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Super-server
A super-server, sometimes called a service dispatcher, is a type of Daemon (computer software), daemon run generally on Unix-like systems. Usage A super-server starts other Server (computing), servers when needed, normally with access to them checked by a TCP Wrapper, TCP wrapper. It uses very few resources when in idle state. This can be ideal for workstations used for local web development, client/server development or low-traffic daemons with occasional usage (such as ident protocol, ident and Secure Shell, SSH). Performance The creation of an Process (computing), operating system process embodying the sub-daemon is deferred until an incoming connection for the sub-daemon arrives. This results in a delay to the handling of the connection (in comparison to a connection handled by an already-running process). Whether this delay is incurred repeatedly for every incoming connection depends on the design of the particular sub-daemon; simple daemons usually require a separate s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superserver 2
A super-server, sometimes called a service dispatcher, is a type of daemon run generally on Unix-like systems. Usage A super-server starts other servers when needed, normally with access to them checked by a TCP wrapper. It uses very few resources when in idle state. This can be ideal for workstations used for local web development, client/server development or low-traffic daemons with occasional usage (such as ident and SSH). Performance The creation of an operating system process embodying the sub-daemon is deferred until an incoming connection for the sub-daemon arrives. This results in a delay to the handling of the connection (in comparison to a connection handled by an already-running process). Whether this delay is incurred repeatedly for every incoming connection depends on the design of the particular sub-daemon; simple daemons usually require a separate sub-daemon instance (i.e. a distinct, separate operating system process) be started for each and every incomin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Launchd
launchd is an init and operating system service management daemon created by Apple Inc. as part of macOS to replace its BSD-style init and SystemStarter. There have been efforts to port launchd to FreeBSD and derived systems. Components There are two main programs in the launchd system: launchd and launchctl. ''launchd'' manages the daemons at both a system and user level. Similar to xinetd, launchd can start daemons on demand. Similar to watchdogd, launchd can monitor daemons to make sure that they keep running. launchd also has replaced init as PID 1 on macOS and as a result it is responsible for starting the system at boot time. Configuration files define the parameters of services run by launchd. Stored in the LaunchAgents and LaunchDaemons subdirectories of the Library folders, the property list-based files have approximately thirty different keys that can be set. launchd itself has no knowledge of these configuration files or any ability to read them - that is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xinetd
In computer networking, xinetd (''Extended Internet Service Daemon'') is an open-source software, open-source super-server Daemon (computer software), daemon which runs on many Unix-like operating system, systems, and manages Internet-based connectivity. It offers a more secure alternative to the older inetd ("the Internet daemon"), which most modern Linux distributions have deprecated. Description xinetd listens for incoming requests over a network and launches the appropriate Network service, service for that request. Requests are made using port numbers as identifiers and xinetd usually launches another Daemon (computing), daemon to handle the request. It can be used to start services with both privileged and non-privileged port numbers. xinetd features access control mechanisms such as TCP Wrapper Access control list, ACLs, extensive data logging, logging capabilities, and the ability to make Service (systems architecture), services available based on time. It can place ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ucspi-tcp
ucspi-tcp is a public domain Unix TCP command-line tool for building TCP client-server applications. It consists of super-server ''tcpserver'' and ''tcpclient'' application. Fro"Life with qmail" Dave Sill, 2 January 200 ''ucspi-tcp'' is an acronym for UNIX Client-Server Program Interface for TCP, and it is pronounced ''ooks-pie tee see pee''. tcpserver features built-in TCP Wrapper-like access control. ucspi-tcp competes with several other programs *mconnect client supplied as part of SunOS *faucet and hose, part of the netpipes package *netcat netcat (often abbreviated to nc) is a computer networking utility for reading from and writing to network connections using Transmission Control Protocol, TCP or User Datagram Protocol, UDP. The command (computing), command is designed to be a ... External links * http://cr.yp.to/ucspi-tcp.html Unix network-related software Transmission Control Protocol Public-domain software with source code {{Unix-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systemd
systemd is a software suite that provides an array of system components for Linux operating systems. The main aim is to unify service configuration and behavior across Linux distributions. Its primary component is a "system and service manager" — an init system used to Bootstrapping, bootstrap user space and manage process (computing), user processes. It also provides replacements for various Daemon (computing), daemons and utilities, including device management, login management, network connection management, and event logging. The name ''systemd'' adheres to the Unix convention of naming daemons by appending the letter ''d''. It also plays on the term "System D", which refers to a person's ability to adapt quickly and improvise to solve problems. Since 2015, the majority of Linux distributions have adopted systemd, having replaced other init systems such as SysV init. It has been praised by developers and users of distributions that adopted it for providing a stable, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inetd
