After studying this chapter, you should be able to: Discuss the principal requirements for memory management, understand the reason for memory partitioning and explain the various techniques that are used, understand and explain the concept of paging,. | Module 2: Computer-System Structures Computer System Operation I/O Structure Storage Structure Storage Hierarchy Hardware Protection General System Architecture Operating System Concepts Computer-System Architecture Operating System Concepts Computer-System Operation I/O devices and the CPU can execute concurrently. Each device controller is in charge of a particular device type. Each device controller has a local buffer. CPU moves data from/to main memory to/from local buffers I/O is from the device to local buffer of controller. Device controller informs CPU that it has finished its operation by causing an interrupt. Operating System Concepts Common Functions of Interrupts Interrupts transfers control to the interrupt service routine generally, through the interrupt vector, which contains the addresses of all the service routines. Interrupt architecture must save the address of the interrupted instruction. Incoming interrupts are disabled while another interrupt is being processed . | Module 2: Computer-System Structures Computer System Operation I/O Structure Storage Structure Storage Hierarchy Hardware Protection General System Architecture Operating System Concepts Computer-System Architecture Operating System Concepts Computer-System Operation I/O devices and the CPU can execute concurrently. Each device controller is in charge of a particular device type. Each device controller has a local buffer. CPU moves data from/to main memory to/from local buffers I/O is from the device to local buffer of controller. Device controller informs CPU that it has finished its operation by causing an interrupt. Operating System Concepts Common Functions of Interrupts Interrupts transfers control to the interrupt service routine generally, through the interrupt vector, which contains the addresses of all the service routines. Interrupt architecture must save the address of the interrupted instruction. Incoming interrupts are disabled while another interrupt is being processed to prevent a lost interrupt. A trap is a software-generated interrupt caused either by an error or a user request. An operating system is interrupt driven. Operating System Concepts Interrupt Handling The operating system preserves the state of the CPU by storing registers and the program counter. Determines which type of interrupt has occurred: polling vectored interrupt system Separate segments of code determine what action should be taken for each type of interrupt Operating System Concepts Interrupt Time Line For a Single Process Doing Output Operating System Concepts I/O Structure After I/O starts, control returns to user program only upon I/O completion. wait instruction idles the CPU until the next interrupt wait loop (contention for memory access). At most one I/O request is outstanding at a time, no simultaneous I/O processing. After I/O starts, control returns to user program without waiting for I/O completion. System call – request to the operating system to allow user to .
