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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 file semantics. 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 op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioctl
The bio(4) pseudo-device driver and the bioctl(8) utility implement a generic RAID volume management interface in OpenBSD and NetBSD. The idea behind this software is similar to ifconfig, where a single utility from the operating system can be used to control any RAID controller using a generic interface, instead of having to rely on many proprietary and custom RAID management utilities specific for each given hardware RAID manufacturer. Features include monitoring of the health status of the arrays, controlling identification through blinking the LEDs and managing of sound alarms, and specifying hot spare disks. Additionally, the softraid configuration in OpenBSD is delegated to bioctl as well; whereas the initial creation of volumes and configuration of hardware RAID is left to card BIOS as non-essential after the operating system has already been booted. Interfacing between the kernel and userland is performed through the ioctl system call through the /dev/bio pseudo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NetBSD
NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was fork (software development), 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 Permissive free software licence, 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 its 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sysctl
sysctl is a software mechanism in 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 sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenBSD
OpenBSD is a security-focused operating system, security-focused, free software, 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. The OpenBSD project emphasizes software portability, portability, software standard, standardization, software bug, correctness, proactive computer security, security, and integrated cryptography. The OpenBSD project maintains portable versions of many subsystems as package manager, packages for other operating systems. Because of the project's preferred BSD license, which allows binary redistributions without the source code, 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 c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Version 7 Unix
Version 7 Unix, also called Seventh Edition Unix, Version 7 or just V7, was an important early release of the Unix operating system. V7, released in 1979, was the last Bell Laboratories release to see widespread distribution before the commercialization of Unix by AT&T Corporation in the early 1980s. V7 was originally developed for Digital Equipment Corporation's PDP-11 minicomputers and was later ported to other platforms. Overview Unix versions from Bell Labs were designated by the edition of the user's manual with which they were accompanied. Released in 1979, the Seventh Edition was preceded by Sixth Edition, which was the first version licensed to commercial users. Development of the Research Unix line continued with the Eighth Edition, which incorporated development from 4.1BSD, through the Tenth Edition, after which the Bell Labs researchers concentrated on developing Plan 9. V7 was the first readily portable version of Unix. As this was the era of minicompute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley ( BSD), Microsoft (Xenix), Sun Microsystems ( SunOS/ Solaris), HP/ HPE ( HP-UX), and IBM ( AIX). The early versions of Unix—which are retrospectively referred to as " Research Unix"—ran on computers such as the PDP-11 and VAX; Unix was commonly used on minicomputers and mainframes from the 1970s onwards. It distinguished itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language (in 1973), which allows U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RAID
RAID (; redundant array of inexpensive disks or redundant array of independent disks) is a data storage virtualization technology that combines multiple physical Computer data storage, data storage components into one or more logical units for the purposes of data redundancy, performance improvement, or both. This is in contrast to the previous concept of highly reliable mainframe disk drives known as ''single large expensive disk'' (''SLED''). Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the required level of redundancy (engineering), redundancy and performance. The different schemes, or data distribution layouts, are named by the word "RAID" followed by a number, for example RAID 0 or RAID 1. Each scheme, or RAID level, provides a different balance among the key goals: reliability engineering, reliability, availability, computer performance, performance, and computer data storage#Capacity, capacity. RAID levels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminal Emulator
A terminal emulator, or terminal application, is a computer program that emulates a video terminal within some other display architecture. Though typically synonymous with a shell or text terminal, the term ''terminal'' covers all remote terminals, including graphical interfaces. A terminal emulator inside a graphical user interface is often called a terminal window. A terminal window allows the user access to a text terminal and all its applications such as command-line interfaces (CLI) and text user interface (TUI) applications. These may be running either on the same machine or on a different one via telnet, ssh, dial-up, or over a direct serial connection. On Unix-like operating systems, it is common to have one or more terminal windows connected to the local machine. Terminals usually support a set of escape sequences for controlling color, cursor position, etc. Examples include the family of terminal control sequence standards that includes ECMA-48, ANSI X3.64, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Userspace
A modern computer operating system usually uses virtual memory to provide separate address spaces or regions of a single address space, called user space and kernel space. This separation primarily provides memory protection and hardware protection from malicious or errant software behaviour. Kernel space is strictly reserved for running a privileged operating system kernel, kernel extensions, and most device drivers. In contrast, user space is the memory area where application software and some drivers execute, typically with one address space per process. Overview The term user space (or userland) refers to all code that runs outside the operating system's kernel. User space usually refers to the various programs and libraries that the operating system uses to interact with the kernel: software that performs input/output, manipulates file system objects, application software, etc. Each user space process usually runs in its own virtual memory space, and, unless explici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoterminal
In some operating systems, including Unix-like systems, a pseudoterminal, pseudotty, or PTY is a pair of pseudo-device endpoints (files) which establish an asynchronous, bidirectional communication (IPC) channel (with two ports) between two or more processes. One pseudo-device in the pair, the ''master'', provides means by which a terminal emulator or remote login server (e.g. a Telnet, rlogin, or Secure Shell server) process controls the slave. The other pseudo-device, the ''slave'', emulates a hardware serial port device, and is used by terminal-oriented programs such as shells (e.g. bash) as a processes to read/write data back from/to ''master'' endpoint. PTYs are similar to bidirectional pipes. Devpts is a Linux kernel virtual file system containing pseudoterminal devices. Linux implementation is based on System V-style terminals (commonly referred as UNIX 98 pseudoterminals) and provides POSIX and the Single Unix Specification API in the form of a function since 1998. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remote Login
Remote administration refers to any method of controlling a computer or other Internet-connected device, such as a smartphone, from a remote location. There are many commercially available and free-to-use software that make remote administration easy to set up and use. Remote administration is often used when it's difficult or impractical to be physically near a system in order to use it or troubleshoot it. Many server administrators also use remote administration to control the servers around the world at remote locations. It is also used by companies and corporations to improve overall productivity as well as promote remote work. It may also refer to both legal and illegal (i.e. hacking) remote administration (see Owned and Trojan). Requirements Internet connection Any computer with an Internet connection or on a local area network can be remotely administered. For non-malicious administration, the user must install or enable server software on the host system in ord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Port
A serial port is a serial communication Interface (computing), interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in Parallel communication, parallel. Throughout most of the history of personal computers, data has been transferred through serial ports to devices such as modems, computer terminal, terminals, various peripherals, and directly between computers. While interfaces such as Ethernet, FireWire, and USB also send data as a serial Stream (computing), stream, the term ''serial port'' usually denotes Computer hardware, hardware compliant with RS-232 or a related standard, such as RS-485 or RS-422. Modern consumer personal computers (PCs) have largely replaced serial ports with higher-speed standards, primarily USB. However, serial ports are still frequently used in applications demanding simple, low-speed interfaces, such as industrial automation sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
