Archive for the 'Linux Examples' Category
Linux Operating System Errors and Resolution
HTML clipboard
Linux is the most popular operating system so far as security and performance is concerned . It is a Unix-like operating system and is the best example of open source development and free software; generally all underlying Linux source code can be modified, redistributed and used freely by anyone. Red Hat Enterprise Linux 5. 2 is the latest version of Linux operating system. As we all know every operating system has its demerits or failures and can give errors at any time with out any prior information. There are some common error messages faced by Linux users while using this operating system. Some of the most common ones are the following: • Unknown terminal type Linux. • Unrecognized option ‘-m486′. • bdflush not running • cannot read table of mounted file systems • Unknown terminal type Linux. • Cannot initialize drive XYZ? • EPERM Operation not permitted. • Unrecognized option ‘-m486′. • Modprobe can’t locate module, “XXX,” and similar messages. • Mounting unchecked file system. • EINTR Interrupted system call. In most the situations given above a user faces any of the mentioned problems, it becomes difficult for him/her to access or manage his data. He/she won’t be able to do normal tasks which can otherwise be performed effortlessly. If the data which has been rendered inaccessible is important then it becomes essential to recover that data as soon as possible. In this case, he/she would need the help of Linux data recovery software. Linux Data Recovery Software is an ultimate way out for all Linux related data recovery problems. It also recovers data from formatted hard drives also where file systems have been changed. It recovers lost logical drives and data from physical disk or any removable media. Stellar Phoenix Linux Recovery software provides data recovery from Ext2, Ext2 and Reiser FS file systems of Linux operating system.
Linux and Security
Linux is an alternative operating system for computers. It’s one of the most well-known example for free softwares and open source codes. It can be freely modified, used, and redistributed by anyone.
In the interest of the system’s security the most important and the available files are separated. Linux can be used by more users. This would make the computer more vulnerable but it doesn’t. The users don’t have access to the root’s applications so we can’t modify them accidentally. The viruses can’t access to the system settings because the configure files are in a /etc directory and all this together gives the stability of the Linux.
Security-Enhanced Linux (SELinux) is an extra security service. We can define in one configuration that who has access to which applications and server and network procedures. This makes our network more protected.
SELinux implements security policies with the use of Linux Security Modules. LSM is a framework that lets Linux kernel to support security models. It has a lot of features for example the interfaces are well-defined, the policy is very flexible and it support for policy changes. The controls over the file systems, directories, files, messages and network interfaces are strong.
SELinux has become available for simple users with in a package with Red Hat Enterprise Linux version 4 and all future releases as well. It can be installed not only with Red Hat but with Fedora, Hardened Gentoo and Yellow Dog as well.
www. infosecuritylab. com
Police Career – Linux Computer Systems in Law Enforcement
Law enforcement recently has been following the general tide of government and public service groundswell by seeking computing solutions in the Linux direction. Particularly in law enforcement, their needs match well with open source software. They have to work lean on a taxpayer’s budget, and open source is free or low cost. They need top security, and Linux is still the highest-scoring operating software in official government assessments. They need mission-critical reliability, and Linux is so stable, it doesn’t just outrank the competition in stability – it makes the competition disappear!
Some recent examples of law enforcement agencies finding a solution in open source:
* Kent Police have lowered the cost of running their major criminal investigations system by a factor of 90% using Novell Linux Open Enterprise Server. The migration to Novell enabled Kent to scale up their Holmes II investigation system to work on larger projects with a broader scope – something they’d never been able to do before. They were also able to run it on their cheapest hardware they could find, thanks to Linux’s light requirements. A new policing operating system, named Genesis, is now being tested for scalability on Linux servers.
* Delivery of the first Linux systems to the West Yorkshire police force could see police forces throughout England and Wales unanimously switching to Linux desktops in a new pilot scheme. The deployment is taking place under a contract awarded by the UK Police IT Organization. If successful, it will lead to over 60,000 desktops deployed. In West Yorkshire alone, the installed base is around 3,500, and a spokesman reckoned that the savings from this would be around one million pounds per year!
* The New South Wales Police department is currently undertaking a major upgrade to its information infrastructure, made necessary due to the increasing volume of data handled by the force, and they’re switching to Linux systems to handle the load. Because the Linux systems are proving so reliable, they are looking forward to the higher capacity network more efficiently archiving and transmitting data stored as evidence, such as surveillance videos and audio material.
