CS 221 IT 221 Lecture 01

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CS 221/ IT 221Lecture 01

• Introduction,
• Von Neumann architecture,
• and basic logic gates
• Dr. Jim Holten

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Introduction

• Yes, this is Cramer 203 and the class is
• CS 221 -- Computer System Organization and/or
• IT 221 -- Computer and Network Organization
• I am
• Dr. Jim Holten
• Regularly visit the class web site
  http//www.cs.nmt.edu/cs221/
• My office hours are in Cramer 210a (or the Fidel
  Center coffeeshop) on MW at 930-1030 (right
  after class)At any other time I am NOT
  available except by prior appointment, as I work
  at ICASA.

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Attendance

• Print name
• User ID (on TCC systems)
• Your preferred e-mail address for class
  correspondence
• Your registered course number (IT or CS)
• Today's date
• List the programming languages in which you feel
  comfortable writing programs.
• Finish a sentence starting with
• I like computer CS (or IT) because ---

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Overview

• Main topics for the course
• The Von Neumann Architecture (VNA)
• The hardware and software that allow us to use
  the VNA
• The Intel microprocessors and their instruction
  set
• Other architectures of interest
• Other topics I will emphasize regularly
• Good system engineering habits are ESSENTIAL.
  Computers are stupid. They will do exactly what
  you tell them to, no matter how wrong it is.
  Humans make mistakes, and a computer can easily
  repeat one mistake 10 million times before a
  human can stop it.
• Communications, communications, communications --
  Understand the customer's needs and desires.
  Listen well and take notes, then get sign-off
  that they agree with what you thought they said.
  Document your plans and intent. That way you
  don't have to start over with your initial plans
  just to find out what you did wrong in the code.

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The Von Neumann Architecture
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The Memory

• Physical Address Space?
• Like an Array of address locations in
  hardware
• The number of locations is limited by the size
  of an address
• Location types
• Bytes (8 bits) (Modern systems)?
• Characters (6 or 8 bits) or digits (4 bits)
  (earliest systems)?
• Words (8, 12, 16, 30, 32, 48, 60, 64, , even 256
  bits)?

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The Control Unit

• A Finite State Machine
• states
• Inputs/transitions/outputs
• Controls processing cycles
• instruction states (fetch instruction, decode,
  execute)
• data states (fetch, store)
• Instructions, Addresses, and ALU result flags are
  its inputs
• Control signals are its outputs

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The Arithmetic Logic Unit (ALU)?

• Contains registers and/or accumulator for
  calculations and intermediate results
• Implements
• data load/store
• basic arithmetic operations
• logic operations
• bit manipulations

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The Input/Output (I/O)?

• Basic I/O allows data and control flags to be
  passed
• from external devices to registers
• From registers to external devices
• Direct Memory Access (DMA) passes blocks of data
• from memory directly to external devices
• ?from external devices directly to memory

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The Von Neumann Architecture
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How is a VNA built?

• Based on Boolean Logic (Some experimenters use
  multi-state logics)
• ?
• Implemented via digital logic gates combined into
  digital building blocks

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Boolean Logic Components

• Each variable is a 1 or a zero at any given time
  binary digit, or bit
• Foundations generally use NOT, AND, and OR
  operations
• Digital logic normally uses NOT and NAND or NOR
  gates

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Basic Digital Building Blocks

• Logic Gates
• Bit storage -- flip flops
• Registers (collections of flip flops)
• Buses
• Address Selection Logic
• Synchronizing via a System Clock

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Basic Boolean Operators
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Common In Digital Logic
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Basic Bit Storage a set/reset (SR) flip-flop
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Buses

• Memory bus addresses, data, and control flags
  for memory accesses
• I/O bus addresses, data, and control flags for
  I/O interactions

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Common Variant
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Memory Bus Structure
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Address Decoder Logic (one bit)