News and information for Unix Sysadmins
Updated: 17 hours 26 min ago
Security always requires a multi-layered scheme. SSH is a good example of this. Methods range from simple sshd configuration through the use of PAM to specify who can use SSH, to application of port-knocking techniques, or to hide the fact that SSH access even exists. Applying these techniques can make life much harder for possible intruders, who will have to go past three unusual barriers."Learn 3 ways of hardening SSH access to your system to block would-be crackers"
Bazaar is used to produce the Ubuntu Linux distribution, which is an enormous software project with thousands of components. If you're using a UNIX or Linux system, chances are that your distribution offers a pre-built Bazaar package. Bazaar is flexible enough to accommodate Subversion - a centralized system and Git - a decentralized system. This article introduces you to Bazaar's many appealing features."Intro to Bazaar, a great place to keep your code"
As the kernel and user space exist in different virtual address spaces, there are special considerations for moving data between them. Explore the ideas behind virtual address spaces and the kernel APIs for data movement to and from user space, and learn some of the other mapping techniques used to map memory."An introduction to Linux memory and user space APIs"
Python programmers shouldn't get too smug. While many people agree that Python is designed in a way that makes it a highly readable language, there can still be problems with legacy, untested Python code too. Porting legacy Perl to Python can be a daunting task. In this article, learn some of the theory behind dealing with legacy code, including what not to do."Techniques for migrating legacy, untested Perl to Python"
The IBM AIX operating system provides a highly scalable IT infrastructure for client workloads. Learn about the latest version, AIX 7.1, an open standards-based UNIX operating system, that includes significant new capabilities for virtualization, security features, availability features, and manageability."Learn about the latest version of AIX 7.1 - an open standards-based UNIX operating system"
PowerHA for AIX is the new name for HACMP (High Availability Cluster Multiprocessing). HACMP is an application that makes system fault resilient and reduces downtime of applications. This article introduces PowerHA and provides a detailed explanation of how to configure a two node cluster. This document is very useful for understanding PowerHA and setting up a two node cluster."Get Power high availability by Configuring a PowerHA cluster" Introduction to PowerHA
Learn how to check the integrity of your Linux filesystems, monitor free space, and fix simple problems. Use the material in this article to study for the Linux Professional Institute (LPI) 11 exam for Linux system administrator certification or just to check your filesystems and keep them in good working order, especially after a system crash or power loss. Today's world relies heavily on technology, and at times technology can fail us. That is why, unlike traditional methods of storage s
Ksplice applies kernel patches on-the-fly - no reboot required in a fraction of a second. Here's a hands-on guide to performing painless system updates. Learn how to patch a live kernel and give reboots the boot."Avoid reboots of your system with live Kernel updates using Ksplice" Live Kernel Patches with Ksplice
Amaze your friends with cool vi tips and tricks that will improve the efficiency of your file editing. This article takes you through ten of the less well-known vi commands that should form part of any serious vi user's toolkit."Become a vi editing wizard with these 1 tips" vi tips and tricks: Ten cool commands
Great article describing level one and two memory caching in zfs."L2ARC is a new layer between Disk and the cache (ARC) in main memory for ZFS. It uses dedicated storage devices to hold cached data. The main role of this cache is to boost the performance of random read workloads. The intended L2ARC devices include 1K/15K RPM disks like short-stroked disks, solid state disks (SSD), and other media with substantially faster read latency than disk." Understanding ZFS & ZFS ARC/L2ARC
The GNU Image Manipulation Program (GIMP) is a robust application for editing and manipulating digital images. In this article, you will learn how to get started with the GIMP code, how to build the project from the Git repositories, and how to find your way around the code tree. And you will build an example application that creates a whole new painting tool for the program."Dive into the code base of the GNU Image Manipulation Program and add to it"
Java language is the tool of choice for Android developers. The Android runtime uses its own virtual machine, Dalvik, which is not the usual Java virtual machine that most Java developers are used to. In this article you will learn advanced Java features and how they are implemented on Android. This includes features such as concurrency, networking, and database access."
Implement concurrency, networking, and database access in Android" http://www.ibm.com/developerworks/library/x-gourmetand
Look at how the leading Python testing frameworks provide robust auto-discovery of your application tests. Make sure your applications are written right the first time, and that they stay working through months and years of further tweaks and improvements.
In Part 1 learn to Install and configure a simple cluster and discover ways to monitor and manage Hadoop using its core Web interfaces. In Part 2 Install configure a multinode cluster and dig into the management aspects of Hadoop.
"How to use Hadoop in a single-node and multinode cluster" http://www.ibm.com/developerworks/linux/library/l-hadoop-1/index.html?ca=dgr-lnxw1HadoopP1dth-LX
In this five-part series, you will take a closer look at several new technologies that are part of HTML5, that can have a huge impact on mobile Web application development.
Part 1: Combine HTML5, geolocation APIs, and Web services to create mobile mashups
Part 2: Unlock local storage for mobile Web applications with HTML5
Part 3: Make mobile Web applications work offline with HTML5
Part 4: Using Web Workers to speed up your mobile Web applications
Part 5: Develop new visual UI features in
With the Linux virtual file system switch (VFS), you can create file systems on a variety of devices, from traditional disk, USB flash drives, memory, and other storage devices. You can even embed a file system within the context of another file system. Discover what makes the VFS so powerful, and learn its major interfaces and processes. Understanding the dynamics of such a system will benefit you in the long run. In today's ever growing technological era you must try and stay up to date
Do you know what to do when the performance of your UNIX network and the speed at which you can transfer files or connect to services suddenly comes to a stop? How do you diagnose the issues and work out where in your network the problems lie? This article looks at some quick methods for finding and identifying performance issues and the steps to start resolving them.
Much like a vernacular, the universe of UNIX tools changes almost perpetually. New tools crop up frequently, while others are eternally modernized and adapted to suit emerging best practices. To speak UNIX fluently, you have to keep up with whats New and good.
Linux ordinarily uses Cron to automatically perform routine system maintenance on desktop or laptop computers, however not running Cron routinely can result in monstrously large log files and other problems. You can offload most or all of your usual daily and longer-interval Cron jobs onto Anacron enabling your computer to run regular maintenance jobs whenever the computer is powered on, even if those times are unpredictable.
Accelerate your porting efforts by following this six-step guide to porting from Solaris to Linux on POWER. Learn the differences between Solaris and Linux on POWER that you commonly encounter during a port. Also learn about tools for performance analysis and software packaging for Linux on POWER.