Study Notes

Lynx is a type of browser in text mode running in terminal.Download the install package named as “.tar,gz” from internet, and then issue the following commands:

# tar zxvf  lynx-2.8.4dev.19.tar.gz
# cd /lynx-2.8.4
# ./configure
# make  

After executed the final command, the Lynx was installed in the system successfully.Opening a new terminal or hit “ctrl + alt + F2”, issues the “lynx”,and then ,we will get in a text mode browser.Its default homepage is “www.lynxbrowser.org”,we can just modify the startpage in the file which is located on “/usr/local/lib/lynx.cfg” or “$home/lynx-2.8.4/lynx.cfg”.Both of above two files are linked to one file in fact.
I tried to change the language setting to display simplify Chinese and traditional Chinese,but failed.As result,it seems only English would have been supported.In the Lynx browser,it does not show the pictures and flash movies,so it speeds up the opening rate greatly.I think it would be more useful in those machines which run very slowly,for example,486 or higher computers.

This afternoon,Cao Sheng and I went to UP Co. in order to resolve the fiber ether devices installing problem.The customer said he did what I’ve told him to do by email of yesterday.He selected the packages and installed the operating system as Red Hat Linux 9.0, but had found no ethernet device afer rebooting when completed installing processing. In the UP lab, I installed the operating system again by myself,and issued the following command:

# insmod e1000

which I thought the customer did not do this job after issuing “make install”.Before I executed the insmod command, I found no ethernet device by issuing “ifconfig” which is used to checking the net device.After issuing this command,and then check the ethernet devices again :

# ifconfig
# service network restart   

or

# /etc/rc.d/init.d/network reload

the ethernet devices were listed in the terminal or Network interface in GNOME.
Using ping command to identify these device,they runs OK.

SaX2 of SuSE Linux is used to configure the hardware’s parameter,for example,graphics card,ethernet device.SaX2 acts as like Devices Administrator in Windows.
Yast administrates the files throught GUI which like Source Explorer in Windows.

“The device has been validated to run at 80MB/s and should support,(**) 320MB/s when the operating system is loaded” . Configure the RAID0 included two harddisk and left one disk.

What’s LVD?Low Voltage Differential.

#hostname 
#vi /etc/sysconfig/hostname

Using the above commands to show or set the system’s host name.

#vi /etc/inittab

find the strings like “id:x initdefault”. x=3 means startup in text mode,and x=5 means GUI mode.We could configure the x parameter to decide the mode which we want Linux to start in.

mount ISO files

#mount -o loop /abc.iso /mnt/cdrom

mount DVD.

#mount -t iso9660 /dev/dvd /mnt/cdrom
#mount -t udf /dev/dvd /mnt/cdrom

Check hardware info:

#cat /proc/cpuinfo
#cat /proc/meminfo
#cat /proc/interrupt
#cat /proc/ioports
#cat /proc/partitions         
#cat /proc/pci
#cat /proc/swaps

To configure the language of system.

#vi /etc/sysconfig/i18n

Convert cdrom files to ISO files.

#cp /dev/cdrom *.iso
#dd if=/dev/cdrom of=/tmp/*.iso

SMP: symmetric multiple processor
UP : unique process
bigmem: support memory which is more than 1G.

View the color setting by default.

#dircolor -p

If want to install other language package after completing install system,we would insert the RH 9.0 CD3, and then find the specific language package.

To select or un-select the service running.

#chkconfig --list
#ntsysc
#setup

RedHat 9.0 common packages installed:
Desktop:
-X window system
-GNOME Desktop Environment
Application:
-None
Servers:
-None
Development:
-Development Tools
-Kernel Development
-X software Development
System
-Administration Tools
-System Tools

We can remember these packages by the numeric strings “2-3-2”.

PR2510 is based on Intel 7520BD2 server broad.There are total four SCSI harddisks.The customer need three disks to form RAID0 and install Windows server 2003.After configuring the parameter of LSI SCSI,the following messages displayed in the screen:the partition of RAID0 by three disks has 320MB/s rate,however the left one harddisk’s rate is only 80M/S! Below the rate list,these texts displayed: The harddisk is 80M/S,and will support 320M/s when operation system is loaded.

Tang said the state is not error.I will read the LSI documents to probe his words.

Server Platform: Intel 7520JR2
Operating system: Red Hat Linux 9.0(2.4.20)

Using the following commands to install Intel 82545 ethernet card who driver is same as Intel 82546(The board has two 82546 ethernet card,and we added four 82545 card through external card inserted in two slots).

