Bushra Zafar. Bilal Ahmad. Hajra Masood. Sadat Iftikhar. Bsit 3 Semester. Mester 2006_2010
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BUSHRA ZAFAR. BILAL AHMAD. HAJRA MASOOD. SADAT IFTIKHAR. BSIT 3RD SEMESTER. MESTER 2006_2010.
Introduction of topics INPUT OUTPUT VIA EXTERNAL DEVICES. I/O MODULES AND THEIR FUNCATIONS I/O TECHNIQES I/O CHANNEL AND PROCESSOR
External devices that provide a means of exchanging data between the external environment and the computer (both input and output.
Types of external devices. Human readable: communicating with the computer user Example: Monitor, printer, keyboard, mouse.
Machine readable: communicating with equipment Example: Hard drive, CD ROM
Communication: Communicating with remote devices. Example : network interface card or modem
Variable of I/O devices. I/O
devices contain and transfer different types of data as text, Graphics, video, audio The speed of data transfer (receive or send) of devices varies as e.g. laser printer = 106 bps
Why we use I/O modules? CPU clock speed is greater ass compare to speed of I/O. An interface is needed to link the I/O devices with system. I/O modules act as interface between system (CPU/ memory) and I/O devices .
Bus
Functions of I/O modules. The basic function of I/O modules are. Control and timing. Devices communication. Processor’ s communication. Error detection. Data buffering.
I/O module coordinate the flow of data b/w external devices and Control and timing. internal resources (CPU,RAM).
check status of devices. (operating well or not). Data transfer.
Device communication. I/O devices communicate with system via I/O
module. I/O device receive control signal and send interrupt signal to CPU via I/O module. I/O send status information to I/O module.
Processor’ s communication. I/O module communicate with I/O devices Accepting commands from CPU.
(read, write, seek, scan, record address).
Exchange data. Check status of device (ready or busy). Recognize address of I/O devices in memory.
Error detection. I/O module check I/O devices for error detection
periodically. Mechanical errors as paper jam. Electrical error as fluctuating power supply.
Data buffering. Data is buffered (temporarily stored) in I/O modules. I/O module receive data from memory ,buffered it, send to I/O
device at it’s rate. I/O module receive data from I/O device and send to memory at it’s rate.
Input output techniques. Programmed I/O.
CPU transfer data between I/O device and memory. Interrupt driven I/O.
CPU transfer data and also execute other programs. Direct memory access.
DMA controller transfer data independently.
Programmed I/O. CPU issues I/O command to I/O module.
Control signals. Check status of I/O. Read and write commands. I/O modules performs tasks. CPU waits for completion of task Status registers of i/o is updated after completion of task. CPU check status of I/O .
Programmed I/O. CPU ISSUE COMMNADS
I/O MODULE PERFORM TASK I/O MODULE UPDATE STATUS REGISTER. CPU CHECK STATUS
Issues of programmed I/O. The CPU needs waits for completion of data transfer. CPU check the status of I/O module. programmed I/O waste time and misuse CPU. Ultimately degrade system performance.
Interrupt driven I/O. CPU issues I/O commands to I/O module.
(does not wait for completion , it continues executing subsequent instructions.) I/O modules upload data from I/O devices. I/O modules send interrupt to CPU. (device is ready) CPU send commands for data transfer. I/O modules transfer data.
Interrupt driven I/O. CPU ASSIGN TASK I/O MODULE LOAD DATA I/O SEND INTERUPPT TO CPU CPU SEND COMMANDS
DATA TRANSFER COMPLETED
Direct memory access. CPU assign task to DMA controller.
(Execute other programs) DMA controller take over control of bus from CPU. (cycle stealing). DMA controller perform data transfer. DMA send interrupt when completed.
Direct memory access. CPU ASSIGN TASK
DMA CONTROLER TAKE OVER BUS
DMA CONTROLER TRANSFER DATA
DMA SEND INTERRUPT TO CPU.
Structure of Programmed I/O and DMA.
DMA
Evolutions of I/O techniques. Processor directly controls device. Processor uses Programmed I/O. Processor uses Interrupts. Processor uses DMA. Some processing moved to processors in I/O module
that access programs in memory and execute them on their own without CPU intervention (I/O Module referred to as an I/O Channel).
Distributed processing where I/O module is a computer
in its own right(I/O Module referred to as an I/O Processor).
