Computers: How They Work 1. What is a Computer 2. Components of Computer 3. World’s First Computers and CPUs 4. Mother Board 5. Machine Code and the processor’s.

Computers: How They Computers: How They WorkWork

1.1. What is a ComputerWhat is a Computer2.2. Components of ComputerComponents of Computer3.3. World’s First Computers and CPUsWorld’s First Computers and CPUs4.4. Mother BoardMother Board5.5. Machine Code and the processor’s Instruction Set – SoftwareMachine Code and the processor’s Instruction Set – Software6.6. Memory types (ROM, DRAM, SRAM, FLASH)Memory types (ROM, DRAM, SRAM, FLASH)7.7. Hard DriveHard Drive8.8. Compact DiskCompact Disk9.9. KeyboardKeyboard10.10. MonitorMonitor11.11. The MouseThe Mouse12.12. Other I/OOther I/O13.13. DSL and connection to InternetDSL and connection to Internet14.14. File CompressionFile Compression

DemonstrationsDemonstrations► PC Mother BoardsPC Mother Boards► MemoryMemory

Hard DriveHard Drive Magnetic TapeMagnetic Tape Punch CardsPunch Cards CDsCDs SIMM cardsSIMM cards

► Polarized FilmsPolarized Films► LCDsLCDs► KeyboardKeyboard► CCD chipsCCD chips

What is a Computer?What is a Computer?

A machine that A machine that stores stores instructions and datainstructions and data and and operatesoperates on on information/data.information/data.

Jacquards Loom

Circa 1804

http://www.sscnet.ucla.edu

Charles Babbage’s first Charles Babbage’s first attempt at a Computer attempt at a Computer The Analytical EngineThe Analytical Engine, c. , c.

1822 1822 ► Designed to use Jacquard Designed to use Jacquard

punch cards to store and punch cards to store and run a programrun a program

► Mathematician, Mathematician, Augusta Ada LovelaceAugusta Ada Lovelace, , created programscreated programs

► Steam PoweredSteam Powered► 25,000 parts25,000 parts► 15 tons and 8 feet high15 tons and 8 feet high► Never completedNever completed

http://concise.britannica.com

Difference Engine IIDifference Engine II

►Designed to Designed to calculate calculate polynomials polynomials and compute and compute trig and log trig and log functionsfunctions

►C. 1847C. 1847►Crank Crank

operatedoperatedhttp://www.computerhistory.org/babbage/

MicroprocessorMicroprocessor

► A A logic machinelogic machine that that can execute a a can execute a a small set of small set of instructions. instructions.

► A Central Processing A Central Processing Unit (CPU) Unit (CPU) integrated into a integrated into a single chip single chip (i.e. constructed as (i.e. constructed as an integrated circuit an integrated circuit on a single piece of on a single piece of Silicon)Silicon)

http://en.wikipedia.org/wiki/Central_processing_unit

Components of a ComputerComponents of a Computer

► ProcessorProcessor► Memory Memory ► Input/OutputInput/Output

Processor

Input(Keyboard, MouseUSB Drive, DSL,

Touchscreen, Microphone,Hard Drive)

Output(Monitor, speakers,USB Drive, Printer,

DSL, Hard Drive)

Memory(ROM, RAM,

Registers, Cache)

USB – Universal Serial Bus DSL – Digital Subscriber Line

What’s Inside a basic CPU?What’s Inside a basic CPU?(Central Processing Unit)(Central Processing Unit)

► ALU (Arithmetic Logic Unit)ALU (Arithmetic Logic Unit) Performs addition, division, etc.Performs addition, division, etc.

► Instruction DecoderInstruction Decoder► Program CounterProgram Counter► Instruction Register – stores current Instruction Register – stores current

instruction being worked on.instruction being worked on.► Data Registers – stores current data Data Registers – stores current data

being worked with.being worked with.► Accumulator (place for storing a sum)Accumulator (place for storing a sum)► Clock for sequencing operationsClock for sequencing operations

Memory – A Device that Memory – A Device that “remembers” a previous input.“remembers” a previous input.

Registers are the high speed memory Registers are the high speed memory on the CPU chip. These registers are on the CPU chip. These registers are used for storing data that is frequently used for storing data that is frequently needed. needed.

Instructions are pre-fetched and stored Instructions are pre-fetched and stored in registers too so that they are ready in registers too so that they are ready when needed. when needed.