# make install

Configure eth0’s IP and name

# vi /etc/sysconfig/networking-scripts/ifeth0

Copy the driver file for eth1,because they use same drivers.

# cp ifeth0 ifeth1

Configure eth1’s parameter,change the IP and name

# vi /etc/sysconfig/networking-scripts/ifeth1

Copy the driver file for eth2,because they use same drivers.

# cp ifeth0 ifeth2

Configure eth2’s parameter,change the IP and name

# vi /etc/sysconfig/networking-scripts/ifeth2 

……
Copy the driver file for eth5,because they use same drivers.

# cp ifeth0 ifeth5

Configure eth5’s parameter,change the IP and name

# vi /etc/sysconfig/networking-scripts/ifeth5 

Identify whether these devices are installed correctly

 # service network restart

or

# /etc/rc.d/init.d/network reload 

In the PT6250 which is based in Intel SE7221BA1-E platform,using the following command to reflash bios: iflash. Before sending our server machines to the customers,the products’s bios logo would be reflashed with specificed sign which even maybe of OEM’s logo.We usually make updating bios file with ITK tools introduced by Intel.Note,it is necessarily to set the firmware parameter from 4 mega to 8 mega if we use ITK 2.7 to make SE7221’s new bios file.And then,adding the specified picture that is bmp or jpg formation.At last,generate the new bios file and save it to the harddisk.

There will be some trouble when using a picture with deep blue,red or green.The SE7221’s bios program does not support these deep color blocks as well as other light colors such as sky blue.However,as productors,we could not change the logo picture of the customers.
Perhaps contacting with Intel’s TME could resolve this problem.

Other server broad,for example, SE7520BD2 platform,using “run” command with “.rom” file to reflash the BIOS.The latest bios release of SE7520BD2 is 7.40.

A customer requested for proving four FiberCards which are using two external cards in different slots could be installed in the same SE7520JR2 platform.The Operating system the customer said is Linux 8.0. In the supporting operating system lists of SE7520JR2,I found no recorders about Linux 8.0,but Red Linux 9.0,AS 2.1u4, AS 3.0(u1 or u3) and SUSE series exist in this table.I plan to install this four Fiber netcard in Windown system to identify whether the platform hardware could support these devices or not.

Some identified port list: SMTP 25,POP 110, DNS 53, Web 80, FTP 21 or 23, SSH 22.
IP tunneling,which is supported in router and switch software involves encapsulating a packet supporting one protocol with another packet that run the same or a different protocol.
Key components of tunneling:tunneled protocol, transport protocol, multiplexing identifier.

Load balancing feature: High availiability, Scalability.High availability can be defined as redundancy.Scalability is an application’s ability to support a growing number of users.Of the many methods available to balance a server load, the main two are DNS round robin and Hardware load balancers.Each of them has its own advantages and disadvantages.DNS round robin make several IP address directing to the same logic IP, in the scene,all the nodes combine as one to user transparently.This method only distributes IP to every node,but not distribute actural load to nodes because the load of each connect will not be same.

The problem is thart brower caches that server’s IP address.Once the cache expires the broweer make another request to the DNS server for the IP address associated with the domain name.If the DNS server returns a different IP address that of anther server in the cluster.The session information is lost.Changes to the cluster take time to propagate.One reason is that many large organizations,ISPs,coporations,agencies cache their DNS request to reduce netword traffic and request time.When a user within these organizations make a DNS request,it’s checked against the cache’s list of DNS names mapped to IP addresses.If if finds an entry,it returns the IP address to the user.If the entry is not found in its local cache,the ISP send this DNS request to the DNS server and caches response.

When a cached entry expires,the ISP updates its local database by contacting other DNS servers.When your list of servers changes,it can take a while for the cached entries on other organization’s network to expire and look for the updated list of servers.During that period,a client can still attempt to hit the downed server mode,if that client’s ISP still has an entry pointing to it.In such a case,some users of that ISP could not access your site on their first attempt,even if your cluster has rundundant servers up and running.

This is a bigger problem when removing a node than when adding one.When you drop a node,a user may be trying to hit a non-existing server.When you add one, the server may just be under-utilized until its IP address proprogates to all the DNS servers.Although this method tried to balance the number of users on each server,it doesn’t necessarily balance the server load.Some user could demand a high load of activity during their session than uses on another servers.The electrocircuit module suppling processor power in the mainbroad is called VRM.

