sstream of consciousness - Software

No need to be overzealous

Mon, 07 Aug 2006 17:53:07 -0600

Fedora Core Linux's official UI theme is called Bluecurve and distro maintainers try to keep it consistent across different desktop frameworks (KDE and Gnome that is).

I stumbled upon a Bluecurve page on FC Wiki. New isometric icons look nice... but only where isometric look is appropriate.

It's kind of stupid to have isometric icons for "back", "forward", "fast forward" and so on. Consistency is good, but if you have to tilt your head or rotate an icon mentally even a little bit, this is not good for usability at all. And usability is really what is important at the end of the day.

My thoughts on RSS use cases

Wed, 15 Feb 2006 21:37:30 -0700

Brad Feld announced that Boulder Software Club is planning an event to discuss usage of RSS, first of all in enterprise.

For a long time, I actually wanted to write my thoughts about RSS and its place in technology landscape, so Brad's post gave me a reason to finally overcome my laziness (heh). I'll start by my take on some topics that will be discussed there.

Why RSS instead of e-mail – isn’t it just the same thing? Isn’t this just for bloggers?

No, RSS is not the same as e-mail, though similar. RSS is better suited for some use cases, not only for technical but for psychological reasons too. If I wear reader's hat, I strongly prefer RSS over a a mailing list, because if I loose or cancel my mail account for some reason, I need to reroute all my subscriptions which is tedious and error-prone, whereas with RSS, I just need to carry my OPML around. Subscribing to and unsubscribing from mailing lists is more evolved than same actions with RSS feeds and usually requires two-step process. Second big advantage is that I get precisely what I subscribed to in my blogroll, and mailboxes tend to become spam targets. As an author I may prefer RSS to mailing list because my (potential) readers prefer RSS to e-mail (see above).

RSS is not just for bloggers, it may be used in all areas that needs some kind of periodic update protocol. Software packages may use RSS to get information about available updates. Microsoft is going to use RSS for synchronization.

What are typical use-cases of RSS applied to the enterprise ...

Take for example a typical situation in corporate environment: you need to propagate some kind of a knowledge but you are just not sure about target audience. For example, you are a software developer and finished some important feature. Now you may need to send a notice to your immediate manager, that's a no-brainer, but then things start to get complicated. Documentation needs to be updated but you just do not know who in documentation team is now responsible for that area, so you send e-mail to Documentation Team leader or to the whole documentation team. Now, QA manager needs to know about feature too to test it, check. But oops, you forgot sales engineers, some of them will be caught with 'deer in the lights' look when curious customers ask them about that new feature. Your immediate manager and QA manager consider this feature (and good tests' results) as an important milestone so your e-mail gets forwarded to VP of engineering. Twice. VP of engineering wonders if VP of marketing may need to know about that feature, and whether it will help in lead generation, so she forwards it just in case...

As an employee of medium or large corporation you often faced with a dilemma: you do no want to send e-mails to too many people - some of them may not be that interested and you appreciate their attention span, so you do not send your e-mail to too many addresses. On the other hand, you may not know that some of your colleagues need exactly that information, right now, so you do not want to miss some important addressees. RSS transfers this burden to the shoulder of your readers and they are usually in better position to know what kind of information they need.

If you are a manager you may choose a subscription style that fits your management style. Control freaks may subscribe to every single feed and keep tabs on everything, and fans of delegation may read only blogs of their key subordinates and higher management, hoping that if anything interesting pops up, it will be reblogged by one of the bloggers they read (analog of e-mail forwarding in the RSS world).

RSS is also beneficial if you want employees to roll out ideas more freely and often. The thing is, people generally do not want to send non-critical e-mails to others, because they believe they may be annoying, but will happily blog them. It's like instead of approaching you bosses with your idea one-by-one you speak about it at company lunch and all who listen to you, know about it (What's that sound? It's an analogy police knocking on my door).

Deleting unapproved comments in Drupal

Sat, 11 Feb 2006 20:01:58 -0700

I use Drupal to run this site. While Drupal looks like a bit of an overkill for running just a personal blog, I don't want to switch to any other blogging engine now (No, not even to trendy WordPress, thank you).

And of course Drupal has its long-standing annoying quirks. One of them is a deletion of a comment spam - you have to hit a delete button for each comment individually - which results in a horrible user experience when you have Web-based interface. Fortunately there is a workaround.

One piece of advice though - change URL from the article to something which cannot be guessed or, better yet, add authentication. I hope Drupal maintainers will get the message and turn this workaround into feature.

Shooting the troubles

Wed, 08 Feb 2006 21:30:35 -0700

Probably the most interesting part of web log statistics for my site is a page with keywords that people use in search engines to come to my pages. The most popular search is for information about C++ string streams. Ironically, this blog does not provide much help here, though I put some useful links on my front page.

Over the course of my career I bumped into many different technical problems. Often these problems required a lot of time or mental effort to investigate. Needless to say, web search engine made that task way easier, but sill there were problems I had to spend considerable time on. Once I had this blog I have started to put some results of my troubleshooting sessions, primarily as a sign of gratitude to all the people who do the same.

