INPUT AND OUTPUT ARCHITECTURE

INTPUT AND OUTPUT ARCHITECTURE.

INPUT DEVICES

·         Papan kekunci

·         Tetikus

·         Scanner

·         CD-ROM

·         Pengawalan (controller)

OUTPUT DEVICES

·         Monitor

·         Printer

·         Disk drives

·         Floppy disk

·         CD RW-ROM

·         Speakers

Input - hantar arahan kepada CPU.

Output – terima arahan daripada CPU.

I/O devives can bee characterized by:

Behaviour : input , output , storage.

Partner : human or machine

Data rate: bytes/sec, transfers/sec.

I/O devives can bee characterized by:

·         How the component (controller, memory, processor) can be communicated each others by using bus system.

·         All component have their own bus system.

·         Graphics output – monitor.

·         Network -  LAN network.

I/O module:

·         Interface to CPU and memory.

·         Interface to one or more peripherals

·         Example : printer

Have their own interface I/O module.

Controller and timing

1.       CPU asks I/O module to check the status of attached devices.

2.       I/O module tells the status.

3.       CPU request for data transfer to I/O module if devices is ready.

4.       I/O module gather the data and transfer to the CPU.

Example : pen  drive - we put the new devices in our computer.

                  : printer -  if we would like to print something.

CPU Communication.

1.       Command decoding

·         Tulis(write) and baca (read)

2.       Devices communication

·         Involves command , status communcations.

3.       Data buffering

·         Proses ditangguhkan / kita kena tunggu sampai buffer tersebut telah bersedia.

·         Essential function to overcome speed mismaten.

·         Contoh : you tube – kita kena tunggu juga walaupun kita dah tekan butang mainkan.

: printer -  kitanak print nota, printer tutakterus print nota tu sebab dia nak baca dulu data kita baru dia akan print seperti yang diminta.

4.       Error detection

·         Paper jam or stunk , bad data etc.

·         Contoh :printer - kita nak print nota tapi kertas sudah habis jadi dia akan keluarkan pop up di skrin komputer untuk bagi tahu kita yang kertas tiada.

I/O system characteristics

·         kebergantungan sangat penting

§  selalunya apabila kita naks impan devices

·         mengukur setiap persembahannya.

§  Latency (tindakbalas terhadap masa melalui desktop dan embedded)

INTERCONNECTING COMPNENT

Ø  Need interconnecting between CPU, memory, I/O controller.

Ø  Bus : share communication channel

o   Can became a bottleneck.

Ø  Performance limited by physical factors

o   Wire length, number of connections

Ø  More recent alternative : high-speed serial connections with switches.

o   Like network.

I/O MANAGEMENT

·         I/O is mediated by the operating system.

§  Multiples program shared I/O resources.

Ø  Need protection and scheduling.

§  I/O causes synchronous interrupts.

Ø  Same machine as exceptions

§  I/O programming is fiddly.

Ø  Operating system abstractions to program..

                                                                                                                                   -nurul ain farhana-