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Peripheral Devices and IO Management
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Peripheral Devices and IO Management
Peripheral Devices and IO Management
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1
Question
What are peripheral devices?
Answer
Peripheral devices are hardware components that connect to a computer but are not part of the core computer architecture. They can be classified into input devices (e.g., keyboard, mouse) and output devices (e.g., screen, printer).
2
Question
What is the purpose of the Input/Output (IO) interface?
Answer
The Input/Output (IO) interface provides a method of transferring information between the system's storage and external IO devices.
3
Question
How do peripheral devices compare in speed to CPU and memory?
Answer
Peripheral devices are usually slower than CPU and memory, which operate at much faster speeds.
4
Question
What units do peripheral devices and CPU memory use for information transfer?
Answer
Peripheral devices typically use byte or blade as the unit of information, while CPU memory uses word.
5
Question
What is the role of the I/O interface in data transfer?
Answer
The I/O interface helps resolve differences in speed and data representation between peripherals and CPU memory, and can contain synchronization mechanisms.
6
Question
What are the types of registers in an IO interface?
Answer
The types of registers in an IO interface include data registers, control registers, and status registers.
7
Question
What is the difference between Isolated IO and Memory Mapped IO?
Answer
In Isolated IO, there are separate control lines for IO read/write operations and memory address spaces. In Memory Mapped IO, there is no special instruction format needed; any memory-addressing technique can be used for IO commands.
8
Question
What is synchronous data transfer?
Answer
Synchronous data transfer uses one clock source, meaning all devices are synchronized using a common clock line.
9
Question
What is asynchronous data transfer?
Answer
Asynchronous data transfer does not use a common clock between units. It requires control signals to indicate the timing of data transmission between devices.
10
Question
What is the purpose of a strobe pulse in asynchronous data transfer?
Answer
A strobe pulse indicates when data transfer will occur, providing timing for the sending and receiving units.
11
Question
What are the two types of handshaking in asynchronous data transfer?
Answer
Handshaking can be either source-initiated, where the sender unit sends a strobe pulse, or destination-initiated, where the receiver unit sends a strobe pulse.
12
Question
What is the difference between serial and parallel data transfer?
Answer
Serial transfer sends data one bit at a time, while parallel transfer uses multiple communication lines to transmit multiple bits simultaneously.
13
Question
What is a UART?
Answer
UART stands for Universal Asynchronous Receiver Transmitter, which translates between CPU and peripherals by converting parallel data from the CPU into serial bits, adding start and stop bits for correct data interpretation.
14
Question
What is the purpose of a First In-First Out (FIFO) buffer?
Answer
A FIFO buffer temporarily stores data to smooth out the speed difference between the sender and receiver and ensures correct order of data.
15
Question
What is program controlled IO?
Answer
In program controlled IO, the CPU continuously checks if the IO devices are ready to send or receive data, using polling or status checking.
16
Question
What is interrupt initiated IO?
Answer
Interrupt initiated IO generates an interrupt when IO devices are ready, allowing the CPU to process data transfer only after this interrupt is raised.
17
Question
What is Direct Memory Access (DMA)?
Answer
DMA is a method that allows high-speed IO devices to transfer large blocks of data directly to or from memory without requiring CPU intervention.
18
Question
How does the priority system work with interrupts in IO management?
Answer
The priority system determines which interrupt should be processed first when multiple interrupts occur simultaneously. Higher priority interrupts can preempt lower priority ones.
19
Question
What is an interrupt register?
Answer
An interrupt register contains bits that hold interrupt requests from different sources or priority levels, and can be cleared by a program instruction.
20
Question
What is the function of the interrupt enable signal (IEN)?
Answer
The interrupt enable signal (IEN) indicates whether interrupts are enabled or disabled.
21
Question
What does the interrupt acknowledgment signal (INTACK) do?
Answer
The interrupt acknowledgment signal (INTACK) activates the tri-state buffer to load the vector address determined by the priority logic.
22
Question
Describe the interrupt cycle process.
Answer
At the end of each instruction cycle, the CPU checks if IEN is active and if IST indicates an interrupt. If both are true, an interrupt cycle begins where current tasks are saved, the interrupt is processed, and then the CPU returns to its original status.
23
Question
What is the role of the Input/Output Processor (IOP)?
Answer
The IOP is a specialized processor that handles peripherals and communicates directly with memory using cycle stealing. It executes instructions from a channel program in main memory that specifies actions for peripheral devices.