This command-line tool analyzes a single server by processing the event log to determine reliability, availability, and current uptime. The target system can either be the local system or a remote system.
In its simple form, the tool displays the current system uptime, that is, the length of time since the last restart. An advanced option allows you to access more detailed information such as shutdowns, restarts, operating system failures, and Service Pack installation. Many factors affect these calculations, and the results displayed by this tool should be considered estimates.
No special privileges are required for basic operation. But it is best to run the tool under an administrative account, since much more information is available to calculate system uptime and availability. For instance, the time zone of the system, which is important to many of the calculations, can only be reliably obtained by an administrator. Additionally, when calculating the Current System Uptime, Uptime attempts to use the System Performance Counter for Uptime. However, if the user is not an administrator, this counter may be unavailable. In this case, an estimate is made based on the last recorded boot noted in the event log.
Availability calculations require:
The system heartbeat is a date/time stamp that is written to the system registry at a fixed interval. This heartbeat is available in Windows 2000 and Windows NT 4.0 Service Pack 4 or later. It is enabled by default on Windows 2000 Server. Since the heartbeat causes the registry to be written to the disk at regular intervals, it can interfere with systems running various forms of power management. It is not recommended that you enable the heartbeat of a laptop system.
To enable the heartbeat, run:
uptime /heartbeat [\\computer]If the heartbeat is disabled, or if you are not running Service Pack 4 or later, Uptime may report that the event logs do not contain sufficient information to calculate system availability. This is because the tool detects an abnormal shutdown (for instance a Stop error (also known as "blue screen") or power failure) but cannot determine how long the system was down during this abnormal outage.
Application Failure event detection is dependent upon Dr. Watson (a Windows 2000 diagnostic utility) being enabled.
Stop error detection is dependent upon the system being configured to write an event to the event log if the system stops unexpectedly.
To enable Stop error event logging for Windows NT 4.0:
To enable Stop error event logging for Windows 2000:
All calculations are based on the entries in the event log. If the system time is altered significantly, this has a dramatic affect on the calculations made. Additionally, if the event logs have been cleared, or have become so full that additional events cannot be written, the tool's ability to accurately estimate system availability is affected.
The heartbeat is generally written every five minutes, so the amount of downtime calculated for abnormal outages is limited in accuracy to this window.
Systems that are members of a cluster are currently unsupported by Uptime. If the tool detects that the target system might be a member of a cluster, it displays a message stating that the results might be in error.
Uptime Topics
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