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Archive for April, 2012

Linux Mint

26.04.2012 1 comment

What is up with Linux?

I use Linux a lot. For years I’ve been using Gentoo Linux. Gentoo is great if you want to learn about Linux, how it works and how it’s put together. On Gentoo you choose all packages that you want installed and also you have choice of what options you want enabled in every package. Gentoo compiles all the packages you chose and their dependencies from sources. It also comes with excellent documentation describing most setup and configuration options, esp. for popular packages.

After years of using Gentoo I determined that one of its drawbacks started bothering me: updating. I kept updating it too often, and updating Gentoo takes a lot of time, because all packages are compiled from sources. Also a very common problem was that newer packages quite often tended to break things in the system. Most often some auxiliary package or library didn’t compile, or was provided with options incompatible with or breaking other packages, and I had to search for workarounds. At other times configuration files changed and I had to find out how to use the new ones. So I was spending too much time on fixing these breakages.

At some point I decided to switch to Ubuntu, which used to be the most popular distribution. I switched to Ubuntu only at home, and left Gentoo on my desktop at work. It mostly worked fine, but I didn’t use it too much. Ubuntu gets major updates every six months, in addition to that updating is easy, you just click and it just downloads the updated packages. Unfortunately it sometimes breaks portions of the system when you update, apparently no Linux distribution out there figured out how to avoid breaking users’ systems during updating. For example sometimes in the middle of updating the process would stop because of some configuration problem and I had to find out how to work around it to continue the upgrade. At other times some packages stopped working (e.g. Bluetooth) and I needed to fix them.

But the most annoying thing about Ubuntu is that it is changing default programs all the time. For example the program for browsing images would change once a year, i.e. the update process would remove the old program and install a new, different one. Or the program for playing music would change. The settings would not be copied from the old program, so I would have to configure the new one from scratch. In the latest incarnation, half a year ago, the default desktop environment was changed to Ubuntu-sponsored one (Unity). That was the end of Ubuntu for me.

I found about Linux Mint. This is another Debian-based distribution (similarly to Ubuntu), but it comes in several flavors, so it’s easier to choose the flavor you like. I am particularly a fan of XFCE desktop environment, which is very simple and fast, yet has all the features of the major desktop environments (KDE, Gnome).

So I switched to Linux Mint. This time I switched to Linux Mint both at home and at work (although I still keep Gentoo on the side for some tasks, since it’s very convenient for development due to its nature). In my opinion Mint is generally nicer than Ubuntu, probably because it comes in many flavors and the XFCE version appealed to me. Of course you could say that you can install and use XFCE in Ubuntu too, but then you would also have to keep KDE or Gnome, and that I wouldn’t like – I especially don’t like keeping a lot of garbage which I don’t use. The package manager and updater are also nicer on Mint than on Ubuntu.

Very shortly after switching to Mint I found out an inconvenient truth: sound does not work! It did not work neither at home nor at work, and these computers have very different, but not uncommon motherboards. Actually ALSA supports them just fine and I never had any problems with sound in Gentoo or Ubuntu. Fortunately I don’t do much sound-related things on Linux. I determined that the problem lies in pulseaudio, which is one of many sound managers for Linux. This is a general problem with Linux (still after so many years!) – there is no single sound solution. I don’t know why some distributions choose pulseaudio, it just doesn’t work for so many people. Pulseaudio is very crappy, because it just doesn’t work. After spending many hours trying to get any sound out of it, I uninstalled pulseaudio and got sound working through ALSA in most applications. Except Flash! I still don’t know how to get sound in my browser. I hope that Google soon releases Chrome with built-in flash and it will just work. It looks like currently Chrome uses Flash from the distribution, and Mint has its own version of Flash. Another possibility could be to replace Mint’s flash with another build, but I haven’t tried that yet.

Recently I did a major upgrade of Mint and I also got serious issues with the update. The update died in the middle with a couple of broken packages because my partition ran out of space. Somehow it is hard for the package manager to figure out that it’s going to run out of space and warn the user. Again I had to look on the Web and find a solution, which involved reverting to apt to fix that (a command line tool). Then graphics drivers stopped working and it took me some time to figure out that one package has been mysteriously uninstalled during the update and I had to reinstall it manually. Afterwards the update finished fine and I had no other issues. But I feel like these issues shouldn’t have happened in the first place. It’s a pity their package updaters are so crappy. Like I wrote before, no Linux distribution has figured out how to handle system updates gracefully.

