Posts tagged ‘Linux’

A Whole Lot of OSes at Once

2013-08-29 23:11

I realized I haven’t talked yet about my workspace setup, including the choice of computer(s) and operating system(s) which I prefer. A topic like that is a perfect opportunity to provide fuel for countless flamewars raging through the Internet forums, so it seems like a no-brainer if you want to round up some passionate readers ;)
So, what’s the best these days? Is it Windows or Linux? Or maybe OS X? Should you get a Mac or a(n other kind of) PC? Make it a desktop or just a laptop? Or perhaps subscribe to the post-PC doctrine and grab a tablet?…

Well, I don’t know. I won’t really advise anything here. Myself, I take more… holistic approach. I just use all of these things :)

Use ALL the systems!

Desktop split in two

As I see it, desktop PC is the place where stuff gets done. Be it “work” or play, you cannot easily forfeit the conveniences of big monitor(s), full keyboard layout, snappy mouse that fits your palm, and a comfortable chair.

Thing is, those two activities require two completely different operating systems. When it comes to games, Windows is still reigning supreme, with only some small glimpses of what might shake up this status quo. Sadly, I have little hope much will change here in the foreseeable future.
On the other hand, it’s pretty much given that the best system for most kinds of development work is some flavor of Linux, preferably sporting such powerful a package manager as apt-get. There are no (good) alternatives for certain vendor lock-ins (*cough* iOS) but if you are not forced to comply with them, anything else is almost certainly an inferior choice.

How to reconcile those requirements? There is dual booting, of course, but the need of frequent resets would get old very quickly. So instead of that, and after conducting a bit of a research, I opted for virtualization, choosing a simple solution of running Linux as guest OS through VirtualBox.
This turned out to be super easy to set up; the only “trick” was to flip a switch in BIOS in order to enable CPU virtualization features, required to run a 64-bit system as guest. With these on, performance is a non-issue: it feels like running directly on the hardware, for all intents and purposes – including running Android emulator inside the VM :)

Laptop as versatile substitute

Now, if only all that goodness could be made available on the go… Although some may pretend it is, most (sane) people cater to their mobility needs by getting a laptop. This is immediately a compromise because of the form factor alone, but even more so because of inevitably inferior hardware specs one could cram into it.

So no, I didn’t try to replicate the VM-based setup described above :) While possible, it seemed way more sensible to try and kill two birds with one stone by getting a computer that:

  • adequately (though not perfectly) substitutes Windows for gaming and Linux for coding
  • runs the third major operating system, in case that ever comes handy e.g. for testing purposes

As you’ve likely guessed, that description accurately fits a MacBook. Of its virtues and woes I have already written elsewhere, so let’s just say it fulfills its purpose pretty well.

And even when it doesn’t, there is always Chrome Remote Desktop to bridge the gap :)

Windows 8 Is Coming and I Don’t Care

2012-10-09 19:56

The upcoming release of Windows 8 is stirring up the tech world, mostly because of some controversial decisions Microsoft has made regarding the new version of their flagship OS.

Were it a few years ago, I would likely participate in various discussions about this, springing up on message boards I typically frequent. Probably I would have also tested the development preview which was made available several months before. Most likely, I would have clear opinion about viability of the new Metro UI, WinRT apps’ platform or the overall push in the general direction of HTML5.

I would… But I do not. Actually, I couldn’t care less about the whole thing.

It’s not only because I touch my Windows installation once in a blue moon, almost exclusively for gaming. No, that’s mostly because it’s 2012, and Windows still doesn’t support some crucial functionality you could expect from modern operating system.

Unfortunately, most users don’t expect it because they never knew any better. Therefore I will try to highlight some features from alternative operating systems (typically Linux or OSX) that I think Windows can be rightfully scorned for lacking.

DreamPie with virtualenv

2012-05-10 20:44

If you haven’t heard about it, DreamPie is an awesome GUI application layered on top of standard Python shell. I use it for elaborate prototyping where its multi-line input box is a significant advance over raw, terminal UX of IPython.

However, up until recently I didn’t know how to make DreamPie cooperate with virtualenv. Because it’s a GUI program, I scoured its menu and all the preference windows, searching for any trace of option that would allow me to set the Python executable. Having failed, I was convinced that authors didn’t think about including it – which was rather surprising, though.

