1. CS270 Computer Organization
Slides based on G. T. Byrd, NCState, © McGraw-Hill,
With modifications/additions by CSU Faculty

2. To answer the questions How? and Why?
Why are you here?
To answer the questions How? and Why?
Then use that information to write better code
So far you have learned to write code but not how that code actually controls a computer or how a computer works.
Answering these questions is generally what this class is going to cover

3. Who am I Phil Sharp Masters in Computer Science
CS270 student in Fall 16
The TAs
GTAs
Zara, Pooria
TAs
Kacey, Elinor, Nathan, Ryan

4. What is the output of the C code fragment shown below?
CS160 - Intro
CS160 - Intro
What is the output of the C code fragment shown below?
hello 2 0x1a 5.68
Hello 2 0x1a 5.68
Hello 50 0x1a 5.68
Hello 2 0x
Hello 2 0x1A 5.67
char *s = “Hello”;
char c = 50;
int x = 26;
float f = ;
printf(“%s %c 0x%02x %.2f\n”, s, c, x, f);
Answer is B), Hello is capitalized, ASCII 50 is 2, 26 is 0x1a (not 0x1A), and %.2f rounds not truncates. 4

5. Lecture Goals Review course logistics Introduce key concepts
Assignments & quizzes
Policies
Organization
Grading Criteria
Introduce key concepts
Role of Abstraction
Software versus Hardware
Universal Computing Devices
Layered Model of Computing

6. Logistics Lectures: See syllabus Staff: See syllabus
Recitations: See syllabus
Help desks: See Piazza
Office hours: See syllabus
Materials on the website:
Piazza: access through Canvas, or directly

7. Policies Grading Criteria Late Policy Academic Integrity
Assignments (20%)
Recitations (10%)
Quizzes and iClicker (10%)
Two Midterm Exams (20% each)
Final Exam (20%)
Late Policy
Two days on assignments
Academic Integrity
Do your own work
Cannot copy and paste any code, unless provided by us
Not sequential, we will start on C programming right away!

8. Assignments & Quizzes Assignments Quizzes
Posted on Progress page of the course website
Programming (C, LC-3) or Logisim circuit designs
See Canvas for due dates
Submit via Checkin before 11:59 PM (unless otherwise specified).
Late period for assignments – two days, 20% deduction
Quizzes
Can be on-line (canvas) or in-class (using iClicker)
iClicker quizzes will be randomly assigned and used for attendance
iClicker practice quiz next class period (no points)

9. Worksheets Worksheets Worksheets will be done as part of the lecture
Can work with your neighbors
No points
for now
Questions may appear on tests
We will go over worksheets at the beginning on the following class period
Great way to test your understanding of the material
Bring a laptop to lookup material
Questions could appear on a test

10. Attendance ~6 iClicker attendance quizzes throughout the semester
Random dates
One freebie
Always bring your iClicker
iClicker practice on Thursday

11. Organization C programming Instruction set architecture
data types, language syntax, variables and operators, control structures, functions, pointers and arrays, memory model, recursion, I/O, data structures
Instruction set architecture
machine/assembly code, instruction formats, branching and control, LC-3 programming, subroutines, memory model (stack)
Computer hardware
numbers and bits, transistors, gates, digital logic, state machines, von Neumann model, instruction sets, LC-3 architecture
Not sequential, we aill start on C programming right away!

12. Top Down Perspective Multilayered view We will see
Higher layers serves as the specification.
Lower layer implements provides the implementation
We will see
How a higher level language (C) is implemented by a processor instruction-set architecture (ISA), LC-3 in our case
How an ISA is implemented using digital circuits?
How are digital circuits implemented using transistors?
And so on …
Not sequential, we aill start on C programming right away!

13. Grading Criteria
Letter Grade
Points A
≥90% B
≥80% C
≥70% D
≥60%
We will not cut higher than this, but we may cut lower.
Your average score on exams must be ≥65% to receive a passing grade in this course.
Solutions to the odd number problems are given on the class website.

14. How to be successful in this class
Read the textbook
It takes multiple passes to understand new material
Attend all classes and recitations.
Random iClicker attendance quizzes
Take the in-class and on-line quizzes as required.
Do the worksheets
Do all the assignments yourself
Ask questions (early! (but not too early!)) if you run into trouble.
Take advantage of lab sessions where help is available from TAs
Try to do it yourself first, too much help can be harmful.
Solutions to the odd number problems are given on the class website.