inetd (internet service daemon) is a super-server Daemon (computer software), daemon on many Unix systems that provides Internet services. For each configured service, it listens for requests from connecting clients. Requests are served by spawning a process which runs the appropriate executable, but simple services such as ''echo'' are served by inetd itself. External executables, which are run on request, can be single- or multi-threaded. First appearing in BSD, 4.3BSD, it is generally located at /usr/sbin/inetd. inetd is based on the (service) activator pattern Function Often called a super-server, inetd listens on designated TCP and UDP port, ports used by Internet services such as File Transfer Protocol, FTP, POP3, and telnet. When a Transmission Control Protocol, TCP packet or User Datagram Protocol, UDP packet arrives with a particular destination port number, inetd launches the appropriate server program to handle the connection. For services that are not expected to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Process (computing)
In computing, a process is the Instance (computer science), instance of a computer program that is being executed by one or many thread (computing), threads. There are many different process models, some of which are light weight, but almost all processes (even entire virtual machines) are rooted in an operating system (OS) process which comprises the program code, assigned system resources, physical and logical access permissions, and data structures to initiate, control and coordinate execution activity. Depending on the OS, a process may be made up of multiple threads of execution that execute instructions Concurrency (computer science), concurrently. While a computer program is a passive collection of Instruction set, instructions typically stored in a file on disk, a process is the execution of those instructions after being loaded from the disk into memory. Several processes may be associated with the same program; for example, opening up several instances of the same progra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ident Protocol
The Ident Protocol (Identification Protocol, Ident), specified iRFC 1413 is an Internet protocol that helps identify the user of a particular TCP connection. One popular daemon program for providing the ident service is identd. Function The Ident Protocol is designed to work as a server daemon, on a user's computer, where it receives requests to a specified TCP port, generally 113. In the query, a client specifies a pair of TCP ports (a local and a remote port), encoded as ASCII decimals and separated by a comma (,). The server then sends a response that identifies the username of the user who runs the program that uses the specified pair of TCP ports, or specifies an error. Suppose host A wants to know the name of the user who is connecting to its TCP port 23 (Telnet) from the client's (host B) port 6191. Host A would then open a connection to the ident service on host B, and issue the following query: 6191, 23 As TCP connections generally use one unique local port (619 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secure Shell
The Secure Shell Protocol (SSH Protocol) is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution. SSH was designed for Unix-like operating systems as a replacement for Telnet and unsecured remote Unix shell protocols, such as the Berkeley Remote Shell (rsh) and the related rlogin and rexec protocols, which all use insecure, plaintext methods of authentication, like passwords. Since mechanisms like Telnet and Remote Shell are designed to access and operate remote computers, sending the authentication tokens (e.g. username and password) for this access to these computers across a public network in an unsecured way poses a great risk of 3rd parties obtaining the password and achieving the same level of access to the remote system as the telnet user. Secure Shell mitigates this risk through the use of encryption mechanisms that are intended to hide th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Web Development
Web development is the work involved in developing a website for the Internet (World Wide Web) or an intranet (a private network). Web development can range from developing a simple single static page of plain text to complex web applications, electronic businesses, and social network services. A more comprehensive list of tasks to which Web development commonly refers, may include Web engineering, Web design, Web content development, client liaison, client-side/ server-side scripting, Web server and network security configuration, and e-commerce development. Among Web professionals, "Web development" usually refers to the main non-design aspects of building Web sites: writing markup and coding. Web development may use content management systems (CMS) to make content changes easier and available with basic technical skills. For larger organizations and businesses, Web development teams can consist of hundreds of people (Web developers) and follow standard methods like Ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Workstations
A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating systems. The term ''workstation'' has been used loosely to refer to everything from a mainframe computer terminal to a PC connected to a network, but the most common form refers to the class of hardware offered by several current and defunct companies such as Sun Microsystems, Silicon Graphics, Apollo Computer, DEC, HP, NeXT, and IBM which powered the 3D computer graphics revolution of the late 1990s. Workstations formerly offered higher performance than mainstream personal computers, especially in CPU, graphics, memory, and multitasking. Workstations are optimized for the visualization and manipulation of different types of complex data such as 3D mechanical design, engineering simulations like computational fluid dynamics, animation, video editing, image ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
