A system monitor is a hardware or

software Software is a set of computer programs and associated software documentation, documentation and data (computing), data. This is in contrast to Computer hardware, hardware, from which the system is built and which actually performs the work. ...

component used to monitor system resources and performance in a computer system. Among the management issues regarding use of system monitoring tools are resource usage and privacy.

Overview

Software monitors occur more commonly, sometimes as a part of a

widget engine A software widget is a relatively simple and easy-to-use software application or component made for one or more different software platforms. A desk accessory or applet is an example of a simple, stand-alone user interface, in contrast with ...

. These monitoring systems are often used to keep track of system resources, such as

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...

usage and frequency, or the amount of free

RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch ...

. They are also used to display items such as free space on one or more hard drives, the temperature of the CPU and other important components, and networking information including the system

IP address An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...

and current rates of upload and download. Other possible displays may include the date and time, system uptime, computer name, username, hard drive S.M.A.R.T. data, fan speeds, and the voltages being provided by the power supply. Less common are hardware-based systems monitoring similar information. Customarily these occupy one or more

drive bay A drive bay is a standard-sized area for adding hardware to a computer. Most drive bays are fixed to the inside of a case, but some can be removed. Over the years since the introduction of the IBM PC, it and its compatibles have had many form f ...

s on the front of the

computer case A computer case, also known as a computer chassis, is the enclosure that contains most of the hardware of a personal computer. The components housed inside the case (such as the CPU, motherboard, memory, mass storage devices, power supply unit ...

, and either interface directly with the system hardware or connect to a software data-collection system via USB. With either approach to gathering data, the monitoring system displays information on a small

LCD A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but i ...

panel or on series of small analog or LED numeric displays. Some hardware-based system monitors also allow direct control of fan speeds, allowing the user to quickly customize the cooling in the system. A few very high-end models of hardware system monitor are designed to interface with only a specific model of

motherboard A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...

. These systems directly utilize the sensors built into the system, providing more detailed and accurate information than less-expensive monitoring systems customarily provide.

Software monitoring

Software monitoring tools operate within the device they're monitoring.

Hardware monitoring

Unlike software monitoring tools, hardware measurement tools can either located within the device being measure, or they can be attached and operate from an external location. A hardware monitor is a common component of modern

s, which can either come as a separate chip, often interfaced through I²C or

SMBus The System Management Bus (abbreviated to SMBus or SMB) is a single-ended simple two-wire bus for the purpose of lightweight communication. Most commonly it is found in computer motherboards for communication with the power source for ON/OFF instru ...

, or as part of a

Super I/O Super I/O is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a var ...

solution, often interfaced through

Low Pin Count The Low Pin Count (LPC) bus is a computer bus used on IBM-compatible personal computers to connect low-bandwidth devices to the CPU, such as the BIOS ROM (BIOS ROM was moved to the Serial Peripheral Interface (SPI) bus in 2006), "legacy" I/O ...

(LPC). These devices make it possible to monitor temperature in the

chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpa ...

, voltage supplied to the motherboard by the power supply unit and the speed of the

computer fan A computer fan is any fan inside, or attached to, a computer case used for active cooling. Fans are used to draw cooler air into the case from the outside, expel warm air from inside and move air across a heat sink to cool a particular compon ...

s that are connected directly to one of the fan headers on the motherboard. Many of these hardware monitors also have fan controlling capabilities. System monitoring software like SpeedFan on Windows, lm_sensors on Linux, envstat on NetBSD, and sysctl hw.sensors on OpenBSD and DragonFly can interface with these chips to relay this environmental sensor information to the user.

Privacy

When an individual user is measuring the performance of a

single-user system Multi-user software is computer software that allows access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving t ...

, whether it is a standalone box or a

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized har ...

on a

multi-user system Multi-user software is computer software that allows access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving ...

, access does not impede the

privacy Privacy (, ) is the ability of an individual or group to seclude themselves or information about themselves, and thereby express themselves selectively. The domain of privacy partially overlaps with security, which can include the concepts of a ...

of others. Privacy becomes an issue when someone other than the end-user, such as a system manager, has legitimate need to access data about other users.

Resource usage

When events occur faster than a monitor can record them, a workaround is needed, such as replacing event recording with simple counting. Another consideration is not having major impact on the CPU and storage available for useful work. While a hardware monitor will usually have less impact than a software monitor, there are data items, such as "some descriptive information, such as program names" that must involve software. A further consideration is that a bug in this domain can have severe impact: an extreme case would be "cause the OS to

crash Crash or CRASH may refer to: Common meanings * Collision, an impact between two or more objects * Crash (computing), a condition where a program ceases to respond * Cardiac arrest, a medical condition in which the heart stops beating * Couch s ...

