Resume and bio of the author Couple of articles related to my hobby - robotics
My impressions about immigration to Australia. In Russian only. Recipes for everyday problems solving
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Andrey Mikhalchuk’s Blog

Technoblog about life

Apr 11, 2014 Attaching >2Tb disks to Linux

Here is the sequence of commands to make disk space usable in Linux for disks >2Tb (so your regular fdisk won’t help you here).

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Sep 27, 2013 rPlay rocks!

I’m currently beta-testing rPlay and this software totally rocks! What’s rPlay? Well, imagine yourself willing to share content of your iPhone or iPad screen with you family. There are couple ways to do this: you can get an Apple TV ($99) or … well, that’s actually it. AirPlay is a proprietary protocol so the number of options is actually extremely limited.

Last year a small revolution happened: Raspberry Pi got released to the markets. Raspi (short for Raspberry Pi) is awesome. For just $35 you can get a computer powerful enough to output 1080p video to your TV yet small enough to fit your pocket. There are currently dozen mostly Linux-based operating systems running on this computer and the platform is totally open (unlike Apple). Obviously it didn’t take long for hackers to implement AirPlay on Raspi so now for just $35 (well, plus SD card, cables, power supply, case, shipping = about $70) you can play music from any i-device to speakers attached to Raspi. Effectively you can turn Raspi into an Apple equivalent of AirPort Express, but not Apple TV.

For streaming video Apple uses slightly different functionality called AirPlay Mirroring and this protocol was not implemented on Raspi yet. Until now. Smart guys from VMLite finally figured out a way to mirror video from iPhone/iPad via Raspi to the TV. Not sure how long it took them to do this incredible work, but it actually works. Well, it is still in beta, but totally usable and shows great performance.

rPlay is a great tool for presentations, sharing Youtube videos with your friends and family or playing iPhone games on a large screen. Here are a few great features of this software:
– It supports both landscape and portrait mode (rotate your iPhone and the image on the TV will rotate as well)
– Has great video and sound synchronization – something a lot of streaming software lacks. Well, there is a half-second delay when you output sound via HDMI, but if you plug speakers via USB port all is in sync. I guess that’s why they call it beta.
– It is quite stable. I kept switching streaming from one iDevice to another and once it froze. But, again, this is beta and I kept beating it hard, so given the circumstances it is very solid even in beta-version
– One extra cool feature is a limited support for Google Chromecast. Personally I do not use it much as AirPlay covers it all but for Android users that’s some great news.

I already mentioned multiple times that the current version is in beta stage, so there are a fe quirks which hopefully will get resolved in the final version:
– the video and sound being not in sync when sound is played over HDMI (use USB sound output to fix this problem)
– Netflix 1080p streaming is not smooth enough. If you overclock Raspi it gets better, yet still not as smooth as being played without mirroring
And that’s basically it. I saw a lot of “final versions” being released with such minor defects. Microsoft would totally release it :) Still I’m really glad VMLite decided to keep polishing the software until perfect and can’t wait for the final product.

Sep 6, 2011 Netbeans doesn’t stop on breakpoints while debugging a RoR (Ruby on Rail) app

I recently switched to a different computer and got all gems in the system updated approximately at the same time. Not sure what exactly lead to the problem, but debugging the app in NetBeans became impossible because it stopped stopping on breakpoints. To add some confusion, breakpoints were still working in tests, as I discovered later, just not when I was doing something in Firefox. I tried all recipes including

  • Upgrading Netbeans to the most recent version supporting RoR (Netbeans sropped Ruby support and the latest version still supporting it is 6.0.1)
  • Checking the extended attributes of all folders. Apparently in MacOS if the project folder has an extended attribute NetBeans can’t debug it. Every time you use “extended” HFS+ features like changing background color of a directory in Finder MacOS adds an “extended” attribute to that folder. You can see it but running “ls -l” and noticing “@” character in the file permissions.
  • checking if rdebug is running fine. I used telnet and wireshark to see the communications between rdebug and NetBeans and saw all breakpoints set properly.

So nothing helped until …

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Oct 28, 2010 Rails: what happens when memcached goes down

I tried to figure out how rails reacts to the fact that memcached goes down. Unfortunately there is no god documentation about this besides saying that everything will be fine. Also there are couple misleading posts in different forums saying that rails will never rediscover memcached server that went down and came back again. Here’s what is actually happening…

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Jun 19, 2010 Fix: Error: register r24, r26, r28 or r30 required

I was recently compiling some Arduino code with NewSoftSerial and got hit by infamous “Error: register r24, r26, r28 or r30 required” error. NewSoftSerial is a great library and those using older avr-gcc compiler enjoy it alot. Problem is the newer gcc doesn’t like one nasty error in the code and here is how to fix it …

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May 25, 2008 Consolidating All Media Files With Archos 605 and Linux Media Server

Many people are dreaming about consolidating all media files (video, music, pictures etc) in a single place. For some it is a huge full of DVDs, CDs and photos. Others buy hardware media servers and store all files in them. I chose a solution based on Archos 605 WiFi and a Linux Server running UPnP Media Server. Here’s how it works …

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Apr 24, 2008 MineStream Defender – the ultimate network security device

MineStream Defender - the ultimate network security deviceLast 12 months I was working on an interesting device that provides the network security features many companies and families are dreaming about. You probably already have heard about different threats out there like internet predators, viruses, spyware, dangerous websites, confidential information leaking from your business and others. Also you probably tried to find answers to questions like

  • Is my office network used appropriately? Do people really use it for work and not something else?
  • Are my kids safe in the Internet? Are their virtual friends really friends?
  • Why is my internet so slow?
  • Who in my network is using the internet most, when and what for?
  • How can I prevent my children or employees from browsing inappropriate content, wasting time in chats or games?

Finally, you might want to get answers to the questions immediately and you don’t want to spend a lot of time configuring every single computer in your network, installing software and other techi stuff … So the answer to all those questions is one small box called MineStream Defender and here is what it can do …

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Apr 17, 2008 Solving “configure: error: C++ compiler cannot create executables” problem

c++You ran ./configure and got “configure: error: C++ compiler cannot create executables”. Here is how to fix it …

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Apr 17, 2008 Squid: unrecognized httpd_accel_port, httpd_accel_with_proxy on, httpd_accel_uses_host_header

Squid proxyI was recently installing squid at home as a single caching proxy for all computers in my home network. The simple way is just running squid on your linux router as is and configuring every single browser on all computers in your network so they access internet using squid. That’s doable, but boring. The more interesting way is setting up transparent proxy so all your http traffic goes through squid automatically. I’m not going to explain how to setup the transparent proxy as there are tons of articles in the internet about that, for instance:


The documentation is very straightforward, and has just one problem: it is outdated and doesn’t work with the most recent versions of squid. I’ve read several instructions and was always ending up with these error messages:

2008/03/23 01:51:52| parseConfigFile: line 26 unrecognized: 'httpd_accel_port 80'
2008/03/23 01:51:52| parseConfigFile: line 27 unrecognized: 'httpd_accel_with_proxy on'
2008/03/23 01:51:52| parseConfigFile: line 28 unrecognized: 'httpd_accel_uses_host_header on'

Here’s how to fix the problem …

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Mar 8, 2008 Software review

I prepared a page with my favorite software review. Most (if not all) of the utilities are for free and I hope you will enjoy those useful tools.

Site Map (c) Andrey Mikhalchuk, 2005-2008