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Learn C

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Re: Learn C

#101

Post by norswap »

pjmlp wrote: post #53
kmm wrote: post #21

Earlier quoted context omitted.

Was there any study done to the (un)reliability of C? I know for a fact practically every piece software I use is programmed in either C or C++. The sole exceptions are Anki and Gentoo's portage system, both Python. And I'm pretty sure the reason portage is so extremely slow is because it is in Python (I've checked, it's not I/O-bound). And Anki is some very unreliable software. In fact, give me a single big desktop…

Just three, ask for more if you wish: The original version of Skype was done in Delphi. The first versions of Mac OS were done in Apple Pascal. Photoshop was originally done in Apple Pascal.

It's all "original" and "first versions", which kinds of strengthen the op's point.

Re: Learn C

#102

Post by betterunix »

com2kid wrote: post #54
betterunix wrote: post #33

Earlier quoted context omitted.

I think the disagreement we have may stem from our notions of what constitutes "fundamental computing concepts." I rank the lambda calculus much higher than C or assembly language when it comes to that. I would say that knowing your data structures and how to analyze algorithms asymptotically is vastly more important than knowing how code is being executed at a low level. Even for the cases where low-level code must…

> There is no particularly good reason for C to be anywhere in the software stack; Really? Not anywhere? Who is handling your hardware interrupts? How is your keyboard and mouse input being handled? What about your video card drivers? Now I will grant that you can bootstrap an initial run time in assembly and place your favorite high level language4 on top of that, if you add extensions to your favorite language to b…

As you said, there is no reason you cannot bootstrap in a high level language. Operating systems were written in Lisp at one time; they had device drivers, interrupts, etc.

My point is not that C is not used, but that there is no compelling technical reason to use C anywhere. The fact that Lisp and ML do not have standardized features for low-level operations is not really much of an argument. We could add those features, and we could do so with ease (CMUCL and SBCL already have low-level pointer operations and a form of inline assembly language); the only reason we do not is that nobody has time to rewrite billions of lines of C code, or perhaps more that nobody will spend the money to do such a thing. The existence of C at various levels of the software stack is a historical artifact, primarily a result of Unix having been written in C and OSes written in other languages having been marketed poorly.

The lesson is not that C is good for writing low-level code; the lesson is that technical features are not terribly important.

I would also point out that an OS is not just about interrupt handlers and device drivers. Most of an OS is high-level code that is connected to interrupt handlers and device drivers through an interface. Even if C were the best language in the world for writing low-level code, I would still question the use of C elsewhere (imagine, as an alternative, an OS that follows the design of Emacs -- a small core written in C, the rest written in Lisp).

Re: Learn C

#103

Post by zeeshanl »

mimog wrote: post #76
zeeshanl wrote: post #32

Earlier quoted context omitted.

As a person with a masters in music, a bachelor in film, and now programming for a living, I def. believe that having a persistant interest in learning about those "fundamental software concepts" is what makes such a gig achievable, especially if you keep doing the extra work in your spare time (like taking Dan Grossman's unbelievable Programming Languages class or going through Zed's LCTHW).

Given that you have a masters degree in music I would wager it would take me a very long time to get to your level in playing, writing and understanding music. It's doable of course, but I would have a lot of learning and work ahead of me. I think the same would apply to you catching up to someone having a masters degree in computer science or related fields.

I don't have a high opinion of my musical abilities :), but I agree that catching-up is both a doable and daunting process.

But, finding niches of interest to focus on usually helps, as it does when crafting really good songs in a specific style, one that matches your musical abilities and understanding. You may not have the chops, but you can still create amazing work.

With programming, I have the issue of wanting to catch up on everything and do side-projects (eventually, I'll run through this class => http://faculty.cs.byu.edu/~jay/courses/2012/fall/330/course/...), but I have found success in trying to pick-up things in conjunction with a task at hand. If I have to build a web service, I'll start that research simultaneously. Starting IOS work... then spend time with C, understand Objective-C's runtime, read about the history (and play around with Smalltalk). This piece-meal approach seems to make the jump more "doable" in my opinion.

I think that people without a CS degree can obtain a good, challenging gig if they have a good niche to school themselves in, and of course, pick-up the gaps from the people they work along with who have that background/knowledge.

Re: Learn C

#104

Post by tracker1 »

foobarbazqux wrote: post #86
danso wrote: post #23

For anyone who hasn't browsed through Peter Seibel's "Coders at Work," one of his subjects is Fran Allen...it's kind of funny because I do agree that learning C has been valuable to the high-level programming I do today (but only because I was forced to learn it in school). But there's always another level below you that can be valuable...Allen says C killed her interest in programming...not because it was hard, but…

Actual song from PLDI'07 where she received the Turing Award, which we all sang to the tune of Take Me Out to the Ball Game: Let’s all sing to Fran Allen For the great things she’s done. PTRAN and Blue Gene and E C S Fran, we’ve gathered to toast your success. As we ponder all you’ve accomplished, Our colleague extraordinaire, Here’s to you, Fran Allen, you’re truly beyond compare Optimizing compilers Parallel transf…

Using functional paradigm with immutable types does take care of a lot of the complexities of parallel computing... It allows you to make a lot of assumptions (from the underlying platform's perspective) and can break up work in very interesting ways, not just across cpu cores, but even in distributed computing environments. If you combine this with a scriptable language, you can even carry the workload with the code to operate on the load.. which takes things a bit farther. You could create a literal farm of workers that grab a bit of data, process it against the defined load, and then return the result with the next step to run against the data...