* Scottish police forces have also developed a Linux-based system for ensuring that they comply with the Freedom of Information Act legislation, an act which is intended to facilitate ‘open government’ by allowing the public to request access to government data. Since open source and open information go hand in hand, the system has scaled easily and saved tons of labor. The force doesn’t have to worry about proprietary media formats interfering with the public’s ability to access the data, and the efficiency of the Linux system allows a lot of manual tasks to be automated where they couldn’t before. The system is literally returning officers to the streets because it has saved everyone so much work.
* Police in the city of Munich have switched 14,000 of their department computers from Microsoft’s Windows operating system to Linux. The motivation for the decision was to make the government less dependent on one information technology supplier, and to save money while increasing capabilities. One technology analyst even compared the break-through migration to the fall of the Berlin wall, referring to the oppressive requirements of dealing with a proprietary software company’s agenda.
That government feels friendly with open source should come as no surprise. Traditionally, the Internet has been 80% Linux and Unix-based systems since its creation. The first Internet services were started and maintained by government providers, who used Unix system’s built-in multitasking features and excellent speed to create a fast, reliable network. Linux, a modern version of that Unix ideal, has already established itself as the leading system for server-room deployment, but now the effects are beginning to trickle down to the desktop user level and workstation deployments, where they are discovering that Linux systems have workspace-ready features built in which other commercial operating systems are just now beginning to discover and implement.
Furthermore, Linux systems come with the guarantee that because they are open source, no commercial company can restrict their usage in the future. A platform ported to Linux can stay on Linux, without support dying out and constant upgrades creating problems down the road.
Finally, the inherent security of the Unix computing model guarantees the effectiveness of Linux without the worries over security problems. Because there are in effect no viruses which can infect a Linux system known, and no critical security exploits found in the systems even by government security standards, departments are also considering Linux as a measure to protect our national data under concerns over national security and the terrorist threat in our modern times.
Top Ten Reasons to Learn Damn Small Linux – Number 2, Lots of Free Applications
Just to set the record straight, we must tell you that Microsoft Windows comes with plenty of free applications. The most widely used freebie is Internet Explorer. To find most of the others go to Start, All Programs, Accessories, and start clicking. Why don’t you take a look right now? Outside of Internet Explorer how many free Windows applications do you actually use? When you feel like word processing do you fire up Notepad, Word Pad, or Microsoft Word? Guess which two of these word processors are free.
Equipping an office with the standard Windows applications is an expensive activity. Some Microsoft applications make you purchase the software itself and then pay additional licensing fees when you connect your Microsoft client computer to a Microsoft server computer.
Damn Small Linux applications are free. Some of them are included with the initial download while others have to be downloaded and installed subsequently. There are several reasons for this seemingly intricate procedure. Not everybody wants to use the same applications. Furthermore, the very strict selection of the applications in its base package helps the Damn Small Linux distribution to respect the hard to believe 50 Megabyte limit. Once you have installed Damn Small Linux you can download Open Source (free) versions of Office and run them under Linux. Please note that you can download and run these programs under Microsoft Windows as well.
All work and no play makes Jack a dull boy. Well Jack doesn’t have to worry if he’s running Damn Small Linux. It comes with lots of free games. Somehow we have the impresssion that you will not need any tutorials to get the games running.
Some Linux applications are not only free but are actually superior when compared to the corresponding Windows applications. For example, have you ever heard of an e-mail client called Sylpheed? This application is part of the basic Damn Small Linux distribution. It has several advantages over those extremely popular (perhaps we should say unpopular) Microsoft e-mail offerings, Outlook and Outlook Express. Sylpheed handles spam much better than do its Windows counterparts. And Sypheed allows you to process threads of e-mail messages. For example, you correspond with several people about wholesale wine purchases. Sypheed makes it easy to process those messages while ignoring unrelated ones.
Since we’re talking about email, what about it’s cousin the Internet? That will be the subject of our next article in this series.
The Top Ten Concepts for Beginners to Linux – Number 3, Users
Unlike Windows, Linux users must have an account. This account is accorded permissions such as reading and writing files and executing programs. Accounts are combined into groups to simplify their management. Users who are members of a given group may be assigned additional permissions that smooth the process of accessing common files. Let’s take a closer look at how Linux handles these users. A future article examines permissions and groups.
Linux provides two categories of users, ordinary users essentially restricted to working with files of their own creation, and the superuser, or root, who administers the system and is allowed to do almost anything. The real situation is of course somewhat more complex. For example, ordinary users may be accorded restricted access to additional files deemed to be of interest to everyone. The superuser can assign some privileges to deputies reducing an otherwise crushing workload.
