khugepaged eats up all the cpu in Fedora 15

see https://bugzilla.redhat.com/show_bug.cgi?id=735946, the following seems to help

echo never > /sys/kernel/mm/transparent_hugepage/defrag
echo madvise > /sys/kernel/mm/transparent_hugepage/defrag

Android copy apps from old sd to new sd card

First, do not do automount, otherwise all the ownership and permission will be wrong. Format new sd card from windows.

# mount /dev/sde1 /mnt/oldsd
# mount /dev/sdg1 /mnt/newsd
# cp -a /mnt/oldsd/* /mnt/newsd
# cp -a /mnt/oldsd/.* /mnt/newsd
# cd /mnt/newsd
# rsync -av /mnt/oldsd .
# umount /mnt/oldsd
# umount /mnt/newsd

Now the apps on the new sd will be recognized.

Editing Initrd

extracting initrd

mkdir initrd
cd initrd
zcat ../initrd.img | cpio -i --make-directories

repacking

(find . | cpio -H newc -o) > ../initrd.img
cd ..
gzip initrd.img
mv initrd.img.gz initrd.img

upbacking modules.cgz

gzip -dc modules.cgz > /tmp/modules.cpio
cd /tmp/
mkdir modules
cd modules
cpio -idumv < ../modules.cpio

repacking modules.cgz

find . -print -depth |cpio -H crc -ovF ../modules.cpio
cd ..
gzip -S .cgz modules.cpio 
cp modules.cpio.cgz  modules.cgz

custom kernel with rpmbuild

make targets:

make
make modules
make modules_install

Generate patch:

diff -Naurp old new > my.patch

Modify kernel steps
put the following in .rpmmacros:
cat ~/.rpmmacros
%_topdir %(echo /home/user/mypath)/rpm
%_tmppath %(echo /home/user/mypath)/rpm/tmp
%debug_package %{nil}

• install the src package

  rpm -i kernel*.src.rpm

• generate patches and put in SOURCES
• modified kernel*.config in SOURCES
• modified SPEC/kernel*.spec to pickup the patches
  Patch3000: my.patch
  %patch3000 -p1

apply the patch (cd to SPECS)

rpmbuild -bp --target=i686 kernel-2.6.spec

build:

rpmbuild -bb --with baseonly --without debug --without debuginfo --without kabichk --target=i686 kernel-2.6.spec

use buildid to change buildname
build without rpm

rpmbuild -bp kernelsrc.rpm
cd rpm/kernel/sourcedir
cp favor_config to .config
make menuconfig # set prefix
make -j8
make modules_install
make install

Java

http://triton.towson.edu/~mzimand/os/Lect2-java-tutorial.html
http://en.wikipedia.org/wiki/Comparison_of_Java_and_C%2B%2B
http://triton.towson.edu/~mzimand/os/Lect2-java-tutorial.html