OSK2014 08 Input Output

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Organisasi Sistem Komputer

Priyanto

E-mail : [email protected]

Program Studi Pendidikan Teknik Elektronika

Jurusan Pendidikan Teknik Elektronika

FT UNY 2014

Input Output (IO)

1


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2

IO controller

IO devices

Storage

Device mana yang paling lambat?


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I/O devices serve two main purposes To communicate with outside world

To store data

I/O controller acts as an interface between the systems

bus and I/O device Relieves the processor of low-level details

Takes care of electrical interface

I/O controllers have three types of registers

Data

Command

Status


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Basic I/O hardware ports, buses, devices and controllers

I/O Software

Interrupt Handlers, Device Driver, Device-Independent Software, User-Space I/O Software

Important concepts

Three ways to perform I/O operations Polling, interrupt and DMAs

Copyright : Nahrstedt, Angrave, Abdelzaher 4


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Storage devices (disk, tapes)

Transmission devices (network card, modem)

Human interface devices (screen, keyboard,mouse)

Specialized device (joystick)

Barcode reader



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I/O units typically consist of A mechanical component: the device itself

An electroniccomponent: the device controller oradapter.

Interface between controller and device is a very lowlevel interface.

Example:

Disk controller converts the serial bit stream, comingoff the drive into a block of bytes, and performs errorcorrection.



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Device-specific code to control an IO device, is usually written

by device's manufacturer

disk driver has to know about sectors, tracks, heads, etc).

A device driver is usually part of the OS kernel

Compiled with the OS

Dynamically loaded into the OS during execution

Each device driver handles

one device type (e.g., mouse)

one class of closely related devices (e.g., SCSI disk driver to handle

multiple disks of different sizes and different speeds.).

Categories:

Block devices

Character devices



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Cadangan

Input Output

Memory

Input Output

Cadangan

Cadangan

Memory

00 0

1023

40954095

4096

5119

4096

5119

Memory Mapped IO Mapped (Isolated IO)

5120 5120


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Main

MemoryCPU IO Port 1 IO Port 2 IO Port 3

Write

Read

Data

Address

IO Device 1 IO Device 2Memiliki 2

instruksi

sekaligus untuk

Memori dan IO

Write

Read


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Main

MemoryCPU IO Port 1 IO Port 2 IO Port 3

M Read

M Write IO Write

IO Read

Data

Address

IO Device 1 IO Device 2Memiliki 4

instruksi

untuk memori

dan IO

M Write

M Read

IO Write

IO Read


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Programmed IO

Interrupt Driven

Direct Memory Access

(DMA)


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Mulai

Baca Status

Periksa Status

Divais

Siap?

Layani Divais

Lakukan tugas

lain

Ya

Tidak


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Connections between devices and interrupt controller actuallyuse interrupt lines on the bus rather than dedicated wires


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Menangguhkan eksekusi program yang sedang

berlangsung

Menyimpan statusnya Melompat ke interrup service routine (ISR)

Kembali untuk melanjutkan eksekusi program

yang diinterupsi

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Permasalahan programmed I/O Waktu CPU terbuang untuk polling, contoh:

Menunggu keyboard ditekan

Menunggu keyboard dilepas Tidak memenuhi untuk batasan waktu yang berkaitan

dengan beberapa divais:

Membaca dan menulis ke disk

DMAMembebaskan prosesor dari tanggung jawab

transfer data


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DMA is implemented using a DMA controller DMA controller

Acts as slave to processor

Receives instructions from processor

Example: Reading from an I/O device

Processor gives details to the DMA controller

I/O device number

Main memory buffer address Number of bytes to transfer

Direction of transfer (memoryI/O device, or vice

versa)


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Contoh DMA untuk Disk

CPU memprogram DMAC: men-set register untuk

menentukan alamat sumber/tujuan, jumlah byte,

dan informasi kontrol (read atau write)

DMAC melanjutkan untuk mengoperasikan bus

memori secara langsung tanpa bantuan CPU utama

Disk controller mentransfer data ke memori utama

Disk controller ackstransfer to DMA controller



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D a ta

C o n t r o l

S ta tu s

P r o g ra m m e d

I /O in te r fa c e

I /O d e v ic e

A d d r e s s /d a ta

b u s

a n d r e a d /w r i t e

c o n tr o l s ig n a l M e m o r y

C P U

l i

l i l


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D a ta

C o n t r o l

S ta tu s

P r o g r a m m e d

I /O in te r fa c e

I/O d e v ic e


b u s


c o n tr o l s ig n a l

M e m o r y

In te r r u p t s ig n a l

C P U


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S ta tu s

D a ta

C o n tr o l

P r o g ra m m e d

I/O in te r fa c e

I/ O d e v ic e


b u s


c o n tr o l s ig n a l M e m o r y

C P UIn te r r u p t s ig n a l

D M A s ig n a l


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There are many standards for I/O buses and

interfaces

Standards allow open architectures Many vendors can provide peripheral (I/O) devices

for many different systems

Most systems support several I/O buses andI/O interfaces


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Expansion buses or slots Disk interfaces

External buses

Communications interfaces


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These are slots on the motherboard

Examples

ISAIndustry Standard Architecture

PCIPersonal Component Interconnect

EISAExtended ISA SIMMSingle Inline Memory Module

DIMMDual Inline Memory Module

MCAMicro-Channel Architecture

AGPAccelerated Graphics Port VESAVideo Electronics Standards Association

PCMCIAPersonal Computer Memory Card InternationalAssociation (not just memory!)


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3 ISA

slots

5 PCI slots Pentium CPU6 SIMM

slots

2 DIMM

slots


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External buses

Communications buses


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ATAAT Attachment (named after IBM PC-AT) IDEIntegrated Drive Electronics (same as ATA)

Enhanced IDE

Encompasses several older standards (ST-506/ST-412, IDE, ESDI,

ATA-2, ATA-3, ATA-4)

Floppy disk

SCSISmall Computer Systems Interface

ESDIEnhanced Small Device Interface (mid-80s, obsolete)

PCMCIA (Personal Computer Memory Card International

Association)

SATASerial AT Attachment


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High-speed serial connection between motherboardand drive

Serial cables can be longer than parallel ones

Cables are easier to work with

Speeds of 150MB/sec and higher possible


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External buses



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Parallelsometimes called LPT (line printer) Serialtypically RS232C (sometimes RS422)

PS/2for keyboards and mice

USBUniversal Serial Bus IrDAInfrared Device Attachment

FireWirenew, very high speed, developed by

IEEEFireWire kalah dengan USB di pasaran.


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External buses



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For connecting systems to systems

Parallel/LPT

special purpose, e.g., using special software

(Laplink) to transfer data between systems Serial/RS232C

To connect a system to a voice-grade modem

Ethernet To connect a system to a high-speed network


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OSK2014 08 Input Output

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