Shlomi Fish has written a new essay titled "When C is the Best? (Tool for the Job)". Its theme is giving several reasons (besides high speed and low memory consumption) why some code should still be written in C.
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Member since:2005-06-29
C code should function the same on different architectures if you mind your types...
It's only when you get into things that aren't really within c's logic you get into trouble: Using ints as pointers, using shift operators, and writing asm sections.
As long as you are on a "c machine" and since Lisp machines seem to have dissappeared (physically speaking), I think you can be pretty sure you'll be on a "c machine."
Developers are conservative because they don't like menial tasks like porting that c code to the latest fad language. It's not perfection you need in a language, it's having it still be there in 10 years that you need. (Not to mention all the other important stuff, like not sucking so bad you can't do anything in it).
I'd say that code written in a portable language is portable.... It sort of "inherits" its portability from the portability of the compiler/runtime/machine. The trouble is that a lot of c code is written with a specific machine in mind, and that machine wasn't the c machine it was say Intel x86. So they did nice things like assuming sizeof *int == sizeof *(char *). Or assuming that int x = 1; x = x >> 48 would equal x >> 16.
Member since:2005-07-06
As long as you are on a "c machine" and since Lisp machines seem to have dissappeared (physically speaking), I think you can be pretty sure you'll be on a "c machine."
Good Lisp implementations have existed for both Lisp machines and C machines. Good C implementations have never existed for a Lisp machine. What does that say about C's vaunted portability? You're basically saying: C is portable as long as you only try to port it to machines designed for C. Duh. Does that mean it is portable, or does that merely mean that it's so popular that most machines are designed for it?
Member since:2005-08-08
Member since:2005-07-07
Illusion ? It is the most portable language (of course, by portability we mean source code portability).
It's portable as long as your program only does portable things, like text processing and math.
However, C is a portability nightmare when it comes to things like networking, graphics, and several other things. Additionally, people talk about C like there's only one version of it. There are in fact several, the most popular of which are K&R, ANSI C 89, ANSI C 99, and GNU C. Yes, GNU C does add its own extensions, and yes programmers do use them. (It is possible to have vendor lock-in in open source, it just isn't as big of a problem when it happens.)
C is also unportable during the act of compiling and linking. There are several different C compilers that use different command line options. Commonly used C libraries can be placed in any number of locations and given any number of names on people's computers. That's why we have the mess that is the GNU autotools.
Member since:"Most portable language"?!? You know how easy it is to get endianess wrong or to use non-portable libraries in C (yes that's source compatibility even)? Now compare that to java or c#, or look at all the apps for ms-windows that can't/won't be ported to linux/unix and then look at all the java apps that run out of the box on linux, macos/x and windows.
Member since:Code portability with C means to the same compiler on a different platform. C Compiler compatibility is a different matter. Each compiler seems to have its own features and quirks which can cause the same C code to behave differently depending on which compiler it was compiled with (assuming it will compile the foreign code at all). And then of course there are platform dependencies in the actual code which are hard to avoid because nothing shields you from the system specific hardware and system specific libraries except programmer discipline.
Java has the advantage of a well specified language (unlike C), well specified run-time environment (unlike C) and well specified APIs (unlike C). The behavior of Java programs on different implementations of the run-time engine and compiled with different versions of the compiler against different implementations of APIs is well defined: anything deviating from the spec may be considered a bug. So you can can compile with the ibm compiler on AIX and test on webshpere, run on the sun jvm on solaris and jboss or use Jrockit to run it on win32 with bea weblogic. If any of this requires code changes you have encountered a bug in either the compiler, run-time environment or the API implementation. The before mentioned application servers are known to have interoperability issues due to different implementations of the huge amount of APIs they support.
Hopefully you'll understand that source portability is probably pretty damn close to perfect. Most of the portability problems of java programs from one platform to another are caused by api portability problems. For example the oracle implementation of the servlet API is on paper equivalent to the apache tomcat implentation. Indeed many applications that use this API run fine on both, but not all. The reason is that oracle did nog quite get all the semantic details right in their implementation. If you depend on the correct behavior of some of these things, you will encounter problems.
The problem isn't any different if you compare the SUN linux jvm and the win32 jvm. Indeed most of the java code of the library is identical for both platforms (no problems there). The native code it depends on however is not. A considerable part of the java API has been designed to cover up for native code portability issues (graphics, io, processes & threads). Sometimes it fails to do that properly and that's when you encounter problems porting java applications from win32 to linux or vice versa.
Official Apple statement on PRISM and privacy: "Regardless of the circumstances, our Legal team conducts an evaluation of each request and, only if appropriate, we retrieve and deliver the narrowest possible set of information to the authorities. In fact, from time to time when we see inconsistencies or inaccuracies in a request, we will refuse to fulfill it." This is basically Apple re-publishing their earlier statement in a more official manner. You either believe it, or you don't.