Types of I/O channels (a) Selector: Each device or a small set of device is handled by a controller. (b) Multiplex channel : Multiplex devices are handled by a single controller. controller is called multiplexer
Types of I/O
??
Thanks for your Attention.
Introduction of topics INPUT OUTPUT VIA EXTERNAL DEVICES. I/O MODULES AND THEIR FUNCATIONS I/O TECHNIQES I/O CHANNEL AND PROCESSOR
External devices that provide a means of exchanging data between the external environment and the computer (both input and output.
Types of external devices. Human readable: communicating with the computer user Example: Monitor, printer, keyboard, mouse.
Machine readable: communicating with equipment Example: Hard drive, CD ROM
Communication: Communicating with remote devices. Example : network interface card or modem
Variable of I/O devices. I/O
devices contain and transfer different types of data as text, Graphics, video, audio The speed of data transfer (receive or send) of devices varies as e.g. laser printer = 106 bps
Why we use I/O modules? CPU clock speed is greater ass compare to speed of I/O. An interface is needed to link the I/O devices with system. I/O modules act as interface between system (CPU/ memory) and I/O devices .
Bus
Functions of I/O modules. The basic function of I/O modules are. Control and timing. Devices communication. Processor’ s communication. Error detection. Data buffering.
I/O module coordinate the flow of data b/w external devices and Control and timing. internal resources (CPU,RAM).
check status of devices. (operating well or not). Data transfer.
Device communication. I/O devices communicate with system via I/O
module. I/O device receive control signal and send interrupt signal to CPU via I/O module. I/O send status information to I/O module.
Processor’ s communication. I/O module communicate with I/O devices Accepting commands from CPU.
(read, write, seek, scan, record address).
Exchange data. Check status of device (ready or busy). Recognize address of I/O devices in memory.
Error detection. I/O module check I/O devices for error detection
periodically. Mechanical errors as paper jam. Electrical error as fluctuating power supply.
Data buffering. Data is buffered (temporarily stored) in I/O modules. I/O module receive data from memory ,buffered it, send to I/O
device at it’s rate. I/O module receive data from I/O device and send to memory at it’s rate.
Input output techniques. Programmed I/O.
CPU transfer data between I/O device and memory. Interrupt driven I/O.
CPU transfer data and also execute other programs. Direct memory access.
DMA controller transfer data independently.
Programmed I/O. CPU issues I/O command to I/O module.
Control signals. Check status of I/O. Read and write commands. I/O modules performs tasks. CPU waits for completion of task Status registers of i/o is updated after completion of task. CPU check status of I/O .
Programmed I/O. CPU ISSUE COMMNADS
I/O MODULE PERFORM TASK I/O MODULE UPDATE STATUS REGISTER. CPU CHECK STATUS
Issues of programmed I/O. The CPU needs waits for completion of data transfer. CPU check the status of I/O module. programmed I/O waste time and misuse CPU. Ultimately degrade system performance.
Interrupt driven I/O. CPU issues I/O commands to I/O module.
(does not wait for completion , it continues executing subsequent instructions.) I/O modules upload data from I/O devices. I/O modules send interrupt to CPU. (device is ready) CPU send commands for data transfer. I/O modules transfer data.
Interrupt driven I/O. CPU ASSIGN TASK I/O MODULE LOAD DATA I/O SEND INTERUPPT TO CPU CPU SEND COMMANDS
DATA TRANSFER COMPLETED
Direct memory access. CPU assign task to DMA controller.
(Execute other programs) DMA controller take over control of bus from CPU. (cycle stealing). DMA controller perform data transfer. DMA send interrupt when completed.
Direct memory access. CPU ASSIGN TASK
DMA CONTROLER TAKE OVER BUS
DMA CONTROLER TRANSFER DATA
DMA SEND INTERRUPT TO CPU.
Structure of Programmed I/O and DMA.
DMA
Evolutions of I/O techniques. Processor directly controls device. Processor uses Programmed I/O. Processor uses Interrupts. Processor uses DMA. Some processing moved to processors in I/O module
that access programs in memory and execute them on their own without CPU intervention (I/O Module referred to as an I/O Channel).
Distributed processing where I/O module is a computer
in its own right(I/O Module referred to as an I/O Processor).
Types of I/O channels (a) Selector: Each device or a small set of device is handled by a controller. (b) Multiplex channel : Multiplex devices are handled by a single controller. controller is called multiplexer
Types of I/O
??
Thanks for your Attention.
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