your first question, mainly people still use it because in certain situations it's the best tool for the job.
As far as whether or not you should learn it, I say if you have the time and the desire go for it. Even if C++ is never the correct tool for any of the projects you take on a decent understanding of concepts that are necessary in C++ will make you a better developer in every language.
We are currently developing carrier grade telecom applications in C++, Rational Rose and Java to run on an embedded platform based on Enea OSE which provides interfaces for the above three languages (actually C, Rose and java).
I'm interested in increasing the productivity by choosing other more productive languages. I would like your opinion on what languages I should consider. Pretty much it either has to be able to be compiled to run directly on a PowerPC processor or compiled to Java byte code.
These applications probably has to be supported for 20+ years so maturity and (linux based) tools support (debugger, static and dynamic analysers like lint and purify in the C world, profilers, eclipse plugins etc) is paramount. The applications does not have any hard time or memory constraints but efficency is a plus.
What languages would you guys suggest? Are any other languages up for the challenge?
Depends on your goals.
For long term support and maintainability, you're probably not going to beat Java.
For productivity--that's a bit of a question.
Since the telcom industry is fairly heavy into testing and process, reducing your number of lines of code isn't really the thing that will speed you up.
If you have a Very Smart Group, you might consider Scala since it's 100% Java compatible and has a lot of advanced features, but the problem with that is you are counting on having Scala developers in the future.
I don't know, overall I'd say doing a smart Java design would be a lot more helpful than another language. Perhaps patches of Groovy as a scripting language in places where that is appropriate.
If you're willing to live on the cutting edge, you may want to take a look at Clojure.
Runs on the JVM
Fully compiled, so you can get pretty decent performance (I'm confident enough to be writing a game in it!)
Designed for concurrency from the ground up
Functional programming - extremely productive with great support for powerful LISP-style macros, lazy evaluation, tools for implementing DSLs etc.
Integrates very well with Java - to the extent that I mix Java and Clojure files in the same projects in my Eclipse environment, and there is effectively zero overhead calling back and forth between Clojure and Java. This is extremely important for me as I have a lot of Java code that I'm not planning to rewrite any time soon!
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 4 years ago.
Improve this question
I didn't find any useful information about programming languages for real time systems. All I found was Real Time Systems and Programming Languages: Ada 95, Real-Time Java and Real-Time C/POSIX (some pdf here), which seems to talk about extensions of Java and C for real times systems (I don't have the book to read). Also, the book was published in 2001, and the information may be obsolete now.
So, I'm dubious whether these languages are used in real world applications, or if real time systems in the real world are made in other languages, like DSLs.
If the second option is true for you, what are the outstanding characteristics of the language you use?
I am an avionics software engineer.
I was able to participate in several development projects.
The languages I used in those projects are: C, C++, and Real-time Java.
C is great.
C++ is not so bad but C/C++ require strict coding standards for the safety considerations such as DO-178B.
I think Real-time Java is the way to go but I don't see many avionics applications, yet.
Korean jet trainer T-50 will have a mission computer running RT Java application serving HUD and MFD displays, and all of the mission critical functions.
The Real-Time Specification for Java now has several commercial-grade implementations:
Sun's JavaRTS
IBM's WebSphere Real-Time
Aonix PERC
aicas JamaicaVM
Apogee Aphelion
These products span the continuum from compilation to native code (Aonix) to J2ME (aicas, apogee), to full J2SE (Sun, IBM). Most, if not all, have seen deployments in small numbers of safety- or mission-critical systems, but momentum is building. Examples include Eglin AFB's space surveillance radar modernization and the US Navy's use of RTSJ in the DDG-1000/Zumwalt destroyer. Sun also claims deployment in the financial transaction processing domain.
If you are interested in RTSJ, I suggest Peter Dibble's Real-Time Platform Programming, or Professor Wellings' Concurrent and Real-Time Programming in Java.
On a related note, there is also work underway to provide a Safety-Critical profile for the Java programming language, built as a subset of RTSJ. Also, an expert group has formed to explore a Distributed RTSJ DRTSJ, but the work is stalled.
The book covers use of Ada 95, the Java Real-Time System and realtime POSIX extensions (programmed in C). None of these is directly a domain specific language.
Ada 95 is a programming language commonly used in the late 90s and (AFAIK) still widely used for realtime programming in defence and aerospace industries. There is at least one DSL built on top of Ada - SparkAda - which is a system of annotations which describe system characteristics to a program verification tool.
