文档介绍：CS61C Anatomy of I/O Devices: Networks Lecture 14
March 5, 1999
Dave Patterson (/~patterson)
/~cs61c/
Review 1/2
Operating System started as shared I/O library
Support for OS abstraction: Kernel/User bit, stacked KU bits, syscall
MIPS follows coprocessor abstraction to add resources, instructions for OS
Interrupt control: Interrupt Enable bit, stacked IE bits, Interrupt Priority Levels, Interrupt Mask
Re-entrant via restricting int. to higher priority
DMA to accelerate data movement
Outline
Buses
works?
A Simple Example: work Basics
Protocol,
Administrivia, “Computers in the News”
working, Protocol Suites, TCP/IP
Performance Pitfalls
Conclusion
Recall : ponents of puter
Processor
(active)
Computer
Control
(“brain”)
Datapath
(“brawn”)
Memory
(passive)
(where
programs,
data live
when
running)
Devices
Input
Output
Keyboard, Mouse
Display, Printer
Disk,
Network
Lectures 1-11
Lectures 12-15
Connecting works (and Other I/O)
Bus - shared medium munication that can connect to many devices
Hierarchy of Buses in a PC
Buses in a PC
CPU
Memory bus
Memory
Data rates
Memory: 100 MHz, 8 bytes 800 MB/s (peak)
PCI: 33 MHz, 4 bytes wide 132 MB/s (peak)
SCSI: “Ultra2”(40 MHz), “Wide”(2 bytes) 80 MB/s (peak)
PCI:
Internal (Backplane)
I/O bus
SCSI:
External
I/O bus
(1 to 15 disks)
SCSI
Interface
Interface
Local
Area Network
works?
Originally sharing I/O devices puters (., printers)
municating puters (, file transfer protocol)
municating between people (., email)
municating works puters , WWW
Types works
Local work ()
Inside a building: Up to 1 km
(peak) Data Rate: 10 Mbits/sec, 100 Mbits/sec,1000 Mbits/sec
Run, installed work administrators
Wide work
Across a continent (10km to 10000 km)
(peak) Data Rate: Mbits/sec to 2500 Mbits/sec
Run, installed by panies
ABCs works: puters
Starting Point: Send bits between puters
Queue (First In First Out) on each