Downloaded 100 times
Uploaded byMOHIT AGARWAL
Modes Of Transfer in Input/Output Organization
This document discusses different modes of data transfer between I/O devices and memory in a computer system. It describes three main modes: programmed I/O, interrupt-initiated I/O, and direct memory access (DMA). Programmed I/O involves constant CPU monitoring during transfers. Interrupt-initiated I/O uses interrupts to notify the CPU when a transfer is ready. DMA allows I/O devices to access memory directly without CPU involvement for improved efficiency.
Engineeringâ—¦
In this document
Powered by AI
Presentation by Pulkit Zaveri and Mohit Agarwal, highlighting key information on I/O operations.
CPU executes instructions and interacts with memory as the ultimate data source/destination.
Data transfer modes include Programmed I/O, Interrupt-Initiated I/O, and Direct Memory Access (DMA).
Programmed I/O requires CPU to monitor peripherals actively, leading to inefficiency during data transfer.
With Interrupt-Initiated I/O, CPUs can execute other tasks until an interrupt signals the readiness for data transfer.
Interrupts can be internal/external and include program, timer, I/O, and hardware failure types.
DMA allows I/O devices to communicate directly with memory, minimizing CPU involvement to improve efficiency.
Three DMA modes include Block Transfer, Cycle Stealing, and Transparent DMA for effective data handling.
More Related Content
Similar to Modes Of Transfer in Input/Output Organization
Modes Of Transfer in Input/Output Organization
- 1. BY: PULKIT ZAVERI –161080107063 MOHIT AGARWAL – 161080107026 SEM : 4 BRANCH : COMPUTER
- 2. WHY ARE THEYUSED ? CPU merely executes instruction and accepts data temporally from I/O devices. Ultimate source and destination is memory. Data transfer is handled in a variety of modes.
- 3. WHAT ARE THEDIFFERENT MODES? Data transfer can be handled in one of Three Modes:  Programmed I/O  Interrupt-Initiated I/O  Direct Memory Access (DMA)
- 4. PROGRAMMED I/O ď‚—Each dataitem transfer is initiated by an I/O instruction written in a computer program. ď‚—Transferring data under program control requires constant monitoring of the peripheral by CPU. ď‚—In this method, the CPU stays in a program loop until I/O unit is ready for data transfer. ď‚—This time-consuming process keeps the processor needlessly busy.
- 5. An example ofdata transfer from an I/O device through an interface into a CPU in given below: I/O DeviceCPU Data valid Data accepted Data bus Interface I/O Read Data bus Data Register Status Register F Address bus I/O Write
- 6. INTERRUPT-INITIATED I/O ď‚—Instead ofcontinuous monitoring of CPU, interface will be informed to issue an interrupt request signal. ď‚—Meanwhile, CPU proceeds to execute another program and the interface keeps monitoring the device. ď‚—When device is ready for data transfer, it generates interrupt request. ď‚—Here the CPU stops the task it is performing, processes the data transfer then resumes the original task.
- 8. TYPES OF INTERRUPTS There are various sources of interrupts, these could be both internal or external : • Program Interrupts : They are generated by some condition that occurs as a result of an instruction execution. • Timer Interrupts : They are generated within the processor, and allow the OS to perform certain operations on regular basis. • I/O Interrupts : They are generated for initiation or completion of I/O operation. • Hardware Failure Interrupts : They are generated by failure, such as power failure or memory parity error.
- 9. DIRECT MEMORY ACCESS(DMA) Direct Memory Access (DMA) means CPU grants I/O module authority to read from or write to memory without involvement. DMA module itself controls exchange of data between main memory and the I/O device.  CPU is only involved at the beginning and end of the transfer and interrupted only after entire block has been transferred.
- 10. DMA controller (DMAC)manages the data transfers and arbitrates access to the system bus.
- 11. DMA DATA TRANSFERMODES  Data can be transferred in several different ways under DMA control :  DMA BlockTransfer : In this mode a block of data of arbitrary length can be transferred in a single burst.  Cycle Stealing Mode : Here, the DMA controller is allowed to use the system bus to transfer one word at a time, after which it must return control of the bus to CPU.  Transparent DMA : In this mode DMA is allowed to steal only those cycles when the CPU is not using system bus.