Comment by amadeusw | Hacker News Reader

Comment by amadeusw | Hacker News Reader

Besides describing programming concepts, this paper reveals what it was like to be a programmer:

As I understand it, it was expected from a programmer to completely understand workings of the algorithm and a tracing subroutine seems to not be in favor. Currently the systems we're working with are so complex that we can't comprehend all algorithms and need to use debugging and tracing tools:

> However the interpretive routine retains control and so it is possible to print out extra information about the course of the programme. This extra information makes it possible to follow the meanderings of the program in detail thus helping to locate the errors of a programme. This is not a good method of finding errors in programmes as it takes a long time and the programmers knowledge of the programme is not utilized - as it should be - in tracing the fault.

Other bits I enjoyed reading:

Writing good docs was hard even back in 1951!

> there still remains the considerable task of writing a description so that people not acquainted with the interior coding can nevertheless use it easily. This last task may be the most difficult.

Timeless piece of advice

> All complexities should - if possible - be buried out of sight.

> Currently the systems we're working with are so complex that we can't comprehend all algorithms and need to use debugging and tracing tools:

Oh, not sure you'll get universal agreement on that one. https://lwn.net/2000/0914/a/lt-debugger.php3

I have a feeling that attitude of Linus will age badly, to the point that in 2038 it will be taught in schools as an example of how not to behave.

He is at liberty to be very selective about who contributes to the kernel, and how they do it. He's blunt, picky and pragmatic, but he has a valid point from the compsci and project management point of view:

> I happen to believe that not having a kernel debugger forces people to think about their problem on a different level than with a debugger. I think that without a debugger, you don't get into that mindset where you know how it behaves, and then you fix it from there. Without a debugger, you tend to think about problems another way. You want to understand things on a different _level_.

Those of us who have spent multiple weeks on single bugs in systems that were made by people who also did not believe in debuggers politely disagree.

I see a debugger as a means of last resort, if all else fails and you've spent that week reasoning about the problem where you already know how it behaves and in spite of that you still can't fix it a hint can help a lot.

Linus is showing an attitude in this message that simply does not help, at least he acknowledges it. Essentially he's saying that a debugger being present in the kernel would open up the kernel to lesser gods contributing and he can do without that, if you can't cross the hurdle then you're not welcome in the elite kernel hackers group.

It's his playground so I'm fine with that but this attitude probably is one of the reasons why the Linux kernel keeps on giving when it comes to really old bugs. As every experienced programmer knows: what the code seems to be doing is not always what the code actually does and in the presence of optimizing compilers a debugger can come in quite handy. Especially if those compilers themselves are of the buggy variety.

Making kernel writing a black art serves nobody, it just reduces the pool of contributors. I often wonder if Linux became as successful as it was because or in spite of Linus' character, even after a couple of decades I haven't been able to decide but I'm grateful for its existence anyway.

It's also another reason why I'm a big fan of micro kernels (the real variety), it makes operating systems much easier to debug because each and every little module lives in a process of its own, isolated from messing up other processes' memory. That's well worth the speed penalty.

Also Robert C. Martin, aka Uncle Bob: http://www.artima.com/weblogs/viewpost.jsp?thread=23476

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