When the writer wants to write to the pipe it uses the standard write library functions. Yet throughout many school systems, the software in use on computers is closed and locked, making educators partners in the censorship of the foundational information of this new age. While an AWS-like service isn't …

Aliases are expanded when a command is read, not when it is executed. Commands run as a result of command substitu- tion ignore the keyboard-generated job control signals SIGTTIN, SIGTTOU, and SIGTSTP. People who are completely new to open source software often wonder how a group of random people can …

Most of the malware are propagated through the Internet. You might also wonder whether ext4 is still in active development at all, given the flurries of news coverage of alternate filesystems such as btrfs, xfs, and zfs. It is sad to see that people today actually have to use the …

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 …

Linux protects against this by maintaining lists of adjustments to the semaphore arrays. There are three types of partition supported by fdisk, primary, extended and logical. The first filesystem mounted is located in the root of the namespace, /, and is called the root filesystem. It doesn't take long to realize …

The new vm_area_struct structure is put into the list of vm_area_struct pointed at by the shmid_ds. Internally, the quality assurance department runs rigorous regression test suites on each new pass of the operating system, and reports any bugs. It then restores the state of the new process (again this is …

After moving the Linux I've noticed a dramatic improvement in the speed and performance of my work flow, with the exact same tools I used on Windows. What does this mean to you? Each individual semaphore operation may request that an adjustment be maintained. The Free Software Movement would be …

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 …

This, in turn, allows for the use of the pathnames with which all Unix users are familiar-for example, /home/blackbeard/concorde.png. Figure 5.1 shows that each file data structure contains pointers to different file operation routine vectors; one for writing to the pipe, the other for reading from …

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 …

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 …

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 …

Physical filesystems reside on block storage devices, such as CDs, floppy disks, compact flash cards, or hard drives. Today open source software has become critical for almost every organization. If you love the rolling Linux distributions (here are some fixed vs rolling release differences), then you don't need to look …

The Linux kernel, supporting both preemptive multitasking and virtual memory, provides every process both a virtualized processor and a virtualized view of memory. This is true even if the device is a modem being used by the PPP daemon to connect a Linux system onto a network. Therefore Linux adds …

But it starts at the top. For Linux, a vendor can create a device driver for a specific hardware device and expect that, within reason, it will operate across most distributions. When Corporations are happy with the used software they donate money to the communities in order to be able …

To do this the IDE subsystem uses the minor device number from the device special identifier, this contains information that allows it to direct the request to the correct partition of the correct disk. Both of these flags are used for demand loaded modules. Unix and Linux are similar in …

There are several web sites that provide drivers and assistance for configuring WinModem based devices. Often, the users who identify the bugs can fix the problem because they have the source code, or they can provide detailed descriptions of their problems so that other developers can fix them. A good …

The UEFI boot manager boots the mini-bootloader, then, in turn, it boots the standard Linux bootloader image. The exact wording of a recipe as it is written by its author is protected under copyright law, but the information itself (i.e., the names of the ingredients, their quantities and the …

By opening the code to widespread examination, more people take part in finding its bugs and security flaws, in testing for broad compatibility across platforms, and in providing new ideas. This means that when the next process that attempts to access this memory gets a page fault, the shared memory …

Why make it easier for them. However, in most cases it is closed source (i.e., the source code is kept secret), and there are often restrictions on the use of the executable version. If all of the semaphore operations would have succeeded and the current process does not need …

Perhaps the most confusing thing about installing Linux for new users is the large number of options that are available to choose from. The early popularity of distributions like Slackware and then Red Hat gave the "common PC user" of the 1990s access to the Linux operating system and, with …

The job of cache coherency is done partially by the hardware and partially by the operating system. One side note is that the popularity of the macOS hardware and operating system as a platform for development that mainly targets Linux may be attributed to the BSD-like macOS operating system. There …

Processes that are started at boot time usually run as root or nobody. As a Linux user today you have all the means of getting to know your system inside out, but it is no longer necessary to have that knowledge in order to make the system comply to your …

Whenever we refer to a file or directory we are using one of these paths. Popular distributions include Debian, Fedora, Mint, and Ubuntu, but there are many others. The CPU can access both the system space memory and the I/O space memory, whereas the controllers themselves can only access …

All of the read/write heads are attached together, they all move across the surfaces of the platters together. A common sector size is 512 bytes and the sector size was set when the disk was formatted, usually when the disk is manufactured. There is yet one other weakness: if …

If you do this, or try to exit again immediately, you are not warned again, and the stopped jobs are terminated. Once a Linux module has been loaded it is as much a part of the kernel as any normal kernel code. This value is called the inode number, often …

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 …

Therefore, mastering Linux for configuring and maintaining servers is a must to have skill for any technological entrepreneur who operates end-to-end applications. The scalability and flexibility of Linux enable many of these massive deployments to actually work, while the significantly reduced cost barriers of Linux make them more financially feasible …

Linux is open-source. With all the activity around Unix at Berkeley, a new delivery of Unix software was born: the Berkeley Software Distribution, or BSD. Furthermore, the developer writing Python or Ruby or Scala can still benefit from knowledge of system programming, as an understanding of the soul of the …

It is vital that there is an uninterrupted stream of knowledge, and that information is not held back for personal benefit at the cost of others. Most of the time you will be issuing commands. Anyone can join the Linux community by participating in and contributing to this mailing list …

Now Linux must check that any waiting, suspended, processes may now apply their semaphore operations. Much of enterprise IT's excitement is focused on advancements at the application level (and rightly so), but it's Linux that powers these innovations and helps to drive modern computing forward. If you're interested in writing …

Linux (as well as many other areas of information technology) is particularly well suited for studying at home because (1) no equipment is needed other than an ordinary personal computer and (2) there is a large amount of free or modestly priced study material that is available from bookstores, in …