So, when I look at search term statistics, I am always glad to find that people came to the solution at my site, using search keywords describing their problems, like the problem of putting spaces to LD_PRELOAD environment variable or Coloured bash prompt screwing multiline input in a terminal.

Maybe separate articles or pages instead of blog entries is more appropriate for that kind of texts, but I am pretty happy with the present format now.

In near future I am going to post a couple of entries explaining problems related to GNU C library application binary interface (ABI) revisions and incompatibilities and problems with C++ language ABI.

Software projects

Sat, 03 Dec 2005 19:39:18 -0700

This page contains my small software projects that I decided to put online.

furl-save

Furl-save is a Perl script that does a backup of your categorized, keyword-tagged web bookmarks and their respective page contents stored on online service furl.net

Tested on following platforms:

RedHat Linux 7.3
RedHat Linux 9.0
Fedora Core 4, 5, 6 on Intel x86
Microsoft Windows XP with ActivePerl installed

Download furl-save version 1.0.3

Coloured prompt in Unix - the right way

Wed, 21 Sep 2005 21:11:52 -0600

The first thing I always change in my .bashrc and .profile files on any Unix is a bash prompt.

Bash prompt on Unix is defined by environment variable PS1. Default prompt on most systems is usually set to somethings stupid. I need two things from my prompt: host name and current directory name. I also like '>' sign to be at the end of a prompt, not '$' or '#'. So I put into my .bashrc:
PS1='\h:\w>'

I also like my prmpt to be colored so I could visually distinguish it from the surrounding text - it really helps when you have output from several consecutive commands in your terminal. There are many articles on the Web which advise how to add colours to the prompt, and it seemingly works but it is easy to do it wrong.

Each time I am asked: 'If I need to wrap long command in bash, my command line is messed up, why?', I ask back: 'Do you have a coloured prompt?'. I invariably hear 'Yes'.

The problem is that terminal accounts colour-changing control symbols for string length, but in fact they do not take additional space. That discrepancy messes up a multiline input.

So here's the right way to enter colour changing control symbols:
\[033[B;Cm\]
Instead of B you must put either 0 - for normal colours, or 1 - for bright colours. Substitute C with a number of a colour:

30 - Black/Dark grey
31 - Red
32 - Green
33 - Yellow
34 - Blue
35 - Magenta
36 - Fuscia
37 - White/light grey
38 - Default foreground color. Use it at the end of the prompt, so that further text is not coloured.

I like to have bright yellow prompt (I use black background), so I put into my .bashrc:
PS1="\[\033[1;33m\]\h:\w>\[\033[0;38m\]" export PS1

If you want other information to appear in bash prompt, here is the reference:
\a an ASCII bell character (07) \d the date in "Weekday Month Date" format (e.g., "Tue May 26") \e an ASCII escape character (033) \h the hostname up to the first `.' \H the hostname \j the number of jobs currently managed by the shell \l the basename of the shell's terminal device name \n newline \r carriage return \s the name of the shell, the basename of $0 (the portion following the final slash) \t the current time in 24-hour HH:MM:SS format \T the current time in 12-hour HH:MM:SS format \@ the current time in 12-hour am/pm format \u the username of the current user \v the version of bash (e.g., 2.00) \V the release of bash, version + patchlevel (e.g., 2.00.0) \w the current working directory \W the basename of the current working direcÂ tory \! the history number of this command \# the command number of this command \$ if the effective UID is 0, a #, otherwise a $ \nnn the character corresponding to the octal number nnn \\ a backslash \[ begin a sequence of non-printing characters, which could be used to embed a terminal conÂ trol sequence into the prompt \] end a sequence of non-printing characters

So, jump into your favourite editor, hack your .bashrc. Experiment, and I am sure many of you will find coloured prompt handy.

There are many other ways you may customize your bash prompt. It is actually possible to include output of any programs into the prompt or even change the prompt (and colours within it) depending on some external conditions. For example you might turn your prompt red if last program finished with non-zero error status (which means something bad or unexpected happened) or green if everything went well. But this is probably a topic for a separate article.

How to specify library name with spaces in LD_PRELOAD

Mon, 19 Sep 2005 15:30:45 -0600

Recently several of my colleagues bumped into an interesting problem.

We use LD_PRELOAD environment variable in couple of places. For those of you not familiar with it: LD_PRELOAD is an environment variable which allows you to specify dynamic libraries which will be loaded before all other libraries. This technique allows you to intercept calls to standard libraries is used by many debugging and analysis tools. Or you could alter behaviour of tsndard libraries for different purposes (e.g. fault injection).

As other variables like PATH or LD_LIBRARY_PATH, this variable may contain list of library namesseparated by colons. But... for compatibility with legacy systems it is possible to separate LD_PRELOAD elements by spaces. And older systems did not understand escaping so it turns oout it is impossible to put full library paths into LD_PRELOAD if they contain spaces.

But here is the trick. You may put library directory name(s) with spaces into LD_LIBRARY_PATH (which is kind of a PATH but for dynamically linked/loaded libraries) and put short library name(s) into LD_PRELOAD. Of course, short library file name must not contain spaces but this is less of a limitation.

