370 likes | 481 Views
CS24: Introduction to Computer Systems. Day 1: March 29, 2004 Introduction and Overview. Today. What Who Why What Detail (Overview) How (Course Details). What. How the computer works below the programming language (mostly above the physics) How processor is organized
E N D
CS24:Introduction to Computer Systems Day 1: March 29, 2004 Introduction and Overview
Today • What • Who • Why • What Detail (Overview) • How (Course Details)
What • How the computer works below the programming language • (mostly above the physics) • How processor is organized • How your computation is actually performed • Why is there an Operating System • And what does it do for you?
What lies between the Programming Language Physics Abstraction Stack What
What • New class • First time being taught here • Only course in CS undergraduate core that actually deals with computers as physical machines • Dynamics / typical case • How we manage computer systems • Coordinate shared resources • Not just one program • How do we deal with technology • Technology change
Who? • Two Instructors • Jason Hickey • represent high-level view • What does the Programmer want? • André DeHon • Represent the low-level view • What does the hardware want? • How does it perform well?
Who? • TAs: • Michael Wrighton • Cristian Tapus
Why? (low road) • As programmers: want to understand your tool. • How does it work? • When does it break? • What are those constants we kept ignoring in CS20, CS38? • How do you get the most out of it? • Why is this a challenge?
Why? • As innovators: want to understand the prior art • How does it work? • What’s wrong with it? • How can we make it better?
Why? (high road) • What problems does it solve? • What are the big ideas that makes this work? • Is the Instruction Set Architecture (ISA) abstraction necessary? • Isolation? • Virtualization? • …
Why? (Future) • This will all break down in the next 10-20 years. • Low-end: Approaching Atomic scale • Time to pay attention to low-level physics • Sequential processor at end of scaleable life • High-end: Scale of modern systems/software already stressing (breaking?) model • How do we enable bigger systems? • In critical roles? • Reduce human time?
Why? (Future) • This will all break down in the next 10-20 years. • We’re going to have to rebuild it. • What were the good/high-level ideas we need to keep? Can and should be transferred? • You: • May need to help lead the transition • At least need to understand the big ideas to survive the transition
Why? • We are not learning this to pay homage to • Bill Gates • Dennis Richie, Ken Thompson • Linus Torvalds • Fred Brooks, Gene Amdahl • John Hennessey, Dave Patterson • Bob Colwell • Learning this so we can move forward while not repeating the mistakes of the past • Keep the good ideas • Discard the bad ones • Solve problems they didn’t need to…
Physics • Ultimately, we can build machines which compute because the physical world computes • SF=0,F=ma, F=-kx, … • SI=0,V=IR, DV=(I DT)/C, Id=Is(e[qv/kt]-1)
Devices • From these phenomena we can build useful devices • Store charge store value • Switch current based on value
Gates • From these devices we can build gates
Boolean Logic • From gates we can build any particular boolean function • E.g. o=(a+/b)(b+c)+/b*/c Day 2
Universal Turing Machine • From CS21 (CS20), you know we can, in theory, • build a machine which will emulate any other machines • A Universal Machine…
Programmable Logic • Likewise, we can build collections of gates which will perform any function
Programmable Machine • …and ultimately, a machine which can perform (almost) any computable function Week 2
How Organize Programmable Machine? • Theory tells us that we can build such a machine? • Engineering asks how we should build such a machine
Raw Machine • Even this is pretty raw • add, or, xor, ld, st, br • How do we make it usable? • Invent conventions: • Using memory • Representing data • Making procedure calls
Runtime Systems • Over time, we build up a collection of software necessary to run the machine • Load program • Allocate/deallocate memory • Perform I/O • Handle asynchronous events • …
It might be nice if… • Could run more than one program • All the programs didn’t need to know about each other • Could run more than one program at a time • Didn’t require a physical processor for each program want to run • Could use more memory than you have physical RAM • Could communicate with other programs
It might be nice if… • One program crashing didn’t crash the machine • Could monitor a running (crashed) program • Could share the machine amongst people (programs) that don’t necessarily know about or trust each other…
Operating System • …we need some way to virtualize and manage our physical resources • This is what an Operating System provides • Most of our programs run in the context of an operating system and an instruction set processor • API: Application Programming Interface
What lies between the Programming Language Physics Abstraction Stack What
Text (CS:APP) Lectures Recitations Fri. 4pm here Also Fri. 2pm (TBD) Homework 9 weekly labs Midterm, final Grade: 70% for best 8 of 9 labs 10% midterm 20% final Course Components
Resources • Course Web Page <http://www.cs.caltech.edu/courses/cs24/> • Administrative handout • Give you all of these details • Mailing Lists • Forum • Computer Accounts
Pragmatics • Programming in C and Assembly • First recitation on C • Text has asides for “new” C programmers • …will learn assembly bottom up • …will help C, since C is so close to assembly… • Online submission systems
Feedback Sheets • Please fill one out each class • anonymous • New course • Need to understand what works • So can improve for future lectures • So can improve for future years
You Action Items • Get book • Read chapter 1 • Find web page • Read administrative handout • Signup for mailing list, find forum • Get computer account • If don’t already have one • Read Assignment 1 • Pickup support code
Big Ideas • Valuable not to program physics directly • (most of the time…) • Abstraction hierarchy • From programming language to physics • Valuable to abstract and share resources • Need to Understand Hierarchy • to make the most of machines • to improve/re-invent