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Sysctl
sysctl is a software utility of some Unix-like operating systems that reads and modifies the attributes of the system kernel such as its version number, maximum limits, and security settings. It is available both as a system call for compiled programs, and an administrator command for interactive use and scripting. Linux additionally exposes sysctl as a virtual file system. BSD In BSD, these parameters are generally objects in a management information base (MIB) that describe tunable limits such as the size of a shared memory segment, the number of threads the operating system will use as an NFS client, or the maximum number of processes on the system; or describe, enable or disable behaviors such as IP forwarding, security restrictions on the superuser (the "securelevel"), or debugging output. In OpenBSD and DragonFly BSD, sysctl is also used as the transport layer for the hw.sensors framework for hardware monitoring, whereas NetBSD uses the ioctl system call for its sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sysfs
sysfs is a pseudo file system provided by the Linux kernel that exports information about various kernel subsystems, hardware devices, and associated device drivers from the kernel's device model to user space through virtual files. In addition to providing information about various devices and kernel subsystems, exported virtual files are also used for their configuration. sysfs provides functionality similar to the sysctl mechanism found in BSD operating systems, with the difference that sysfs is implemented as a virtual file system instead of being a purpose-built kernel mechanism, and that, in Linux, ''sysctl'' configuration parameters are made available at ''/proc/sys/'' as part of procfs, not sysfs which is mounted at ''/sys/''. History During the 2.5 development cycle, the Linux driver model was introduced to fix the following shortcomings of version 2.4: * No unified method of representing driver-device relationships existed. * There was no generic hotplug mecha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ioctl
In computing, ioctl (an abbreviation of input/output control) is a system call for device-specific input/output operations and other operations which cannot be expressed by regular system calls. It takes a parameter specifying a request code; the effect of a call depends completely on the request code. Request codes are often device-specific. For instance, a CD-ROM device driver which can instruct a physical device to eject a disc would provide an ioctl request code to do so. Device-independent request codes are sometimes used to give userspace access to kernel functions which are only used by core system software or still under development. The ioctl system call first appeared in Version 7 of Unix under that name. It is supported by most Unix and Unix-like systems, including Linux and macOS, though the available request codes differ from system to system. Microsoft Windows provides a similar function, named "DeviceIoControl", in its Win32 API. Background Conventional oper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procfs
The proc filesystem (procfs) is a special filesystem in Unix-like operating systems that presents information about processes and other system information in a hierarchical file-like structure, providing a more convenient and standardized method for dynamically accessing process data held in the kernel than traditional tracing methods or direct access to kernel memory. Typically, it is mapped to a mount point named ''/proc'' at boot time. The proc file system acts as an interface to internal data structures about running processes in the kernel. In Linux, it can also be used to obtain information about the kernel and to change certain kernel parameters at runtime ( sysctl). Many Unix-like operating systems support the proc filesystem, including Solaris, IRIX, Tru64 UNIX, BSD, Linux, IBM AIX, QNX, and Plan 9 from Bell Labs. OpenBSD dropped support in version 5.7, released in May 2015. It is absent from HP-UX and macOS. The Linux kernel extends it to non–process-rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenBSD
OpenBSD is a security-focused operating system, security-focused, free and open-source, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by fork (software development), forking NetBSD 1.0. According to the website, the OpenBSD project emphasizes "portability, standardization, correctness, proactive security and integrated cryptography." The OpenBSD project maintains software portability, portable versions of many subsystems as package manager, packages for other operating systems. Because of the project's preferred BSD license, many components are reused in proprietary and corporate-sponsored software projects. The firewall (computing), firewall code in Apple Inc., Apple's macOS is based on OpenBSD's PF (firewall), PF firewall code, Android (operating system), Android's Bionic (software), Bionic C standard library is based on OpenBSD code, LLVM uses OpenBSD's regular expression library, and Windows 10 uses OpenSSH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NetBSD
NetBSD is a free and open-source Unix operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was forked. It continues to be actively developed and is available for many platforms, including servers, desktops, handheld devices, and embedded systems. The NetBSD project focuses on code clarity, careful design, and portability across many computer architectures. Its source code is publicly available and permissively licensed. History NetBSD was originally derived from the 4.3BSD-Reno release of the Berkeley Software Distribution from the Computer Systems Research Group of the University of California, Berkeley, via their Net/2 source code release and the 386BSD project. The NetBSD project began as a result of frustration within the 386BSD developer community with the pace and direction of the operating system's development. The four founders of the NetBSD project, Chris Demetriou, The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardware Monitoring
