Technologies that matter to our freedom are used in our voting systems, our leisure, our work, education, art and our communication. If you are used to developing for Windows or Mac OS, the biggest shock when developing for Linux is probably the wide variety of Linux environments. Users are expected …

Once ready, make your new file executable using chmod command with an option +x. Modules that have other modules dependent on them must maintain a list of references at the end of their symbol table and pointed at by their module data structure. It has subdirectories, they have subdirectories and …

While there are other options, the most common scripting language is Bash. Programmers write Linux source code in many different programming languages. In user space, Linux implements threads in accordance with POSIX 1003.1c (known as Pthreads). In the preceding example, the kernel starts at /, gets the inode for home …

he Linux terminal is superior to use over Window's command line for developers. You may have heard of Unix, which is an operating system developed in the 1970s at Bell Labs by Ken Thompson, Dennis Ritchie, and others. Linux has an excellent ecosystem with mature APIs as well as an …

What most of us call "files" are what Linux labels regular files. It stands to affect the people of the world at least as profoundly as the Industrial Age. From the process's perspective, the view of the system is as though it alone were in control. This operation is called …

Instead, a file is referenced by an inode (originally short for information node), which is assigned an integer value unique to the filesystem (but not necessarily unique across the whole system). The result of test and set operation is the addition of the current value of the semaphore and the …

Users of closed source operating systems must report the bug to the manufacturer and wait for the manufacturer to develop, test, and release a solution to the problem, known as a hot fix. Thus, there is no term free mathematics. Outsource open source software development to O2I and benefit from …

Some cross-site-scripting attacks are possible when the attacker finds a weak spot in your source code and they can even leave the malicious code dormant for a long time before executing it. Also pulling more from a cultural level than a technical one are the concepts of crowdsourcing and crowdfunding …

It's highly recommended for advanced programmers and system administrators. Special files are kernel objects that are represented as files. Although, there's no rocket science in it. Or, you can make a profit on support and ancillary sales on things like manuals, mouse pads or whatever suits your fancy.

Redirecting output …

We who are enthusiastic about GNU/Linux want to spread that freedom around. However, this is no less "programming" than anything else. Recently, Linux has replaced this security system with a more general capabilities system. Because it is free software, licensed under the GNU General Public License, Linux obviates the …

The API merely defines the interface; the piece of software that actually provides the API is known as the implementation of the API. Most recently, the U.S. Before I became involved in Free Software, I had far different opinions, ideas, and beliefs than I do today. This highly stable …

The mini-bootloader acts as a middleman in the boot process. If you hit Tab again it will show you those possibilities. Even if you are an aged UNIX guru, what follows is probably of interest to you. If a match is found, that builtin is invoked.

A lazy person's guide …

There are editors, compilers and interpreters for nearly every language ever created, debuggers, parser generators, you name it. What exactly do the kernel and the C library provide? Whereas it had previously been the norm to assist colleagues and freely share ideas and software, such cooperation suddenly became forbidden and …

The system itself is designed with a very open-ended, feature-minded approach. I moved on to larger applications and contributions. Other drivers can be loaded as kernel modules when they are needed. It would not be enough to stop here, though.

Get the most out of ClusterKnoppix

In Linux, blocks are generally larger than the sector, but they must be smaller than the page size (the smallest unit addressable by the memory management unit, a hardware component) Common block sizes are 512 bytes, 1 kilobyte, and 4 kilobytes. Even so, most software developers, even those who have …

Most of the time you will be issuing commands. This is because IP addresses are simply an addressing concept, the ethernet devices themselves have their own physical addresses. Advocates of copyleft respond by pointing out that there is no such thing as absolute freedom. To see what is meant by …

Its entries are also device_struct data structures. Copyright does not protect facts, discoveries, ideas, systems or methods of operation, although it can protect the way they are expressed. Remember that the shell is a program providing you with an interface to the Linux system. Binary compatibility is maintained across a …

They are accessed via block device files. Freedom not to have to pay $300 or $400 for making your computer even useful, for something other than a calculator. The application can then trap into the kernel through this well-defined mechanism and execute only code that the kernel allows it to …

Its own Software Center has tons of free applications that make it a great Linux OS for programming. Another good example is the PCI bus which allows each device (for example a graphics card) to be accessed independently. Apart from the ability of a loaded module to crash the operating …

In addition to steadfast stalwarts like Fortran and C/C++, many scripting and other computer languages are at home on (or were even designed to work best with) Linux. The Linux kernel must be able to interact with them in standard ways. It is the scheduler that must select the …

