A system monitor is a hardware or

software Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital comput ...

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. Monitoring can track both input and output values and events of systems.

Overview

Software monitors occur more commonly, sometimes as a part of a widget engine. These monitoring systems are often used to keep track of system resources, such as CPU usage and frequency, or the amount of free RAM. 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 assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface i ...

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 Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical ...

. With either approach to gathering data, the monitoring system displays information on a small LCD 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. The primary function of a few very high-end models of hardware system monitor is to interface with only a specific model of

motherboard A motherboard, also called a mainboard, a system board, a logic board, and informally a mobo (see #Nomenclature, "Nomenclature" section), is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It ho ...

. 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, or as part of a Super I/O solution, often interfaced through Low Pin Count (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 a manufactured object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...

, voltage supplied to the motherboard by the power supply unit and the speed of the computer fans 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 A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

information to the user.

Privacy

When an individual user is measuring the performance of a single-user system, whether it is a standalone box or a

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

on a multi-user system, 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 "cause the OS to crash".

List of software monitors

Single system: * Activity Monitor * AIDA64 * CPU-Z * 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 (software), top. It shows a frequently updated list of the processes running on a computer, normally ordered by t ...

* hw.sensors on OpenBSD and DragonFly BSD *

iftop Iftop is a free software command-line system monitor tool developed by Paul Warren. It produces a real-time stream of incoming and outgoing network communications from the operating system iftop is running within. By default, the connections are ...

* iostat * KDE System Guard (KSysguard) * lm_sensors * monit * Monitorix * Motherboard Monitor * Netdata * nmon * ntop * Process Explorer * Resource Monitor (resmon) * Samurize * Sar in UNIX * SpeedFan * sysmon/ envsys on NetBSD * systat * System Monitor (sysmon) *

top Top most commonly refers to: * Top, a basic term of orientation, distinguished from bottom, front, back, and sides * Spinning top, a ubiquitous traditional toy * Top (clothing), clothing designed to be worn over the torso * Mountain top, a moun ...

* vmstat * Windows Desktop Gadgets *

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 names of ...

Distributed: * Argus (monitoring software) * Collectd *

Ganglia A ganglion (: ganglia) 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 a ...

* GKrellM * HP SiteScope * Icinga * monit (paid version M/monit) * NMIS * Munin *

Nagios Nagios is an event monitoring system that offers monitoring and alerting services for servers, switches, applications and services. It alerts users when things go wrong and alerts them a second time when the problem has been resolved. Ethan ...

* 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 an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE ...

, 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