Study Notes

Intel server board SE7520BD2 has six DIMMs,each three DIMMs are belong to one channel.There are two banks in this board,each bank contains four ranks.In this way,there would be only four Dual rank of DDR333 in the serverboard. If we use DDR266,there is no limitation for DDR266 memory series.The board could support DDR266 up to 24GB and DDR333 up to 16GB. Single rank DDR333 memory really exist,which I’ve found in the SE7520’s memory list report.However,this report does not give us the details of 4GB DDR333.

I modified the “/etc/rc.d” file by adding “swapon /Swapdir/Swapfile” strings in order to run this command automatically when system start up.

ftp command
Formation: ftp -v -d -i -n -g [hostname]
-v : display all responsable messages
-d : debug mode
-i : elimitate automatical logining
Inner commands of ftp:
1. ![cmd[args]] : use the local shell in ftp command statue.
2. account[passwd] : supply the username and password
3. bye : turn off the ftp session.
4. cd remote-dir : cd the directory of remote-host
5. cd up : cd Up level directory
6. close : shutdown ftp connection between localhost and remote server
7. delete remote-file
8. debug[debug value]
9. dir : list all directories and files in the remote host.
10. disconnect : = close
11. get remote-file [local-file] : download file from remote host to local host.
12. hash : it will display a “#” after every 1024 bit has been transferred.
13. open host [port] : identify the remote host and its port
14. put local-file [remote-file] : upload file from localhost to remote host.
15. pwd : show the current working directory of remote host.
16. recv : = get
17. reset : clear message queue.
18. send local-file [remote-file] : = put
19. size file-name : show the file size of remote host
20. status : show the current ftp status
21. system : show the operated system of remote host
22. user username [passwd] [account] : indicate user’s profile to remote host.

If the ftp server permits,we could issue the following command to change user’s passward:

ftp> quote "site pswd oldpasswd newpasswd" 

In the Linux,there is a ftp tool named “lftp”,for example:

# lftp remote-host
# lftp > open remote-name
# lftp > user username
...... 

(testing ftp: 219.133.55.11 username:product)

In the Red Hat Linux9.0, the default X window setting is Gnome.I installed KDE desktop and then, I changed the desktop starting parameter in order to start x window with KDE. when the setting was confirmed,I rebooted the system. I usually start up my Linux9.0 in text mode,and in this way,input the username and password,issued the “startx” command.Yes,it really opened a KDE window,however,there was nothing in the screen except a living mouse.

I thought it may be caused by something wrong when system initialize.But the same thing happened after restarting the system again. When issued the “startx gnome” command,some error messages displayed and no GUI has been running up.It seemed no way to start my X window again.Some documents I found in the Internet said editing a file named “.xinitrc” could resolve this problem.It was dissapointed when I found no usrful message in both /etc/X11/xinit/.xinitrc.d and /etc/X11/xinit/.xinitrc file. I do not want to lose my operation system and re-install it,it will take me so much time.So,researching in the internet again untill I’ve found this “switchdeskop” command which is used to switch desktop windows between Gnome and KDE. And this command could only be issued before executing “startx” command. I restarted operating system again,and issues the following commands:

# switchdeskop Gnome
# startx 

Yeah!!! I was succeed!The system started up with Gnome desktop.Hmmm,I must found the reason caused this matted through system had been running up.”.Xclient-default” was included in switchdeskop’s manual(by issued: # man switchdeskop) contains messages what I want.For example,the “.Xclient-default” file’s content was listed here:

# pwd
/root
# cat .Xclient-default
*content*
---------------------------
# Created by Red Hat Deskop Switcher
exec gnome-session 

I think the switchdeskop command modified the “.Xclient-default” file so that the initial program read this message and start X window by this setting. To prove my guessing,I changed default starting desktop from Gnome to KDE,and restarted the system again.When system was restarted,the “.Xclient-default”file had really been modied,the string “gnome-session” had been insteaded by the string “startkde”.I changed the “startkde” to “gnome-session” and issued the “startx” command again,the system started up by Gnome desktop.I am right.The “.Xclient-default”file was operated by command “switchdeskop”.

Nautilus is the skin of Gnome.

