15-410 F’13 Lecture Notes: Computer Hardware and Interrupt Handling, Slides of Operating Systems

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15-410, F’

Hardware Overview

Sep. 4, 2013

Dave Eckhardt

Dave Eckhardt

Todd Mowry

Todd Mowry

L04_Hardware

“Computers make very fast, very accurate mistakes.”

--Brandon Long

15-410, F’

Synchronization

Partner signups

Partner signups

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~12 group signups so far – thanks!

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Please sign up as soon as you decide!

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This helps other students

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Both partners please sign up!

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This helps course staff detect “love triangles”

15-410, F’

Synchronization

Personal Simics licenses

Personal Simics licenses

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Simics machine-simulator software is licensed

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We have enough “seats” for the class

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Should work on most CMU-network machines

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Will not work on most non-CMU-network

machines

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CMU operates a VPN server for off-campus users

»

http://www.cmu.edu/computing/network/vpn

»

There is an open-source alternative (OpenConnect)

• It used to not work with the campus server
• Recently rumor has it that it does

15-410, F’

Synchronization

Simics on Windows?

Simics on Windows?

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Simics simulator itself is available for Windows

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15-410 build/debug infrastructure is not

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Can be hacked up, issues may arise

»

Version skew, partner, ...

Options

Options

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Dual-boot Linux/Windows, run Linux in VMware

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Usability via X depends on network latency

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May be too slow – though we are experimenting

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Port to cygwin (may be non-trivial)

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There are some cluster machines...

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WeH 5207, GHC 3000, GHC 5201/

15-410, F’

Inside The Box - Historical/Logical

CPU

Memory

Graphics

Ethernet

IDE

Floppy

USB

15-410, F’

Inside The Box - 1997-

CPU

Memory

AGP Graphics

IDE

Floppy

USB

North Bridge

South Bridge

P

C

I

Ethernet

SCSI

15-410, F’

CPU State

User registers (on Planet IA32)

User registers (on Planet IA32)

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General purpose - %eax, %ebx, %ecx, %edx

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Stack Pointer - %esp

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Frame Pointer - %ebp

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Mysterious String Registers - %esi, %edi

15-410, F’

CPU State

Non-user

Non-user registers, a.k.a....

registers, a.k.a....

Processor status register(s)

Processor status register(s)

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Currently running: user code / kernel code?

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Interrupts on / off

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Virtual memory on / off

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Memory model

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small, medium, large, purple, dinosaur

15-410, F’

Story time!

Time for some fairy tales

Time for some fairy tales

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The getpid() story (shortest legal fairy tale)

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The read() story (toddler version)

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The read() story (grade-school version)

15-410, F’

The Story of getpid()

User process is computing

User process is computing

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User process calls getpid() library routine

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Library routine executes TRAP $

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In Intel-land, TRAP is called “ INT ” (because it

isn't one)

REMEMBER: “ INT ” is not an interrupt

The world changes

The world changes

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Some registers dumped into memory somewhere

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Some registers loaded from memory somewhere

The processor has

The processor has entered kernel mode

entered kernel mode

15-410, F’

Entering Kernel Mode

Operating

System

Process 1

Process 2

CPU

save

15-410, F’

Entering Kernel Mode

Operating

System

Process 1

Process 2

CPU

Ethernet

SATA

Floppy

USB

15-410, F’

The Story of getpid()

Process runs in kernel mode

Process runs in kernel mode

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running->u_reg[R_EAX] = running->u_pid;

Return from interrupt”

Return from interrupt”



Processor state restored to user mode



(modulo %eax)

User process returns to computing

User process returns to computing

 Library routine returns %eax as value of getpid()

15-410, F’

Returning to User Mode

Operating

System

Process 1

Process 2

CPU

restore