But hey, DreamPie is open source! So I went to look around its code to see whether I can easily enhance it with an ability to specify Python binary. It wasn’t too long before I stumbled into this vital fragment:

  1. def main():
  2.     usage = "%prog [options] [python-executable]"
  3.     version = 'DreamPie %s' % __version__
  4.     parser = OptionParser(usage=usage, version=version)
  5.     # ...
  6.     opts, args = parser.parse_args()

The conclusions we could draw from this anecdote are thereby as follows:

  • It is indeed true that source code is often the best documentation…
  • …especially for open source programs where actual docs often suck.

With this newfound knowledge about dreampie arguments, it wasn’t very hard to make it use current virtualenv:

  1. $ dreampie $(which python)

And after doing some more research, I ended up adding the following line to my ~/.bash_aliases:

  1. alias dp='(dreampie $(which python) &>/dev/null &)'

Now I can simply type dp to get a DreamPie instance operating within current virtualenv but independent from terminal session. Very useful!

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Author: Xion, posted under Applications, Programming » Comments Off on DreamPie with virtualenv

Counting Lines in Multiple Files

2012-04-06 13:40

Looks like using Linux is really bound to slowly – but steadily – improve your commandline-fu. As evidence, today I wanted to share a little piece of shell acolyte’s magic that I managed to craft without very big trouble. It’s about counting lines in files – code lines in code files, to be specific.

For a single file, getting the number of text rows is very simple:

  1. $ wc -l some.file
  2.   142 some.file

Although the name wc comes from “word count”, the -l switch changes its mode of operation into counting rows. The flexibility of this little program doesn’t end here; for example, it can also accept piped input (as stdin):

  1. $ cat some.file | wc -l
  2. 142

as well as multiple files:

  1. $ wc -l some.file other.file
  2.   142 some.file
  3.    54 other.file
  4.   196 all

or even wildcards, such as wc -l *.file. With these we could rather easily count the number of lines of code in our project:

  1. $ wc -l **/*.py
  2.     3 foo/__init__.py
  3.   189 foo/main.py
  4.    89 foo/utils.py
  5.    24 setup.py
  6.   133 tests.py
  7.   438 all

Unfortunately, the exact interpretation of **/* wildcard seems to vary between shells. In zsh it works as shown above, but in bash I had it omit files from current directory. While it might make some sense here (as it would give a total without setup script and tests), I’m sure it won’t be the case all projects.

And so we need something smarter.

Pimp My WLAN

2012-03-03 20:41

About two weeks ago I moved to Netherlands, landing in a medium-sized but cozy town of Groningen. This of course deserves a general blogpost on its own right (more than a single one, in fact), but the story I wanted to share today is extremely specific. For the most part, it’s also purely technical, exhibiting typical hacker’s dynamics. An overarching theme is an “itch” that needs to be scratched.

Let’s start then, first by defining the problem at hand.

On architectural features

I happen to live in a square which is referred to as town’s center, where significant fraction of buildings – maybe even majority – look kinda like this. Don’t pay too much attention to the outside appearance, as it can be very misleading. Despite their seemingly old architectural style, they’re often quite new and modern, but have been “retrofitted” to match the surrounding urban landscape. Final effect is rather pleasing aesthetically, I’d say.

What is more important and relevant here, though, is the size of windows. By my standards at least, they are simply enormous – and this fact precludes simple evaluation. (On one hand, there’s a lot of sunlight! On the other hand, there’s a lot of sunlight…). Moreover, it hints at how remarkably long the vertical distance between floor and the ceiling is. In my case, it’s about 2.8 m (that’s 9 ft for you Imperalists), having a significant impact on how spacious the apartment feels.

On insufficiently vertical waves

But for the issue I want to talk about, this was actually a downside. The matter concerns Internet access, which is shared among mine and three neighboring apartments through a Wi-Fi network with a single access point. In theory, the area it has to cover spans just couple of meters. In practice, however, it’s hindered not only by walls and doors, but also – and maybe even primarily – but this significant distance along the vertical axis.

