The ports used by NFS server can be dynamically assigned by rpbind to any higher number. We need to fix the ports used by NFS server to configure firewall or port forwarding mechanism. The ports used by NFS server and how to fix these ports will be introduced in this post. There are seven ports…
Port forwarding (or tunnelling) is a method to forward one network traffic to another. We will introduce how to forward ports using SSH tunnel in this post. A simple example Let’s start with a simple and useful example: we want to forward local port 8080 to server:port. We can easily do this by using ssh…
Update on Nov. 18, 2012: ATI fglrx driver works well on Fedora 17 with GNOME 3 Shell. Should work well with later releases. Great driver, ATI! Update on Nov. 29, 2011: ATI fglrx driver works on Fedora 16 with GNOME 3 Shell with Catalyst driver 11.11 (xorg-x11-drv-catalyst-11.11). Update on Oct. 9, 2011: GNOME 3 shell…
The performance of Xen’s Dom0 is important for the overall system. The disk and network drivers are running on Dom0. I/O intensive guests’ workloads may consume lots Dom0′s CPU cycles. The Linux kernel calculates various network related parameters based on the amount of memory at boot time. The kernel also allocate memory for storing memory…
In this post, how to unified Linux login and home directory using OpenLDAP and NFS/automount will be introduced. 0. System environment This solution is tested on Fedora 12 systems and CentOS 5. LDAP and NFS server: IP: 10.0.0.2 OS: Fedora 12 x86_64 ldap base dn: “dc=lgcpu1″ Clients: IP: 10.0.0.1/24 OS: Fedora 12 x86_64 1. LDAP…
UDP has its advantages over TCP, such as being relatively lightweight and receiving one packet per read call (recvmsg), although the programmers need to handle related issues, such as packet lost and out-of-order packets delivery. This post gives information and references on how to write UDP programs in a C/Linux environment. What is UDP Check…
It is quite common to measure the time in programs using APIs like clock() and gettimeofday(). We may also want to measure the time “accurately” for certain purposes, such as measuring a small piece of code’s execution time for performance analysis, or measuring the time in time-sensitive game software. It is hard to measure the…
John Ousterhout is a professor of Deparment of Computer Science from Stanford University. One recent project he is working on is the RAMCloud, a “new class of storage, based entirely in DRAM, that is 2-3 orders of magnitude faster than existing storage systems”. He posts his “Favorite Sayings” on his homepage. These sayings are precious…
If /etc/fstab file is created with errors or the hardware configuration changes such as adding hard disks, Linux will boot into failure state. We can bypass the fstab failure by adding booting parameters to Linux. We can do this in two methods: Method 1: Boot to single user mode When booting into single user mode,…
In Linux, we use passwd to change password, but passwd requires input from stdin to get the new password. It is common case that we may want to change the password non-interactively, such as creating new user accounts and change or set password for these accounts on a number of Linux boxes when the new…
WordPress has a very rich set of plugins and a combination of them can make anti-spam in WordPress quite easy. Here is a list of plugins that can help prevent spammers from registering spam account (if the site allows registration of new users) and posting spam comments. Anti spam comments Use the Akismet WordPress plugin….
The socks proxy I created following Proxy Using SSH Tunnel works very well on both Linux and Windows. However, when I try to configure my iPhone and iPad with iOS, I find iOS does not support socks proxy in its settings interface. I don’t know why it is not added while socks proxy is indeed…
Software Engineering Advice from Building Large-Scale Distributed Systems by Jeff Dean. You can download the slides from Software Engineering Advice from Building Large-Scale Distributed Systems by Jeff Dean. These slides contain the “Numbers everyone should know” which everyone working on systems should be familiar with. Numbers Everyone Should Know L1 cache reference 0.5 ns Branch…
xclip is a tool to copy the copy the output of commands from a command line in a terminal to X selection or clipboard. It connects the command line interface and the X selections (clipboard) and is a very useful tool. For example, processing some text in vim in a terminal and then copying it…
Here is a list of tutorials for learning how to write MapReduce programs on Hadoop, the opensource MapReduce implementation with HDFS. MapReduce Tutorials The official tutorial on Hadoop MapReduce framework: http://hadoop.apache.org/docs/r1.0.4/mapred_tutorial.html. Yahoo! Hadoop Tutorial A comprehensive tutorial on Hadoop from Yahoo! Developer Network: http://developer.yahoo.com/hadoop/tutorial/. More about MapReduce To better understand the design behind MapReduce, it…
MediaWiki set’s the default page (the homepage) to the “Main Page” by default. The name “Main Page” is too general and does not give more meanings. Usually for a specific site, we may change it to some meaningful name and URL. This is a configurable in MediaWiki. This tutorial introduces how to change MediaWiki’s Main…
MediaWiki’s Sidebar can be configured as a special page. This page’s title is “MediaWiki:Sidebar”. For example, if a MediaWiki site www.example.com is configured to use [[search-engine-friendly-url-for-mediawiki]], the URL for edit the Sidebar is: http://www.example.com/w/MediaWiki:Sidebar It may look like this: * navigation ** mainpage|mainpage-description ** recentchanges-url|recentchanges ** randompage-url|randompage ** currentevents-url|currentevents ** portal-url|portal ** helppage|help * SEARCH…
This article is an instruction of how to use https://www.systutorials.com/proxy-using-ssh-tunnel/ on a Windows machine. The mechanism is similar as the one in https://www.systutorials.com/proxy-using-ssh-tunnel/ with “Proxy listening to localhost port only”. Download PuTTY PuTTY is the software we use here for port forwarding. Please download it following the links in https://www.systutorials.com/open-source-and-portable-ssh-scp-sftp-and-vnc-clients-for-windows-to-remote-control-linux/. Configure PuTTY and create a…
More and more users are browsing the Internet using a mobile device. It is preferred to provide good experience for these users. One method to service a mobile version of the page to a user with a mobile device. This tutorial introduces how to add mobile skin support for MediaWiki. Skin for mobile devices I…
MediaWiki is the wiki-engine that runs Wikipedia. In this tutorial, we introduce how to configure search engine friendly URLs in MediaWiki. ==Search Engine Friendly URLs== Default MediaWiki URLs look like www.example.com/w/index.php?title=TITLE which is a little ugly. To make it more search engine friendly, we will change it to SEO-friendly URLs like www.example.com/w/TITLE. ==Enabling Search Engine…