Guys, As per my observation and study I don't think virtual memory is virtual that has implemented on linux/windows operating system. So, you can ask me why it's not virtual? And you guys can say "in computer science everyone believes that there is virtual memory which is abstract layer of the memory space". Ok if this is the case then explain why it's virtual? What I suspect that your answer would be like "the term "virtual" is a really a abstract view and idea or guess that doesn't have any real existance since cpu generates the logical addresses...
Saturday, 22 January 2011
Thursday, 20 January 2011
How to allow secure mail SMTP ports at the firewall?
Posted on 23:01 by Unknown
Guys,Following iptables rules will allow server SMTPS incoming client request (open port 465) for server ip address "server_IP" :----------#iptables -A INPUT -p tcp -s 0/0 --sport 1024:65535 -d server_IP --dport 465 -m state --state NEW,ESTABLISHED -j ACCEPT#iptables -A OUTPUT -p tcp -s server_IP --sport 465 -d 0/0 --dport 1024:65535 -m state --state ESTABLISHED -j ACCEPT----------Note : Please replace the server_IP with your server's IP address where mail server has setup.Try...
Monday, 17 January 2011
How to check the network driver on the linux machine?
Posted on 01:13 by Unknown
Ans :=======================#dmesg | grep eth0o/p :[root@kmaiti net]# dmesg | grep eth00000:00:19.0: eth0: (PCI Express:2.5GB/s:Width x1) f0:de:f1:27:4d:ad0000:00:19.0: eth0: Intel(R) PRO/1000 Network Connection0000:00:19.0: eth0: MAC: 9, PHY: 10, PBA No: a002ff-0ffADDRCONF(NETDEV_UP): eth0: link is not readye1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: None0000:00:19.0: eth0: 10/100 speed: disabling TSOADDRCONF(NETDEV_CHANGE): eth0: link becomes readyeth0: no IPv6 routers presente1000e: eth0 NIC Link is Up 100 Mbps Full Duplex,...
Sunday, 16 January 2011
How to increase the size of virtual memory on linux?
Posted on 10:37 by Unknown
Guys,When a Linux system is initially set up, a swap partition is created on the hard drive that will be used as virtual memory in Linux, along with other partitions used for data.Here are the steps to create the swap file :======#dd if=/dev/zero of=/mnt/swapfile bs=1M count=1024#mkswap /mnt/swapfile#swapon /mnt/swapfile#echo "/mnt/swapfile none swap defaults 0 0" >> /etc/fstab======That's it :Note : I shall discuss about the virtual memory(What exactly it is) and how kernel is creating virtual address space for a process before loading the...
Wednesday, 12 January 2011
How to use tcpdump command to capture the network packet?
Posted on 21:30 by Unknown
1. Capture complete to tcp packets :tcpdump -nnvXSs 1514 -c2 tcp* host // look for traffic based on IP address (also works with hostname if you're not using -n)# tcpdump host 1.2.3.4* src, dst // find traffic from only a source or destination (eliminates one side of a host conversation)# tcpdump src 2.3.4.5# tcpdump dst 3.4.5.6* net // capture an entire network using CIDR notation# tcpdump net 1.2.3.0/24* proto // works for tcp, udp, and icmp. Note that you don't have to type proto# tcpdump icmp* port // see only traffic to or from a certain port#...
First assembly programme on 64bit linux machine??
Posted on 21:27 by Unknown
Platform : x64 bit intel archProcessor : intel core i5 processorOS : RHEL6 linuxCompiler name : NASMAssembly compiler src :http://www.nasm.us/pub/nasm/releasebuilds/2.09.03/nasm-2.09.03.tar.gzcommand : nasm ====Programme :vi hello.asm-----section .data ;section declarationmsg db "Hello, world!",0xa ;our dear stringlen equ $ - msg ;length of our dear stringsection .text ;section declaration;we must export the entry point to the ELF linker orglobal _start ;loader. They conventionally recognize _start as their;entry...
How to create shared object file on linux ?
Posted on 21:19 by Unknown
Dynamically Linked "Shared Object" Libraries: (.so)=============How to generate a shared object: (Dynamically linked object library file.) Note that this is a two step process.1. Create object code2. Create library3. Optional: create default version using a symbolic link.Library creation example:gcc -Wall -fPIC -c *.cgcc -shared -Wl,-soname,libctest.so.1 -o libctest.so.1.0 *.omv libctest.so.1.0 /opt/libln -sf /opt/lib/libctest.so.1.0 /opt/lib/libctest.soln -sf /opt/lib/libctest.so.1.0 /opt/lib/libctest.so.1This creates the library libctest.so.1.0...
