federal government. A pipe (its two file data structures, its VFS inode and the shared data page) is created in one go whereas a FIFO already exists and is opened and closed by its users. Another disadvantage of Open Source is the support service. If the expiry time for an …

If the process has not blocked the signal and is waiting but interruptible (in state Interruptible) then it is woken up by changing its state to Running and making sure that it is in the run queue. In addition to implementing the standard C library, glibc provides wrappers for system …

If you find a bug, report it! The format most common in Linux is called Executable and Linkable Format (ELF). But all things come to an end eventually. You would want that file access to be strictly coordinated.

How much do you know about the Linux rlogin command?

The same good practices and understanding of the underlying system inform and benefit all forms of programming. That way you can still change the GRUB 2 bootloader image without having to worry about the digitally signed shim.efi file. Because your server will be probably Linux-based as well, it will …

Libraries were written and ported, filesystems developed, and hardware drivers written for many popular devices. An exit status of zero indicates success. Tied closely to IoT is the drone trend, that of remotely controlled flying robots. A character device is accessed as a linear queue of bytes.

Shortcuts for nameif …

It does not obligate you to run it on a determined platform like some proprietary software. However, this is definitely no loss. Its interface with the BSD socket layer is through the set of Internet address family socket operations which it registers with the BSD socket layer during network initialization …

Some applications are written exclusively to higher-level abstractions. This means that you cannot DMA directly into the virtual address space of a process. Whenever you refer to a file or directory on the command line you are actually referring to a path and your path can be constructed using any …

The GPL subsequently became by far the most widely used license for free software. Currently, in Distrowatch's past 6 months ranking, it sits at #3. Linux is a topic which is equally suitable for study in the classroom (such as at a university or a specialized computer school) or at …

Different distributions have chosen varying approaches to file placement, software management, and other subtleties, in such a way that makes it almost impossible to make an applications distribution that will install and run cleanly across the Linux spectrum. For people wanting to become more than just casual users, it can …

The U-Boot bootloader program can boot from any type of disk, and load any type of boot image. Linux can do everything NT does, usually faster, definately more stable and at a fraction of the cost. Both have similar tools for interfacing with the systems, programming tools, filesystem layouts, and …

It was coined in 1997 with the intention of replacing the term free software in order to avoid the negative connotations that are sometimes associated with the word free and thereby make it more attractive to corporations. Hard links do not incur this additional overhead-there is no difference between accessing …

The world economy will not collapse if creators of software choose to share their work with the world. When adding a user to a system you will be asked for your root i.d. In all of the cases above, the synergy created between the pairs has only gone to …

How these modes are supported by the underlying hardware differs but generally there is a secure mechanism for getting from user mode into system mode and back again. Given that Linus was using several GNU tools (e.g., the GNU Compiler Collection, or GCC), the marriage of the GNU tools …

It is as old as computers themselves. As the information age went on, though, corporations became progressively more obsessed with controlling the spread of knowledge. The boom in interest around the Internet of Things (IoT), the notion of a network of devices, big and small, that can "talk" to each …

By contrast, most software carries fine print that denies users these basic rights, leaving them susceptible to the whims of its owners and vulnerable to surveillance. There is no problem with using an older computer, for example, an elderly 500MHz Pentium PC with as few as five gigabytes of hard …

A server is a computer with an operating system that is configured to allow other computers to connect to it from across a network. This is one of those arguments that sounds good superficially but which is not borne out by the evidence. If you plan to incorporate such software …

Initially, there is only one directory on the disk, the root directory. But note that this book does not cover the Linux programming environment -for example, there is no tutorial on make in these pages. The count is the number of kernel entities that are dependent on this module. In …

Named pipes (often called FIFOs, short for "first in, first out") are an interprocess communication (IPC) mechanism that provides a communication channel over a file descriptor, accessed via a special file. I say somewhat, because the use of sed in conjunction with pipes is somewhat more comfortable (at least to …

A keyboard is an example of a character device. Not only you earn more capabilities as a developer, you also learn (sometimes the hard way) how to solve issues, monitor your machine for potential problems, configure different components and more. However, free software itself is not. The takeover of software …

Internal commands are, as you might expect, built into the shell program. In contrast, the source code for closed source operating systems is not released to the public for scrutiny, which means customers must rely on the vendor of that closed source operating system to provide secu- rity. Frequent emails …

However, this is no less "programming" than anything else. On these foundationless grounds, what would be the problem with using Skype and locking not only yourself, but also all of your friends, into one company's software and protocol? It uses YUM for package management. A host wishing to know the …

Linux is a popular platform for everything from middleware to embedded computing and clusters, to parallel supercomputers and gadgets. Anyone who knows what they are doing is welcome to develop for the core, and submit patches. All controllers are different, but they usually have registers which control them. A block …

The issues with the Diebold [2] voting systems in the US is testament [3] to the need for transparent systems that are trustworthy. In the above example, the vfat and msdos modules are both dependent on the fat module and so it has a count of 2. For Linux, a …

Therefore, an alias definition appearing on the same line as another command does not take effect until the next line of input is read. Let's face it; Windows OS is vulnerable to different types of attacks (or hacks). Grep will take the output for that command, which is the name …

Proficiency with the proprietary Unixes has always been considered valuable, and it is well rewarded in the job market. The results of such concurrent accesses rely on the ordering of the individual operations, and are generally unpredictable. But I don't see the need for a true Linux Advocate to spotlight …

Linux systems always have a root filesystem. Linux does not. Signals have no inherent relative priorities. Even in the days before the Internet, information and so-called "intellectual property" could still be, and were, exchanged.

A simple guide to resize2fs

For example, software that can be freely modified but that does not have the same strict requirements for redistribution as the GPL is also considered open source. This means that it's not enough for a Linux platform to support what an enterprise needs right now. People who are completely new …

Although initially intimidating for many inexperienced users, using an all-text mode, also referred to as a command line interface (CLI) or a shell, can provide valuable experience for those who want to become truly proficient at Linux. Even so, most software developers, even those who have grown up during this …