This is used by gateways, which respond to ARP requests on behalf of IP addresses that are in the remote network. Many, if not most, PCI modems available on store shelves these days are WinModems. This means that subsequent INET socket calls can easily retrieve the sock data structure. Figure …

It is time for the opening of the tools that will be needed to build this new age. The physical on-disk form of this mapping-for example, a simple table or a hash-is implemented and managed by the kernel code that supports a given filesystem. The reality is that not only …

Therefore, when moving to the PDP-11 as the main hardware platform, the developers started C as the as a core language for Unix. Advocates of copyleft respond by pointing out that there is no such thing as absolute freedom. The test and set operation is, so far as each process …

All of the read/write heads are attached together, they all move across the surfaces of the platters together. Some users have reported success configuring and installing drivers for the various winmodems, including Lucent, Conexant, and Rockwell chipsets. Yet throughout many school systems, the software in use on computers is …

Authorization in Linux is provided by users and groups. This is also true for a number of major system tasks where the hardware and software must cooperate closely to achieve their aims. It was unbelievably naive of them to think they could stop the spread of an idea. Later on …

Functions are defined by using the function keyword and followed by function body enclosed by curly brackets. The data is read by a head, which can detect whether a particular minute particle is magnetized. FLOSS OSes tend to include many applications that are usually sold separately in proprietary systems (including …

The exact mechanism varies from architecture to architecture. Those programs or issues that have not yet been addressed or resolved for Linux can still reside on the original drive and remain operational as long as they are needed. GNU/Linux increases personal computing freedom. Usually Linux based malware are extremely …

In a multiprocessing system many processes are kept in memory at the same time. The kernel does not impose any restrictions on concurrent file access. This software universe had been going on behind my back for years. Just maybe that crash you reported will save some people from a major …

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 …

With Linux, you can throw out the entire concept of organized development, source control systems, structured bug reporting, or statistical analysis. Processes are always making system calls and so may often need to wait. Behavior changes and features are added. Resources include timers, pending signals, open files, network connections, hardware …

Getting involved with kernel development is, paradoxically, both easier than it seems like it should be, and also ridiculously difficult. Advocates of these extremely short and simple licenses contend that they provide even greater freedom than the GPL because they grant the freedom for source code to be incorporated into …

The first data written into the pipe is the first data read from the pipe. Like the rest of the kernel, device drivers use data structures to keep track of the device that it is controlling. These controllers are connected to the CPU and to each other by a variety …

In this case, Direct Memory Access (DMA) controllers are used to allow hardware peripherals to directly access system memory but this access is under strict control and supervision of the CPU. This creates a new vm_area_struct data structure describing the shared memory for this process. The thrust behind Linux development …

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. For example, software that can be freely modified but that does not have the same strict requirements for redistribution as the …

Whereas MINIX is based on a microkernel that contains the bare minimum amount of code necessary to run an operating system, Linux has a monolithic kernel, which means that functions like the file system, virtual memory, and various system calls all take place in privileged kernel space. Built in to …

Figure 11.3 shows both mechanisms. For example, %ce refers to a stopped ce job. The partitions of a hard disk are described by a partition table; each entry describing where the partition starts and ends in terms of heads, sectors and cylinder numbers. If something is in the public …

The device identifier for the first partition of that disk (/dev/hdb1) is (3,65). Shell scripting is really what separates novice Linux consumers from advanced Linux users. This is why our previous shell script works even without us defining bash as an interpreter. The inode contains metadata associated with …