See, most of the typical household wireless routers have directional antennae which are deliberately set to output signal mostly in the horizontal plane. While this allows for a single AP to easily cover even big apartment, it is also a liability in a setting similar to mine. Because the access point is on ground floor, it fails to appropriately cover the higher levels. And since this includes the very place I’m living in, I’ve been having rather annoying problems caused by signal’s low strength and quality: dropped packets, lost connections, and all that stuff. Even web browsing (or similar activities that doesn’t really depend on latency) has been very cumbersome, despite sitting less than 5 meters in straight line from the access point! It’s almost amazing how one can get screwed over by such simple design limitation like the direction of an antenna.

So, you can easily see how this was a problem that yearned to be solved. But how? One does not simply make the waves go further, right?…

On re-purposing of the old hardware

Actually, this is perfectly possible: devices known as WLAN repeaters do just that. Serving as sort of amplifier, they can extend the range of wireless network by relaying its signal between base access point and the final receiver, e.g. WLAN interface in a laptop. Basic physics suggest that it obviously cannot be done for free, so side effects include decreased performance of such range-extended networks due to reduced bandwidth. But where applicable, this solution is usually worth its while.


The Router

My scenario was definitely one of those, as I vastly prefer “not ideal Wi-Fi connectivity” to “almost no Wi-Fi connectivity at all”. So I went to investigate how I could procure such a device. Specifically, I had an old router lying around unplugged and useless – and it quickly gained my attention.

I cannot say that I’m any sort of expert when it comes to telecommunication, electronics or hardware of any kind (that’s vastly below the level abstraction I typically operate on), but I have some basic idea of what a wireless router really is. Elementary deduction suggest it’s a transceiver, an equipment able to receive and send out radio signals. What those signals are – that should be pretty much irrelevant, as long as (1) they fit into physical characteristics of the device and (2) the only thing we want to do is to propagate them further.

In short, it should be capable of acting as a repeater! Yay?

On awesomeness of the open source

Well, not really – not at a first glance, at least. While many routers feature the repeater option in their firmware, mine is somewhat old and low-end model: it doesn’t even support IPv6, not to mention goodies like the 802.11n band. Acting as a relay was also on this “nay” list, because being an ordinary access point is pretty much the only thing this inconspicuous black box used to know.

But thanks to one impressive piece of hackery, it was possible for its limitations to be lifted. What I’m talking about is DD-WRT – a community project that provides a custom firmware for variety of different models of popular routers. This firmware is very powerful and allows to easily tap into device’s hidden power, exposing capabilities omitted in vendor software. In my case, it promised to provide the crucial Client Bridge feature: ability to create more then one virtual, wireless interface and form a bridge between them in order to relay network traffic.

On thrills & perils of low-level hacking

I set to try it out – and it turned out to be non-trivial, to say the least. Some steps of the process were amusing due to their obscurity – like setting up a local server for the archaic TFTP protocol. Turns out it was needed for the actual transfer of new firmware and a small Linux distro that works on top of that. I suppose you have to do same when installing Linux on a microwave, but admittedly, I haven’t tried that just yet ;)

The most troublesome part was actually the very beginning. It involved connecting to the device via Ethernet wire and then telnetting at the right moment during it’s boot-up. This way, it is possible to access the RedBoot bootstrapping shell and perform all kinds of surgery on software internals.
Unfortunately, the instruction for making this happen was hopelessly unclear. I spent good several quarters troubleshooting any potential issues, even going as far as to use Wireshark to monitor any traffic originating from the router, looking into how it identifies itself within this crude two-node network.

Fortunately, I’ve later found a much better instruction that didn’t lack the rather important part about holding down the RESET button for, well, long time. From there everything went rather smoothly.

On trickery of network management

The last part was tweaking numerous options and settings in DD-WRT’s web interface in order to make the router talk to its cousin downstairs. This level of abstraction was obviously much more comfortable for me to work at. Still, there was some sorcery involved, as in deciding whether I’d like to have my own subnet or operate within existing one – essentially a choice between WLAN-to-WLAN router or “switch”. The second option was of course much more appealing because it was completely transparent to clients. Choosing it, I didn’t have to reconfigure the vast multitude of my 3 (three) devices that use Wi-Fi :)

This variant ended up being more complicated, though. And again, I have found both good and rather crappy instructions on how to make it happen – but unlike last time, now they were both coming from the DD-WRT wiki. Well, seems like documentation is not among the strongest sides of this project…

It works!

But rest assured: this story has a happy ending :) Yes, it was preceded by juggling IP configuration of my PC and few reboots of the router, but it would be malicious to consider this as something more than a little nuisance.