Other issues I have with Mint are: Apple Magic Mouse doesn’t work. Apparently the drivers for that mouse are unusable. The mouse works fine in Windows 7. Also QEMU which comes with Mint hangs. I tried QEMU compiled manually, but it’s very slow. I ended up using QEMU compiled on Gentoo and that works great, so far I haven’t had time to figure out what’s wrong on Mint.

Besides the problems I described above, I am still happy with Mint and it seems to work better for me on desktop than Ubuntu (has XFCE and I choose what I want to have installed) and Gentoo (no constant lengthy updates and manual fixes, at least not that often). On the other hand because of these problems I don’t know if I would recommend Linux to people who are not computer gurus.

Besides Linux I also use MacOSX, Windows XP, Windows 7, iOS and Android. All of them have their goods and bads. Linux is nice on the desktop for software development if you get used to it. Although I must say that I like MacOSX better, but that could be a topic for another post…

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Categories: Computing

How to buy a gaming rig

22.04.2012 Leave a comment

I used the Diablo III Open Beta to see how my 7 year old computer will be able to handle it. Well, it is not really 7 years old. 5 years ago I upgraded the CPU from a single core 2GHz to a dual core 1.8GHz. This year I upgraded the graphics card to GF 460GT and added a second gig of RAM. But you could say that except the graphics card, everything else is quite old in that “rig”. The motherboard supports only PCI Express 1.0, which is twice as slow as the 2.0 standard supported by this graphics card.

I tried the beta on a MacBook Pro with Intel Core 2 Duo, 2.66GHz (above the recommended spec for this game) and GF 9600M GT (the bottom of the minimum spec). It plays horribly with the minimum resolution (800×600) and all settings set to low. Barely playable.

Then I tried the beta on the dual-core Opteron 1.8GHz (much below the minimum spec, which is 2.2GHz) and GF 460GT (above the recommended spec, but PCI Express 1.0 only). It plays smoothly at 1920×1080 with all settings set to high. The beta is supposedly not optimized, the final game will probably play even smoother.

The bottom line: if you’re buying or beefing up a gaming rig, buy as cheap a CPU as you can find, then spend the saved money on a graphics card.

Categories: Other

Diablo III Open Beta

20.04.2012 Leave a comment

This weekend, you can play Diablo III Beta without a special key! It’s time to check if the hardware will be able to handle the game. ūüôā

Link to Battle.net

Categories: Other

How to hire great programmers?

20.04.2012 Leave a comment

Noticed on Herb Sutter’s blog: quotes from Steve Jobs.

The interesting quote is: “In most businesses, the difference between average and good [employee] is at best 2 to 1. […]¬†But in software, it’s at least 25 to 1. […]¬†The secret of my success is that we have gone to exceptional lengths to hire the best people in the world.”

I guess the difference between people in the middle of that range (12) and the people closer to the end (1) can easily be spotted per my previous post. But how do you tell the difference between the best ones (25) and the middle ones (12)? Especially this: how do you tell whether a person has the potential to become a “25”? How did Steve do that?

Categories: Computing, Other

C++ renaissance

12.04.2012 Leave a comment

Today I stumbled upon this very interesting comparison of which languages are used to write popular software (it was mentioned on Herb Sutter’s blog).

I encourage you to go through the table yourself and contemplate it. To sum it up, most of the popular software which we use every day is written in either C or C++. The author makes a point that other languages, esp. languages which don’t compile directly to executable machine code (a.k.a. native code), are still in a niche and always will be, because no matter how fast computers become, we will use their extra power and resources for new features instead of wasting them on non-native languages.

Back in the old days, when the Moore’s law directly influenced CPU frequencies, the advocates of non-native languages always used the argument that at some point CPUs will become so fast that native languages will lose their usefulness due to their clunkiness. Among other similar arguments.

The year 2006 came and CPU frequencies hit a wall. It turned out that in order to make further progress in performance CPU manufacturers have to start packing more and more cores into their products. We can leverage that in many algorithms which are parallelizable, but there is still a lot of things our programs have to do sequentially and there is no way to go around that. Sure multiple applications can leverage separate cores, but multiple cores don’t make miracles, we are stuck with a frequency limit!

Before the year 2006 everything went well, Java was at its peak and Microsoft promoted C# and .NET as their thing of the future. Today Microsoft backs C++11 and encourages developers to “go native”, while the future of C# is uncertain (there are fears that Microsoft will drop .NET).

