thinkiii

uboot - set up memory tags

2012-02-05T06:21:00.001-08:00

arch/arm/lib/bootm.c
setup_memory_tags

tmux

2012-02-05T05:53:00.000-08:00

1) switch panes

ctrl-b + o

2) scroll back

crtl-b + [

to quit scroll mode, press 'q'

tmux.conf

2012-02-05T05:32:00.000-08:00

set-option -g prefix C-a

remap control prefix to ctrl+a

screenrc

2011-12-29T07:30:00.003-08:00

startup_message off
termcapinfo xterm ti@:te@
defscrollback 5000
#caption always "%{= kw}%-w%{= BW}%n %t%{-}%+w %-= @%H - %LD %d %LM - %c"
caption always "%{= kw}%-w%{= BW}%n %t%{-}%+w"
screen -t alpha bash
screen -t bravo bash
screen -t charlie bash
screen -t delta bash
screen -t echo bash
screen -t foxtrot bash
screen -t glof bash
screen -t hotel bash
screen -t india bash
screen -t juliet bash
select alpha

vimrc

2011-12-29T07:30:00.001-08:00

set nu
syntax on
colorscheme evening
set cul
set hlsearch
set ruler
set ai
set nojoinspaces
set formatoptions=qtcor
"set foldmethod=marker
set history=500

"ctags
"use the ctags for tag search
set tags=$CTAGFILE
"search non-cscope tag first
set csto=1
ab tl Tlist
ab tls TlistSync

"cscope
"use cscope to find caller, callee...
set nobackup
set cscopetag
cs add $CSCOPEFILE
map c :cs find c =expand("")
map d :cs find d =expand("")
map e :cs find e =expand("")
map f :cs find f =expand("")
map g :cs find g =expand("")
map i :cs find i =expand("")
map s :cs find s =expand("")
map t :cs find t =expand("")

ab sc set spell
ab nsc set nospell
ab #i #include
ab #d #define
ab #e #endif
ab #p #pragma
ab pn PRINT_NOTICE("start\n");
ab pi PRINT_INFO
ab pe PRINT_ERR
ab pd PRINT_DEBUG
ab #c \////////////////////////////////////////////////////////////////////////////////
\
\
\//////////////////////////////////////////////////////////////////////////////

autocmd BufReadPost *.c set sts=8
autocmd BufReadPost *.c set sw=8
autocmd BufReadPost *.c set expandtab
autocmd BufReadPost *.c set cin
autocmd BufReadPost *.cpp set sts=8
autocmd BufReadPost *.cpp set sw=8
autocmd BufReadPost *.cpp set expandtab
autocmd BufReadPost *.cpp set cin
autocmd BufReadPost *.h set sts=8
autocmd BufReadPost *.h set sw=8
autocmd BufReadPost *.h set expandtab
autocmd BufReadPost *.h set cin
autocmd BufReadPost *.tex set tw=80
autocmd BufReadPost *.tex set ai
autocmd BufReadPost *.sh set sts=8
autocmd BufReadPost *.sh set sw=8
autocmd BufReadPost *.sh set expandtab
autocmd BufReadPost *.sh set cin

bashrc

2011-12-29T07:28:00.000-08:00

# .bashrc

# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi

# check terminal
if [ "$TERM" = "rxvt-unicode" ]; then
alias vim='TERM=xterm vim'
fi

# set a fancy prompt (non-color, overwrite the one in /etc/profile)
PS1='${debian_chroot:+($debian_chroot)}\u@\h:\$ '

# User specific aliases and functions

alias ls="ls --color -F"
#alias ls="ls"
export P4CONFIG=.p4config
export SVN_EDITOR=vim
export PATH=/sbin:$PATH

