Deep Blue Architecture

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Deep Blue Architecture
Murthy Ganapathibhotla
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Agenda

• Introduction
• Overview of Deep Blue Architecture
• Conclusion

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• INTRODUCTION

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INTRODUCTION

• What is Deep Blue ?
• What is a Chess Computer ?
• How are Moves Computed ?
• History of Deep Blue.

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Introduction

• What is Deep Blue ?
• Deep Blue was IBMs Chess Playing
• Computer.
• It was the First Computer System to win
  
• Against the world chess champion
• Garry Kasparov.

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Deep Blue
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Introduction

• What is a Chess Computer ?

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Introduction

• What is a Chess Computer ?
• A Computer that plays Chess !

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Introduction

• What does a chess computer have to do
• in order to defeat the world champion !

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Introduction

• If we take a closer look at the way chess is
  played
• Each player has 16 pieces of chess coins to play
  with and 20 possible moves.

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Introduction

• Lets say White begins the game.
• It has 20 possible moves.
• The same options are there even for a
• Black player.
• 20 possible moves.

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Chess Board
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Introduction

• Total Number of Moves For White 20
• Moves for Pawns 8 8 16
• ( one step) ( 2 steps)
• Moves for Knights 2 2 4
• Total
  20

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Introduction
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Introduction

• Level 1 20 possible moves for white.
  
• Level 2 20 20 400 possible moves
  for black, depending on what white does.
• Level 3 400 20 8,000 for white.
• Level 4 8,000 20 160,000 for
  black...
• For all possible Chess Board Positions
• You need to Evaluate 10 120 possible moves!

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Introduction

• What will a Chess Computer do ?
• Evaluates 5 or 10 or 20 moves ahead in
  advance.
• The depth of the tree it can generate depends on
  the speed of the computer
• Once it generates the tree it needs to evaluate
  the positions using some evaluation function .

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Introduction

• So The Faster Your Computer generates the
  Moves,
• The Better would be the Performance !

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History Of Deep Blue

• Started as Chip Test at
• Carneige Mellon University by Feng-Hsiung Hsu.
• Then It Became Deep Thought
• And
• Finally Deep Blue.

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• Deep Blue Architecture

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Deep Blue Architecture

• Overview
• Chess Chip
• Chess Chip Evaluation Functions
• RS /6000 Processor
• Software Issues

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Overview

• Based on IBM RS/6000 SP Super Computer.
• Contains 30 IBM RS/6000 Processors connected
  through a high speed switching network.
• Each processor in the system controls upto 16
  chess chips
• So, Deep Blue had 480 chess chips !

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Chess Chip
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Chess Chip

• Move Generator Generates next possible
  move.
• Position Evaluator Evaluates a leaf
  position.
• Single Move Takes
• 40,000 General purpose instructions
• At 2 to 2.5 million chess positions per second ,
  one chess chip is equivalent to 100 billion
  instructions per second
• Super Computer !

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Chess Chip Evaluation Functions

• Piece Placement Evaluation
  Each
  piece on Every Square
• End Game Evaluation
• Counts of Various Pieces on the Chess board.
• Slow Evaluation
• It computes various concepts such as
• King safety

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Chess Chip
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• RS / 6000 PROCESSOR

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RS / 6000 Processor

• Stands for RISC System / 6000
• Belongs to the S family --
• IBM Symmetric Multiprocessor Family
• Supports 32 bit and 64 bit applications.
• Gives High End Commercial Performance.

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Rack Packaging

• 2 Enclosures
• Central Electronics Complex
• - Processor Cards
• - Memory Controller
• - Memory Cards
• - Power Supplies and Cooling Systems.
• A Rack for 4 I/O drawers - One for
  primary SCSI drawer and room for other I/O
  expansion.

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Processor Card

• 6 Processors per card.
• Runs at 455 MHz.
• Separate 128 KB internal L1 Cache for
  instructions and data.
• L2 Cache Controller and 4 way set associative
  8 MB L2.
• 5 Pipeline Execution Units
• Branch, Load/Store, Fixed Point, Complex Fixed
  Point and Floating Point.

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System Bus

• System bus uses 128 bit data path and
• Separate 64 bit address path
• Address, Data , Control Parity Checked
• Operates in true Split Transaction mode

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Memory

• Base Configuration includes
  2 GB SD RAM.
• Max Configuration is 64 GB.
• Accommodates up to 16 Memory Cards
• Memory Cards are used in Sets of four called
  Quads.
• SDRAM cards directly attached to the memory
  cards.

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Remote I/O Connections

• The I/O Subsystem is connected to the RIO Chip
  Interface by means of System buses.
• Four RI/O connections are connected to a single
  Hub chip.
• Offers Buffering as well !

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I/O Drawer

• Cooling effect is provided by means of Fans.
• Primary I/O Drawer Contains
• 12 hot plug DASD bays, one available media bay,
  one floppy disk drive, one CD ROM,
• One mouse port, two serial ports and a parallel
  port.
• The I/O sub system is expandable
• By attaching 4 I/O Drawers to a single CEC.

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• Software Issues In Deep Blue

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Operating System

• IBM AIX Operating System.
• Uses Message Passing method of
  parallelization.
• Whole program code is written in C !
• Algorithm used is the minimum window
  alpha-beta search algorithm.

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Search Strategy

• Search through all possible moves
• Until you find the best possible move !
• Make sure that when you lose a piece, you lose
  it optimally, i.e. let the penalty be just
  adequate without hurting much.

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What Deep Blue did ?

• Searched 40 billion positions for each move
  !
• Search was distributed among
• IBM RS/6000 Network
• Micro channel bus inside
  workstation node.

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Brief Description

• Take for example,
• A 12 ply search ( ply Move)
• The master node among the 30 nodes will
  evaluate the first four plies in software. Now ,
  number of positions increases about a 1000
  times.

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Brief Description

• All the 30 processors (including master)
• Will evaluate the next four plies in software.
• Now the number of positions increases about a
  1000 times
• Now the remaining 4 plies are taken care by the
  Chess Chips.

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Brief Description

• Therefore,
• Software is responsible for 1 of the moves
• And evaluating 2/3rd the depth of the tree.

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• CONCLUSION

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• Behind every Great
  Innovation, there is a meticulous human brain .

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Murray Campbell
Feng-hsiung Hsu
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Kasporov vs Deep Blue Match

• The various moves of this match can be watched
  at this web site
• http//www.research.ibm.com/deepblue/watch/html/c.
  shtml

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A Philosophical Statement

• Deep Blue entirely used Brute Force approach
  --- Can It Match the thinking process of a
  Human Brain ?
• During the match, it seems the engineers have
  given Human input !
• So , shall we wait for a Re Match ?

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Final Word

• Lets see whether the honor of the human race
  will be defended during a rematch in the future !

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References

• Wikipedia
• http//en.wikipedia.org/wiki/Deep_Blue
• How Stuff Works
• http//computer.howstuffworks.com/chess2.htm
• The RS/6000 Enterprise Server Model S80
  Technology and Architecture
• (Technical White paper from IBM)
• http//www.cs.berkeley.edu/sergiu/cs267/assigname
  nt0/
• IBM Research
• http//www.research.ibm.com/deepblue/

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Any Questions ?
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Any Questions ?

• Thank You !