Computer Organization: I/O Operations and DMA

Questions and Answers

What is the primary role of the Operating System (OS) in controlling computer resources?

To manage computer resources and control smaller user programs

What happens when a user program completes its execution?

The control is passed back to the OS

What is one of the problems of early computer systems?

Inability to share computer resources

What is the main function of accounting in an Operating System?

To manage resources Signup and view all the answers

What is the role of the OS in controlling the computer's basic functions?

To control the computer's basic functions and pass control to user programs Signup and view all the answers

What is the purpose of error detection and response in an Operating System?

To detect and respond to errors Signup and view all the answers

What is the primary function of the Control Language Interpreter in the Resident Monitor?

To read and execute instructions from one level to the next level Signup and view all the answers

What is the Loader responsible for in the Resident Monitor?

Loading system and application programs into main memory Signup and view all the answers

What is the primary function of the Device Driver in the Resident Monitor?

To manage the connecting input-output devices to the system Signup and view all the answers

What is the Interrupt Processing part of the Resident Monitor responsible for?

Processing all occurred interrupts to the system Signup and view all the answers

Which part of the Resident Monitor acts as an interface between the user and the system?

Device Driver Signup and view all the answers

Which part of the Resident Monitor is responsible for fulfilling user requests?

Device Driver Signup and view all the answers

What is a key feature of RISC processor architecture?

Large number of GP registers and/or use of compiler technology to optimize register usage Signup and view all the answers

What is the primary benefit of cache memory in computers?

Improves performance Signup and view all the answers

What is a characteristic of RISC pipelining?

One instruction per cycle Signup and view all the answers

What is the primary goal of microprogrammed control unit?

To ease the design and implementation task of the control unit Signup and view all the answers

What is a benefit of pipelining in computers?

Introduces parallelism into the fetch-execute cycle Signup and view all the answers

What is a characteristic of RISC architecture?

Few, simple instruction formats Signup and view all the answers

What is the purpose of handshaking in I/O operations?

To request permission to send data and acknowledge receipt Signup and view all the answers

What is the advantage of using parallel interfaces?

Higher speed data transfer due to multiple wires Signup and view all the answers

Why is it necessary to use an internal buffer in I/O operations?

To compensate for speed differences between the interface and the bus Signup and view all the answers

What is a characteristic of serial interfaces?

Data is transferred one bit at a time Signup and view all the answers

What is a limitation of parallel interfaces?

If one wire fails, the entire transfer is affected Signup and view all the answers

Why are serial interfaces used for slower peripherals?

They are suitable for slower data transfer rates Signup and view all the answers

What can be done to upgrade the performance of slower peripherals?

Implementing a higher clock speed controller Signup and view all the answers

What is a problem that arises when connecting I/O devices directly to the system bus?

Incompatibility with the bus speed Signup and view all the answers

What is the main purpose of DMA in a computer system?

To transfer data between I/O modules and main memory without CPU intervention Signup and view all the answers

What is the role of the DMA controller in a DMA operation?

To manage the system bus and transfer data between I/O modules and main memory Signup and view all the answers

What information does the CPU need to provide to the DMA controller for a DMA operation?

The I/O module involved, location of data in memory, and size of the block of data to be transferred Signup and view all the answers

What happens when the DMA controller completes a data transfer?

The DMA controller sends an interrupt to the CPU to notify it of the completion Signup and view all the answers

Why is it necessary for the CPU and DMA controller to share the system bus?

Because the system bus is a shared resource that needs to be managed Signup and view all the answers

What is the benefit of using DMA in a computer system?

Reduced CPU intervention in data transfer Signup and view all the answers

What is the main difference between a DMA transfer and a CPU-controlled data transfer?

The CPU's involvement in the transfer Signup and view all the answers

What is the purpose of the DMA controller sending an interrupt to the CPU?

To notify the CPU of the completion of the data transfer Signup and view all the answers

Study Notes

Input/Output (I/O) Operations

In addition to the CPU, another strategy is used to manage I/O operations: Direct Memory Access (DMA)
DMA controller takes over the system bus and transfers data between I/O modules and main memory without CPU intervention

DMA Controller

The CPU instructs the DMA controller to:
- Read/write data
- Specify the device address
- Provide the starting address of the memory block for data
- Specify the amount of data to be transferred
The DMA controller handles the data transfer and sends an interrupt to the CPU when finished

I/O Transfer Modes

Parallel Interface: multiple wires connect the I/O module to the peripheral, allowing for simultaneous data transfer
Serial Interface: a single wire connects the I/O module to the peripheral, transferring data one bit at a time

Performance and Problems

Parallel interfaces have higher speed but are prone to errors on multiple wires
Serial interfaces are slower but can be upgraded with higher clock speed controllers

I/O Problems

Controlled access to files
System access
Error detection and response
Accounting: managing resources and controlling computer basic functions

Operating System (OS) Functions

Manages computer resources (CPU time, memory, I/O) with all programs
Acts as a master program, controlling smaller user programs
Has control over the computer's basic functions

Resident Monitor Components

Control Language Interpreter: reads and carries out instructions from one level to the next level
Loader: loads necessary system and application programs into main memory
Device Driver: manages connecting input-output devices to the system
Interrupt Processing: processes all occurred interrupts to the system

Advances in Computer Systems

Microprogrammed control unit: eases design and implementation of control unit
Cache memory: improves performance
Pipelining: introduces parallelism into fetch-execute cycle, executing multiple instructions at once
Multiple processors: with various organizations and objectives

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Description

Learn about the role of Direct Memory Access (DMA) in managing I/O operations, and how it interacts with the CPU and main memory. Understand the instructions given by the CPU to the DMA controller for efficient data transfer.