When Google came out with its Chrome browser and revolutionized – if not leveled – the browser landscape, some of their most significant improvements went into the JavaScript engine. The Chrome browser was released in the midst of a JavaScript performance war between Firefox and Opera, but Chrome did it better. After years of improving their JavaScript engine Google declared that they gave up on JavaScript performance, they decided to develop a new language (Dart) which will be typed and will compile in browser into native code. Consider this: web scripting is important and performance of website scripts must improve, but to get there Google decided they can’t rely on a non-native language anymore! This does not mean that JavaScript will go away, but Google puts its bet on Dart which is a native language for the future of more sophisticated web programming.

I think non-native languages are still very useful for scripting, prototyping and other similar tasks where you need a simple language which does not have to produce lightning fast results. But non-native languages cannot replace native languages for more sophisticated tasks where the software must meet resource constraints. In other words, usefulness of Java, C# et al has been strongly overrated, they will remain niche languages at least for the next decade.

Update

A friend of mine pointed out that job postings indicate that Java is in higher demand than C or C++. That is a valid point, every language has its own purpose and application. It does not change the fact that non-native languages will replace native languages any time soon.

Categories: Computing

Interviewing

1.04.2012 2 comments

However easy it may seem, interviewing software engineers is hard.

If you have a little experience in developing software, you are probably participating in the hiring process once in a while. It goes like this: you come up with a few questions, see how candidates tackle them and give your opinion whether the candidates will fit into the position you are interviewing for or not. Sounds easy.

But how do you know that you can measure anything with your questions? If you are a novice interviewer, you will make mistakes. You will sometimes make bad judgements even if you are a seasoned interviewer. This is why most companies throw several interviewers at each candidate. If all interviewers agree about a candidate, the hiring manager has an easy task. If there is too much disagreement between interviewers, the manager will either dismiss the candidate or recommend him to another team. Also sound easy. But it’s far from perfect, let’s look how the process works and what could be improved.

How hiring works at most companies

The first steps of the hiring process involve getting candidates, e.g. by advertising open job positions. When the candidates send in their resum√©s, they go through the HR filter, which is typically based on keywords. For this reason, if you are looking for a job, you should put in as many keywords and acronyms as you can come up with into your “experience” section, to just get through the Great Filter. If you are a C++ developer applying for a C++ position, but you have used C# in the past, just throw it in, even if you are not interested in a C# position or have very little experience with it – to an HR person you may appear as more valuable than other potential candidates.

The great fault of this process is not that bad candidates slip in through the filter Рthose who have no experience but a pretty resumé Рbut that the filter potentially rejects good candidates. Some candidates may be missing resumé writing skills, but could make great employees.

Then there is the interview series, where multiple interviewers question each candidate, as described above. Usually it is easy to dismiss weak candidates. For example, most candidates are unable to answer simple programming questions, hiring a person who does not care about programming won’t make a great employee, unless the goal is to hire a bunch of drones for a thoughtless job, which is always a bad idea – such approach is usually a sign of bad management.

The fault here is not that this sieves through the sea of candidates lacking competence for this particular job. The problem is that the process fails to distinguish between great hires and mediocre hires and also usually fails to match candidates for a particular position (about this later).

The last step is salary negotiation, which I am not going to cover here, although this is also an interesting topic.

Questions

Probably everybody has their own favorite types of questions. So there are the technical questions, which focus on knowledge. For a long time this was my favorite kind, the problem was that almost no candidate was able to answer them all. For example I would ask about five various C++ keywords. I could count on the fingers of one hand the candidates who actually knew them all. Most candidates are able to guess a few keywords.

I am asking, why are you applying for a position, which specifies a particular language you will be using, and you are not even willing to learn what all its keywords are for? OK, C++ is one of the most difficult languages and has over 60 keywords. I have seen several candidates claiming being “advanced” or “experienced” in C++, and still not able to even guess some keywords. You might say, some of these keywords are rarely used or not useful, or it’s easy to look them up, but would you expect the candidate to do his job seriously with attention to details if he is not even willing to prepare for the interview? (BTW. “I could look it up” is also not an entirely bad answer)

Indeed, too technical questions do not help us to determine how good a fit a particular candidate is for the job. Knowing rare keywords by heart does not help with good design, thorough testing or finishing the job at all.

For years I would indulge myself and abuse the fact that there were other interviewers interviewing the candidates as well, so they would compensate for my being too harsh. I would also throw in a piece of C code where the candidate would have to track what number gets printed in the end. Very tedious. Not everybody knows that 1.0f is represented as 0x3F800000U. But I was not satisfied, in the end knowledge != wisdom. I realised that I am looking for something more than just knowledge in the candidates.