How kernel invokes system call function on linux ?
Posted on 10:14 by Unknown
Guys,I have mentioned the steps here so that you'll get an idea about the invoking of the system call.============1. Executing any command or task. Process has been generated.2. Process calls library function in user space.3. Library is consisted of different types of object files and object files contain "system call" function(s). Library also pushes arguments on the stack.4. Library will issue syscall (int 0x80 / sysenter / ...)5. Execution will switch to syscall context in kernel mode.6. kernel will look up systemcall table and dispatch to respective...
Thursday, 6 January 2011
How to install video player(real player) on linux system?
Posted on 23:30 by Unknown
Guys,You can install real player on the linux machine to play the video files. Please install the package. You'll get it from here.======http://www.real.com/realplayer/download======Install the rpm like :rpm -ivh rpm_name. You can install using auto installer.Then go to "application >> sound & video >> find the real player.Select the video file and enjoy it.Try...
How to install mplayer on linux machine?
Posted on 23:00 by Unknown
Guys,mplayer can be used to watch video files on linux machine. You can download the software using svn(subversion) tool. Just make it sure that svn has installed on the machine(check like : which svn). If it's there then stop the firewall and follow to compile the mplayer package. If svn is not present on the machine please install it first. Please refer the following URL to do the same :-------------http://kmaiti.blogspot.com/2011/01/how-to-install-subversion-svn-on-linux.html-------------Environment : RHEL 6, 64 bit OSKernel : 2.6.32-71.7.1.el6.x86_64Then...
configure: error: could not find library containing RSA_new
Posted on 04:03 by Unknown
Guys,It seems you have enabled the SSL option during configuring the package. Please either resolve that dependency or disable the SSL option.Example (configuring neon, needed to install svn) : With SSL :--------cd ../neon./configure --enable-shared --prefix=$HOME \--with-libs=$HOME --with-ssl--------Without SSL :--------cd ../neon./configure --enable-shared --prefix=$HOME \--with-libs=$HOME --------try...
How to install subversion (svn) on linux ?
Posted on 03:32 by Unknown
Guys,I have referred the second procedure to install svn on my rhel6 mc.Procedure 1 : =========cd /usr/local/src/wget http://subversion.tigris.org/downloads/subversion-1.4.5.tar.gzwget http://subversion.tigris.org/downloads/subversion-deps-1.4.5.tar.gzwget http://www.sqlite.org/sqlite-3.5.2.tar.gztar xzf subversion-1.4.5.tar.gztar xzf subversion-deps-1.4.5.tar.gztar xzf sqlite-3.5.2.tar.gzcd sqlite-3.5.2./configuremakemake installcd ../subversion-1.4.5./configuremakemake install================Note : If above one doesn't work please refer the following...
Wednesday, 5 January 2011
How to install ksar on linux machine?
Posted on 01:20 by Unknown
Guys,To view the system activities on a graph of linux machine, you need to install ksar package. Just download the package and execute "sh run.sh" command inside that downloaded directory on konsole. It'll open java applet and run the local command at "Data" option. That's it.Source file of the package : ==========http://sourceforge.net/projects/ksar/files/ksar/5.0.6/kSar-5.0.6.zip/download?use_mirror=biznetnetworks==========Try...
Tuesday, 4 January 2011
How to configure tata photon + on linux machine + rdehat
Posted on 09:27 by Unknown
Guys,Please read the article before proceeding to configure the USB modem.==============[root@kmaiti ~]# wvdial--> WvDial: Internet dialer version 1.60--> Cannot get information for serial port.--> Initializing modem.--> Sending: ATZ^RSSILVL: 60--> Sending: ATQ0ATQ0OK--> Re-Sending: ATZATZOK--> Cannot get information for serial port.--> Initializing modem.--> Sending: ATZATZOK--> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0OK--> Modem initialized.--> Sending: ATDT#777-->...
ATDT#777 ERROR --> Invalid dial command
Posted on 09:24 by Unknown
Guys,==============[root@kmaiti ~]# wvdial--> WvDial: Internet dialer version 1.60--> Cannot get information for serial port.--> Initializing modem.--> Sending: ATZ^RSSILVL: 60--> Sending: ATQ0ATQ0OK--> Re-Sending: ATZATZOK--> Cannot get information for serial port.--> Initializing modem.--> Sending: ATZATZOK--> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0OK--> Modem initialized.--> Sending: ATDT#777--> Waiting for carrier.ATDT#777ERROR--> Invalid dial command.==============I...
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