Author Archives: jeffrin

Tools

1. GNU core utilities http://savannah.gnu.org/projects/coreutils 2. Miscellaneous system utilities http://userweb.kernel.org/~kzak/util-linux/ 3. utilities for making and checking MS-DOS FAT filesystems http://www.daniel-baumann.ch/software/dosfstools/ 4. Undelete utility for the ext2 file system http://e2undel.sourceforge.net 5. utilities for manipulating files in an ext2/ext3 filesystem http://home.earthlink.net/~k_sheff/sw/e2tools/index.html 6. Determines file type using “magic” numbers http://www.darwinsys.com/file/ 7. filesystem activity monitoring tool http://mytty.org/fspy 8. realtime …

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stackable filesystems . Wrapfs filesystem .

Classroom. Wrapfs is a full-fledged stackable null-layer (or loopback) filesystem that simply passes all operations and objects (unmodified) between the VFS and the lower filesystem. Wrapfs itself, however, is not easy to write for one main reason; it has to treat the lower filesystem as if it were the VFS, while appearing to the real …

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What is a tracepoint ?

Topic Tracepoint Explanation A tracepoint placed in code provides a hook to call a function (probe) that you can provide at runtime. A tracepoint can be “on” (a probe is connected to it) or “off” (no probe is attached). When a tracepoint is “off” it has no effect, except for adding a tiny time penalty …

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Endianness .. Little endian .. Big endian.

Topic Endianness Explanation Endianess is the byte order of the number in the computer’s memory. The number can have any size of bits, bu the most common numbers used are 32 bits (4 bytes) and 16 bits (2 bytes). source : http://www.rapidtables.com/prog/endianess.htm Theory Drop In computing, the term endian or endianness refers to the ordering …

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ls ( -I option ) do not list implied entries matching shell PATTERN

UNIX Command $ls bp cfg.c cfg.h CVS gtk Makefile sample.cfg simpleproxy.c $ls -I gtk bp cfg.c cfg.h CVS Makefile sample.cfg simpleproxy.c $ls -I gtk CVS Entries Repository Root $ls -I CVS gtk main.c Makefile simpleproxy-gtk.c $ls -I cfg.c bp cfg.h CVS gtk Makefile sample.cfg simpleproxy.c $ls -I bp cfg.c cfg.h CVS gtk Makefile sample.cfg simpleproxy.c …

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hung_task_timeout_secs ( modifying system parameters under /proc/sys file tree)

Linux Parameter $cat /proc/sys/kernel/hung_task_timeout_secs 120 $ Parameter Related TEST-MAIL1 ~ #dmesg [cut] “echo 0 > /proc/sys/kernel/hung_task_timeout_secs” disables this message. rm D ffff88107f472c40 0 16705 22512 0x00000000 ffff881014693810 0000000000000086 ffff881000000000 ffff88102013b040 0000000000012c40 ffff880471855fd8 0000000000012c40 ffff880471854010 ffff880471855fd8 0000000000012c40 ffff881017ff8e40 0000000100000000 Call Trace: [] ? schedule_timeout+0x1ed/0x2d0 [] ? dlmlock+0x8a/0xda0 [ocfs2_dlm] [] ? wait_for_common+0x12c/0x1a0 [] ? try_to_wake_up+0x280/0x280 [] ? …

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