So, what’s the point in all of this?… I guess the bottom line would be about not being afraid to experiment if something needs to be improved. Risk aversion is powerful, true – but sometimes even failure is not that bad, especially if everything remains inside the realm of software. Here, even if you “blow” something up there will be no holes left to cover with duct tape ;-)

Nieoficjalne debugowanie na Androidzie

2010-12-22 22:00

System Android, jak powszechnie wiadomo, jest licencjonowany kategorią open source, więc istnieje możliwość w miarę łatwego umieszczenia go na urządzeniach mobilnych bez konieczności współpracy z Google. Wykorzystują to producenci różnego rodzaju mniej lub bardziej “nieoficjalnego” sprzętu, działającego pod kontrolą tego systemu. Mogą to być produkty, które trudno klasyfikować inaczej niż jako tanie imitacje, ale także sprzęt produkowany przez (u)znane firmy – jak choćby tablet stworzony przez Creative. Ich wspólną cechą jest domyślny brak wsparcia przez narzędzia wspomagające pisanie aplikacji dostępne w ramach SDK Androida – przede wszystkim Android Debug Bridge (adb), czyli usługę umożliwiającą między innymi debugowanie aplikacji bezpośrednio na urządzeniu. Dla zwykłego użytkownika to oczywiście żadna wada, ale co mają zrobić biedni programiści?…
Okazuje się jednak, że przeszkodę tę da się pokonać. Dzisiaj udała mi się ta sztuka ze wspomnianym tabletem Creative’a i dlatego czuję się upoważniony podzielić się swoim rozwiązaniem :) Wydaje się ono przy tym na tyle ogólne, że powinno stosować do dowolnego urządzenia.

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Author: Xion, posted under Programming » Comments Off on Nieoficjalne debugowanie na Androidzie

Więcej pulpitów

2010-12-09 23:23

Pracując przez chwilę na Linuksie, odkryłem poważną zaletę jego interfejsu graficznego, którą Windows domyślnie nie może się pochwalić. Wirtualne pulpity, bo o nich mowa, to koncept, który w pierwszej chwili może wydawać się nieco dezorientujący. W końcu czasami ma się problem z ogarnięciem okien na jednym tylko pulpicie, więc co dopiero powiedzieć o – powiedzmy – czterech? :) Ale więcej miejsca na bałagan to także więcej miejsca na porządek i jeśli tylko potrafimy dobrze tę powiększoną przestrzeń zagospodarować, możemy znacznie zyskać na efektywności. Ograniczamy bowiem konieczność przełączania między programami za pomocą powolnych i niewygodnych metod, takich jaki klikanie w przyciski na pasku zadań czy pracowite przechodzenie po liście okien za pomocą przełącznika Alt+Tab.

To doprawdy wstyd, że Windows nie oferuje takiego mechanizmu wbudowanego w system. Jakby się jednak chwilę nad nim zastanowić, nie jest on żadnym rodzajem magii. Można go przynajmniej symulować za pomocą odpowiednio przemyślanego ukrywania i odkrywania okien na żądanie użytkownika, przechodzącego między kolejnymi “wirtualnymi «wirtualnymi pulpitami»”. Zdaje się, że właśnie na takiej zasadzie działają programy, które uzupełniają system Windows o tę pożyteczną funkcjonalność.
Rozwiązaniem wypróbowanym przeze mnie jest VirtuaWin. Jest to bardzo mała, ale całkiem zmyślna aplikacja. Bez widocznego narzutu na zasoby systemowe (kilka megabajtów w pamięci) wprowadza ona możliwość przełączania się między wirtualnymi pulpitami przy pomocy typowych kombinacji klawiszy (czyli Ctrl+Alt+strzałki). I to niemal dowolną liczbą wirtualnych pulpitów, do których można automatycznie przypisywać okna na podstawie ustalonych (bazujących np. na klasie okna lub jego tytule). Jedyne, czego tu brakuje, to ładna animacja przełączania zamiast znikających i pojawiających się okien… ale cóż, nie można mieć wszystkiego ;)

W każdym razie polecam przyjrzenie się możliwości powielenia swojego pulpitu nawet bez przyłączania dodatkowych ekranów. Opłaca się.

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Author: Xion, posted under Applications » 2 comments
 


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