COM 249 – Computer Organization and Assembly Language Chapter 1 Computer Abstraction and Technology Greet class Based on slides from D. Patterson and www-inst.eecs.berkeley.edu/~cs152/

COM 249 Spring ‘09 Where are we going?? Arithmetic Single/multicycle Datapaths µProc 60%/yr. (2X/1.5yr) DRAM 9%/yr. (2X/10 yrs) 1 10 100 1000 1980 1981 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 CPU 1982 Processor-Memory Performance Gap: (grows 50% / year) Performance Time “Moore’s Law” COM 249 Spring ‘09 IFetch Dcd Exec Mem WB Pipelining Y O U R C P Memory Systems I/O

Where Are We Going? Performance issues (Chapter 1) overview, vocabulary and motivation A specific instruction set architecture (Chapter 2) Arithmetic and how to build an ALU (Chapter 3) Constructing a processor to execute our instructions (Chapter 4) Pipelining to improve performance (Chapter 4) Memory: caches and virtual memory (Chapter 5) I/O (Chapter 6) Multicores, Multiprocessors (Chapter 7) Key to a good grade: reading the book!

How programs are translated into the machine language What You Will Learn How programs are translated into the machine language And how the hardware executes them The hardware/software interface What determines program performance And how it can be improved How hardware designers improve performance What parallel processing is and what implications it has for programmers

Introduction Rapidly changing field: vacuum tube -> transistor -> IC -> VLSI (see section 1.3) doubling every 1.5 years: (Moore’s Law) memory capacity processor speed (Due to advances in technology and organization) Things you’ll be learning: how computers work, a basic foundation how to analyze their performance (or how not to!) issues affecting modern processors (caches, pipelines) Why learn this stuff? you want to call yourself a “computer scientist” you want to build software people use (need performance) you need to make a purchasing decision or offer “expert” advice

Understanding Performance Algorithm Determines number of operations executed Programming language, compiler, architecture Determine number of machine instructions executed per operation Processor and memory system Determine how fast instructions are executed I/O system (including OS) Determines how fast I/O operations are executed

COM 249: So what's in it for me? Learn some of the big ideas in CS & engineering: 5 Classic components of a Computer Data can be anything (integers, floating point, characters): the program determines what it is Stored program concept: instructions just data Principle of Locality, exploited via a memory hierarchy (cache) Greater performance by exploiting parallelism Principle of abstraction, used to build systems as layers Compilation vs. interpretation through system layers Principles/Pitfalls of Performance Measurement Designer’s “conceptual” toolbox

“Conceptual” Tool Box? Evaluation Techniques Levels of translation (e.g., Compilation) Levels of Interpretation (e.g., Microprogramming) Hierarchy (e.g, registers, cache, memory, disk, tape) Pipelining and Parallelism Indirection and Address Translation Synchronous /Asynchronous Control Transfer Timing, Clocking, and Latching CAD Programs, Hardware Description Languages, Simulation Static / Dynamic Scheduling Physical Building Blocks (e.g., Carry Lookahead) Understanding Technology Trends

Our Goals To understand modern computer architecture in its rapidly changing form To explore the relationship between hardware and software To design by leading you through the process of challenging design problems and by examining real designs To learn how to test and to design for improved performance

Where is “Computer Organization and Assembly Language”? Application (Netscape) Operating Compiler System (Windows 2K) Software Assembler Instruction Set Architecture Hardware Processor Memory I/O system Datapath & Control Digital Design COM249 Circuit Design transistors Coordination of many levels of abstraction

Dual Level Abstraction SOFTWARE Negation, Add, Double, Subtract Higher Levels HARDWARE Negation, Add Lower Levels CHANGED

Computer Architecture Includes: Instruction set architecture (ISA) (programmer’s abstraction of a computer) Organization or microarchitecture (internal implementation of a computer at the register and functional unit level) System architecture (organization of the computer at the cache and bus level) See Computing Curriculum 2001 – pages 97-101 http://www.acm.org/education/education/curric_vols/cc20 01.pdf

Instruction Set Architecture (ISA) A very important abstraction interface between hardware and low-level software standardizes instructions, machine language bit patterns, etc. advantage: different implementations of the same architecture disadvantage: sometimes prevents using new innovations Modern instruction set architectures: 80x86/Pentium/K6, PowerPC, DEC Alpha, MIPS, SPARC, HP

Hardware Levels CPU, Memory, Etc. Level 2 Digital Logic Circuits Transistors Level 0

Software Levels High-Level Languages Level 6 Assembly Language Level 5 Operating Systems Level 4 Machine Language Level 3

At higher levels (above Level 2) Software At higher levels (above Level 2) Level 3: Machine language Level 4: Operating system services Level 5: Assembly language Level 6: High-level languages Most programs are written at Level 6. Hardware only understands Level 3 instructions. CHANGED

