Uptime

From Free net encyclopedia

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 non-operational. The uptime and reliability of computer and communications facilities is sometimes measured in "nines". Five nines means 99.999% reliability, which translates to a total downtime of no longer than five minutes per year.

It is often used 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.

The uptime(1) command on Unix systems will show the current time, the uptime, the number of users, and load averages, from the last 1, 5, and 15 minute intervals.

$ uptime
 04:09PM   up 137 days,   8:48,  2 users,  load average: 0.16, 0.33, 0.35

Amongst geeks uptime of a personal computer is sometimes displayed as a badge of honour on their email signature or web site. This was especially true in the Windows 9x days, where GNU/Linux, Windows NT and Windows 2000 users would boast of uptimes of more than 30 days, whereas many real-world Windows 9x installations crashed most days. In more recent times very long uptimes for home users with Unix, Windows NT and Windows 2000 machines are less striking because the Windows 9x line has been replaced by the Windows NT-based Windows XP.

Netcraft maintains the uptime records for many thousands of web hosting computers.

Windows XP Professional systems need to type systeminfo at the command prompt to display all system information, including the System Up Time.

To display just the uptime in Windows XP Professional, type systeminfo | find "System Up Time:" at the command prompt.

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