Synchronous jobs started by bash have signals set to the values inherited by the shell from its parent. The use of pipes, on the other hand, turns Unix and Linux into software LEGO, which lets you build complex programs out of a simple set of building blocks. insmod copies the …

The entire Linux kernel was written from scratch, without employing any code from proprietary sources. Instead of a simple binary check, capabilities allow the kernel to base access on much more fine-grained settings. The most popular include Perl, Python, PHP, and Tcl. If you can use a computer or other …

Linux moving into the mainstream is a great thing. Background processes that attempt to read from (write to) the terminal are sent a SIGTTIN (SIGTTOU) signal by the terminal driver, which, unless caught, suspends the process. Another excellent source for assistance (and encouragement) is a local Linux Users Group (LUG …

A thread is the unit of activity within a process. This is also the reason serious Linux users prefer the command line. However, such programs are typically also made available for free (usually as a free download from the Internet). lsmod simply reformats /proc/modules which is built from the …

Slackware includes LILO and Loadlin for booting Slackware Linux. Instead, Linux aims toward compliance with two of the most important and prevalent standards: POSIX and the Single UNIX Specification (SUS). It is as old as computers themselves. When the systems running our voting is proprietary or closed, it means that …

There are three types of partition supported by fdisk, primary, extended and logical. The device driver maps the bytes over a seekable device, and user space is free to access any valid bytes in the array, in any order-it might read byte 12, then byte 7, and then byte 12 …

Missing a character, or reading them in any other order, would make little sense. For the most part, the Linux community communicates via various mailing lists and USENET newsgroups. Some tasks will be just as easy in either environment. There is also a level of indirection introduced that makes accesses …

It may use the API as-is, or not use it at all: take it or leave it! The device identifier for /dev/hdb, the slave IDE drive on the primary IDE controller is (3,64). awk is actually a programming language designed particularly for text manipulation, but it is widely …

To accomplish more complex tasks, tools would simply be connected together, using pipes. Like so many others I have always thought that one of the greatest attributes of Linux is its diversity of choice, but there are those outside of the Linux world that see this as a negative. None …

A vi-style line editing interface is also available. The Linux command line offers a wealth of power and opportunity. We can compare and contrast system programming with application programming, which differ in some important aspects but are quite similar in others. As you can see, by use of scripting, any …

If the kernel handles the signals, it will do the default actions required for this signal. The first method is most often the easiest, as long as your system UEFI boot manager allows you to disable the secure boot feature. The kernel allocates a new module data structure and enough …

Until recently, most modems were 8 or 16 bit ISA cards. Free software is also very different from public domain software. There are times when controllers need to read or write large amounts of data directly to or from system memory. The device driver places bytes onto the queue, one …

The second essential factor for a positive and efficient conversion to Linux is directly related to the Hardware Factor. When the last process sharing the memory detaches from it, the pages of the shared memory current in physical memory are freed, as is the shmid_ds data structure for this shared …

On i386, for example, a register is used for each possible parameter-registers ebx, ecx, edx, esi, and edi contain, in order, the first five parameters. As users developed ways around the methods, the methods kept getting progressively harsher, severely punishing casual proprietary software users who had been legally using and …

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 …

Some tasks are best suited to a GUI, word processing and video editing are great examples. You can easily configure and access any corner in your computer, monitor processes and manage virtual environments for different projects. First is the Human Factor, which includes the psychological issues with change, any kind …

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

Sustainable technologies are about ensuring access to knowledge forever. Traditionally, all Unix programming was system-level programming. Critical mass will be reached when people are given a CD that they can install just as easily as Windows and will provide them with all the tools that they are accustomed to on …

Most of this is going to be very important for your management of the machine. In the rare event of a system call with more than five parameters, a single register is used to point to a buffer in user space where all of the parameters are kept. That aside …

Currently, in Distrowatch's past 6 months ranking, it sits at #3. Linux clearly needed a better filesystem! Named pipes act like regular pipes but are accessed via a file, called a FIFO special file. You can interpret the answer into the GUI tool of your choice.