Morgan Kaufmann Publishers April 23, 2018 Below Your Program Application software Written in high-level language (HLL) System software Compiler: translates HLL code to machine code Operating System: service code Handling input/output Managing memory and storage Scheduling tasks & sharing resources Hardware Processor, memory, I/O controllers §1.2 Below Your Program Chapter 1 — Computer Abstractions and Technology

Levels of Representation temp = v[k]; v[k] = v[k+1]; v[k+1] = temp; High Level Language Program (e.g., C) Compiler lw $t0, 0($2) #load word lw $t1, 4($2) sw $t1, 0($2) #store word sw $t0, 4($2) Assembly Language Program (e.g.,MIPS) Assembler Machine Language Program (MIPS) 0000 1001 1100 0110 1010 1111 0101 1000 1010 1111 0101 1000 0000 1001 1100 0110 1100 0110 1010 1111 0101 1000 0000 1001 0101 1000 0000 1001 1100 0110 1010 1111 Machine Interpretation wire [31:0] dataBus; regFile registers (databus); ALU ALUBlock (inA, inB, databus); Hardware Architecture Description (e.g., Verilog Language) Architecture Implementation wire w0; XOR (w0, a, b); AND (s, w0, a); Logic Circuit Description (Verilog Language)

Revolutions 1. Agricultural 2. Industrial 3. Information / computer Computers have become part of daily life and are ubiquitous (in cars, ATMs, microwave ovens, cell phones, etc.) Classes: desktops, servers, supercomputers, embedded Software: Systems- Operating systems, compilers, assemblers Applications- Word processors, databases, spreadsheets, games, etc...

Classes of Computers Desktop computers General purpose, variety of software Subject to cost/performance tradeoff Server computers Network based High capacity, performance, reliability Range from small servers to building sized Embedded computers Hidden as components of systems Stringent power/performance/cost constraints

Embedded Computers Run one set of related applications, such as those in cell phones, TVs, cars, game machines, etc. Growth of cell phones, with embedded computers, has been faster than desktop computers. In 2004 there were 1 PC, 2.2 cell phones, and 2.5 TVs for every 8 people on the planet. In 2006, a US family owned 12 gadgets (3 TVs, 2 PCs, and others –MP3 players, cell phones, game consoles.)

Morgan Kaufmann Publishers April 23, 2018 The Processor Market Chapter 1 — Computer Abstractions and Technology

The Computer Revolution §1.1 Introduction Progress in computer technology Underpinned by Moore’s Law Makes novel applications feasible Computers in automobiles Cell phones Human genome project World Wide Web Search Engines Computers are pervasive

Moore’s Law Moore's Law, states that the number of transistors on a chip will double about every two years. Almost every measure of the capabilities of digital electronic devices is linked to Moore's law: processing speed, memory capacity, even the number and size of pixels in digital cameras http://en.wikipedia.org/wiki/Moore's_law http://www.intel.com/technology/mooreslaw/index.htm

From High Level to Low Level Advantages of High Level Languages Think in more natural terms about real world objects Improve programmer productivity Programmers independent of machine Advantages of Low Level Language Faster Communicate directly with hardware

Components of a Computer Same components for all kinds of computer Desktop, server, embedded Input/output includes User-interface devices Display, keyboard, mouse Storage devices Hard disk, CD/DVD, flash Network adapters For communicating with other computers The BIG Picture

Anatomy: 5 components of any Computer Personal Computer Keyboard, Mouse Computer Processor Memory (where programs, data live when running) Devices Disk (where programs, data live when not running) Control (“brain”) Input That is, any computer, no matter how primitive or advance, can be divided into five parts: 1. The input devices bring the data from the outside world into the computer. 2. These data are kept in the computer’s memory until ... 3. The datapath request and process them. 4. The operation of the datapath is controlled by the computer’s controller. All the work done by the computer will NOT do us any good unless we can get the data back to the outside world. 5. Getting the data back to the outside world is the job of the output devices. The most COMMON way to connect these 5 components together is to use a network of busses. Datapath (“brawn”) Output Display, Printer

Anatomy of a Computer Output device Network cable Input device

Anatomy of a Mouse Invented by Doug Englebart (1967) Mechanical (roller ball) Optical mouse LED illuminates desktop Small low-res camera Basic image processor Looks for x, y movement Buttons & wheel Supersedes roller-ball mechanical mouse

Through the Looking Glass LCD screen: picture elements (pixels) Mirrors content of frame buffer memory

LCD Displays Liquid Crystal Display- thin, low power Uses rod shape molecules in a liquid forming a twisted helix that bends light. Rods straighten when current is applied and do not bend the light. Uses an active matrix of tiny transistors to control current and form sharper images. Images are composed of red, green and blue dots.

Forming Images An image is composed of picture elements or pixels, represented as a matrix of bits, called a bit map. Display matrix can be 640 x 480 to 2560 x 1600 pixels in size. A color display uses 8 bits for each of the 3 (RGB) colors, or 24 bits/pixel, creating millions of colors. A raster refresh or frame buffer is the hardware to support graphics. It stores the bit map.