This interview of April 6, 2006 indicates some of the classes and virtual machine changes which make up the Java Real-Time System. It doesn't mention any domain specific language extensions. I haven't come across use of Java in real-time systems, but I haven't been looking at the sorts of systems where I'd expect to find it (I work in aerospace simulation, where it's C++, Fortran and occasionally Ada for real-time in-the-loop systems).
Realtime POSIX is a set of extensions to the POSIX operating system facilities. As OS extensions, they don't require anything specific in the language. That said, I can think of one C based DSL for describing embedded systems - SystemC - but I've no idea if it's also used to generate the embedded systems.
Not mentioned in the book is Matlab, which in the last few years has gone from a simulation tool to a model driven development system for realtime systems.
Matlab/Simulink is, in effect, a DSL for linear programming, state machines and algorithms. Matlab can generate C or HDL for realtime and embedded systems. It's very rare to see an avionics, EW or other defence industry real-time job advertised which doesn't require some Matlab experience. (I don't work for Matlab, but it's hard to over emphasis how ubiquitous it really is in the industry)
Real time applications can be made in almost any language. The environment (operating system, runtime and runtime libraries) must however be compliant to real time constraints. In most cases real-time means that there's always a deterministic time in which something happens. Deterministic time being ussually a very low time value in the microseconds/milliseconds range.
Real time systems depend solely on this criteria, as the specificiations usually say something like 'Every x (period of time) (do something | check something)'. Usually this happens if the system interfaces with external sensors and controls life-saving or life-threatening systems.
I was working on an in-car navigation and infotainment system developed mostly in C/C++ with an operating system configured specifically to meet the real-time constraints to provide real-time navigation and media playback.
But this is not all to real-time systems: Usually the selection of algorithms in the entire system is made to have deterministic runtimes according to the Big-O notation, mostly using linear or constant time. Everything else is considered non-deterministic and thus not useable for real-time systems.
All of the real-time systems I have worked with were predominantly written in C with some bits of assembler, or written mostly in assembler with little bits of C. (Depending on whether we're talking the 90s and beyond, or the 80s, respectively.) However, some of the real-time systems I've worked with have used -- not exactly DSLs -- special homegrown code generators.
Real-time oriented language?
What is real-time
First we have to define what real-time mean.
Of course depending on how your tool will work against the physical environment pure real-time couldn't be effectively done, mostly because there will be a lot of third party dependencies.
If you are building embed stuff by using microcontrollers like arduino, the language to use will be limited by the hardware, but with more complex stuff like Raspberry Pi, the language choice is very wide.
Granularity
This is depending on what you are measuring, if you're working with:
weather temperatures, one read each 10 minute could be enough
people height or weight, one or maybe four read by day
server status, between 1 second for fine debugging to approx 1 hour for quiet unimportant secondary server.
atomic collision count: something finer...
Event based reading
The right (better) way for collecting data is based on value change event... whenever the device do permit it.
Your tool have to not poll values from device, but the device have to send values to your tool, when they change.
This could be done by using an hardware interrupt trigger or by using port protocole like RS-232 staying listening on some serial port, for sample.
Monitoring environment
The last thing to be warned is how legitimate user will interact with.
If you're building embed standalone device, like robot, you may use graphic libraries to interact with touch screen.
If you're building web based monitor, you may have to keep in mind that the client could be an old 800x600 monochrome screen, using poor internet connection and small processor... But depending on final goal if you may interact with clients, you could ensure strong hardware and strong internet connections. Anyway you have to watch for connexion loosing and event for communication delay between server and client. There is mostly third party dependencies.
Which programming language?
From there, the language choice is wide and clearly depend on
your knowledge.
granularity requested (by using event-based too, of course)
the amount of time you have to build the tool (money;)
delay, co-workers...
kind of device
kind of monitoring
some other political reasons
You could build real-time monitoring engine by using bash and sql only, I've seen sophisticated engines that was built under postgresql only... I've personally built a web based, solar energy monitor by using perl, mysql and javascript.
I cannot believe no one has mentioned LabVIEW programming language which is widely used for Real-time safety-critical systems. It has extensive libraries and well-known design patterns for architecturing and implementing for RT systems.
Also National Instruments makes various hardware (cRIO, PXI and etc) which are designed for real-time applications.
We use LabVIEW for Fracking (Hydraulic Fracturing) which is used in safety-critical environments.