If you have spent a lot of time on Windows this may take a while to get used to. The source code for proprietary software is usually not made publicly available, or, if it is, there are generally severe restrictions on its use. This means that the maximum number of …

Resources include timers, pending signals, open files, network connections, hardware, and IPC mechanisms. Originally, gcc was GNU's version of cc, the C Compiler. What would happen if ACME went out of business or stopped supporting the software due to lack of sales? Collectively the memory space that the hardware peripherals …

For block (disk) and character devices, these device special files are created by the mknod command and they describe the device using major and minor device numbers. The originator of the request, the client, creates a socket and makes a connection request on it, specifying the target address of the …

Free software, as the term is usually used, and public domain software resemble each other in that both are usually free both in a monetary sense and with regard to use. Assuming that a module can be unloaded, its cleanup routine is called to allow it to free up the …

A security breach unnoticed by the vendor can easily be exploited by the wrong person. That aside, FIFOs are handled almost exactly the same way as pipes and they use the same data structures and operations. Although there are numerous distributions available, most of the older, well-known distributions are good …

When one single governing body gains absolute control over something, it is only a matter of time before that governing body increases its power tremendously. The application can then trap into the kernel through this well-defined mechanism and execute only code that the kernel allows it to execute. When the …

To accomplish more complex tasks, tools would simply be connected together, using pipes. As such it is possible to have two or more files and directories with the same name but letters of different case. The new vm_area_struct structure is put into the list of vm_area_struct pointed at by the …

The examples continue, but all hit the same chord: there is no use in preventing the spread of information. Well, you can't actually look at the four of them at the same time, but this doesn't matter since your eyes can't look in two directions at once, right? To help …

Some users have reported success configuring and installing drivers for the various winmodems, including Lucent, Conexant, and Rockwell chipsets. The application tells the kernel which system call to execute and with what parameters via machine registers. Each surface of the platter is divided into narrow, concentric circles called tracks. Another …

Every device in the system is represented by a device special file, for example the first IDE disk in the system is represented by /dev/hda. But there may have a possibility of spreading malware to the Linux based systems if they are connected with Windows based systems. This is …

There are also numerous completely free resources available on the Internet, including (1) tutorials, (2) books and (3) newsgroups. This might seem a very unreliable method but every process in the system is making system calls, for example to write a character to the terminal, all of the time. In …

So when you're writing something in your word processor and you want to check out something on the web, no need to review all your windows to find your browser, stacked all the way behind the others. Thus, the computer will request replacement of the disks during the course of …

The vm_next_shared and vm_prev_shared pointers are used to link them together. A real-world example of an API is the interfaces defined by the C standard and implemented by the standard C library. In other words, a thread is the abstraction responsible for executing code and maintaining the process's running state …

(See "Shell Built-in Commands.") Readline has variables that can be used to further customize its behavior. This led to the development of the free software movement by Richard Stallman. If a parent process terminates before its child, the kernel will reparent the child to the init process. The price for …

The second, newer, mechanism uses a linked list of timer_list data structures held in ascending expiry time order. In most cases, good results can be obtained by just using the default options. Every distribution contains hundreds or thousands of programs that can be distributed along with it, and each of …

The most interesting case recently was when Sony purposely added spyware [4] to their music CDs that silently and automatically installed itself onto Microsoft Windows systems to search for piracy breaches. Only the truly dedicated -- those who have no personal lives, or those who are being paid to do this …

Yes, the house is ruining the sacred area, but nobody informed the homeowner in question about this problem before the purchase, so the shame should be placed elsewhere. This is also in sharp contrast to Microsoft Windows, for which modification of the software is generally not permitted. Mounting other filesystems …

Block devices are accessed via the buffer cache and may be randomly accessed, that is to say, any block can be read or written no matter where it is on the device. Among the easiest to try at first are the text editors, word processors, image viewers, calculators and games …

This modest computer's official Raspbian OS comes loaded with tons of programming tools, connector pins, and other useful ports. We are not done with hardware vulnerabilities, and speculative-execution vulnerabilities in particular. Alternatively, the process may have specfied its own signal handler. But imagine that if you can delete this system …

In the Linux world, a large number of users will always prefer to compile applications from source, rather than using an installer package. Outsource open source software development to O2I and benefit from high-quality services at a cost-effective price. However, that can leave your Linux system vulnerable to attack, and …