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IRQ 8 – real-time clock (RTC) IRQ 9 – Advanced Configuration and Power Interface (ACPI) system control interrupt on Intel chipsets. [6] And/or left for the use of peripherals (use depends on OS) IRQ 10 – The interrupt is left for the use of peripherals (for example, SCSI or NIC)
A hardware interrupt is a condition related to the state of the hardware that may be signaled by an external hardware device, e.g., an interrupt request (IRQ) line on a PC, or detected by devices embedded in processor logic (e.g., the CPU timer in IBM System/370), to communicate that the device needs attention from the operating system (OS) [7] or, if there is no OS, from the bare metal ...
The front-half (or first level) receives the initial interrupt in the context of the running process, does the minimal work to restore the hardware to a less urgent condition (such as emptying a full receive buffer) and then marks the back-half (or second level) for execution in the near future at the appropriate scheduling priority; once ...
The IRR specifies which interrupts are pending acknowledgement, and is typically a symbolic register which can not be directly accessed. The ISR register specifies which interrupts have been acknowledged, but are still waiting for an end of interrupt (EOI). The IMR specifies which interrupts are to be ignored and not acknowledged.
MSI (first defined in PCI 2.2) permits a device to allocate 1, 2, 4, 8, 16 or 32 interrupts. The device is programmed with an address to write to (this address is generally a control register in an interrupt controller), and a 16-bit data word to identify it. The interrupt number is added to the data word to identify the interrupt. [1]
A Deferred Procedure Call (DPC) is a Microsoft Windows operating system mechanism which allows high-priority tasks (e.g. an interrupt handler) to defer required but lower-priority tasks for later execution. This permits device drivers and other low-level event consumers to perform the high-priority part of their processing quickly, and schedule ...
BIOS interrupt calls perform hardware control or I/O functions requested by a program, return system information to the program, or do both. A key element of the purpose of BIOS calls is abstraction - the BIOS calls perform generally defined functions, and the specific details of how those functions are executed on the particular hardware of the system are encapsulated in the BIOS and hidden ...
Under Microsoft Windows the APIC timer is not a shareable resource. [11] The aperiodic interrupts offered by the APIC timer are used by the Linux kernel tickless kernel feature. This optional but default feature is new with 2.6.18. When enabled on a computer with an APIC timer, the kernel does not use the 8253 programmable interval timer for ...