PLCs run ladder and fbd code which is really a real-time dsl in the sense that your options are so limited that it is difficult to program in a way that would result in unpredictable runtime performance
A really purposeful application of the C language to real-time programming - and all related issues (such as parallel programming) - is offered by my Kickstarter
http://www.kickstarter.com/projects/767046121/crawl-space-computing-with-connel
It is called "Wide Programming" and I've been doing it most of my life. The rewards include a software library and a book - designed to be useful.
the company I've been working for since 2003 has been developing and deploying a Scada/Mes platform. Original implementation started in 1993, used Modula2 on OS/2. Later (1998) it was ported to Ada95 and Windows. Currently (2019) we use Ada compiler by AdaCore. Our system was ported and has been deployed to 32/64 Windows, HPUX, OpenVMS (and lately even to Raspberry). We have multiple installation in central Europe (gas industry, refineries, factories, power plants).
We feel Ada's features give our system a high degree of reliability and prevents a lot of errors that would easily occour if we used languages like C.
See also my blog
https://www.ipesoft.com/en/blog/what-language-is-the-d2000-written
This is probably more of a subjective question, but which language (not API like .NET or JDK) would you use should you write your own operating system? Which language provides flexibility, simplicity, and possibly a low-level interface to the hardware? I was thinking Java or C...
C, of course.
Haskell.
Once you have flipped the right hardware bits, C is a terrible language to use for the rest of the OS. Things like the scheduler, filesystems, drivers, etc. are complex high-level algorithms, and you don't want to be writing those in assembly language (or C; same thing). It's too hard to get right. (The VM subsystem and memory manager may need to be written in something low-level, as you will need to bootstrap your high-level langauge's runtime somehow.)
Anyway, this isn't just a crazy idea that I am coming up with for SO. Here is an OS written in Haskell: http://programatica.cs.pdx.edu/House/
Lisp is another good choice; the original Lisp machines were infinitely more tweakable (at runtime) than "modern" OSes like UNIX and Windows.
Sometimes history forgets good ideas (often in the name of "maximum performance"), and that makes me sad.
D would be an interesting choice. From its own description:
D is a systems programming language. Its focus is on combining the power and high performance of C and C++ with the programmer productivity of modern languages like Ruby and Python. Special attention is given to the needs of quality assurance, documentation, management, portability and reliability.
The D runtime assumes the existence of a garbage collector, which would not be appropriate for the very lowest levels of the kernel. However, it would be appropriate for many of the higher layers.
Build the basic components like task schedulers and drivers etc with Assembly, then build the higher level components like applications and tools with C
I believe this is how Windows XP was built too (unsure about Windows Vista and Windows 7).
Definitely... C
C, ASM, C#
Singularity
Low-level in something like Haskell or D. Productivity over performance, in my opinion. You can rewrite slow parts in C++ or even assembly later if the need arises.
High-level in Python or Ruby. Ideally I'd also have a really fast JIT-capable VM for that language, but that's not going to happen for either language for a while. Lua would be a good alternative if speed gets in the way.
The kernel has to be written in a low-level language, C is by far the best choice for this, because it is so memory efficient. The higher levels could be built with a combination of Java or more ideally Objective-C, and scripting languages like python and ruby, or lua.
Honestly, I would either use C or some hierarchy of languages that I had either designed or fit together completely seamlessly. What I would be looking for is a seamless experience that starts at the bare metal level and then I could move to higher and higher level languages as I moved up the problem space. I would probably chose something like:
C - for bare metal stuff like drivers, kernel, etc
Java/C# - for application-level things like administration consoles, OS apps
Python/PowerShell - for scripting activities like common administrative tasks (creating a new user, etc)
Personally, I think C/C#/PowerShell is more tightly integrated and the type of experience I'd be looking for. Of course, if I ever got so ambitious as to write an OS, I would have a lot of spare time on my hands and would probably really enjoy tackling the language stack first. So maybe it would be L/L#/LScript ...
BitC seems to have this in mind. Despite it's name it seems to be the midpoint of assembly language and lisp. The goal was to make a language with a strong correspondence with machine language but have an intermediate representation that supports stronger correctness inferences than is possible with most other common languages. The languages was created as part of the Coyotos project, an operating system with lofty goals of security and reliability. Formal verification is made significantly possible with the ir used in BitC.