15. Textbook
Introduction to Computing Systems: From Bits and Gates to C and Beyond 2nd Edition Yale N. Patt and Sanjay J. Patel

16. Other Resources
Computer Organization and Design by David Patterson, John Hennessy
C Programming Language by Dennis Ritchie, Brian Kernighan
MIT Open Courseware 6.004
Introduction to the Theory of Computation by Michael Sipser

17. CS160 - Intro
CS160 - Intro
What are the binary and hexadecimal equivalents of the decimal number 137, assuming 8-bit precision, unsigned?
, 0x83
, 0x85
, 0x87
, 0x89
None of the above
Correct answer is D) 17

18. Chapter 1 Welcome Aboard

19. Two Recurring Themes Abstraction Hardware vs. Software
Productivity enhancer – don’t need to worry about details…
Can drive a car without knowing how the internal combustion engine works.
…until something goes wrong!
Where’s the dipstick? What’s a spark plug?
Important to understand the components and how they work together.
Hardware vs. Software
It’s not either/or – both are components of a computer system.
Even if you specialize in one, you should understand capabilities and limitations of both.

20. Big Idea #1: Universal Computing Device
All computers, given enough time and memory, are capable of computing exactly the same things. = =
PDA
Workstation
Supercomputer

21. Classes of Automata

22. Tadd Tmul Turing Machine
Mathematical model of a device that can perform any computation – Alan Turing (1937)
ability to read/write symbols on an infinite “tape”
state transitions, based on current state and symbol
Every computation can be performed by some Turing machine. (Turing’s thesis)
Tadd
a,b
a+b
Turing machine that adds
Tmul
a,b ab
Turing machine that multiplies
For more info about Turing machines, see
For more about Alan Turing, see

23. Universal Turing Machine
A machine that can implement all Turing machines -- this is also a Turing machine!
inputs: data, plus a description of computation (other TMs) U
a,b,c
c(a+b)
Universal Turing Machine
Tadd, Tmul
U is programmable – so is a computer!
instructions are part of the input data
a computer can emulate a Universal Turing Machine
A computer is a universal computing device.

24. From Theory to Practice
In theory, computer can compute anything
that’s possible to compute
halting problem computable/decidable?
given enough memory and time
In practice, solving problems involves computing under constraints.
time
weather forecast, next frame of animation, ...
cost
cell phone, automotive engine controller, ...
power
cell phone, handheld video game, ...

25. Big Idea #2: Transformations Between Layers
Problems
Algorithms
Language
Instruction Set Architecture
Microarchitecture
Digital Circuits
Devices

26. How do we solve a problem using a computer?
A systematic sequence of transformations between layers of abstraction.
Problem
Software Design:
choose algorithms and data structures
Algorithm
Programming:
use language to express design
Program
Compiling/Interpreting:
convert language to machine instructions
Instr Set
Architecture

27. Deeper and Deeper… Processor Design:
Instr Set
Architecture
Processor Design:
choose structures to implement ISA
Microarch
Logic/Circuit Design:
gates and low-level circuits to implement components
DigCircuits
Process Engineering & Fabrication:
develop and manufacture lowest-level components
Devices

28. Descriptions of Each Level
Problem Statement
stated using "natural language"
may be ambiguous, imprecise
Algorithm
step-by-step procedure, guaranteed to finish
definiteness, effective computability, finiteness
Program
express the algorithm using a computer language
high-level language, low-level language
Instruction Set Architecture (ISA)
specifies the set of instructions the processor (CPU) can perform
data types, addressing mode
Time flies like an arrow

29. Descriptions of Each Level (cont.)
Microarchitecture
detailed organization of a processor implementation
different implementations of a single ISA
Logic Circuits
combine basic operations to realize microarchitecture
many different ways to implement a single function (e.g., addition)
Devices
properties of materials, manufacturability
Examples of problems that span layers:
CMU Computer Architecture Intro Lecture

30. Many Choices at Each Level
Solve a system of equations
Gaussian
elimination
Jacobi
iteration
Red-black SOR
Multigrid
FORTRAN C
C++
Java
Intel x86
PowerPC
ARM
Centrino
Pentium 4
Core
Ripple-carry adder
Carry-lookahead adder
CMOS
Bipolar
GaAs
Tradeoffs:
cost
performance
power
(etc.)
Sun and Java are trademarks of Sun Microsystems, Inc. Intel, Pentium, Centrino, and Xeon are trademarks of Intel Corporation. AMD and Athlon and trademarks of Advanced Micro Devices, Inc. Atmel and AVR are registered trademarks of Atmel Corporation. PowerPC is a trademark of International Business Machines Corporation.

31. Course Outline Computer systems: what is next? Bits and Bytes
How do we represent information?
C Programming
How do we write programs in C?
How do we implement high-level programming constructs?
Instruction set architecture/Assembly language
What operations (instructions) will we implement?
How do we use processor instructions to implement algorithms?
How do we write modular, reusable code? (subroutines)
I/O, Traps, and Interrupts: How does processor communicate with outside world?
Digital Logic and processor architecture
How do we build circuits to process and store information?
How do we build a processor out of logic elements?
Computer systems: what is next?