Posts Tagged ‘habits’

Habits are the peripheral vision of the mind

March 24th, 2016 3 comments

Achieving a basic proficiency in a new skill requires an investment of conscious cognitive effort, i.e., thinking a lot. Students are constantly in the process of achieving basic proficiency in new skills and conclude that thinking is required for all intellectual activities (an incorrect assumption also held by many teachers).

To get past the conscious thinking stage lots of time has to be spent performing the skill. Repetition provides the opportunity for performance via conscious thought to migrate to subconscious performance (driving being a common example).

Real-time performance requires fluency, that is, being able to handle technical details without having to think about them. Thinking (i.e., conscious thought) is slow and requires lots of effort. It is best held in reserve for the important stuff.

To paraphrase Alfred Whitehead: “Software development advances by extending the number of important operations which we can perform without thinking about them.”

Somebody who has spent 100 hours or so (an hour or two a week for a year) learning to code has the same level of fluency as I have in communicating in a foreign language using a phrase book, or Google translate.

After a 1,000 hours of programming a person should be a very fluent coder.

It is said that becoming an expert requires 10,000 hours of practice. The kind of practice involved is deliberate practice, not unconscious use of what is already known. Becoming an expert requires learning lots of new things, not constantly applying what is already known. Old habits have to be broken and new ones acquired.

Programming is not Zen, although it contains elements that are. Why would a developer want to create a program without conscious thought (that is what scripts are for)?

I used to run ‘advanced’ programming courses for professional developers with 2+ years in industry. In many ways the material was a rerun of what they had learned at the start of their programming career. The difference was that this time around they could ignore the mechanics of writing code, now an ingrained habit, and concentrate on the higher level stuff. The course had to have advanced in its title because experienced developers would never sign up for an introductory course. Most of my one-on-one tutoring effort went on talking people out of bad habits they had picked up over time.

Perhaps live coding can be done with a Zen mind, probably why I don’t regard it as real programming (which I think requires some conscious thought).

Talking about details and high level material in the same breath is what beginners do because they have not yet learned to tell the two apart and be able to ignore one of them.

Like life, programs are mostly built from sequences of commonly occurring patterns. Our minds have evolved to subconsciously detect and take advantage of patterns. Programmers don’t know what the common source code patterns are any more than a native speaker can specify the syntax rules of the language they speak.

Fingerprinting the author of the ZeuS Botnet

May 11th, 2011 3 comments

The source code of the ZeuS Botnet is now available for download. I imagine there are a few organizations who would like to talk to the author(s) of this code.

All developers have coding habits, that is they usually have a particular way of writing each coding construct. Different developers have different sets of habits and sometimes individual developers have a way of writing some language construct that is rarely used by other developers. Are developer habits sufficiently unique that they can be used to identify individuals from their code? I don’t have enough data to answer that question. Reading through the C++ source of ZeuS I spotted a few unusual usage patterns (I don’t know enough about common usage patterns in PHP to say much about this source) which readers might like to look for in code they encounter, perhaps putting name to the author of this code.

The source is written in C++ (32.5 KLOC of client source) and PHP (7.5KLOC of server source) and is of high quality (the C++ code could do with more comments, say to the level given in the PHP code), many companies could increase the quality of their code by following the coding standard that this author seems to be following. The source is well laid out and there are plenty of meaningful variable names.

So what can we tell about the person(s) who wrote this code?

  • There is one author; this is based on consistent usage patterns and nothing jumping out at me as being sufficiently different that it could be written by somebody else,
  • The author is fluent in English; based on the fact that I did not spot any identifiers spelled using unusual word combinations that often occur when a developer has a poor grasp of English. Update 16-May: spotted four instances of the debug message “Request sended.” which suggests the author is not as fluent as I first thought.
  • The usage that jumped out at me the most is:
    for(;; p++)if(*p == '\\' || *p == '/' || *p == 0)

    This is taking to an extreme the idea that if a ‘control header’ has a single statement associated with it, then they both appear on the same line; this usage commonly occurs with if-statements and this for/while-statement usage is very rare (this usage also occurs in the PHP code),

  • The usage of true/false in conditionals is similar to that of newbie developers, for instance writing:
    return CWA(kernel32, RemoveDirectoryW)(path) == FALSE ? false : true;
    // and
    return CWA(shlwapi, PathCombineW)(dest, dir, p) == NULL ? false : true;
    // also
    return CWA(kernel32, DeleteFileW)(file) ? true : false;

    in a function returning bool instead of:

    return CWA(kernel32, RemoveDirectoryW)(path);
    return CWA(shlwapi, PathCombineW)(dest, dir, p) != NULL
    // and
    return CWA(kernel32, DeleteFileW)(file);

    The author is not a newbie developer, perhaps sometime in the past they were badly bitten by a Microsoft C++ compiler bug, found that this usage worked around the problem and have used it ever since,

  • The author vertically aligns the assignment operator in statement sequences but not in a sequence of definitions containing an initializer:
    // = not vertically aligned here
        DWORD itemMask = curItem->flags & ITEMF_IS_MASK;
        ITEM *cloneOfItem = curItem;
    // but is vertically aligned here:
        desiredAccess       |= GENERIC_WRITE;
        creationDisposition  = OPEN_ALWAYS;

    Vertical alignment is not common and I would have said that alignment was more often seen in definitions than statements, the reverse of what is seen in this code,

  • Non-terminating loops are created using for(;;) rather than the more commonly seen while(TRUE),
  • The author is happy to use goto to jump to the end of a function, not a rare habit but lots of developers have been taught that such usage is bad practice (I would say it depends, but that discussion belongs in another post),
  • Unnecessary casts often appear on negative constants (unnecessary in the sense that the compiler is required to implicitly do the conversion). This could be another instance of a previous Microsoft compiler bug causing a developer to adopt a coding habit to work around the problem.

Could the source have been processed by an code formatter to remove fingerprint information? I think not. There are small inconsistencies in layout here and there that suggest human error, also automatic layout tends to have a ‘template’ look to it that this code does not have.

Update 16 May: One source file stands out as being the only one that does not make extensive use of camelCase and a quick search finds that it is derived from the ucl compression library.