List of software monitors

Single system: * Activity Monitor *

AIDA64 AIDA64 is a system information, diagnostics, and auditing application developed by FinalWire Ltd (a Hungarian company) that runs on Windows, Android, iOS, Windows Phone, Tizen, ChromeOS and Sailfish OS operating systems. It displays detailed ...

CPU-Z CPU-Z is a freeware system profiling and monitoring application for Microsoft Windows and Android that detects the central processing unit, RAM, motherboard chip-set, and other hardware features of a modern personal computer or Android devic ...

* GPU-Z * Conky *

htop htop is an interactive system-monitor process-viewer and process-manager. It is designed as an alternative to the Unix program top. System monitor It shows a frequently updated list of the processes running on a computer, normally ordered by ...

* hw.sensors on OpenBSD and DragonFly BSD *

iftop Iftop is a free software command-line system monitor tool that produces a frequently updated list of network connections. By default, the connections are ordered by bandwidth usage, with only the "top" bandwidth consumers shown. It is analogou ...

* iostat *

KDE System Guard KDE System Guard, also known as KSysGuard, is the task manager and performance monitor for the KDE platform on Unix-like systems. It can monitor both local and remote hosts, accomplished via running ksysguardd on the remote host, and having the ...

(KSysguard) * lm_sensors * monit * Monitorix * Motherboard Monitor * Netdata *

nmon nmon (''Nigel's Monitor'') is a computer performance system monitor tool for the AIX and Linux operating systems. The nmon tool has two modes a) displays the performance stats on-screen in a condensed format or b) the same stats are saved to a ...

ntop ntop is computer software that probes a computer network to show network use in a way similar to what the program top does for processes. Software In interactive mode, it displays the network status on the user's terminal. In Web mode, it act ...

Process Explorer Process Explorer is a freeware task manager and system monitor for Microsoft Windows created by SysInternals, which has been acquired by Microsoft and re-branded as Windows Sysinternals. It provides the functionality of Windows Task Manager along ...

* Resource Monitor (resmon) *

Samurize Serious Samurize (or simply Samurize) is a freeware system monitoring and desktop enhancement engine for Microsoft Windows. The core of Samurize is the desktop client that displays PC statistics (similar to a widget or gadget) anywhere on the sc ...

* Sar in UNIX * SpeedFan * sysmon/

envsys The envsys framework is a kernel-level hardware monitoring sensors framework in NetBSD. , the framework is used by close to 85 device drivers to export various environmental monitoring sensors, as evidenced by references of the sysmon_envsys_ ...

on NetBSD * systat *

System Monitor A system monitor is a hardware or software component used to monitor system resources and performance in a computer system. Among the management issues regarding use of system monitoring tools are resource usage and privacy. Overview Software ...

(sysmon) * top * Vigilo NMS (Community Edition) * vmstat *

Windows Desktop Gadgets Windows Desktop Gadgets (called Windows Sidebar in Windows Vista) is a discontinued widget engine for Microsoft Gadgets. Desktop Gadgets have been replaced by Windows 10 Taskbar Widgets. It was introduced with Windows Vista, in which it features ...

Windows Task Manager Task Manager, previously known as Windows Task Manager, is a task manager, system monitor, and startup manager included with Microsoft Windows systems. It provides information about computer performance and running software, including name of ru ...

Distributed: *

Argus (monitoring software) Argus is a systems and network monitoring application. It is designed to monitor the status of network services, servers, and other network hardware. It will send alerts when it detects problems. It is open-source software originally written ent ...

* Collectd *

Ganglia A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympath ...

* GKrellM *

HP SiteScope Micro Focus SiteScope is agentless monitoring software focused on monitoring the availability and performance of distributed IT infrastructures, including Servers, Network devices and services, Applications and application components, operating s ...

* monit (paid version M/monit) * NMIS * Munin *

Nagios Nagios Core , formerly known as Nagios, is a free and open-source computer-software application that monitors systems, networks and infrastructure. Nagios offers monitoring and alerting services for servers, switches, applications and servic ...

* NetCrunch * Opmantek * Pandora FMS * Performance Monitor (perfmon) * Prometheus (software) * symon * Vigilo NMS (Enterprise Editions) * Zenoss Core

References

{{reflist, refs= {{Cite conference , author= Constantine A. Murenin , date= 2007-04-17 , url = http://sensors.cnst.su/IEEE_ICNSC_2007 , title= Generalised Interfacing with Microprocessor System Hardware Monitors , conference= Proceedings of 2007 IEEE International Conference on Networking, Sensing and Control, 15–17 April 2007. , location= London, United Kingdom , publisher=

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operati ...

, doi = 10.1109/ICNSC.2007.372901 , isbn = 978-1-4244-1076-7 , id = IEEE ICNSC 2007, pp. 901—906.

External links

Monitoring a Linux System with X11/Console/Web-Based Tools
Computer peripherals Liquid crystal displays System administration Utility software types