#alias expctgp="export CTAGFILE=$HOME/Perforce/tags; cd ~/Perforce/"
#alias expctgw="export CTAGFILE=$HOME/workshop/tags; cd ~/workshop/"
alias expctgl="export CTAGFILE=$HOME/workshop/source/linux-3.1.1/tags; export CSCOPEFILE=$HOME/workshop/source/linux-3.1.1/cscope.out; cd $HOME/workshop/source/linux-3.1.1"

set_ctag() {
echo "export CTAGFILE=`pwd`/$@"
export CTAGFILE=`pwd`/$@
}

set_cscope() {
echo "export CTAGFILE=`pwd`/$@"
export CSCOPEFILE=`pwd`/$@
}

# convert a number into decimal format
n2d() {
perl -e "printf \"%d\n\", $@"
}

# convert a number into decimal format (floating number)
n2f() {
perl -e "printf \"%f\n\", $@"
}

# convert a number into hex format
n2h() {
perl -e "printf \"%08X\n\", $@"
}
alias n2x="n2h"

# convert a number into binary format
n2b() {
perl -e "printf \"%08b\n\", $@"
}

# convert a number into number of mage (2^20)
n2m() {
perl -e "printf \"%d (M)\n\", $@/1024/1024"
}

# convert binary number into hex format
b2h() {
perl -e "printf \"%02x\n\", 0b$@"
}
alias b2x="b2h"

converting hex/decimal/bianry with bash

2011-04-21T03:14:00.000-07:00

put this functions in the ~/.bashrc

# convert a number into decimal format
n2d() {
perl -e "printf \"%d\n\", $@"
}

# convert a number into hex format
n2h() {
perl -e "printf \"0x%X\n\", $@"
}

# convert a number into binary format
n2b() {
perl -e "printf \"0b%b\n\", $@"
}

格言

2011-02-07T17:34:00.001-08:00

李叔同大師說佛----佛家禪宗處世格言
有才而性緩，定屬大才。
有智而氣和，斯為大智。
氣忌盛，心忌滿，才忌露。
有作用者，器宇定是不凡，
有智慧者，才情決然不露。
意粗性躁，一事無成，
心平氣和，千祥駢集。
世俗煩惱處，要耐得下，
世事紛擾處，要閒得下，
胸懷牽纏處，要割得下，
境地濃艷處，要淡得下，
意氣忿怒處，要降得下。

原文網址: 李叔同大師說佛 | 阿彌自在皆佛陀，八方自由皆心誠。 | alix | NOWnews 部落格 http://blog.nownews.com/article.php?bid=3025&tid=73300#ixzz1DKKhsB4V

2011年度目標

2011-02-05T16:52:00.003-08:00

健康
家人
朋友

事業 (降低長期風險、創造自己的大運氣

set default window size and font in gVim

2010-10-29T05:50:00.000-07:00

click on
edit>startup settings to edit the vimrc in windows

"set defautl window size
set lines=24
set columns=90
"set default font:size
set guifont=Courier\ New:h14

OS development

2010-10-10T07:29:00.000-07:00

http://www.cs.ucla.edu/~kohler/class/10f-aos/lab1.html

google C++ coding style

2010-10-04T17:14:00.000-07:00

http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml

gen_ctags

2010-09-27T05:12:00.000-07:00

# setting
WORKDIR=`pwd`
# get all file list
echo "get all file list"
rm ctags.Uranus ctags.utopia 2>/dev/null
find $WORKDIR/Uranus/ -name '*.[HhCc]' >> ctags.Uranus
find $WORKDIR/Uranus/ -name '*.cc' >> ctags.Uranus
find $WORKDIR/Uranus/ -name '*.cpp' >> ctags.Uranus
find $WORKDIR/utopia/ -name '*.[HhCc]' >> ctags.utopia
find $WORKDIR/utopia/ -name '*.cc' >> ctags.utopia
find $WORKDIR/utopia/ -name '*.cpp' >> ctags.utopia