There are some error messages displayed after installed Marvell Ethernet device in Linux operating system such as Red Hat AS 3.0 and Fedora 1.I issued the following command to check ethernet device’s driver information.

# dmesg | grep eth

Though errors were listed,the other things run very well.Using the ping command to test Marvell Ethernet device is ok,and I could find the right configuration of Marvell Ethernet in the GUI interface.It seems Marvell Ethernet device could work normally.But I still confused why these error messages were showed.

In the Marvell’s installation manual,it shows the matter I meet is caused by compiling in single processor statue.But in factor,there are two Xeon processors in my platform.Why and How?
I’ve called Intel’s support term,they did the installation test and then told me there are no error messages.Did I install the device in a wrong way?

First,I choose the second step to create a pitch during installation.Second,issue the following command:

# ./install.sh

When the driver’s compiling completed,

# modprobe sk98lin

In the GUI,System Setting – Network,I could find Marvell Ethernet device in the hardware list.Click the Device tip, and then click New button to create new profile.For example,Devices – New – Ethetnet Connection ,select Marvell Ethernet device and configure it.Finally,issue the checking command again:

# dmesg | grep eth0

I found no error messages were showed. and then I rebooted system.
In the Linux services,kutzu serviee was used to check and configure new hardware.In the first time rebooting after install Marvell Ethernet device,kutzu asked users to configure the new hardware.
Because I’ve installed Marvell Ethernet device,I choose “Do Nothing” .I issued “# dmesg | eth0”,everything is ok.how could this happen?I think maybe I usually choose “Configure the device” in the kutzu service,and the error messages exist.

DNS,domain name server,usually has a cache server in the font which has a special database.If the request are listed in the database of cache server,turn the specified IP address to user.If the request could not be found,the cache server pass the request to the really DNS server to resolve the address.The /etc/named.conf file contains the parameters of DNS setting,and the /etc/named/named.ca is owned by cache server.The file named “named.ca” will ofen be updated,there are total 13 root DNS server all around world,these root machine’s IP address are indicated in the “named.ca” file.

E-mail system has two main partitions:UA(user agent) and MTA(Message Transfer Agent).US are installed in the client used to write and read mails,many softwares are developed for US,for example,Outlook express,Foxmail or Evolution of Linux.MTA is also called mail server which provides storage and re-sending the mails utilities.There are three common protocol:SMTP,POP3 and IMAP.SMTP(simple mail transport protocol) put the mail to the target address step by step.IMAP(Internet Message Access Protocol) acts like POP3 which is more popurlar.

Linux Mail Server are the following:Sendmail,Qmail,CommuniGate ProMessaging Server for linux,Mail studio 2000.

Sendmail service is installed in the Linux by default.It re-writes the mail’s address,if the address is local,the mail will be saved at /var/spool/mail.

# /etc/rc.d/init.d/sendmail start
# /etc/rc.d/init.d/sendmail stop
# /etc/rc.d/init.d/sendmail restart

In the morning, When inserted the USB device and issued the “fdisk -l” command,there was no item for USB device like sda1 in the list.I had to restart the computer and issued the former order again,the same thing happened with the following messages:

usb.c: USB device 2 (vend/prod ox9a6x0x8001) 
is not claimed by any active driver.

I was very surprised,and then tried to execute the command:

# mount /dev/sda1 /mnt/usb
# ls /mnt/usb

It’s very strange!I could read the files from the USB device.I still did not know the reason.

Grub configuration. Grub is used to boot,it is written in the MBR(boot sector) of harddisk.Grub can boot many operating systems,such as NetBSD,windows.The /boot/grub/grun.conf is the boot manu created by grub,it also contains some important setting information.I will explain this file in detail. The string “timeout” of this file indicates the period of timeout,and the “default = 0” is used to set the default boot operating system,0 is the first listed operating system, and 1 means the second.The string “title” is the name of operating system, users can modify this name by themselves.I’ve renamed the Windows in this way.However,grub does not support Chinese.Splashimage is the backgroud of grub when starts the program.We can also modify this file whch is ofen in .xpm.gz formation,set our favorite picture to be the new background.I edited a picture and used “gzip -1 1.xpm” to create file named “1.xpm.gz”.however,the effection is not good.In my offic computer,the boot partition is known as (hd0,5) by the grub,but Linux recognizes the boot partition as hda6 by issuing “fdisk -l” command.

