Deep Blue Architecture

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# Deep Blue Architecture - PowerPoint PPT Presentation

Deep Blue Architecture Murthy Ganapathibhotla Agenda Introduction Overview of Deep Blue Architecture Conclusion INTRODUCTION INTRODUCTION What is Deep Blue ? What is a Chess Computer ? How are Moves Computed ? History of Deep Blue. Introduction

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## Deep Blue Architecture

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### Deep Blue Architecture

Murthy Ganapathibhotla

Agenda
• Introduction
• Overview of Deep Blue Architecture
• Conclusion
INTRODUCTION
• What is Deep Blue ?
• What is a Chess Computer ?
• How are Moves Computed ?
• History of Deep Blue.
Introduction

What is Deep Blue ?

Deep Blue was IBM’s Chess Playing

Computer.

It was the First Computer System to win

Against the world chess champion

Garry Kasparov.

Introduction

What is a Chess Computer ?

Introduction

What is a Chess Computer ?

A Computer that plays Chess !

Introduction

What does a chess computer have to do

in order to defeat the world champion !

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.

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.

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

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!

Introduction

What will a Chess Computer do ?

• 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 .
Introduction

So The Faster Your Computer generates the Moves,

The Better would be the Performance !

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”.

Deep Blue Architecture
• Overview
• Chess Chip
• Chess Chip Evaluation Functions
• RS /6000 Processor
• Software Issues
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 !
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 !

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…

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.
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.
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.

System Bus
• System bus uses 128 bit data path and

• Address, Data , Control Parity Checked
• Operates in true Split Transaction mode
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.
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 !
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.

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.
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.
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.
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.
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.
Brief Description
• Therefore,

Software is responsible for 1 % of the moves

And evaluating 2/3rd the depth of the tree.

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

Murray Campbell

Feng-hsiung Hsu

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

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 ?
Final Word
• Lets see whether the honor of the human race will be defended during a rematch in the future !
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/assignament0/
• IBM Research

http://www.research.ibm.com/deepblue/

Any Questions ?

Thank You !