# remove unwanted files

echo "remove unwanted files"
# Uranus
sed -i /Cus60/d ctags.Uranus
sed -i /eCospro/d ctags.Uranus
sed -i /Trunk/d ctags.Uranus
sed -i /u3/d ctags.Uranus
# utopis
sed -i /u2/d ctags.utopia
sed -i /u3/d ctags.utopia

sed -i /t2/d ctags.utopia
sed -i /t4/d ctags.utopia
sed -i /t7/d ctags.utopia
sed -i /t8/d ctags.utopia
sed -i /t9/d ctags.utopia
sed -i /t11/d ctags.utopia
sed -i /t12/d ctags.utopia
sed -i /t13/d ctags.utopia
sed -i /titania4/d ctags.utopia
sed -i /titania7/d ctags.utopia
sed -i /titania8/d ctags.utopia
sed -i /titania9/d ctags.utopia

sed -i /Janus/d ctags.utopia
sed -i /janus/d ctags.utopia
sed -i /j2/d ctags.utopia

sed -i /s7/d ctags.utopia
sed -i /s7j/d ctags.utopia
sed -i /s7ml/d ctags.utopia
sed -i /s7ld/d ctags.utopia
sed -i /s8/d ctags.utopia

sed -i /maria10/d ctags.utopia
sed -i /prans2/d ctags.utopia

sed -i /r2/d ctags.utopia

# generate tag file
cat ctags.Uranus ctags.utopia > ctags.files
echo "generate tag file"
ctags -L ctags.files
#cscope -b -q -k

# generate file list for Perforce
echo "generate file list for Perforce"
ESCSTR=$(echo "$WORKDIR" | sed -e 's/\//\\\//g')
echo $ESCSTR
echo "sed -e 's/$ESCSTR//g' ctags.files > ctags.p4"
sed -e "s/$ESCSTR//g" ctags.files > ctags.p4

# export global variable
echo "===== IMPORTANT ====="
echo "please export the following variable"
echo "export CTAGFILE=$WORKDIR/tags"

linux dump stace functions

2010-09-25T23:53:00.001-07:00

1) dump_stack

哈佛管理世界中有這樣一篇小文 (未查證，不過第一眼感覺寫得不錯)

2010-09-06T22:39:00.000-07:00

一：沉穩

（1）不要隨便顯露你的情緒。

（2）不要逢人就訴說你的困難和遭遇。

（3）在徵詢別人的意見之前，自己先思考，但不要先講。

（4）不要一有機會就嘮叨你的不滿。

（5）重要的決定儘量有別人商量，最好隔一天再發佈。

（6）講話不要有任何的慌張，走路也是。

二：細心

（1）對身邊發生的事情，常思考它們的因果關係。

（2）對做不到位的執行問題，要發掘它們的根本癥結。

（3）對習以為常的做事方法，要有改進或優化的建議。

（4）做什麼事情都要養成有條不紊和井然有序的習慣。

（5）經常去找幾個別人看不出來的毛病或弊端。

（6）自己要隨時隨地對有所不足的地方補位。

三：膽識

（1）不要常用缺乏自信的詞句

（2）不要常常反悔，輕易推翻已經決定的事。

（3）在眾人爭執不休時，不要沒有主見。

（4）整體氛圍低落時，你要樂觀、陽光!

（5）做任何事情都要用心，因為有人在看著你。

（6）事情不順的時候，歇口氣，重新尋找突破口，就結束也要乾淨俐落。

四：大度

（1）不要刻意把有可能是夥伴的人變成對手。

（2）對別人的小過失、小錯誤不要斤斤計較。

（3）在金錢上要大方，學習三施（財施、法施、無畏施）

（4）不要有權力的傲慢和知識的偏見。

（5）任何成果和成就都應和別人分享。

（6）必須有人犧牲或奉獻的時候，自己走在前面。

五：誠信

（1）做不到的事情不要說，說了就努力做到。

（2）虛的口號或標語不要常掛嘴上。

（3）針對客戶提出的"不誠信"問題，拿出改善的方法。

（4）停止一切"不道德"的手段。

（5）耍弄小聰明，要不得！

（6）計算一下產品或服務的誠信代價，那就是品牌成本。

六：擔當

（1）檢討任何過失的時候，先從自身或自己人開始反省。

（2）事項結束後，先審查過錯，再列述功勞。

（3）認錯從上級開始，表功從下級啟動。

（4）著手一個計畫，先將權責界定清楚，而且分配得當。

vimrc

2010-09-02T20:40:00.000-07:00

ab tl Tlist
ab tls TlistSync

where

Tlist is for ctag list
TlistSync is for syncing the ctag navigating window with the current cursor

compound statement expression

2010-06-30T09:23:00.000-07:00

http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html

wield stuff only for gcc, but useful

vimrc

2010-06-29T17:40:00.000-07:00

syntax on
set nu
set ruler
set hlsearch
set cul
colorscheme evening
set vb
cs add cscope.out
set cscopetag
set foldmethod=marker
set tw=80
set ai
set nojoinspaces
set formatoptions=qtcor