For example,” Kernel /vmlinuz-2.4.20 ro root=/dev/hda7 “.”/vmlinuz-2.4.20” means the loading kernel,and “ro root = /dev/hda7” is used to pass parameter.Here “ro” means read only.
“initrd” is used to initialize the linux image.Grub used chainloader technology to load other system’s boot information(eg Windows) into the grub boot loader.This statue seems like a chain so we always call this methed “chainloader”

How to make a grub boot disk?

# mke2fs /dev/fd0
# mount /dev/fd0 /mnt/floppy
# mkdir /mnt/floppy/boot
# mkdir /mnt/floppy/boot/grub
# cp /boot/grub/stage1 /mnt/floppy/boot/grub
# cp /boot/grub/stage2 /mnt/floppy/boot/grub
# grub
grub>root(fd0)
grub>setup(fd0)
grub>quit

How to recovery the grub distroied by Windows?
At first,startup the system by Linux setup CD,and when the installation interface is displaying,press F4 to run into linux rescue mode.

sh#
sh# grub
grub> root(hdx,y)    Here y means the boot partition of linux.
grub>setup(hd0)  Written grub to the MRB of harddisk device.

If grub hasn’t menu for user,how could us start operating system?
Get into the grub command line:

grub>cat (hd0,6)/grub/grub.conf  
(Check the parameter of grub.conf,
note the 'hd0,6' is the boot partition,and then use this parameter to boot)
grub>root(hd0,6)   
grub>kernel(hd0,6)/vmlinuz-2.4.20 ro root=/LABEL=/
grub>initrd (hd0,6)/init-2.4.20-9.img
grub>boot

What can I do if I forget the password of root?
In the grub,press “e”, and add “single” following “kernel(hd0,6)/vmlinuz-2.4.20 ro root=/LABEL=/”,note there is blankspace between “/” and “single”.

grub>kernel(hd0,6)/vmlinuz-2.4.20 ro root=/LABEL=/ single
and then press "enter" and "b" to start the system in single mode.
bash#
bash#passwd root

Here change the password of root.

I had two harddisk with each one has operating system.They were installed separately.One is Linux, and other is Windows.How could add windows boot information to linux’s grub (hd0,0)?
check the /boot/grub/device.map to identify whether “hd1” exist or not.If there was not,we shuold add it manually.and then issue the following command in grub:

grub>map(hd0) (hd1)
grub>map(hd1) (hd0)

This method i do not test is not sure.I’ll try later.

Sending email in telnet:

# telnet mail.phillip.com 25
   helo
   mail from: user@test.com   
  (The mail do not really exist,if use formation like "xxx@phillip.com", 
   the connect was off  because it need certify the user.)
   rcpt to: master@phillip.com
  (The mail must based on "@phillip.com" domain)
   date    (Start writing content)
  mime-version=1.0
  from: phillip@milan.com
  to: cocu@barcelona.com
  cc: huang@china.com
  subject: test letter  
 (Here we should press "enter" twice because of RFC882 rules)

(Here is the main content,and then type "." when complete)

.
quit   (quit the mail server)

I tried this method many times,but many letters were considered as rubbish letters.

1st: Runlevel – morning
A runlevel is a software configuration of the system which allows only a select group of processes to exist.The processes spawned by init for each of these runlevels are defined in the /etc/inittab file. Init can be in one of eight runlevels: 0-6 and S or s.The runlevel is changed by having a privileged user run telinit,which sends appropriate signals to init,telling it which runlevel to change to.

Runlevels 0,1 and 6 are reserved.Runlevel 0 is used to halt the system,runlevel 6 is used to reboot the system,and runlevel 1 is used to get the system down into single user mode.Runlevel S is not really meant to be used directly,but more for the scripts that are executed when entering runlevel 1. S or s will bring system to single user mode and do not require /etc/inittab.

Init is invoked, as the last step of the kernel boot sequence,it looks for the file /etc/inittab to see if there is an entry of the type initdefault.

When starting a new process,init first checks whether the file /etc/inittab script exists,if it does,it uses this script to start the process.Each time a child terminates,init records the fact and the reason it died in /var/run/utmp and /var/log/wtmp provided that these files exist.