Fundamentals of dpkg

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 …

The master disk on the primary controller is /dev/hda and the slave disk is /dev/hdb. It is being widely used in embedded devices such as mobile phones and PDAs (Personal Data Assistants). All the linux commands like grep, cat and ls can be pipelined easily. It sure isn't …

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 …

By applying the foundational principals behind two factors, even the most techno-phobic and proprietary software entrenched small sized companies can painlessly move to Linux on the Desktop. It looks at each member of the operations pending queue (sem_pending) in turn, testing to see if the semphore operations will succeed this …

Becoming familiar with Linux can result in a substantial financial savings because the software (both the operating system and the application programs) is available for free and because Linux can run on older and cheaper computers. In 1978, Kernighan and Ritchie wrote, "The C Programming Language," a book that is …

If the kernel handles the signals, it will do the default actions required for this signal. The target host that owns the IP address, responds with an ARP reply that contains its physical hardware address. First, arrow to the boot option that you want to modify, and then press the …

A vi-style line editing interface is also available. So that modules can use the kernel resources that they need, they must be able to find them. The GNU C library provides more than its name suggests. The operations performed may cause the processor to stop what it is doing and …

It interprets the commands the user types in and arranges for them to be carried out. The process of booting your Linux system can sometimes be easy and sometimes be difficult. Upgrading from one version to another is also painless. In addition to implementing the standard C library, glibc provides …

An interrupt driven device driver is one where the hardware device being controlled will raise a hardware interrupt whenever it needs to be serviced. Thus they are also called built-in commands. Most of the Linux kernel is written in the C programming language, with a little bit of assembly and …

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 …

But, as we all know, there are typically many directories on a system. In either case, the kernel simply resolves the pathname to the correct inode. The editing mode may be switched during interactive use by using the -o option to the set built-in command. Whereas sockets communicating over the …

For new system timers, the entries in the linked list of timer_list data structures are checked. One of the main arguments used for Free Software is the advantage of not reinventing the wheel, yet in the case of nearly every hole in the software platform to fill, there are at …

Symbolic links look like regular files. It is time for the opening of the tools that will be needed to build this new age. In fact, part of the freedom of free software is that anyone has the right to sell an executable program released under a free software license …

When there are no more characters left to read, the device returns end-of-file (EOF). On GNU/Linux systems a file command can be used to identify a type of the file. Unlike most other operating systems, Linux is freely developed and continu- ously improved by a large community of software …

As such it is possible to have two or more files and directories with the same name but letters of different case. I say somewhat, because the use of sed in conjunction with pipes is somewhat more comfortable (at least to this author) for substitution of text in files. Software …

Hard links allow for complex filesystem structures with multiple pathnames pointing to the same data. You may need to go through several rounds of resubmission and additional feedback before your code is accepted, and in some cases it may be rejected. Share your personal experiences (good and bad) with Linux …

Each filesystem is mounted to a specific location in the namespace, known as a mount point. For the old system timers the timer_active bit mask is check for bits that are set. NASA spacecrafts, Motorola cell phones, Google Android smart- phones and tablets, Amazon Kindle eBook readers, TomTom GPS navigation …

In either case, the kernel simply resolves the pathname to the correct inode. Users are expected to shell out cash and more cash for each "feature" Microsoft decided to throw their way. Compare this to a floppy disk which only spins at 360 RPM. It is a synthasisable core and …

It can also be a Macintosh or almost any other type of computer. The overhead of symbolic links is minimal, but it is still considered a negative. Setting up TCP/IP connections is very different from setting up an amateur radio X.25 connection. Red Hat or Slackware) comes with …

This fixing up takes the form of patching the module image in memory. Some of this information will also help Windows users to understand the importance of user accounts. They work because they want to help themselves, their user base, or their software project. Block devices are generally storage devices …