"for C programming
ab #i #include
ab #d #define
ab #e #endif
ab #p #pragma
ab #m Min-Hua Chen

"spell check
ab sc set spell
ab nsc set nospell
"ab #c Author(s): xxx
"\Copyright (c) 2008 xxx
"\Permission to copy, modify, and distribute this program is granted

ab #c Author(s): xxx

autocmd BufReadPost *.c set cin
autocmd BufReadPost *.h set cin
autocmd BufReadPost *.pl set cin
autocmd BufReadPost *.cpp set cin
autocmd BufReadPost *.php set cin
autocmd BufReadPost *.py set si
autocmd BufReadPost *.java set si
autocmd BufReadPost *.java set cino+=j1
autocmd BufReadPost *.java set sw=4

Interesting set intersection by using 'uniq'

2010-04-29T20:01:00.000-07:00

I was asked to find the intersection of two IP lists yesterday. I write a simple program with Perl. The program iterates the two lists to find the repeated IPs, which is a O(n^2) algorithm.


foreach $a (@A) {
    foreach $b (@B) {
        if ($a eq $b) {
        ...
        }
    }
}

X forwarding in ssh

2010-03-31T06:41:00.000-07:00

To enable X forwarding, try the following command
ssh -X xxx.xxx.xxx.xxx

than we can launch a program with GUI through ssh.

Sometimes it does not work as expected, check the DISPLAY environment variable.

export DISPLAY=:10.0

duplicate a new table in Oracle

2010-03-31T06:40:00.000-07:00

create table [new table name] as select * from [table name]

Remove VirtualBox lock

2010-03-17T02:11:00.000-07:00

The lock file of VirtualBox is placed in
/tmp/.vbox-[user name]-ipc

default apache2 username on Debian

2010-02-08T18:51:00.001-08:00

www-data

fighting with oci8 - apache2 + php5 + Oracle

2010-01-12T05:09:00.000-08:00

Connecting to the Oracle database by using apache2 + php5 is simple -- if you already know all the traps along the way.

In order to connect to the Oracle database with my apache2 and php5, I've read several tutorials. Many thanks for them.

I want to talk about my experience -- everything is done correctly, but the phpinfo() still shows no oci8 information.

First, you should take a look at the error log of apache in /var/log.
In my case, my error log shows

PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/200 60613+lfs/oci8.so' - libaio.so.1: cannot open shared object file: No such fi le or directory in Unknown on line 0

The log already told me the answer, all I had to do is to install the lobaio.so. I did so and solved the problem.

Another way to discover the problem is to use the ldd command to exam the oci8.so.

linux-gate.so.1 => (0xb7fb3000)
libclntsh.so.11.1 => /opt/oracle/instantclient/libclntsh.so.11.1 (0xb627b000)
libc.so.6 => /lib/i686/cmov/libc.so.6 (0xb610e000)
libnnz11.so => /opt/oracle/instantclient/libnnz11.so (0xb5ec0000)
libdl.so.2 => /lib/i686/cmov/libdl.so.2 (0xb5ebc000)
libm.so.6 => /lib/i686/cmov/libm.so.6 (0xb5e96000)
libpthread.so.0 => /lib/i686/cmov/libpthread.so.0 (0xb5e7d000)
libnsl.so.1 => /lib/i686/cmov/libnsl.so.1 (0xb5e64000)
/lib/ld-linux.so.2 (0xb7fb4000)
libaio.so.1 => not found

It showed the same problem.

rrdtool - every data is a rate!

2010-01-05T04:59:00.000-08:00

This article is about understanding the rate calculating in the rrdtool.

I'm doing a SA project recently. We get the RTTs(round-trip time) by the ping command and write the RTT to a rrd file, print out the graph, ...