Ada:
Ada is a structured, statically typed, imperative, and object-oriented high-level computer programming language, extended from Pascal and other languages. It was originally designed by a team led by Jean Ichbiah of CII Honeywell Bull under contract to the United States Department of Defense (DoD) from 1977 to 1983 to supersede the hundreds of programming languages then used by the DoD. Ada is strongly typed and compilers are validated for reliability in mission-critical applications, such as avionics software.
Ada, because it was not only specifically developed for such projects, but it also provides support for several very useful high level features (such as support for strong typing, concurrency and abstraction) that are simply not available in standard C.
So that, even as a project grows, you don't have to work around language limitations (think encapsulation, abstraction, namespaces in C).
Don't get me wrong, C works obviously for a great many of projects, but once a project has gained a certain size (think Linux kernel, gcc, GNOME), you will inevitably appreciate certain features of more high level languages to make the development process less tedious and also less obfuscated.
In C however, these features usually end up being -pretty poorly- emulated by excessive and almost pervert use of the pre-processor (this can for example be seen in the gcc code base), so that you get to see lots of nested macros, that from an implementation point of view, actually emulate features found in other programming languages.
In addition, Ada is the only programming language, that I am aware of, that actually provides standardized support for source code analysis using the ASIS, having such a facility in place is however the prerequisite to actually be able to maintain and transform/re-engineer a code base in the long run (think refactoring).
Having an interface like ASIS available, means that you can actually implement "semantic patching", where you can automatically rename a file, function or variable/data structure and it will actually work.
Java ?? no jave runs on a virtual machine which needs an os to run on top of ,
maybe C and some ASM ;)
I would go with D to see whether it can do it.
I would only pick the following 3 out of practicality.
C (good old fashioned)
C++ (C with stuff tacked on. Windows is partially written in this)
Java (the medium level language that just might have a capable garbage collector with controllable pauses with G1).
If I were going to start a new OS I'd do it with the subset of C++ recommended by the embedded industry. You can use things like classes and use it "as a better C" and be just as fast. Just avoid things that have massive overhead. You can even use some template features, if you stick to a certain subet that basically don't have any overhead. Look on embedded.com for features in C++ that have little to no overhead, but will allow you organize your code better than you ever could in C.
Oberon? I guess I miss Pascal too much some times. C paid the bills for quite a while, but I don't really love it.
Lisp of course!
Title text: Some say the world will end in fire; some say in segfaults.
For an OS, you want speed at the lowest levels. So assembly, C, C++, Objective-C, or Java seem to be the current choices. Although it's just recently that Java got fast, and it's hard for me to imagine an OS with garbage collection.
If I were writing my own, it would be a mix of assembly and C.
A C or C++ microkernel with a JIT for a highly dynamic language like Ruby or maybe a language with native support for the Prototype pattern. Even device drivers in that language.
Not because it's practical but because it's really cool. Cool in the way that NeXTStep was cool for using Obj-C for pretty much everything.
http://www.dwheeler.com/sloc/redhat71-v1/redhat71sloc.html - share of languages in Linux's source code.
C, by a number of reasons. Other candidates, like D, are great. However, C has this advantage: there's a lot of available open-sourced C code that you could reuse in your project (much more than is for other languages appropriate for system programming).
I would be torn between using some existing low level language and write my own based on C# but with much better generics support.
In second case I would make each method generic, but all the constraints will be resolved by compiler - to allow "duck typing" like in Scala but still language should be static. Also static virtual methods would lower the codebase.
I've had that idea for a long time, but it never seems to be doable in real timeframe, so who knows maybe in the future. :-)
Some would say Java.
Note that openfirmware is written partly in Forth, and it's very low level.
Have an open mind.
"The kernel has to be written in a low-level language, C is by far the best choice for this, because it is so memory efficient. "
Um... What about FORTH?
FORTH can be low level and high level, so you could have a whole operating system written in FORTH from the ground up, and still have a nice easy REPL scripting environment on top, also in FORTH.
However, any decent operating system should support lots of langauges on top, from C all the way to Python Ruby and Javascript. Making FORTH the basis for it all has a lot of benefits though.
edit: I'd only ever attempt this for an embedded environment with a single known hardware set. Trying to write an OS that could compete with Linux or Windows is a fools job.
If this isn't a hypothetical question, and you're looking to create your own OS, I'd probably go with C because most of the examples out there are written in C.
Also, (And I haven't build an OS yet so take this with a grain of salt), I'm thinking that the c runtime libraries would be a lot easier to port to your new OS than say .NET.
Pascal + Oberon: they have the power of C and C++ but they're not as daunting to use. Both these languages are grossly under appreciated.