what is I.R.Q?

Question

what is I.R.Q,what is the use of it ,where it is found ,how many irq's are there?

Answer 1

In computing, an interrupt request (or IRQ) is a phrase used to refer to either the act of interrupting the bus lines used to signal an interrupt, or the interrupt input lines on a Programmable Interrupt Controller (PIC). Interrupt lines are often identified by an index with the format of IRQ followed by a number. For example, on the Intel 8259 family of PICs there are eight interrupt inputs commonly referred to as IRQ0 through IRQ7. In x86 based computer systems that use two of these PICs, the combined set of lines are referred to as IRQ0 through IRQ15. Technically these lines are named IR0 through IR7, and the lines on the ISA bus to which they were historically attached are named IRQ0 through IRQ15.

Newer x86 systems integrate an APIC that conforms to the Intel APIC Architecture. These APICs support a programming interface for up to 255 physical hardware IRQ lines per APIC, with a typical system implementing support for only around 24 total hardware lines.

When working with computer hardware, installing and removing devices, the system relies on Interrupt Requests (IRQ). There are default settings that are configured in the system BIOS and recognized by the operating system. These default settings can be altered by advanced users. Modern Plug and Play technology has not only reduced the need for concern for these settings, but has virtually eliminated manual configuration.

The easiest way of viewing this information on Windows is to use Device Manager or System Information:

IRQ 0 - System timer. Reserved for the system. Cannot be changed by a user.
IRQ 1 - Keyboard. Reserved for the system. Cannot be altered even if no keyboard is present or needed.
IRQ 2 - Second IRQ controller. See below for explanation.
IRQ 3 - COM 2(Default) COM 4(User)
IRQ 4 - COM 1(Default) COM 3(User)
IRQ 5 - Sound card (Sound Blaster Pro or later) or LPT2(User)
IRQ 6 - Floppy disk controller
IRQ 7 - LPT1(Parallel port) or sound card (8-bit Sound Blaster and compatibles)
IRQ 8 - Real time clock
IRQ 9 - ACPI SCI or ISA MPU-401
IRQ 10 - Free / Open interrupt / Available / SCSI
IRQ 11 - Free / Open interrupt / Available / SCSI
IRQ 12 - PS/2 connector Mouse / If no PS/2 connector mouse is used, this can be used for other peripherals
IRQ 13 - Math co-processor. Cannot be changed
IRQ 14 - Primary IDE. If no Primary IDE this can be changed
IRQ 15 - Secondary IDE

Answer 2

Interrupt Request. It's a request recognized by the CPU as of high priority. They are like hotlines to the CPU to grab immediate attention of the CPU.

This is used by the hardware peripherals. They are 16 in number of which 3 are used for internal purposes like timer, keyboard etc.,. So you are left with 13 of them. Below are the IRQs.

0 System Timer
1 Keyboard Controller
2 Tied to IRQs 8-15
3 COM 2
4 COM 1
5 LPT2 or Sound Card
6 Floppy Diskette Controller
7 LPT 1
8 Real Time Clock
9 Substitutes for IRQ 2
10 Not Assigned
11 Not Assigned
12 PS/2 Mouse Port
13 NPU (Numerical Processing Unit)
14 Primary Hard Disk Controller
15 Secondary Hard Disk Controller

Answer 3

IRQ's are hotlines to the main computer (CPU) that allow devices connected to the computer to signal the CPU that they need immediate attention. If you're a Batman fan, think of IRQ's as the Batphone - getting his attention immediately.

Not all devices require IRQ lines, which is good news because in modern (post IBM XT) computers, we only have 16 of them. Of those, 3 are already dedicated to the main system board itself - the system timer, keyboard, and memory parity error signal. That leaves only 13 for all the other devices connected to your computer. This is why IRQ conflicts are probably the #1 problem faced by computer users when they add hardware to their computer.

Answer 4

IRQ - International Religious Quotient. As answer to the second question - How many are there? Plenty. India itself has one thousand two hundred and twenty two ONLY, give or take a few million.

Answer 5

It is as already mentioned an interupt request, and it is a value assigned to devices connected to your computer

Answer 6

What Is Irq