Registers

4004 Intel Processor

1-bit Latch (Flip Flop)1-bit Latch (Flip Flop)

Static RAM and registers are constructed with this logic. The state of Q is retained as long as power is on.

Static RAM –Non-volatile Random Access Memory

4-word Static RAM

Memory Hierarchy

http://www.surriel.com/lectures/hierarchy.gif

Cache MemoryCache Memory

http://content.answers.com

SRAMSRAM

► Static Random Access MemoryStatic Random Access Memory► Retains data in memory as long as power is Retains data in memory as long as power is

onon► Uses flip flopsUses flip flops (8 transistors each) (8 transistors each)► Fast but more expensive due to more chip Fast but more expensive due to more chip

real-estate needed for each memory real-estate needed for each memory location compared to DRAMlocation compared to DRAM

► Used for cache memoryUsed for cache memory► Fast Access time Fast Access time 10 nanoseconds 10 nanoseconds

DRAM and SDRAMDRAM and SDRAM► Dynamic RAMDynamic RAM

Dynamic refers to the need to Dynamic refers to the need to refresh the datarefresh the data

► Synchronous DRAMSynchronous DRAM (Timing of memory chip is (Timing of memory chip is

synchronized with CPU clock)synchronized with CPU clock)► Data is stored as electrical Data is stored as electrical

charge in capacitorscharge in capacitors► Capacitors will discharge Capacitors will discharge

requiring that memory be requiring that memory be refreshed every few refreshed every few milliseconds. milliseconds.

► Dense therefore least Dense therefore least expensive form of memoryexpensive form of memory

http://www.electronics.dit.ie/staff/tscarff/memory/ram.htm

The word “random” means bytes can be accessed randomly. Data access is not sequential like a magnetic tape.

http://www.cse.scu.edu

SIMM & DIMMSIMM & DIMM

►Single In-line Single In-line memory memory modulemodule

►Dual In-line Dual In-line memory memory modulemodule

►These cards are These cards are DRAMSDRAMS

http://en.wikipedia.org/wiki/DIMM

ROM of three memory locations, each “word” ROM of three memory locations, each “word” of memory is 3 bitsof memory is 3 bits

► Read Only MemoryRead Only Memory► Data contents can Data contents can

not be changednot be changed► Data retained even Data retained even

when power is offwhen power is off► Manufactured with Manufactured with

the datathe data► Used for booting up Used for booting up

computer and computer and loading Operating loading Operating SystemSystem

► Device Driver Device Driver softwaresoftware

http://www.compeng.dit.ie

Diodes

http://tams-www.informatik.uni-hamburg.de

Flash MemoryFlash Memory► (Electrically Eraseable (Electrically Eraseable

Programmable Programmable Memory)Memory)

► Using Floating Gate Using Floating Gate Transistors to store bitsTransistors to store bits

► Non-volatile (power not Non-volatile (power not needed to maintain needed to maintain data)data)

► MP3 Players are flash MP3 Players are flash drives with extra drives with extra circuitry to decode data circuitry to decode data to analog music signalsto analog music signals

► Cellular PhonesCellular Phones► Digital CamerasDigital Cameras► Very resistant to Very resistant to

temperature, shock, temperature, shock, field stressfield stress http://electronicdesign.com/Articles/ArticleID/16383/16383.html

Hard DriveHard Drive120-240 120-240 GBytesGBytes

► Data stored magneticallyData stored magnetically► Permanent Storage, Permanent Storage, Non-volatile memoryNon-volatile memory► Fast - Spins 4,500 to 12,000 rpmFast - Spins 4,500 to 12,000 rpm► Dense and InexpensiveDense and Inexpensive► Data easily erased and rewrittenData easily erased and rewritten► Iron Oxide or very thin magnetic film applied Iron Oxide or very thin magnetic film applied

with a sputtering process stores magnetic with a sputtering process stores magnetic datadata

► Not random accessNot random access

http://www.metallurgy.utah.edu/

Actuator

Actuator Arm Spindle

Read/Write head

Platter

Read-Write Read-Write HeadHead

wikipedia

Multiple Platters

How Stuff Works

www.hddtech.co.uk

Head 20-50 nm from platter surfaceA human hair is 100 nm

The voice-coil actuator controls the The voice-coil actuator controls the movement of the actuator armmovement of the actuator arm

► Positions the Positions the read/write headsread/write heads

► Similar to a speaker!Similar to a speaker!► Uses a coil and Uses a coil and

permanent magnetpermanent magnet► Converts electrical Converts electrical

signals into signals into mechanical mechanical movementmovement

► In this picture, In this picture, magnet has been magnet has been moved to the left moved to the left during disassembly to during disassembly to expose the coilexpose the coil

