Nabendu's Blog

http://forum.cyanogenmod.com/topic/18575-cfs-vs-bfs-kernel-scheduler/

While reading about Sino-japan war.I found Japan was almost winning.Suddenly it attacked Perl Harbor.I could not find the motive.What Google search gave a result with details explanation. http://wiki.answers.com/Q/Why_did_the_Japanese_attack_Pearl_Harbor

This the following minimum boot sequence  1) Bootloader loads the Kernel image to Ram      The image may be compressed or uncompressed.Uboot uses a special header in added        to the kernel image and make it as uImage. Using  mkimage we can make the image zImage/vmLinux 2) Ramdisk loaded in the memory, bootloader do that. 3) Control is given to kernel ,it also provides kernel arguments/command line options.Also bootlader set ramdisk as rootfs. Initial Rootfs filesystem may be of ext2 or minix format.   initramfs is the file can be unpacked by kerne l of following formats . . gzip ,  bzip2 ,  LZMA ,  XZ  and  LZO . 3) Then "linuxrc" ran from initial ramdisk. 4) The root device is changed to that specified in the kernel parameter. 5) The init program  /etc/init  is run which will perform the user configurable boot sequence. if rdinit is used then specified binary is called. qemu-system-arm -M versatilepb -m 128M -kernel linux-3.5.3/arch/arm/boot/uI

I was confused between  arm-none-linux-gnueabi and arm-none-eabi .I didn't know where to use what. The gcc naming convention is like as below arch-vendor-(os-)-eabi so for  arm-none-linux-gnueabi is meant for the compilation to elf which uses linux. and  arm-none-eabi is meant for the compilation of the codes which will run on bare metal arm core. The difference is that they use library accordingly to compile the source codes. 

I recently tried to run Xubuntu 12.04 on virtualbox 1.2.0.It was working fine.Then due to some bug in my head :) tried to upgrade virtualbox to VirtualBox-4.2.0_RC3 from here . Now without uninstalling the previous version I installed it.It created problem.While running any Vms after installing extension pack it gave error [ " failed to load vmmr0.r0 (verr_ldr_mismatch_native)" ]. This issue is intially I couldn't solve.Later I solved the issue as following. Remove virtualBox ,remove folders from Program Files then removing "C:\Users\USERNAME\AppData\Local\VirtualStore\Program Files\Oracle\VirtualBox" {Need administrative privilege} Now install VBox freshly and import the virtual image projects/Disks.

This Makefile tutorial by Alex is small but very useful. http://www.cprogramming.com/tutorial/makefiles_continued.html

I became  confused about the utilization of procfs and sysfs.Which one will be used in which place? What I understand as below. Procfs is much more generic interface to provide information to user space.All the process related information and some parameters are also passed to user space through profs file system, Whereas Sysfs is much more modern implementation like procfs.But it is implemented by following Linux driver model and hierarchy.Sysfs stores driver,device information alongside of process information too.As Greg KH told " sysfs is "1 value per file"" . so can be used for full user level driver implementation. Sysfs can do all the work like procfs ,they normally not used as information interface of process.Procfs will be there holding the process in formations. Update 23/10/2013: Sysfs is extensively used by udev. Whenever any sysfs file node is created udev get event and creates device files according to major and minor no it revived.I'll

Suddenly feeling to take one android phone after my tab crashed and bored with my 900rupee samsung guru.Though Guru is very good but feeling calender, camera reminder video calls are very necessary for me. Doing little bit of research about the feature and performances between the HTC sensetion and Samsung Galaxy S2 .Seems like S2 is obvious winner.Though I like HTC outer look very much.The UI is also very good.I used HTC touch phone for very long time so I am very fond of HTC.But as campared by different user HTC has almost double battery life,fron cam is 2.0M ,weight is less and Samsung given S2 to hackers for making custom ROMs.Last thing is very necessary I feel .I like my own ROM don't want to take anything,, though after sometime only I may use it , if and only if I buy S2.. Here are some good comparisons between the smart phones. HTC Sensation vs Samsung Galaxy S II HTC Sensation vs Samsung Galaxy S2

I had rooted my Spice Mi-720 tab long time back.There is no custom rom .But tried to clean up some systems file with root privileged. As usual I crashed it. :( . System is hanging on the splash screen only.. Try myself first else have to go to service center.Probably it's time to hack android in little bit further. 

http://www.wired.com/epicenter/2012/04/opinion-baio-instagram-trend/

The English titles of "Mr", "Mrs", "Miss", "Ms" are all irrelevant as all people are referred to by the suffix -san ( さん ? ) . The more polite -sama ( 様 ? ) suffix is used only in certain contexts with people who are superior in social standing to you, and is also gender-neutral in usage. The most polite suffix -dono ( 殿 ? ) usually, but not always, refers to males, and is rarely used in modern speech. Both -sama ( 様 ? ) and -dono ( 殿 ? ) should be used with caution, and only with more than basic understanding of Japanese social structures.

In generic Asynchronus I/O (AIO) can be designed using User lavel or in Kernel level. In user level 1) Process needs async callback/notification create another thread and process which goes to sleep on blocking calls (read/write/ioctls/select) 2) One Async master handler (process/thread) keeps track.All the process needs the service submit job to them.The master handler handles the async fd in Blocking mode and reply to requesting processes (or call the callback function) using some async notificatin like signal. In Kernel Level 1) Call some system call and submit some job to kernel workQ .After work is complete kernel notify using signal to user space.   In VxWorks :  aioPxLib provide the POSIX 1003.1b standard.Which is task implementation of aio service. functions available: 1) aio_read() - initiate an asyn. read. 2) aio_write() - initiate an syn write 3) aio_listio() - Initiate a aio list upto LIO_MAX 4) aio_error() - Get an aio error status. 5) aio_return() - Get a

Array can be initialized in definition by normal way as below int a[5] = { 1, 1, 1, 1, 1}; Another a good way to fill the array with 0 using static static int a[5]; which fills up the array with 0s or int a[5] = {0}; fills all elements of the array with 0; Another very good way to fill the array with different values when using gcc compiler is as below int a[10] = {[0-2] = 5, [3-9] = 7}; which fills all the array element with 5 and 7s. for more gcc manual http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Designated-Inits.html