The open source Contiki operating system and its commercial Thingsquare distribution are making strides towards the connected home. According to a Computerworld article, a new LED light bulb manufacturer is putting small computers into their light bulbs. Each computer runs the Contiki OS, which gives each bulb an IP address and allows them to be controlled with a smartphone application. To connect the bulbs to the application, the bulbs use both Wi-Fi and the much lower power IEEE 802.15.4 mesh technology.
"Google asked the secretive Foreign Intelligence Surveillance Court on Tuesday to ease long-standing gag orders over data requests it makes, arguing that the company has a constitutional right to speak about information it's forced to give the government. The legal filing, which cites the First Amendment's guarantee of free speech, is the latest move by the California-based tech giant to protect its reputation in the aftermath of news reports about sweeping National Security Agency surveillance of Internet traffic." Draining the ditch after the cow has drowned in it."I can't find one person who has been using the Nexus 7 for an extended period of time, and hasn't seen a massive downgrade in performance. Just what kind of downgrade are we talking here? I cannot pick up my Nexus 7 without experiencing problems like a lag of ten seconds, or more, just to rotate the display; touches refusing to acknowledged; stuttering notification panel actions; and unresponsive apps." Fully and utterly agreed. My Nexus 7 was blazing-fast and awesome for a few months, and at some point, it just started sucking. Just like that. I've tried loads of ROMs, and nothing helps.A new release of the hobby operating system MenuetOS! The release notes are a bit non-descript, but you'll have to take what you can get: "updates and improvements (picview, httpc, ehci, ...)"."The Internet is one of the most transformative technologies of our lifetimes. But for 2 out of every 3 people on earth, a fast, affordable Internet connection is still out of reach. And this is far from being a solved problem. There are many terrestrial challenges to Internet connectivity - jungles, archipelagos, mountains. There are also major cost challenges. Right now, for example, in most of the countries in the southern hemisphere, the cost of an Internet connection is more than a month's income. Solving these problems isn't simply a question of time: it requires looking at the problem of access from new angles. So today we're unveiling our latest moonshot from Google[x]: balloon-powered Internet access." Insane.
"MineAssemble is a tiny bootable Minecraft clone written partly in x86 assembly. I made it first and foremost because a university assignment required me to implement a game in assembly for a computer systems course. Because I had never implemented anything more complex than a 'Hello World' bootloader before, I decided I wanted to learn about writing my own kernel code at the same time. Note that the goal of this project was not to write highly efficient hand-optimized assembly code, but rather to have fun and write code that balances readability and speed. This is primarily accomplished by proper commenting and consistent code structuring." Just cool.
Jon Rubinstein, former CEO of Palm: "Well, I'm not sure I would have sold the company to HP. That's for sure. Talk about a waste. Not that I had any choice because when you sell a company you don't get to decide that. Obviously, the board and shareholders decide that. If we had known they were just going to shut it down and never really give it a chance to flourish, what would have been the point of selling the company? I think the deal we had with Verizon really hurt us, but who knew that at the time? These things are all hindsight.""And so it is with Dell's Alienware X51 R2, a small form factor gaming PC in console digs. It's shaped similar to Microsoft's Xbox 360 Slim, and though it's slightly larger than either a 360 or PlayStation 3, the X51 R2 would be right at home in a living room setting nestled next to a large screen TV. Indeed, it's adept at running Steam's Big Picture mode, and if your primary objective is to play games in the living room, go ahead and consider the X51 R2 a hybrid game console." This is obviously not the only machine like this - still, these are very valid console alternatives even for those that don't like being hunched over with a cramped WASD-claw. Also, PC gamers among us: could you get away with the $699 model for gaming?
From Bloomberg: "Microsoft, the world's largest software company, provides intelligence agencies with information about bugs in its popular software before it publicly releases a fix, according to two people familiar with the process. That information can be used to protect government computers and to access the computers of terrorists or military foes." The lid has officially been blown off.
Member since:
All the time, we hear repeated that C is portable. This is a misnomer. It gives the wrong impression that identical code will work in the identical way on different architectures. It's not the PROGRAM that is portable, it's the LANGUAGE. It was abstracted so that programs could be written using the same language constructs on different machines; so that you as a programmer could immediately get familiar with another environment on another system; because the compiler was easy to port. But not that the compiler, or your program would give identical results.
This to my mind is one of C's greatest weaknesses - this illusion of portability.
There is a reason for C's longevity. But it's more due to the innate conservativeness of the internal computing world, which is paradoxical given the radical changes IT has brought to the external world, than any inherent strengths in C itself.
Geoff Gigg