IO_Interrupts_Flashcards
What are the primary I/O requirements?
Addressing devices, device-initiated communication, data transfer efficiency, handling varying device speeds, and control requirement management.
What are I/O interfaces needed for?
To handle different data formats, device speed mismatches, and complex device control requirements.
What is programmed I/O?
A simple CPU-controlled I/O method where each I/O device requires individual instruction cycles.
What are interrupts?
Signals that alter CPU instruction flow, freeing the CPU from waiting for external events.
What is the function of interrupt lines?
Special control lines that allow devices to signal the CPU to handle interrupts.
What is an interrupt handler?
A program that services the interrupt, also known as an interrupt routine or device driver.
What is the purpose of saving context during an interrupt?
To allow the program to resume where it left off after the interrupt is handled.
What is a vectored interrupt?
An interrupt with the address of the interrupting device included, requiring additional hardware.
What is a polled interrupt?
A method where the CPU checks each device to identify which one triggered the interrupt.
What is Direct Memory Access (DMA)?
A technique for transferring data directly between memory and an I/O device without CPU involvement.
When is DMA used?
For large data transfers between memory and I/O devices to reduce CPU load.
What are the requirements for DMA to function?
Connection of I/O and memory, device controller with memory access, and conflict management.
What are the main functions of an I/O controller?
Device recognition, data buffering, memory transfer, physical device control, and CPU communication.
What are the benefits of having separate I/O controllers?
Specialized control, simultaneous device management, and CPU workload reduction.
What is a bus?
The physical connection that transfers data across computer components.
What are the four types of signals carried by a bus?
Data, addressing, control signals, and power.
How are buses categorized?
By transmission direction, interconnection method, and signal type.
What is the difference between parallel and serial buses?
Parallel transmits all bits simultaneously, while serial transmits one bit at a time.
What are simplex, half-duplex, and full-duplex transmission modes?
Simplex is one-way, half-duplex is two-way (one at a time), and full-duplex is two-way simultaneously.
What is a point-to-point bus?
A bus that connects a single source directly to a single destination.
What is a multipoint bus?
A bus that connects multiple devices to each other, usually requiring addressing.
What are the advantages of a serial bus over a parallel bus?
Higher throughput over longer distances due to less electrical interference.
What are some examples of devices that might use programmed I/O?
Keyboards and basic I/O controllers.
What is the role of interrupts in time-sharing?
To allocate CPU time among multiple tasks or devices.
What is a maskable interrupt?
An interrupt that can be turned off or ignored by the CPU.
What is an example of a non-maskable interrupt?
A power failure signal, as it requires immediate attention.
What is a bus line?
An individual conductor in the bus used to carry signals.
What is a broadcast bus?
A multipoint bus that allows data transmission to all devices connected to it, like Ethernet.
What does a buffer in an I/O controller do?
Holds data temporarily until it can be transferred to the device or CPU.
What is the role of privileged I/O instructions in DMA?
Used by the OS to set up DMA operations, like data location and transfer direction.
What is daisy chaining in the context of interrupts?
A method of connecting devices in sequence, where each device passes the interrupt signal along until it reaches the CPU.
What is a context switch during an interrupt?
Saving the state of the CPU and current program so the interrupt can be handled, then restoring the state afterward.
How do polled interrupts identify the interrupting device?
The CPU sequentially checks each device’s status to determine the source of the interrupt.
