Idle (CPU)

A computer processor is described as idle when it is not being used by any program.

Every program or task that runs on a computer system occupies a certain amount of processing time on the CPU. If the CPU has completed all tasks it is idle.

Modern processors use idle time to save power. Common methods are reducing the clock speed along with the CPU voltage and sending parts of the processor into a sleep state. On processors that have a halt instruction that stops the CPU until an interrupt occurs, such as x86's HLT instruction, it may save significant amounts of power and heat if the idle task consists of a loop which repeatedly executes HLT instructions.

Most operating systems will display an idle task, which is a special task loaded by the OS scheduler only when there is nothing for the computer to do. The idle task can be hard-coded into the scheduler, or it can be implemented as a separate task with the lowest possible priority. An advantage of the latter approach is that programs monitoring the system status can see the idle task along with all other tasks; an example is Windows NT's System Idle Process.

Idle

Idle (idling) is a term which generally refers to a lack of motion and/or energy.

Uses

In describing a person or machine, idle means the act of nothing or no work (for example: "John Smith is an idle person"). This is a person who spends his days doing nothing could be said to be "idly passing his days." (For example: Mary has been idle on her instant messenger account for hours.) A computer processor or communication circuit is described as idle when it is not being used by any program, application or message. Similarly, an engine of an automobile may be described as idle when it is running only to sustain its running (not doing any useful work), this is also called the tickover (see idle).

Idleness as dependent upon cultural norms

Typically, when one describes a machine as idle, it is an objective statement regarding its current state. However, when used to describe a person, idle typically carries a negative connotation, with the assumption that the person is wasting their time by doing nothing of value.

BatteryMAX (idle detection)

BatteryMAX is an Idle Detection System used for computer power management developed at Digital Research, Inc.'s European Development Centre (EDC) in Hungerford, UK. It was invented by British borne engineers Roger Gross and John Constant in August 1989 and was first released with DR DOS 5.0. It was created to address the new genre of portable personal computers (lap-tops) which ran from battery power. As such, it was also an integral part of Novell's PalmDOS 1.0 operating system tailored for early palmtops in 1992.

Description

Power saving in laptop computers traditionally relied on hardware inactivity timers to determine whether a computer was idle. It would typically take several minutes before the computer could identify idle behavior and switch to a lower power consumption state. By monitoring software applications from within the operating system, BatteryMAX is able to reduce the time taken to detect idle behavior from minutes to microseconds. Moreover it can switch power states around 20 times a second between a user's keystrokes. The technique was named Dynamic Idle Detection and includes halting, or stopping the CPU for periods of just a few microseconds until a hardware event occurs to restart it.

Idle (disambiguation)

Idle generally refers to a lack of motion or energy.

Idle may also refer to:

People

Places

Technology

Central processing unit

A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The term has been used in the computer industry at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

The form, design and implementation of CPUs have changed over the course of their history, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that fetches instructions from memory and "executes" them by directing the coordinated operations of the ALU, registers and other components.

Freescale 683XX

The Freescale 683xx (formerly Motorola 683xx) is a family of compatible microcontrollers that use a Freescale 68000-based CPU core. The family was designed using a hardware description language, making the parts synthesizable, and amenable to improved fabrication processes, such as die shrinks.

There are two CPU cores used in the 683xx family: the 68EC000 and the CPU32. The instruction set of the CPU32 core is similar to the 68020 without bitfield instructions, and with a few instructions unique to the CPU32 core, such as table lookup and interpolate instructions, and a low-power stop mode.

The modules of the microcontroller were designed independently and released as new CPUs could be tested. This process let the architects perform "design-ahead" so that when silicon technologies were available, Motorola had designs ready to implement and go to market. Many of these submodules have been carried forward into the Coldfire line of processors.

The microcontrollers consist of a series of modules, connected by an internal bus:

Rodney (New Glasgow) Airport

Rodney (New Glasgow) Airport, (TC LID: CPU3), is located 4 nautical miles (7.4 km; 4.6 mi) southeast of Rodney, Ontario, Canada.

References