Furl and del.icio.us and market research

Tue, 07 Jun 2005 20:44:17 -0600

Hans van Deum writes on his blog about my comparison of online bookmark managers:

I found this blog which has an interesting comparison between different bookmarking services. This guy is obviously sold on furl. Perhaps I should check it out.

The problem with these sites is that they are only useful for market research when they are the de facto standard, because e-businesses will never pay each site separately to do the same research.

If Hans wants to do market research he is probably better with del.icio.us. It seems to be trendier and user base appears to be bigger. I use Furl, because I need a place to store my bookmarks and easily find them afterwards. It has features that I need, and del.ici.ous does not have them. It is that simple.

Spurl.net has pretty much the same functionality as Furl (at least with regard to functionality I am interested in). If I knew about Spurl before, I would probably have chosen it. So far, I have not seen a "killer feature" that will make me switch.

Klocwork Defect analyzer finds flaws in CVS

Sat, 23 Apr 2005 12:53:16 -0600

My co-worker Alen Zukich reported a bunch of serious defects to CVS development team. And of course, his findings are based on report by Klocwork tools.

We use CVS for version tracking at Klocwork and I am glad we were able to give something back. Our customer list includes many big names and we get a lot of positive feedback from them about our solutions (and yes, we get a lot of requests and scrutiny from them, too). However I am excited that Open Source world benefits from our reports too. Expect more advisories with regard to open source projects originating from Klocwork.

Furl backup script

Mon, 11 Apr 2005 23:14:53 -0600

I created a simple Perl script to backup Furl archive (both XML descriptions and ZIP with pages). Download archive, unpack Perl script and install it to your cron table or use manually. Do not forget to put your username and password into the scipt. I spent just 20 minutes writing it and testing, so it is pretty bare-bones.
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Quick overview of Spurl.net

Thu, 17 Mar 2005 12:57:41 -0700

One of my blog readers epxressed interest in seeing Spurl.net compared against other bookmarking services in my overview.

It usually takes a while for me to get to know all ins and outs. However here is my quick impression.

Spurl.net is rather similar to Furl.net in functionality - it also saves cached copies of pages. However it has some nice features that others do not. For example Spurl.net may give you quick statistical overview of your library and may report broken links. It also attaches small web page thumbnails - for people that tend to remember visual impressions, rather than abstract text. Another feature is 18+ filter - useless for me, so go figure out yourself what it does :).
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Test of new bookmarking service: Filangy roundup, invites

Mon, 28 Feb 2005 20:39:49 -0700

Recently I've got a Filangy invite and I spent some playing with that. Summary: great start but there aree many things to do.

First of all, I updated my bookmarking service comparison table. Now, down to the details.

The most important feature that distinguishes Filangy from other bookmarking services is that it indexes almost everything you browse. By "almost" I mean all web pages that are not under password. Filangy also does not do anything about pages on SSL servers (urls that start with https://).

This is most wonderful and most scary feature of Filangy (and most touted by its creators, too). If you know Slogger, you may think of Filangy as a Slogger that is constantly in record mode but saves results on the Net instead of local drive.
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What mail client does Linus Torvalds use?

Thu, 10 Feb 2005 15:16:39 -0700

Recently I digged Linux Kernel Mailing List. And found that it is possible to see message headers. And you can retrieve a lot of interesting information from them.

Take for example headers of the message by Linus Torvalds. And you instantly will know that Linus Torvalds uses Pine as his mail client and PowerPC based computer (Apple?). For those of you who don't know what's pine - it is text-based e-mail and NNTP client which runs in the terminal. I used Pine for many years myself, when my primary work machine was a Sun SPARC with Solaris 7. But when I got my Linux/Windows dual boot computer, I imediately switched to Thunderbird and never looked back.
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Songs of experience: best e-mail practices

Fri, 04 Feb 2005 19:57:57 -0700

Over many years I've been active user of information technology and devoted many hours to hunting best software, practices, and processes. This post is the first in series that summarize my experience in different areas of personal information technology. Though stuff may seem trivial and obvious to some readers, I hope you will find helpful hints here. In a sense, contents of this posts will be somewhat similar to wonderful O'Reilly "hacks" books.

This chapter is about my most important tool of the trade: e-mail. While some may argue that this technology is obsolete is is gradually replaced by instant messaging, ol' good e-mail is far from dead.
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del.icio.us vs Furl vs Yahoo: Advanced Bookmarking

Thu, 20 Jan 2005 09:52:35 -0700

Recently, I posted a blog entry briefly describing my management of data on the Web. Among other things this entry briefly described my experience with online bookmarking sevices.

First of all, I think term "bookmarking" is a little bit overloaded. Indeed, I bookmark only those sites and pages I use very often: Corporate Intranet site and some specific pages in it, query to the issue tracking system web forntend to see problem reports and change requests I am responsible for, couple of sites I tack with Firefox Live Bookmarks and several bookmarklets. I file all other URLs to Furl.