My favorite star Chirisitian Vieri joins Milan!
Welcome, super Bobo !!!

VIERI JOINS MILAN!
7/5/2005 3:52:00 PM

Christian Vieri is a Milan player. It is finally official. After many talks and rumours, the striker is certain he will wear a red-and-black shirt for the next two seasons. The Italian international, who was released by Inter earlier this week, will find again new enthusiasm and stimulation in a dressing-room where he has known most of the components for a long time. Bobo has scored 179 goals in his professional career, playing in ten different clubs. He made his debut in Serie A at the early age of 17 for Torino. In his first year, he collected six appearances and netted one goal, having all the eyes on him in Italy. The boy from Bologna immediately showed character and the following season, after playing only one game with the Granata side, moved to Pisa in Serie B. He totalled 18 appearances and two nets with the Tuscan side before joining Ravenna the following year. There he estabilished his first goal record in the league, scoring 12 strikes in 32 matches. The attention on him was growing more and more, and with time passing, his qualities emerged distinctly: strength, courage, and ability in the air. Another move the following season and Bobo played his last campaign in Serie B at Venezia where he made 29 appearances and netted 11 goals. The first club who really trusted Christian’s abilities was Atalanta who brought him back in the top flight. In Bergamo he played 19 games and scored only seven goals, but this was just enough for him to win over Juventus who signed him for the following campaign. For the Bianconeri Bobo played 23 games and scored eight goals, with the fans rising against the club when they decided to sell him abroad to Atletico Madrid at the end of the season. In his Spanish experience, under the reign of Arrigo Sacchi, Vieri set a new goal record in the league: an amazing 24 goals in 24 games. But he soon missed the Italian football, and to come back home he accepted the courting of Lazio. In the capital he added 12 more nets to his overall tally, playing 12 games with the Biancocelesti. The most recent part of his career was at Inter who made great sacrifices to sign him. After six years enriched with plenty of goals and appearances, the forward, who will turn 32-year-old next week, has decided to take part from the Nerazzurri. It is summer 2005, the turning point. And Bobo agrees the Milan switch.

Sol-box’s mail server contained such device called Flash-RAM,which has a mini Linux kernel.The Flash RAM is inserted in IDE slot,and always is smaller as being compared with harddisk.Once the kernel in the IDE-ROM startups, it will detect all the modules and initiate the drivers of devices.The data is stored in the harddisk,and the kernel tell the computer to operate with specific devices,such as harddisk.When harddisk halted,it will give the following message:kernal panic and then we should change another harddisk.So the kernel is the soul which is the most important.Kevin said there are about 70 engineers in RD(research and develop) team.They used the kernel of 2.4.30 to product a Linux system named Bax.The Bax includes drivers of ethernet card and Raid controllers.Almost these drivers are based in Intel platform,but do not contain every devices pubulished by Intel.For example,Marvell gigabyte ethernet card.

In many cases,the FAE would be asked to diagnose in console mode.Telnet command is commonly used.First,we should called the customer’s system administrator(In Taiwan,called MI meaning Manager Information),to open port 22 which is for SSH.Perhaps MI has never known about how to configure the firewall to do this or MI is worried about the whole system’s security,they would not open the port.How to check the port 22 has been opened? In the command line statue,issue the following commands:

#ping 192.168.1.26 22

If ssh messages display after pressing Enter,it means the port has been opened successfully,then engineers could connect to the server remotely by telnet.

When the mail is refused by the mail-server, there will be a responsed mail sent to the user.Just image,the reminding mail is sent as soon as the server find rubbish mail,how many remind mails will be in your mail-box?It even becomes another type rubbish mail.So we should configure the mail-server to hold these mails and sent them together to user in specific clock.

The error message of sending email must be in English language for convenience.In the email’s detail mode,text following by title “subject” should be coded for protecting user’s privacy.However,about 70% mail-servers are not in this way.The text in the email’s header contained more than 1500 words is also considered as rubbish letter because ofbehavior which is not common.DoS,and Dictionary attacking usually happen.We can take corresponding strategy to prevent them.For example,MI could filter the IP which tried to send mail by using dictionary if the connect counts are more than three times.

Behavior and culture.Although culture is very differnt, it’s not realistic by using either Black-up strategy or Content Filter.The only way,or the beat measure to prevent rubbish mail is using Behavior judgment.A mail is judged as rubbish or not does not rely on its contents, the behavior of sender Mail-server is our concern.