The root user is the only one authorized to run the adduser or the more complicated useradd command. If you have downloaded Damn Small Linux you can test these commands on your Windows computer. In response to the adduser command Linux requests the user name, the password, and then a few optional fields that may be skipped. An organization with many users has or should have a policy for composing user names.
The password is a key element in protecting the computer’s security. We could easily write an article discussing the password and password selection. Remember that Linux distinguishes between lower-case and upper-case letters. If you’re new to computing you may try working with easily remembered passwords at first. But protecting your account and account information depends on your unguessable passwords.
When Linux creates your account it also creates a directory whose name is easy to remember. If your account name is lucy then your working directory is /home/lucy . I’m leaving it up to you to find out the location of lucy’s working directory for Windows systems.
Damn Small Linux shares an interesting feature with many other Linux systems. The system administrator can provide new users with copies of some directories and folders by placing them in the /etc/skel directory before launching the adduser command.
How is the system administrator supposed to handle creating dozens, hundreds, or even thousands of new users, for example at the beginning of the semester? He or she won’t have the time to undertake this backbreaking task. And there is no way that the root password should be revealed to the employee who is assigned this task. The answer is simple: write a program to create these new accounts. This program can even spiff up the account creation interface and perhaps grab some necessary information from sources such as the student registration file.
Of course we don’t want to create users without the possibility of removing them. The live process is fairly complicated and includes removing the user’s password from the /etc/passwd directory, removing all files from the user directory, and other activities such as making backups of essential information. The next article discusses the related concepts of permissions and groups.
The Top Ten Concepts for Linux Beginners – Number 5, Inodes
Advantages of Cheap Linux Hosting Services
There are a lot of solutions for every site or business web hosting needs, and Linux website hosting may be the best hosting solutions of all of your queries you have ever had about the world of the web hosting solutions. Here we describe about Linux website hosting and the advantages of Linux website hosting over Windows hosting will give for the personal or business web user at Hosting24hour. com.
With Windows hosting, web sites can use e-commerce functions. The old thinking support, If someone has little or no experience webmaster, they should consider Windows hosting, but now the time and features changes and Linux provide efficient features for users to easily use the Linux hosting services. Linux hosting services can be a little harder to manage for someone who does not have much experience but good one in web hosting solutions. Sites that are created on the Windows servers can be difficult to convert, so that they can easily be used on a Linux server. This may be something that you want, when planning your web site or the choice between Windows and Linux hosting.
When you are at the start of your website or business, you don’t need a big website and a huge disk space on the server and probably look for companies offering affordable web hosting plans. Let’s say, you have got your Domain Name (www. hosting24hour. com). Its time to check for a good web hosting service provider to have your files uploaded in the domain.
Linux operating system for computers remains one of the most common examples of free software services available for users. Linux is also known as GNU / Linux. Linux was designed by individuals who proposed the system first for their individual needs that were not been met by a major commercial operating system such as Windows. Best of all is that all of Linux code and source coding is also available to the general public for free use, and for modification purposes as well. Linux has gained strong support from major computer base companies such as IBM and Novell among others. Many personal users and large firms started choosing Linux as well. Linux is quickly gaining steam in the corporate world. Why? Here are the four answers: cost, effectiveness, security, and reliability.
Many reliable Linux web hosting companies have been in business for some nice time and are considered fairly reliable. These Linux website hosting providers are known for their knowledge and the hosting services they can offer. Some sites boast of being in business for five years or more with several trained professional hosting provider on board to assist in offering their hosting services, in technical support, and other elements to an effective web hosting company.
A Linux web hosting company follows in line with a strict tradition of budget web hosting and turning heavy profit in little time and this signifies a lot to the consumer as many consumers react to profit in a positive way, you can see the same at Hosting24hour. com best Linux Hosting Solutions provider for your business hosting services.
Linux is a growing operating system and many consumers and business owners are interested in running their on line business using Linux web hosting.
Most Linux hosting servers are using highly reliable software in their applications and frequently update their programs and services as well. This is a useful feature, especially in dealing with newer web hosting technology and services available on Internet. Linux also uses innovative tools and features that help bring accessibility to new users and confidence to veteran users, by supplying every user with the basics to operate a successful web site.
Where Can I Find Comprehensive And Detailed Linux Video Lessons Or Tutorials That Include Code And Examples?