More information about the rrdtool can be found on their website.
http://oss.oetiker.ch/rrdtool/

I first created a rrd file:
rrdtool create F.rrd \
--step 10 \
DS:rtt1:GAUGE:20:0:U \
RRA:MAX:0.5:1:35712

Then, I updated some values to the F.rrd file. A interesting fact is that when I update the value at exact the time step (say 10, 20, 30, etc.), I'll have a accurate value.

# rrdtool update F 1262733290:3
# rrdtool update F 1262733300:4
# rrdtool update F 1262733310:5
# rrdtool update F 1262733320:6

1262733300: 4.0000000000e+00
1262733310: 5.0000000000e+00
1262733320: 6.0000000000e+00

OK, there is a thing called "heartbeat" in the rddtool, it helps the updates that occur at a not-accurate timestamps. For example, if we update a value at time 1262733331, the rrdtool will put the value to 1262733330. It's a nice feature, since there is always some delays in the networking world.

Let's take a look

# rrdtool update F 1262733331:7
# rrdtool update F 1262733340:8

1262733330: 7.0000000000e+00
1262733340: 7.9000000000e+00

As you can see, the value 7 is updated at 1262733331 but is shifted to 126273330 in the rrd file. But what happened with the next update at 1262733340? We update 8 but the rrd file recorded 7.9. Strange, right?

Here is how 7.9 comes out: since rrdtool treats every data as a rate, if there are more than one samples before a time step, rrdtool tries to calculate the average rate of all the samples before the time step (after the previous time step, of course).

previous time step: 1262733330
when we update 7 at 1262733331; 8 at 1262733340.
the calculation is
(7 * (1262733331 - 1262733330) +
8 * (1262733340 - 1262733331) ) / 10 = 7.9

Here is a figure to help understanding:

OK, Let's do the math with another example:

# rrdtool update F 1262733341:54
# rrdtool update F 1262733342:3
# rrdtool update F 1262733347:31
# rrdtool update F 1262733350:3

To find out the average value at 1262733350:
previous time step: 1262733340
(54 * (1262733341 - 1262733340) +
3 * (1262733342 - 1262733341) +
31 * (1262733347 - 1262733342) +
3 * (1262733350 - 1262733347)) / 10 = 22.1

Read the rrd file to verify our answer:
1262733350: 2.2100000000e+01

It's a perfect match. :-)

I hope this article can help someone who has the same question as I did.

Config language - sqldeveloper

2009-12-30T19:16:00.000-08:00

sqldeveloper\sqldeveloper\bin\sqldeveloper.config

AddVMOption -Duser.language=en
AddVMOption -Duser.region=US

double fork to avoid zombie process

2009-12-13T04:13:00.000-08:00

It is a common mistake to fork a child process without calling waitpid() to wait for the termination of the child process. Without a wait() call, the child process will become a zombie process after its termination because its parent process does not cleanup its process information in the system. A zombie process occupies a pid in the system, decrease the available pids in the system. Zombies are mark as "defunct" if you check the process by the "ps" command.

However, sometimes we do not want the parent process to wait for its child process for a long time. There is a way to achieve both "not create zombie process" and "not wait for the child process to its termination", and the way is to do a double fork.

The idea is simple, when a parent process (say A) want to fork a child process to do "something". Process A does not fork a process to do "something" directly. Process A first forks a child process (say B), and process then forks its child process (say C) to do "something" and process B terminates as soon as process C is created. In this way, process A only has to wait for process B for a short time. In the same time, since it has no parent process (process B is dead), the system will "rechild" process C to the init process. The init process calls wait() for its child process, solving the zombie process problem.