► Coil moves freely Coil moves freely under the magnetunder the magnet

http://www.storagereview.com/guide2000/ref/hdd/op/over.html

Small TolerancesSmall Tolerances

5-80 Mbytes/sec media transfer rate5-80 Mbytes/sec media transfer rate

As an analogy, a magnetic head slider flying As an analogy, a magnetic head slider flying over a disk surface with a flying height of 25 over a disk surface with a flying height of 25 nm with a relative speed of 20 meters/second nm with a relative speed of 20 meters/second is equivalent to an aircraft flying at a physical is equivalent to an aircraft flying at a physical spacing of 0.2 µm at 900 kilometers/hour. This spacing of 0.2 µm at 900 kilometers/hour. This is what a disk drive experiences during its is what a disk drive experiences during its operation.operation. ””

——Magnetic Storage Systems Beyond 2000, George C. HadjipanayisMagnetic Storage Systems Beyond 2000, George C. Hadjipanayis

Software commands HardwareSoftware commands Hardware

while (amt2 <= amt1)while (amt2 <= amt1)

{{amt1 = amt1 + 100;amt1 = amt1 + 100;amt2 = amt2 + amt2 = amt2 +

0.05*amt2;0.05*amt2;year++;year++;

}}

14: while (amt2 <= amt1)004015BB fld dword ptr [ebp-8]004015BE fcomp dword ptr [ebp-4]004015C1 fnstsw ax004015C3 test ah,41h004015C6 je main+70h (004015f0)15: {16: amt1 = amt1 + 100;004015C8 fld dword ptr [ebp-4]004015CB fadd dword ptr [__real@4@4005c800000000000000 (0046f0a4)]004015D1 fstp dword ptr [ebp-4]17: amt2 = amt2 + 0.05*amt2;004015D4 fld dword ptr [ebp-8]004015D7 fld dword ptr [ebp-8]004015DA fmul qword ptr [__real@8@3ffaccccccccccccd000 (0046f098)]004015E0 faddp st(1),st004015E2 fstp dword ptr [ebp-8]18: year++;004015E5 mov eax,dword ptr [ebp-14h]004015E8 add eax,1004015EB mov dword ptr [ebp-14h],eax19: }

C++ high level codes gets compiled/translated into low level machine codes

Fetch-Decode-Execute CycleFetch-Decode-Execute Cycle

►Fetch an Instruction:Fetch an Instruction: Fetch instruction at address stored in Fetch instruction at address stored in

address registeraddress register Increment Program CounterIncrement Program Counter Load the Instruction Register with this Load the Instruction Register with this

InstructionInstruction

►DecodeDecode Decode the InstructionDecode the Instruction Fetch the operandsFetch the operands

►ExecuteExecute ALU or other logic performs the operationALU or other logic performs the operation The result is then written to memory or to The result is then written to memory or to

a register.a register.

A Computer is much more than a processorA Computer is much more than a processor….….► Processor Intel® Core™2 Processor Intel® Core™2

Q6600 Quad-Core (8MB L2 Q6600 Quad-Core (8MB L2 cache,2.4GHz,1066FSB)cache,2.4GHz,1066FSB)

► Video Cards 768MB nVidia Video Cards 768MB nVidia GeForce 8800 GTXGeForce 8800 GTX

► Memory 2GB* Dual Channel Memory 2GB* Dual Channel DDR2 SDRAM at 667MHz - 2 DDR2 SDRAM at 667MHz - 2 DIMMsDIMMs

► Hard Drive: 500GB* - Hard Drive: 500GB* - 7200RPM, SATA 3.0Gb/s, 7200RPM, SATA 3.0Gb/s, 16MB Cache16MB Cache

► Optical Drive Single Drive: Optical Drive Single Drive: Blu-ray Disc Drive Blu-ray Disc Drive (BD/DVD/CD burner (BD/DVD/CD burner w/double layer BD writew/double layer BD write

► Monitors 20 inch E207WFP Monitors 20 inch E207WFP Widescreen Digital Flat Widescreen Digital Flat PanelPanelhttp://www.dell.com

Wikipedia

micron = 10-6 meters

The feature size of an integrated circuit is indicated by the width of a "wire," measured in microns (one micron is one millionth of a meter). Analysis and Design of Analog Integrated Circuits (4th Edition)