Opening the Box

Inside the Processor (CPU) Datapath: performs operations on data Control: sequences datapath, memory, ... Cache memory Small fast SRAM memory for immediate access to data

Inside the Processor AMD Barcelona: 4 processor cores

Morgan Kaufmann Publishers April 23, 2018 Abstractions The BIG Picture Abstraction helps us deal with complexity Hide lower-level detail Instruction set architecture (ISA) The hardware/software interface Application binary interface (ABI) The ISA plus system software interface Implementation The details underlying and interface Chapter 1 — Computer Abstractions and Technology

Morgan Kaufmann Publishers April 23, 2018 A Safe Place for Data Volatile main memory Loses instructions and data when power off Non-volatile secondary memory Magnetic disk Flash memory Optical disk (CDROM, DVD) Chapter 1 — Computer Abstractions and Technology

Morgan Kaufmann Publishers April 23, 2018 Networks Communication and resource sharing Local area network (LAN): Ethernet Within a building Wide area network (WAN: the Internet Wireless network: WiFi, Bluetooth Chapter 1 — Computer Abstractions and Technology

Morgan Kaufmann Publishers April 23, 2018 Technology Trends Electronics technology continues to evolve Increased capacity and performance Reduced cost DRAM capacity Year Technology Relative performance/cost 1951 Vacuum tube 1 1965 Transistor 35 1975 Integrated circuit (IC) 900 1995 Very large scale IC (VLSI) 2,400,000 2005 Ultra large scale IC 6,200,000,000 Chapter 1 — Computer Abstractions and Technology

Overview of Physical Implementations The hardware out of which we make systems. Integrated Circuits (ICs) Combinational logic circuits, memory elements, analog interfaces. Printed Circuits (PC) boards substrate for ICs and interconnection, distribution of CLK, Vdd, and GND signals, heat dissipation. Power Supplies Converts line AC voltage to regulated DC low voltage levels. Chassis (rack, card case, ...) holds boards, power supply, provides physical interface to user or other systems. Connectors and Cables.

Review of Major Components Mouse ( mechanical, optical) Display (CRT, LCD) Motherboard Integrated Circuits (transistors, CMOS) CPU - controls memory, I/O, datapath according to instructions Datapath- performs arithmetic operations

Review of Major Components Memory DRAM - Dynamic RAM - main memory SRAM - Static RAM- faster, more expensive Cache- fast buffer for main memory DIMM and SIMM - small boards that contain DRAM chips RAM, ROM, volatile, non-volatile, primary, secondary, magnetic disk, optical disks (CD, DVD), FLASH based

Memory Comparisons Main Memory vs. Disk Memory Access Volatile Non Volatile Fast(electrical) Slower(mechanical) Expensive (100 * more) Cheaper Memory Access DRAM Disk 40 -80 nanoseconds 5- 15 milliseconds 10-9 10-3 (100,000 times faster)

Computer Technology - Dramatic Change! Processor 2X in speed every 1.5 years (since ‘85); 100X performance in last decade. Memory DRAM capacity: 2x / 2 years (since ‘96); 64x size improvement in last decade. Disk Capacity: 2X / 1 year (since ‘97) 250X size in last decade.

Technology Trends: Processor Performance Intel P4 2000 MHz (Fall 2001) 1.54X/yr Performance measure year We’ll talk about processor performance later on…

Technology Trends: Memory Capacity (Single-Chip DRAM) year size (Mbit) 1980 0.0625 1983 0.25 1986 1 1989 4 1992 16 1996 64 1998 128 2000 256 2002 512 Now 1.4X/yr, or 2X every 2 years. 8000X since 1980!

Tech. Trends: Microprocessor Complexity 2X transistors/Chip Every 1.5 to 2.0 years Called “Moore’s Law”

Networks Advantages Types Communication Resource Sharing Non-local access Types LANs - Ethernet WANs

Computer Technology - Dramatic Change! State-of-the-art PC when you graduate: (at least…) Processor clock speed: 5000 MegaHertz (5.0 GigaHertz) Memory capacity: 4000 MegaBytes (4.0 GigaBytes) Disk capacity: 2000 GigaBytes (2.0 TeraBytes) New units! Mega <= Giga, Giga <= Tera … (Kilo, Mega, Giga, Tera, Peta, Exa, Zetta, Yotta = 1024) Come up with a clever mnemonic, fame!

Technology in the News BIG SMALL LaCie the first to offer consumer-level 1.6 Terabyte disk! $2,200 Weighs 11 pounds! SMALL Pretec is soon offering a 12GB CompactFlash card Size of a silver dollar Cost?? www.lacie.com/products/product.htm?id=10129 www.engadget.com/entry/4463693158281236/

} Processor And in conclusion... Continued rapid improvement in Computing 2X every 1.5 years in processor speed; every 2.0 years in memory size; every 1.0 year in disk capacity; Moore’s Law enables processor, memory (2X transistors/chip/ ~ 1.5 or 2.0 yrs) 5 classic components of all computers Control Datapath Memory Input Output } Processor