The program looks like


void func()
{
     pit_t pid1;
     pit_t pid2;
     int status;

     if (pid1 = fork()) {
             /* parent process A */
             waitpid(pid1, &status, NULL);
     } else if (!pit1) {
             /* child process B */
             if (pid2 = fork()) {
                     exit(0);
             } else if (!pid2) {
                     /* child process C */
                     execvp("something");
             } else {
                     /* error */
             }
     } else {
             /* error */
     }
}

kill all child process

2009-12-07T05:26:00.000-08:00

killtree () {
for child in $(ps -o pid= --ppid $1)
do
killtree $child
done
echo "kill -9 $1"
kill -9 $1 2>/dev/null
}
killtree {some pid}

read line in bash script

2009-12-07T05:08:00.000-08:00

It is very easy to read "words" in a bash script. But what if you want to read a line in a text file? I have this problem today, After some googling, I found a interesting way to do this.

while read l
do
echo $l
done < xxx.txt

It use the xxx.txt as input, and the read command in bash will read the input line by line.

linux 802.1q support

2009-12-07T04:59:00.000-08:00

In the previous article "vlan tag under vmware/virtualbox", I found that the e1000 network driver cannot insert vlan tag to frames. In this article I want to tell you that I WAS WRONG.

After some experiments, I found that the e1000 driver does insert the vlan tag into the frames. The problem is that the e1000 driver automatically remove vlan tags when receiving incoming frames before I was trying to read the incoming frames by tcpdump.

So, we can now use liunx + 802.1q module to communicate with vlan members.

vlan tag under vmware/virtualbox

2009-11-15T20:39:00.000-08:00

When I was trying to add a vlan tag on my network traffic, I found that the tcpdump can read the correct vlan id information when I was using VMware or Virtualbox, but it failed to read that on my host machine.

After a lot of googling and test, I found that the Intel Pro/1000 driver has a bug that it automically filter the vlan tag. The reason that VMware and Virtualbox worded fine is that they do not have a Intel Pro/1000 NIC (network interface card).

I will keep my work on the virtual machines. To test the vlan feature:

promote> vconfig add eth0 101
add a vlan interface named eth0.101
promote> ifconfig eth0.101 10.0.0.7/24 up
give eth0.101 a ip and active it
promote> ping -I eth0.101 xxx.xxx.xxx.xxx
ping a ip through eth0.101

we can dump the packet via tcpdump
promote> tcpdump -ne -i eth0 -xx

you can see output message like:

12:54:08.887252 00:0c:29:6f:2e:e2 > Broadcast, ethertype 802.1Q (0x8100), length 46: vlan 101, p 0, ethertype ARP, arp who-has 23.24.4.43 tell 10.0.0.7
0x0000: ffff ffff ffff 000c 296f 2ee2 8100 0065
0x0010: 0806 0001 0800 0604 0001 000c 296f 2ee2
0x0020: 0a00 0007 0000 0000 0000 1718 042b

where the rea-marked bits are the valn id.

Virtualbox share folder with linux

2009-11-12T05:23:00.001-08:00

mount -t vboxsf [-o OPTIONS] sharename mountpoint

wvdial - using SE w980

2009-11-09T05:48:00.001-08:00

[Dialer Defaults]
Phone = *99#
APN = internet
Stupid Mode = yes
Dial Command = ATDT
Modem = /dev/ttyACM0
Baud = 460800
;Init1 = AT+CPIN=0000
Init2 = ATZ
Init3 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Init4 = AT+cgdcont=1,"IP","internet"
Password = internet
Username = internet
New PPPD = yes
ISDN = 0
Modem Type = USB Modem

adobe plash plug-in for firefox

2009-11-04T15:06:00.000-08:00

1)download the plash player (.tar.gz) from adobe's website.
2)decompress the file.
3)cp the libflashplayer.so to ./mozille/plugins
4)enable the plug-in in the add-on menu.

Java indneting in Vim

2009-10-31T18:54:00.001-07:00

edit the .vimrc file:

autocmd BufReadPost *.java set si
autocmd BufReadPost *.java set cino+=j1

or simply
set si
set cino+=j1

NOTE: cino is the abbr for cinoptions

make iso

2009-10-30T02:51:00.000-07:00

make iso from cdrom/dvd:

dd if=/dev/cdrom of=xxx.iso

make iso from directory:

mkisofs -o /tmp/cd.iso /tmp/directory/

vbox share fold

2009-10-30T01:57:00.001-07:00

connect to the share folder in virtualbox: (guest OS: windowsXP)
x: \\vboxsvr\sharename