NationMaster - Encyclopedia: Uptime

Uptime is a measure of the time a computer system has been "up" and running. It came into use to describe the opposite of downtime, times when a system was not operational. The uptime and reliability of computer and communications facilities is sometimes measured in nines. "Five nines" means 99.999% availability, which translates to a total downtime of approximately five minutes and fifteen seconds per year. Measurement is the estimation of the magnitude of some attribute of an object, such as its length or weight, relative to a unit of measurement. ... In computer science and computer programming, system time represents a computer systems notion of the passing of time. ... This article is about the machine. ... Downtime refers to a period of time or a percentage of a timespan that a machine or system (usually a computer server) is offline or not functioning, usually as a result of either system failure (such as a crash) or routine maintenance. ...

It is often used as a measure of computer operating system reliability and stability, in that this time represents the time a computer can be left unattended without crashing, or needing to be rebooted for administrative or maintenance purposes. Long uptime can also indicate negligence as many critical updates require reboot on some operating systems. An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. ... A crash in computing is a condition where a program (either an application or part of the operating system) stops performing its expected function and also stops responding to other parts of the system. ... This article is about the television program ReBoot. ...

The uptime(1) command on Unix systems will show the current time, the uptime, the number of users and load averages for the past 1, 5 and 15 minute intervals. Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIXÂ®, sometimes also written as or Â® with small caps) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... The system load is a UNIX computing term that describes the amount of work that a computer system is doing. ...

The Uptime-Project, until 1st March 2007, collected data on uptimes from users, and the current record for longest uptime is 6 years, 98 days, 12 hours, 6 minutes and 44 seconds on a computer running SunOS 5.6.^[1] The uptime of a personal computer is sometimes displayed as a badge of honour on an email signature or web site/forum. This was especially true in the Windows 9x days, where Windows NT and Windows 2000 users would boast of uptimes of more than 30 days, whereas many real-world Windows 9x installations crashed more often. In more recent times very long uptimes for home users with Windows NT and Windows 2000 machines are less striking because the Windows 9x line has been replaced by the Windows NT-based Windows XP. SunOS was the version of the UNIX operating system developed by Sun Microsystems for their workstations and server systems until the early 1990s. ... A signature block (often abbreviated as signature, sig block, sig file, .sig, dot sig, siggy, or just sig) is a block of text automatically appended at the bottom of an e-mail message, Usenet article, or forum post. ... Windows 9x is the family of Microsoft Windows operating systems that comprises the 32-bit, DOS-based Windows versions: Windows 95, Windows 98, and often also Windows Me. ... Windows NT (New Technology) is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ... Windows 2000 (also referred to as Win2K) is a preemptive, interruptible, graphical and business-oriented operating system designed to work with either uniprocessor or symmetric multi-processor computers. ... Windows XP is a line of operating systems developed by Microsoft for use on general-purpose computer systems, including home and business desktops, notebook computers, and media centers. ...

Netcraft maintains the uptime records for many thousands of web hosting computers. Netcraft is an Internet monitoring company based in Bath, England (recently having relocated from Bradford on Avon). ... Web hosting is a service that provides individuals, organizations and users with online systems for storing information, images, video, or any content accessible via the Web. ...

Users of Windows XP Professional and Windows Server 2003 systems can type systeminfo at the command prompt to display all system information, including the System Up Time. A typical Windows XP desktop. ... Windows Server 2003 is a server operating system produced by Microsoft. ...

Notes

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 120th day of the year (121st in leap years) in the Gregorian calendar. ...

See also

In information technology, the myth of the nines is the idea that standard measurements of availability can be misleading. ... A protocol and associated execution that ensures a certain relative degree of computing-system operational continuity in any downtime event. ... Downtime refers to a period of time or a percentage of a timespan that a machine or system (usually a computer server) is offline or not functioning, usually as a result of either system failure (such as a crash) or routine maintenance. ... This is a list of Unix programs. ...