I've wanted to create such a system for a while.. right now the closest I could come up with would be to use nodejs with json and a message queue to handle requests/loads. Unfortunately, there's a pretty serious cost to the json serialization, and other issues... but it's an interesting idea that has merit. I think in the end such a system will have a quickly serializable binary expression of both the data and the work to be done.

The catch is that most developers I know aren't used to breaking work up in such a way that it could be very parallelized.

Re: Learn C

#105

Post by betterunix »

trimbo wrote: post #60
betterunix wrote: post #36

Earlier quoted context omitted.

"Reliability and security requirements are up to the developer to impose on any language" This is a common fallback in these discussions, but it is misguided. Yes, you have to work to make software secure in any language; no, this does not mean C is equivalent. In C, you still need to worry about high-level problems like SQL injection, while simultaneously having to worry about low-level problems like integer overflo…

Well, I actually see that as an advantage vs. placing trust in an abstraction you have no control over that can provide security problems for you. So I guess we'll agree to disagree on this one. Curious though, in what would you implement the examples I gave?

For the first two (nuclear power and JSF) and the car I would probably use a language like SML or Haskell, or perhaps even a language like Coq (where your programs are mathematical proofs of their own correctness). For a Mars rover, probably a core written in the languages above, and then bootstrap Common Lisp on top of that core (the core would control critical things that will not need much room to change, Lisp for various AI related things etc.).

Of course, I am not an expert on the requirements of all those projects. Maybe some fact about functional languages makes them entirely unsuitable. If there is a technical reason why C is being used, I would like to know it; if the reason is just, "Well that's what the libraries are written in, that is what most people know, there was a bunch of legacy code, etc." then it only proves that technical reasons are easily trumped by practical concerns. Like I said earlier, it is hard to get away from the large C and C++ codebase that we have to deal with today, despite all the problems of those languages and despite the widespread availability of better languages.

Re: Learn C

#106

Post by jussij »

asveikau wrote: post #43

> You’ll realize that Object Orientation is not the only way to architect software. Actually, pretty much all the "good" C code I've seen is using some form of object orientation, for example using structs with function pointers, or information hiding through incomplete types and void pointers. I think the better observation is that you don't need much language support to do mostly-OOP. That and a lot of people in th…

> For example, many people working in Java or C# especially tend to write lots of indecipherable OO spaghetti.

I would contend that there is nothing OO about the spaghetti they right and you can write spaghetti in any language.

But I tend to agree it probably is easier to create spaghetti using OO languages.

My take why this is comes down to the fact, to do OO correctly needs a hell of a lot of up front OOD (i.e. don't start coding until you've done you OOD).

Most OO places I've worked do next to no upfront OOD before starting to hack out the code. It's feels more like an OOD on the run development model.

Re: Learn C

#107

Post by dylangs1030 »

kmm wrote: post #98
pjmlp wrote: post #84

Earlier quoted context omitted.

The parent poster asked for desktop software written in languages besides C or C++ without any reference of hybrid applications or timeframe when they were written. Since when desktop operating systems are not desktop applications? I can provide other examples, but most likely I will get extra requirements along the way, so why bother... After all, you can always use the argument that any application needs to call C…

What a victim complex. If someone is debating that we should stop using C, and I ask for software not written in C, it's obvious that I'm looking for contemporary software. And the reasoning that every software is "C" because it needs to do system/library calls would be ludicrous, and to provisionally accusing me of that is insulting. I've done some research myself, and there are some interesting and big projects in…

Bingo Card Creator, by our very own patio11 (Patrick Mckenzie) is written in Java.

Re: Learn C

#108

Post by rmrfrmrf »

Please please PUH-LEASE read "The C Programming Language" if you're going to learn C. It is THE most important programming book I've ever read. No other book comes close to concisely and elegantly describing a language.

Re: Learn C

#109

Post by tracker1 »

austinz wrote: post #57
com2kid wrote: post #54

Earlier quoted context omitted.

> There is no particularly good reason for C to be anywhere in the software stack; Really? Not anywhere? Who is handling your hardware interrupts? How is your keyboard and mouse input being handled? What about your video card drivers? Now I will grant that you can bootstrap an initial run time in assembly and place your favorite high level language4 on top of that, if you add extensions to your favorite language to b…

Agreed; OS kernels and firmware for embedded systems all require low-level access to hardware in a way that high-level desktop applications do not. Being able to easily reason about how C is going to use resources and be compiled down to machine code for the architecture you are using can sometimes be an important asset.

I think that the point is that even if you accept that the kernel level code and device drivers are all in C, from there, there's less and less benefit to doing userland code in C from there... you could use Lisp, Erlang, Scheme or a number of other languages for userland and service oriented code.

Although I really don't care for Unity, or Windows 8's UI's I do appreciate some of the directions they are going in terms of being able to create applications that are more abstracted in nature. I personally happen to like higher level languages/environments, and modern hardware has been able to handle them very well for years.

I do think that certain patterns and practices that people have followed need to be re-thought for parallelism, and that a thread/process per request in service oriented architectures has now been a bottleneck... but there are techniques, languages and platforms that can take us much farther without digging into a low-level platform language like C.

I agree that knowing C is helpful, so is knowing assembly... that doesn't mean even a small fraction of developers should be working with them on a daily basis. Most code is one-off line of business application code and related services. It doesn't need sheer performance, it needs to be done and in production sooner... the next thing needs to get done. You can't create software as quickly in C/Assembly as you can in Java/C# (or Python, Ruby, NodeJS).

Re: Learn C

#110

Post by gnuvince »

rmrfrmrf wrote: post #108

Please please PUH-LEASE read "The C Programming Language" if you're going to learn C. It is THE most important programming book I've ever read. No other book comes close to concisely and elegantly describing a language.

If K&R is the most important programming you've read, you have many more books to read methinks :)
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