performance monitor

Performance Monitor (known as System Monitor in Windows 9x, Windows 2000, and Windows XP) is a system monitoring program introduced in Windows NT 3.1. It monitors various activities on a computer such as CPU or memory usage. This type of application may be used to determine the cause of problems on a local or remote computer by measuring performance of hardware, software services, and applications. The program can define thresholds for alerts and automatic actions, generate reports, and view past performance data.
In Windows 9x, System Monitor is not installed automatically during Windows setup, but can be installed manually using the Add/Remove Programs applet, located in the Control Panel. It has few performance measurement criteria (called "counters") available and offers little customization. In contrast, the Windows NT Performance Monitor is available out of the box and has over 350 available counters. Performance Monitor can display information as a graph, bar chart, or list of numeric values, and can update information using a range of time intervals. The categories of information that can be monitored depend on which networking services are installed, but always include file system, kernel, and memory manager. Other possible categories include Microsoft Network Client, Microsoft Network Server, and protocol categories.
In Windows 2000, the System Monitor of Windows 9x and the Performance Monitor of Windows NT 4 and earlier, as well as another program called Network Monitor, were merged into a Microsoft Management Console (MMC) plug-in called Performance, which consisted of two parts: "System Monitor" and "Performance Logs and Alerts". The "System Monitor" naming was kept in Windows XP. However, some third-party publications referred to it as "Performance Monitor", even in Windows 2000 or XP contexts.
The name in the MMC plug-in was changed back to "Performance Monitor" in Windows Vista, though it was also bundled with a Reliability Monitor and a new performance summary feature called Resource Overview. In Windows 7, the resource overview feature was spun off into a stand-alone Resource Monitor application, with the landing page for the Performance Monitor in Windows 7 containing a pointer to the (new) Resource Monitor; Windows 7 also moved the Reliability Monitor to the Action Center. A new feature added to the Performance Monitor in Windows Vista is Data Collector Set, which allows sets of accounting parameters to be easily manipulated as a group. Performance Monitor plots system CPU activity and offers the ability to add counters as a method of plotting performance, an option different from the ability to view CPU activity within Task Manager. Various integrated counters are available, and the tool also offers the option to import them. The tool allows for monitoring selective instances when selecting counters and offers a description of each counter. Additionally, counters can be highlighted if multiple are selected. Also included are various options for monitoring; that is, Chart, Log, and Report:

Chart displays performance monitoring data in graph form.
Within Chart, the Alert feature can be configured to send alerts if certain parameters are exceeded.
Report displays the same data in a numeric-only, non-graphic format.
Log manages options for saving monitoring results to the local computer.
Whatever its version, the tool can be accessed by typing Performance Monitor into the search field on the Windows [[taskbar]], or by using the keyboard shortcut Windows + R and typing perfmon.

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