So there are the riddle kinds of questions. Some companies are famous or excel at giving sophisticated riddles. The proponents of riddles claim this is the best way to hire smart people. So do you really want to hire smart people who don’t know anything about the technology they are going to be working with in the coming years? Or people who are extremely smart, but don’t make good team players? Or nobody wants to work with them because they are rude and don’t respect others’ opinions? I guess the riddle questions are not the best kind.

Two kinds of employees

There are two kinds of employees. It is a simplification, but it boils down to this – the process of recruiting should take this into account, because everything else and the whole “lifetime” of an employee at one company is centered around this. If an employee of one kind takes a position that requires an employee of the other kind, the employment will not be successful and in the best case scenario will be terminated sooner than later, no matter how good the employee really is. This classification applies not only to software engineering, but to most, if not all jobs.

The first kind is more common. These employees must be told what to do. They are not able to find problems and fix them on their own, somebody else must find work to do for them. They are usually not proactive. Novice employees of this kind will not be able to complete tasks without guidance, will not research problems thoroughly, will not look for potential issues. When faced with obstacles, they will be hopelessly stuck until somebody pushes them in the right direction. After many years of work they will finally learn how to cope with most of these problems, they will still need to be told what and when to do and they will still not pursue new potential tasks on their own. Be careful not to dismiss them, they are very valuable when assigned the right job and they can handle many if not most common tasks. They are good are performing repetitive or simple tasks, after long training even sophisticated ones. They are great to have if the direction is clear. They always need supervision.

The second kind is much less common. These employees are the drivers. They go out looking for problems, find solutions and fix them. They are proactive and often don’t require supervision. They should not be micro managed, because they will feel they don’t have control and will not be able to perform and will not be satisfied with their job. These employees are often good at researching difficult problems and driving things to completion. It is always good to have at least one on a team.

There are groups within each kind and there is a special group in the second kind, let’s call them high achievers for now. I admire them the most. They constantly strive to improve themselves, they treat their job almost like an art, they are the¬†craftsmen. Whatever problem you will throw at them, they will always solve it.

Now don’t be fooled, you don’t want to assemble a team of high achievers. The perfect team is a balance of people of each kind, so the entire team can make forward progress as well as solve problems as they are encountered. The last thing you want is to assemble a team of all smart gurus who won’t want to communicate with each other and will rip the team apart.

This is true not only in software development but in most kinds of jobs. For example there have been many attempts of building all-star teams in sports, but eventually these teams were mediocre, because the top players were not able to work together.

The question is, how do you determine during an interview to which group the candidate belongs? Throw in a riddle? People from both groups can be smart and able to solve riddles. Technical questions are not good either. To be frank, I don’t know yet how to distinguish between the two kinds of candidates yet.

Two kinds of employees, second try

To make it easier, somebody suggested to me another classification: those who are hard-working and those who are not. This is orthogonal to the other method of classification. Hard working in this case does not mean willing to do overtime, but it simply means: bent on finishing tasks, finding solutions and being honest about the work. Even people who need constant guidance can be split into those who just don’t care about the job and those who are willing to learn and build their careers.

The nice thing about this classification is that it is easy to devise simple questions with which you can judge with a high level of certainty whether a person is hard-working or not. You can start with asking details about their previous assignments and judge how willing they were to complete them and how competent they are.

I like to think of these two classifications as of two dimensions of employee classification scale. There are other dimensions as well, such as the technical knowledge dimension, which is also important but trivial to assess.

Other dimensions such as “fit for the team” are often overrated and over-advertised by HR or management. What matters is whether a person is a team player or not, but sometimes even this does not matter – if you need a “high achiever” to tackle the difficult problems your team comes across, it does not matter much whether he will be a team player or not, but how effective he will be, although you still need to back other tasks in the project with team players.

The bottom line

The bottom line is whether the candidate will be able to perform the job or not. Will he write good code or not? We he care about the code he writes or not? Will he be willing to improve his skills or not?

Currently I am focusing on presenting the candidates with real world problems and asking them how they would solve them. For example, what would they do if they faced a badly written code? Would they leave it alone or try to fix it and why yes or why not? It still gives me some ideas about the candidates and allows me to compare them, discussing the solutions with them also allows me to judge their experience. I also like to give them some simple (but not too trivial) piece of code to write and see how they cope with the task.

I know this is not a perfect way to interview, I am still looking for a better way.

Categories: Computing