Interrupts in modern computers are a fascinating topic. They are absolutely essential in our modern high-performance systems. They serve both as a communication mechanism between peripheral device and the CPU, and as a way of interrupting a processor's execution to handle something important.

SUMMARY
Interrupts are signals that tell the processor that something important has happened and its immediate attention is required. These signals can be triggered by all sorts of events. For instance, moving your mouse, pressing a key on the keyboard, a storage device finishing a data transfer, or new data arriving in your network card's buffer can all generate an interrupt.

Interrupts can be categorized into two main groups:
• Hardware Interrupts: Asynchronous events typically generated by peripheral hardware devices. Can be delivered to a processor by either IRQ lines, which are dedicated physical lines, or by using Message-Signaled Interrupts (MSI), which uses the modern PCI Express bus to write interrupt messages directly into the processor's interrupt controller.
• Software Interrupts (Exceptions): synchronous events generated by the processor when something unusual or important happens during the execution of an instruction. Exceptions don't need to be delivered to the CPU since they're generated by the CPU itself. They can be further divided into sub-types: Faults, Traps, and Aborts.

Each hardware interrupt and exception is uniquely identified by its Interrupt Vector Number, which ranges from 0 to 255. Exceptions have constant numbers, typically from 0-31, while hardware interrupts are identified by vector numbers chosen by device drivers from the available range, usually 32-255.

Handling an interrupt involves three steps:
1. Storing the state of the currently running process.
2. Calling the appropriate ISR, which then performs the necessary work to handle the interrupt.
3. Either restore the state of the running process or, in some cases, terminate it

LINKS
📚 Computer Memory and Architecture E-Book Collection: https://buymeacoffee.com/bitlemonsoftware/e/427972
📚 Interrupts in Modern Computer Systems (E-Book): https://buymeacoffee.com/bitlemonsoftware/e/420320
📚 The Anatomy of Virtual Memory (E-Book): https://buymeacoffee.com/bitlemonsoftware/e/400638
📚 Beginner's Guide to CPU Caches (E-Book): https://buymeacoffee.com/bitlemonsoftware/e/362123
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SOURCES
The information in this video is based on my book: Interrupts in Modern Computer Systems.

TABLE OF CONTENTS
00:00 Introduction
01:26 Defining Interrupts
02:43 Overview of Interrupt Handling
03:26 Hardware Interrupts
03:52 Interrupt Request (IRQ) Lines
04:58 Message-Signaled Interrupts (MSI)
05:30 Hardware Interrupt Detection
06:19 Software Interrupts (Exceptions)
07:30 Interrupt Vector Numbers
08:00 Servicing Interrupts
09:22 Interrupts in Modern Computer Systems (E-Book)

ATTRIBUTION
Some of the elements in the video were designed by vectorpocket / macrovector / rawpixel.com / Freepik at freepik.com.

#computerscience #memorymanagement #computermemory #operatingsystem #interrupts

BitLemon

Interrupts are signals that allow hardware devices and the CPU itself to notify the processor when important events occur, eliminating the need for inefficient polling. Hardware interrupts are delivered via IRQ lines or message signaled interrupts (MSI), while software interrupts (exceptions) include faults, traps, and aborts generated by the CPU. When an interrupt occurs, the processor saves the current state, executes the appropriate interrupt service routine (ISR) using an interrupt vector table, and then either restores execution or terminates the process.

How Interrupts Work in Modern Computers