External links

Categories: Real-time computing | Unix software | Fault tolerance This article is about operating systems that use the Linux kernel. ... The man page on man Almost all substantial UNIX and Unix-like operating systems have extensive documentation known as man pages (short for manual pages). The Unix command used to display them is man. ... Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIXÂ®, sometimes also written as or Â® with small caps) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... A command line interface or CLI is a method of interacting with a computer by giving it lines of textual commands (that is, a sequence of characters) either from keyboard input or from a script. ... This is a list of UNIX utilities as specified by IEEE Std 1003. ... In Unix shells (like csh, bash, etc. ... The title given to this article is incorrect due to technical limitations. ... chattr is a UNIX program that allows a user to set certain attributes to a file. ... This article does not cite any references or sources. ... The chmod command (abbreviated from change mode) is a shell command in Unix and Unix-like environments. ... chown is a Unix command used to change the recorded owner of a computer file. ... The chgrp command is used by unprivileged users on Unix-like systems to change the group associated with a file. ... Cksum is a POSIX command that reads the files specified by the File parameter and calculates a checksum, cyclic redundancy check (CRC) and the byte count for a file or files. ... cmp is a command line utility for computer systems that use a Unix operating system. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... du (abbreviated from disk usage) is a standard Unix program used to estimate the file space usage; space used under a particular directory or files on a file system. ... df (abbreviated from disk free) is a standard Unix computer program used to display the amount of available disk space for filesystems on which the invoking user has appropriate read access, df is usually implemented by reading the mtab file or using statfs. ... file is a program originated in Unix that runs under the shell (command-line) to determine the file type heuristically instead of other simpler ways to classify it, like with file extensions, MIMEs, etc. ... The system utility fsck (for file system check or file system consistency check) is a tool for checking the consistency of a file system in the Unix system and clones thereof. ... fuser is a UNIX command showing which processes are using a specified file. ... The ln command is used on Unix-like systems to create links between files. ... For other uses, see LS. ls is a command specified by POSIX and the Single UNIX Specification, and is thus implemented in Unix and Unix-like operating systems. ... lsof is a command found in almost any Unix system that reports open files by processes of a Operating System. ... The mkdir command in the Unix operating system is used to make a new directory. ... ... The correct title of this article is . ... The title given to this article is incorrect due to technical limitations. ... The title given to this article is incorrect due to technical limitations. ... This article does not cite any references or sources. ... split is a Unix utility most commonly used to split a file into one or more other files. ... touch is a standard Unix program used to change a files access and modification timestamps. ... The at command is used to schedule commands to be executed once at a particular time in the future. ... A chroot on Unix operating systems is an operation which changes the root directory. ... The crontab command, found in Unix and Unix-like operating systems, is used to schedule commands to be executed periodically. ... Exit is a command used in many operating systems command line shells. ... Wikibooks has more about this subject: kill In Unix and Unix-like operating systems, kill is a command used to send simple messages to processes running on the system. ... killall is a command line utility initially written for use with the GNU/Linux operating systems. ... nice (IPA pronunciation: ) is a command found on UNIX and other POSIX-like operating systems such as Linux. ... pgrep is a command line utility initially written for use with the Solaris 7 operating systems and then ported to GNU/Linux. ... pidof is a Linux utility that returns the process ID (PID) of a running process. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... pstree is a Unix command that shows the running processes as a tree. ... sleep is an instruction for a computer that delays execution for a specified period of time. ... This article is about a Unix command. ... In most Unix-like operating systems, the top command produces a frequently-updated list of processes. ... The correct title of this article is . ... In Unix, watch runs the specified command repeatedly and displays the output on stdout so you can watch it change over time. ... env is a shell utility for Unix-like operating systems (including Linux). ... In computer networking, the Name/Finger protocol and the Finger user information protocol are simple network protocols for the exchange of human-oriented status and user information. ... In computer software, id is a program in Unix operating systems that prints the uid of the account of which the program is executed by. ... Usage: logname [OPTION] Print the name of the current user. ... mesg is a Unix command that sets or reports the permission other users have to write to your terminal using the talk and write commands. ... passwd is a tool on most Unix and Linux systems used to change a users password. ... The Unix su (substitute user or switch user or super user) command is used to assume the login shell of