Kevin,senior engineer from TaiWan,gave us a lecture about mail server producted by his company in Shanghai.

Internet mail,also called e-mail, are invented by some teachers in US, they uses email to exchange message with others as fast way.Twenty years passed, email became more and more important communication tool not only in college but also in business activities.In 2002,experts considered the security of mail was most important,so they work hard in encrypting package flowing in the network.but with the time goes into 2003,something changed,the mail users found a large number of letters contained information they did not want to read had been sent to their own mail-box.It was very annoy.The rubbish mail saved in the harddisk of mail-server causes waste and limit the transimition of network.So people dedicate their life to computer had to resolve this trouble.In 2004,many products about preventing rubbish mail were developed.

There are total three strategies, behavior,black-out,and content filter.

Behavior strategy collects the senders’ information and analyze their behavior, then help us to decide whether receive or refuse.This is the most popular mode.Black-out,which is also called Black name list,filters those mail from the address in the black name list.Such list would be created and update by Mail server administrator or by uses themselves.Content filter,reading the whole text of mail,and compares each word with those in the sepecial dictionary,once matched,the mail-server judged these mails as rubbish and refuse to receive.In fact,it is not a good ider for preventing rubbish mail because perhaps this strategy may refuse the mail which is not rubbish.We always find that the employees of the supermark distribute the colorful ad.paper,Do they break the law?The answer is denial.So does the email.But we must do something firmly to protect people’s privacy and prevent wasting resouces.

How do users access the specific website? The packages are sent to many routers.Routers is such device that direct next step or a good man tell you where to go next.It sent from router to router until find the specific website.Note, what is the difference bwteen http and https?Https means security http transmit by using SSL(security socket layout).In contrast,http does not have high security, because the sniffer installed in some routers may catch the information of packages.

For culture is very different all around world,one same mail,some people may think it is useful,but some people may refuse. So mechanism of mail server should also contain some mail which are judges by users themselves.The uses can read it or delete it without be effected too much.

Kevin said there were many rivals,we should let customer know our pruducts also contain rival’s advantage and surely instead them,or the sales told the Project Manager to improve our products in the next generation.However,we must not give the customer any information about new product in developing.That’s crazy.

Queue is the standard of judging mail server’s performance.A good mail server system has enough queue and send mails as soon as possible.It’s powerful.If the queus is not suitable,it will cause many troubles,for example,the mail is always waiting in the queue, it will never be sent.

SMTP server:snipper(for backup),relay(the most popular,about 90% in this market).

DNS constructure:
-Authority:resolute name step by step liking router(eg,abc.com.cn,cn –> com –> abc)
-Resolution:have a large database to record resolution items,the database is updated as finding new resolution recorder,so it becomes more and more bigger and intelligent.

In the SE7520BD2 platform,when I inserted USB disk any issue the following command:

# fdisk -l

I did not find usb device.So,”lsmod”, and reload the USB modules,”rmmod –> insmod”,and then
execute this command as root:

# cd /mnt
# mkdir a
# mount /dev/sda1 /mnt/a

Then,USB device was installed successfully.

Source code means everything.Once you have the source code, you could modify and re-complie that code wherever you want to use,any situation, any time.
I was very tired last night,and went to sleep at about 22:00.Hmmm,it was a wondelful sleep and I feel I’ve had good rest to continute my work.
In the morning, I heard PR1580 had been cut. I was so surprised that asking Weining Qi,product engineer of PR1580.Qi said Project Manager had resigned one month ago, so this project developed with MSI was cutted with unknown reason.He was also sadly because both of us have put all our heart in this subject since Mar 19th.I think Qi is a good associate,working with him is in high working-rate and spirit.
How long do I not enjoy football? Maybe one year. This afternoon, I called our captain,Zhaoyong Mo.In the 4th village of Melin, we played football with some policeman.I found myself in the ground,enjoyed football game.I love blue sky,white cloud and green grasses.Mo gave me three nice through pass,and I soccered three goals.The most exciting moment is,when I was in left back-ground,I hit a long pass to our mate in the font-right area,he received the ball very easily,however he failed in making a goal.
I went to Carry Four supermark with my mother when I got home.I brought a book,”legend of Hongzhang Li”, writen by Qichao Liang, a famous historian.Li has been argumented by people for many years, some people consider he selt motherland and is a shame,but he is a wisdom man in another people’s eyes.I do not care whether he is good or not, I want to know his thinking in those worst years.Li is a legend,influenced China and world deeply