After it has spawned all of the processes specified,init waits for one of its descendant processes to die, a powerful signal or until it is signaled by telinit to change the system’s runlevel.When one of the above three conditions occurs,it re-examinates the /etc/inittab file.New entries can be added to this file at any time.However,init still waits for one of the above three conditions to occur.

To provide for an instantaneous response,the telinit Q or q command can wake up init to re-examinate the /etc/inittab file.

I tried some test after reading init command manual.The results are listed here.
init 1 telling INIT to go to single user mode.
init 3 restart the system to run in test mode
init 4 restart those service which is default selected but had been cancelled
init 5 get the system to run in GUI mode
init 6 reboot the system

2nd: iostat – afternoon
The target is to get the transfer rate of harddisk reading and write in Linux.Throught seaching in the internet, I used command “hdparm” in the following way: # hdparm -t -T /dev/sda,but I can only get the report about reading and write data from the cache of the harddisk.It’s not useful.
I had to read more documents in the internet,and then find the command named “iostat”.Issue this command in the terminate: # iostat, and then bash told me there was not iostat existing.So I want to locate the iostat command:
#find -name ‘*stat’,as the result,serveral commands about status are listed in the /usr/bin directory,except iostat.What’s the matter?I thought perhaps the problem had some relation with packages installed.

In the Gnome,clicked icon in the toolbar in the following sequence: Applications – System Setting – Add/Remove applications. I checked the packages one by one, and then found the option which said “sysstat-The sar and iostat” contained in the “System Tools Package Details” item.However,this option is not selected by default.Then,choose this item and run updating program that need RHEL 4.0 installation CD 2 and CD3.
After updated,rebooted the operating system and issued the iostat again.That’s find. A report was printed in the screen.We can get statistic about block mount without no parameters added.The data transfered in kilobyte formation seems more useful for us,we can add “-k” following iostat command.for example,# iostat -k

As Oracle’s statepack,we could get the informating at serveral time interval.

# iostat 2 6

It will display six reports at two seconds interval. I got a low transfer rate when no program was running on the system.By using stress which is a common testing tool for Linux,the rate raised much higher when the stress testing block size was from 1G to 3G:

#stress -c 4 -d 2 --hdd-noclean --hdd-bytes 1G(or 3G later)

(138000kB/s when 3G was defined as parameter)
That was the number what we want to get.

How many roads must a man walk down
Before they call him a man
How many seas must a white dove sail
Before she sleeps in the sand
How many times must the cannon balls fly
Before they’re forever banned
The answer, my friend, is blowing in the wind
The answer is blowing in the wind

How many years must a mountain exist
Before it is washed to the sea
How many years can some people exist
Before they’re allowed to be free
How many times can a man turn his head
And pretend that he just doesn’t see
The answer, my friend, is blowing in the wind
The answer is blowing in the wind

How many times must a man look up
Before he can see the sky
How many ears must one man have
Before he can hear people cry
How many deaths will it take
‘Till he knows that too many people have died
The answer, my friend, is blowing in the wind
The answer is blowing in the wind

POP3(Post Office Protocol 3),the 3rd version of post office protocol.It specifies the protocol which contain connection between mail server and person computer,and then downloading the mail from servers.POP3 is the first offline protocol of mail receiving.POP3 server is the mail server following the POP3 protocol.

POP3 commands:

USER username
PASS password
APOP name,digest
STAT status of mail
UIDL n
LIST n list all mails and indicate number and size
RETR n retrieve the content of mail
DELE n delete the mail
RSET comment all delete issues
TOP n,m return the first m lines of the No. n mail
NOOP
QUIT exit
I used telnet to test POP3 commands,for example,issue the following comands in the ternimal:(Note,the port of POP3 is 110)

# telnet mail.tom.com 110
Trying 219.133.55.213...
Connected to mail.powerleader.com.cn (219.133.55.213).
Escape character is '^]'.
+OK POP3 ready

And then,input username and password to list and read all mails.

Identify the language supported by the operating system:

# locale -a 

This command will list all languages supported.

Checking the new hardware:

# /etc/init.d/kudzu {start | stop}

It’s very hot, and I was sick. Feel terrible and have no spirit.
Computer is a friend indeed who does never lie.
It always tell me the turth,whenever and wherever.