tailieunhanh - Lecture Operating system concepts (Sixth ed) - Chapter 13: I/O systems

The role of the operating system in computer I/O is to manage and control I/O operations and I/O devices. Although related topics appear in other chapters, here we bring together the pieces to paint a complete picture of I/O. First, we describe the basics of I/O hardware. Next, we discuss the I/O services provided by the operating system and the embodiment of these services in the application I/O interface. Then, we explain how the operating system bridges the gap between the hardware interface and the application interface. | Chapter 13 I O Systems I O Hardware Application I O Interface Kernel I O Subsystem Transforming I O Requests to Hardware Operations Streams Performance Operating System Concepts Silberschatz Galvin and Gagne 2002 I O Hardware Incredible variety of I O devices Common concepts Port Bus daisy chain or shared direct access Controller host adapter I O instructions control devices Devices have addresses used by Direct I O instructions Memory-mapped I O Operating System Concepts Silberschatz Galvin and Gagne 2002 I O Port Locations on PCs partial Operating System Concepts Silberschatz Galvin and Gagne 2002 Polling Determines state of device command-ready busy Error Busy-wait cycle to wait for I O from device Operating System Concepts Silberschatz Galvin and Gagne 2002 Interrupts CPU Interrupt request line triggered by I O device Interrupt handler receives interrupts Maskable to ignore or delay some interrupts Interrupt vector to dispatch interrupt to correct handler Based on priority Some unmaskable Interrupt mechanism also used for exceptions Operating System Concepts Silberschatz Galvin and Gagne 2002