Where can i find comprehensive and detailed Linux Video Lessons or Tutorials that include code and examples? I want something that shows each step of the process, and give the textual commands along with the video, and includes any other resources that are necessary, and preferably allows me to ask questions if i still do not understand something 
The Top Ten Concepts for Linux Beginners – Number 8, Programming Language Support
Damn Small Linux can be an ideal platform for supporting a wide range of programming languages. You can even program directly from the command line via a programming shell such as Bash. Major programming languages used in this environment include C, C++, and Java. If you are developing for the Internet you may want to use PHP, a web programming language and MySQL, a language for database system development. All these programming languages are also available in the Windows environment. So the question arises, why would you want to program under Linux rather than under Windows?
Many web developers and Internet service providers feel that Linux provides a more stable web site environment than does Windows. The most widely used web server, Apache, is available under both these operating systems but its new features, security enhancements, and bug fixes always are made available first on the Open Source (LAMP) version. And then they filter down to the Windows version. At the time of this writing the Windows version of Apache has problems with its cryptographic functions.
While programming languages are essentially the same across these two operating systems, their libraries are quite different. Basically, when you write complicated programs you want to make use of as much prewritten software as possible to reduce your programming and debugging effort. One example is handling the graphical user interface. As programmers often say, why reinvent the wheel? Linux provides a wider choice of libraries and graphical user interface toolkits.
When you program in Linux it is often fairly easy to port your programs to the Windows environment. Unfortunately, the inverse is rarely true. Of course as Linux systems become more popular, you will find more and more Windows-based programming systems that enable you to convert your programs to run under Linux. To do so makes clear economic sense.
Program conversion tools may be fairly difficult to develop. For example, executing programs must access the actual computer hardware. As you may imagine Linux and Windows programs access hardware quite differently. The modules that manage hardware access are called drivers. Linux drivers tend to be of higher quality than Windows drivers.
These two operating systems differ substantially in the way they manage programs during their execution. In other articles we discussed Linux’s increased security compared to Windows. We conclude this article by repeating a point that we have often made; you can run Damn Small Linux and its associated applications on very reduced hardware. You can do Linux, PHP, and MySQL development on old computers, ones that may have seemed ready for the garbage heap. In contrast many Windows competitors such as SQL Server Developer Edition require substantially more powerful computers, the kind of computers that people purchase for one or a few thousand dollars. When your programs will be used by dozens of people simultaneously, you will need powerful hardware. Don’t forget the operating system; can you guess which one we recommend? Our next subject is the graphical user interface.
Resolving “Must load Linux kernel before initrd” Error Message in Linux Operating System
Boot loaders such as GRUB (Grand Unified Bootloader), LILO (Linux Loader) etc. enable you to select to boot a particular operating system in multiboot or dual boot systems. After selecting the operating system (for example Linux), the booting process initially starts with the booting of Linux Kernel program. A Linux Kernel program is the central component of a computer operating system. It requires the corresponding drivers to access the device on which the file system is based. To avoid any conflict due to all imaginable drivers in the kernel, it uses initial ramdisk (intrd). The intrd is the temporary file system, which is mostly used for preparations before the real root file system can be mounted. Problems might occur when intrd gets loaded before Linux Kernel program. In such situations, the hard drive volume becomes un-mountable and the data saved in the hard drive becomes inaccessible. In such situations, you need to recover your data from the latest backup. In case, no backup is available or the backup is corrupted, you need to use efficient Linux Data Recovery applications to recover your lost data files.
Consider a practical example, when you attempt to boot Linux operating system, you encounter the below error message:
âMust load Linux kernel before initrdâ
The above error message occurs each time you try to boot the Linux operating system on your computer. After the above error message appears, the data saved in the Linux volume becomes inaccessible.
Cause:
The above error message mainly occurs when the intrd gets loaded before the Linux Kernel program.
Resolution:
To resolve the above error and access the data, you need to remove the intrd from your computer. However, if you still encounter an error, then only option left is to access the volume by reinstalling the Linux operating system. A clean reinstall of the operating system will erase all previously stored data in the hard drive. In such scenarios, you need to recover lost data by using effective Linux Data Recovery software. These advanced recovery applications incorporate high-end scanning methods to recover lost data from a logically corrupted hard drive.
Stellar Phoenix Linux Data Recovery serves the purpose of providing reliable and easy Linux Data Recovery. This read only Linux Recovery software supports Ext2, Ext3 and ReiserFS file systems. It gets installed on Windows (Vista, XP, 2003 and 2000) and the affected Linux drive should be connected as slave.