another user without logging out. ... This article is about the Unix command line program. ... In computer software, uname is a program in Unix operating systems that prints the name, version and other details about the running operating system. ... The command w on many Unix-like operating systems provides a quick summary of every user logged into a computer, what that user is currently doing, and what load all the activity is imposing on the computer itself. ... wall is a Unix command line utility. ... who is a Unix-command which creates almost the same output as the Unix-command w; it shows you users currently logged in a system. ... whoami is a Unix-command which outputs the username of the user which runs the command. ... write can refer to several Unix commands. ... AWK is a general purpose computer language that is designed for processing text-based data, either in files or data streams. ... The comm command in Unix is a utility that is used to compare two files. ... cut is a Unix command which is typically used to extract a certain range of characters from a line, usually from a file. ... ed was the original standard text editor on the Unix operating system. ... ex, short for EXtended, is a line editor for Unix systems. ... Usage: fmt [-DIGITS] [OPTION]... [FILE]... Reformat each paragraph in the FILE(s), writing to standard output. ... head is a program that shows the first 10 lines by default of a file or piped data, on Unix and Unix-like systems. ... iconv is a computer program and a standardized API used to convert between different character encodings. ... join is a command in Unix-like operating systems. ... less is a program on Unix and Unix-like systems used to view (but not change) the contents of a text file one screen at a time. ... Example output of the more command. ... Paste is a Unix utility tool which is used to join files horizontally (parallel merging), e. ... The correct title of this article is . ... sort is a standard Unix command line program that prints the lines of its input in sorted order. ... Usage: tac [OPTION]... [FILE]... Write each FILE to standard output, last line first. ... tail is a program on Unix and Unix-like systems used to display the last few lines of a text file or piped data. ... tr (abbreviated from translate or transliterate) is a command in Unix-like operating systems. ... uniq is a Unix utility which, when fed a text file, outputs the file with adjacent identical lines collapsed to one. ... wc (short for word count) is a command in Unix-like operating systems. ... xargs is a command of the Unix and most Unix-like operating system which eases passing command output to another command as command line arguments. ... In computing, a shell is a piece of software that provides an interface for users (command line interpreter). ... basename is a common program found on Unix systems; typically it is the GNU Projects coreutils version, which is Free software. ... echo is a command in Unix (and by extension, its descendants, such as Linux) and MS-DOS that places a string on the terminal. ... expr is a command line Unix utility which evaluates an expression and outputs the corresponding value. ... In Unix-like operating systems, false is the command that always returns the value 1, which is regarded by the shell as the logical value false. ... Several programming languages implement a printf function, to output a formatted string. ... test is a Unix command that evaluates conditional expressions. ... In Unix-like operating systems, true is a command whose only function is to always return the value 0, which is regarded by the shell as the logical value true. ... unset is a Unix shell command. ... The Common Unix Printing System (CUPS) is a modularised computer printing system for Unix-like operating systems that allows computers to act as powerful print servers. ... inetd is a daemon on many Unix systems that manages Internet services. ... This article or section includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... For other uses, see Ping (disambiguation). ... In computing, rlogin is a Unix software utility that allows users to log in on another host via a network, communicating via TCP port 513. ... In computing, netcat is a network utility for reading from and writing to network connections on either TCP or UDP. It is designed in a thin and simple way, which makes it easy to incorporate in larger applications. ... traceroute outputs the list of traversed routers in simple text format, together with timing information traceroute is a computer network tool used to determine the route taken by packets across an IP network. ... For other uses, see Find (disambiguation). ... grep is a command line utility that was originally written for use with the Unix operating system. ... In computer software, strings is a program in Unix-like operating systems that prints the strings found in an executable. ... The banner program displays a large ASCII art version of input text. ... bc is an arbitrary precision calculator language with syntax similar to the C programming language. ... cal is a standard program on Unix that prints an ASCII calendar of the given month or year. ... dd is a common UNIX program whose primary purpose is the low-level copying and conversion of raw data. ... The man page on man Almost all substantial UNIX and Unix-like operating systems have extensive documentation known as man pages (short for manual pages). The Unix command used to display them is man. ... size is a command line utility originally written for use with the Unix-like operating systems. ... yes is a Unix command, which outputs an affirmative response, or a user-defined string of text continuously until killed. ...

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