A system monitor is a hardware or software component used to monitor system resources and performance in a computer system. Among the management issues regarding use of system monitoring tools are resource usage and privacy. Overview Software monitors occur more commonly, sometimes as a part of a widget engine. These monitoring systems are often used to keep track of system resources, such as CPU usage and frequency, or the amount of free RAM. They are also used to display items such as free space on one or more hard drives, the temperature of the CPU and other important components, and networking information including the system IP address and current rates of upload and download. Other possible displays may include the date and time, system uptime, computer name, username, hard drive S.M.A.R.T. data, fan speeds, and the voltages being provided by the power supply. Less common are hardware-based systems monitoring similar information. Customarily these occupy one or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Configuration
A system configuration (SC) in systems engineering defines the computers, processes, and devices that compose the system and its boundary. More generally, the system configuration is the specific definition of the elements that define and/or prescribe what a system is composed of. Alternatively, the term "system configuration" can be used to relate to a ''model'' (declarative) for abstract generalized systems. In this sense, the usage of the configuration information is not tailored to any specific usage, but stands alone as a data set. A properly-configured system avoids resource-conflict problems, and makes it easier to upgrade a system with new equipment..... Sample configuration The following is a basic SC XML System Configuration: ''Description'': This provides information about a single "site" (MyHouse) and specifies that there is one host with ''user-setup'' and ''mysql-db'' components. The host must have an account on it for a user named ''mysql'', with appropriate parame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program. Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A '' cross-compiler'' produces code for a different CPU or operating system than the one on which the cross-compiler itself runs. A '' bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software include, a program that translates from a low-level language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wrapper Function
A wrapper function is a function (another word for a ''subroutine'') in a software library or a computer program whose main purpose is to call a second subroutine or a system call with little or no additional computation. Wrapper functions are used to make writing computer programs easier by abstracting away the details of a subroutine's underlying implementation. Purpose Wrapper functions are a means of delegation and can be used for a number of purposes. Programming convenience Wrapper functions can be used to make writing computer programs easier. An example of this is the MouseAdapter and similar classes in the Java AWT library. Wrapper functions are useful in the development of applications that use third-party library functions. A wrapper can be written for each of the third party functions and used in the native application. In case the third party functions change or are updated, only the wrappers in the native application need to be modified as opposed to changing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glibc
The GNU C Library, commonly known as glibc, is the GNU Project's implementation of the C standard library. Despite its name, it now also directly supports C++ (and, indirectly, other programming languages). It was started in the 1980s by the Free Software Foundation (FSF) for the GNU operating system. Released under the GNU Lesser General Public License, glibc is free software. The GNU C Library project provides the core libraries for the GNU system, as well as many systems that use Linux as the kernel. These libraries provide critical APIs including ISO C11, POSIX.1-2008, BSD, OS-specific APIs and more. These APIs include such foundational facilities as open, read, write, malloc, printf, getaddrinfo, dlopen, pthread_create, crypt, login, exit and more. History The glibc project was initially written mostly by Roland McGrath, working for the Free Software Foundation (FSF) in the 1980s as a teenager. In February 1988, FSF described glibc as having nearly completed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Kerrisk
Michael Kerrisk is a technical author, programmer and, since 2004, software maintainer, maintainer of the Linux man page, man-pages project, succeeding Andries Brouwer. He was born in 1961 in New Zealand and lives in Munich, Germany. Kerrisk has worked for Digital Equipment, Google, The Linux Foundation and, as an editor and writer, for LWN.net. Currently, he works as a freelance consultant and trainer. He is best known for his book ''The Linux Programming Interface'', published by No Starch Press in 2010. This book is widely regarded as the definitive work on Linux system programming and has been translated into several languages. As the software maintainer, maintainer of the Linux man page, man-pages project, Kerrisk has authored or co-authored about a third of the man pages and worked on improving the project's infrastructure. For his contributions he received a Special Award of the 2016 New Zealand Open Source Awards. References Free software programmers Living pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
