How USB assign an address for a new device
When you plug a new usb device, it assigns a new address information even though it is the same device and there was no addition in between this unplug and plug operation. This is because kernel assign a new address each time, it is connected as you can see in below. 914 static void choose_address(struct… Continue reading
Why cached memory doesn’t reclaimed with drop_caches request?
It is very common that your system is suffered from lack of free memory and found that most of the physical memory was consumed by ‘buffer/cache’. Because ‘buffer/cache’ can be reclaimed when memory is under pressure, user usually doesn’t need to worry about that and most of the time, keeping cache is desirable as it… Continue reading
Fast Linux Kernel Compile
Compiling Linux Kernel is a boring job. It takes really long period of time. In my laptop, it took more than an hour. Fortunately, there’s option you can make it faster. Actually, it’s not Kernel’s option. It is provided by ‘make’ command. To speed up the compile, you can create more than one thread for… Continue reading
simple explanation about ‘lsmod’ output
When you execute ‘lsmod’ command, you would see something like this. [root@localhost ~]# lsmod Module Size Used by ipheth 5105 0 cpufreq_stats 3117 0 fuse 51432 3 ebtable_nat 1431 0 ebtables 12142 1 ebtable_nat bridge 57131 0 stp 1438 1 bridge … It shows very simple and clear information but I couldn’t understand what ‘Size’… Continue reading
Simple recipe to build your own LXRed Linux Kernel Source in Fedora 13
$ yum install git inkscape postgresql postgresql-server texlive ctags perl-CGI-Ajax perl-CGI-Simple perl-DBD-Pg perl-HTML-Parser perl-Template-Toolkit perl-Term-ProgressBar.noarch perl-Term-Size perl-TermReadKey perl-Devel-Size gcc gcc-c++ texlive-utils texlive-latex perl-ExtUtils-MakeMaker perl-CPAN perl-YAML libpng libpng-devel texinfo perl-Digest-SHA1 wget http make icoutils xapian-core perl-Search-Xapian perl-CPAN perl-Search-Xapian gifsicle $ cd /tmp && wget http://www.ctan.org/get/fonts/bbding/bbding.ins http://www.ctan.org/get/fonts/bbding/bbding.dtx $ cpan $ cpan -fi Search::Xapian $ mkdir /opt;… Continue reading
Interesting article ‘Interview: Ingo Molnar’
One of the main contributor into the Linux kernel is Ingo Molnar. I found this article while checking removal of ‘get_irqlock()’ in Kernel 2.6. Even though, it doesn’t mention about this in detail, it was good material to understand what jobs Ingo did and what was the main feature of O(1) scheduler and others. Check… Continue reading
How could I reduce kernel’s binary size as small as distribution’s size
The basic steps to compile kernel and modules are similar to following. make modules && make bzImage && make modules_install && make install It will install the kernel related files into the proper location after compile modules and kernel. But maybe you could be surprised by the final binaries size. Sometimes, it shows more than… Continue reading
A software engineer who loves any technologies that makes life easier. That’s why I love Linux and Mac at the same time.