Archive for the Category: Uncategorized

Building a Raspberry Pi-based camera powered by Ethernet

The first built camera was installed in a remote place with no Ethernet connection, so it had to be WiFi-connected. The second camera, however, would replace an existing outdated IP camera, so there was Ethernet connection. Considering this, I decided to power it through Ethernet.

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Reverse-engineering the EMZ karaoke format, or watch out the API calls

Worked on adding support for the EMZ karaoke format to the Karaoke Player application, and would like to share another good reverse-engineering technique. EMZ is a Karaoke format similar to the old Karafun, based on a password-protected ZIP archive. Unlike Karafun, the password is not embedded into the archive, but is derived from a some […]

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Generating C or Java byte array from a binary using command-line tools

Once in a while during development a software engineer needs to embed the binary object as byte array in C or Java language. While coding a solution is simple, it could be achieved by the following command line on Linux or cygwin: For unsigned data: od -v -t u1 <binary file> | cut -c9- | […]

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OpenSuSE 13.2: do not use BTRFS as rootfs

OpenSuSE 13.2 comes with BTRFS chosen as your default rootfs, replacing the old trusted ext4. Unfortunately the kernel version it ships with contains a known flaw which breaks some software using preallocated files and mmap() on them. Known issues have been reported for rtorrent (failed synchronization) and KDE (plasma-desktop crashes and could not be restarted […]


Running Mac OS X under qemu/KVM on AMD CPU

Due to the excellent work of Gabriel L.Somlo it is possible to run the emulated Mac OS X on Linux under Qemu/KVM. The changes seem to be minimal, and the operating system emulation works well – as long as you have the Intel CPU, that’s it. If you have only the AMD CPU, the emulation […]


Practical difference between epoll and Windows IO Completion Ports (IOCP)

Introduction This article compares the difference between the use of epoll and Windows I/O Completion Port (hereby IOCP). It may be of interest to system architects who need to create a high-performance cross-platform networking servers, and to software engineers porting such code from Windows to Linux or vice versa. It may also be of interest […]


Preventing WordPress comments spam

There seem to be an easy way to prevent a significant number of WordPress comment spam. The majority of spam comments nowadays come with either a bunch of URLs, or with a generic message such as: Hi there! Just discovered your site while i was browsing and i must say that i found it quite […]

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Android dialog to choose a directory or file based on AlertDialog

This dialog could be used to let the user choose a file or directory. Since it is based on AlertDialog it doesn’t have to be instantiated through startActivity() and therefore could be used, for example, in a PrederenceDialog subclass. The provided code only selects the directories, but it is easy to modify it to select […]


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