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Digital Electronics Digital Electronics and File Managementand File Management

Unit DUnit D

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ObjectivesObjectives

Introduce Digital Data Introduce Digital Data RepresentationRepresentationIntroduce Integrated CircuitsIntroduce Integrated CircuitsExplore Processor Performance Explore Processor Performance FactorsFactorsUnderstand Computer Memory: Understand Computer Memory: RAMRAMExplore Computer MemoryExplore Computer Memory

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ObjectivesObjectives

Introduce Computer File BasicsIntroduce Computer File Basics

Understand File LocationsUnderstand File Locations

Explore File ManagementExplore File Management

Understand Logical File StorageUnderstand Logical File Storage

Use FilesUse Files

Understand Physical File StorageUnderstand Physical File Storage

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Digital Data Representation Digital Data Representation

The form in which The form in which information is conceived, information is conceived, manipulated and recorded manipulated and recorded on a digital device.on a digital device.

Uses discrete Uses discrete digits/electronic signalsdigits/electronic signals

Byte = 8 bits = 1 character Byte = 8 bits = 1 character

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Numeric DataNumeric Data

Consists of numbers Consists of numbers representing quantities representing quantities used in arithmetic used in arithmetic operations.operations.– Binary system, “Base 2”Binary system, “Base 2”- 1,0 (bits - binary digits)1,0 (bits - binary digits)- On/Off, Yes/NoOn/Off, Yes/No

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Coding Systems Coding Systems

Depends on computer Depends on computer

File headers File headers

ASCIIASCII (7 bits) (7 bits)

Extended ASCIIExtended ASCII (8 bits - (8 bits - current PCs)current PCs)

EBCIDICEBCIDIC (8 bits - older IBM (8 bits - older IBM machines )machines )

UnicodeUnicode (16 bits - good for (16 bits - good for languages - future)languages - future)

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Quantifying Bytes and BitsQuantifying Bytes and Bits

Bit = b Bit = b

Nibble = Half of a byteNibble = Half of a byte

Byte = B Byte = B

Kilobyte (KB) (1024 bytes)Kilobyte (KB) (1024 bytes)

Megabyte (MB) (Million bytes)Megabyte (MB) (Million bytes)

Gigabyte (GB) (Billion bytes)Gigabyte (GB) (Billion bytes)

Terabyte (TB) (Trillion bytes)Terabyte (TB) (Trillion bytes)

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Integrated Circuits Integrated Circuits

A super thin slice of semi–conducting A super thin slice of semi–conducting material packed with microscopic material packed with microscopic circuit elements such as wires, circuit elements such as wires,

transistors, capacitors, logic gates, transistors, capacitors, logic gates, and resistors. Bits are represented as and resistors. Bits are represented as

electrical pulses that travel over electrical pulses that travel over these circuits. these circuits.

Also called a chip, microchip Also called a chip, microchip and computer chip.and computer chip.

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Integrated Circuits (cont.)Integrated Circuits (cont.)

Chips are classified by number of Chips are classified by number of components they containcomponents they contain– SSI (small-scale integration), less than SSI (small-scale integration), less than

100 components per chip100 components per chip– ULSI (Ultra large-scale) over 1 millionULSI (Ultra large-scale) over 1 million

Semi conducting materials used Semi conducting materials used to make chipsto make chips– Silicon and germaniumSilicon and germanium

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Integrated Circuit UsesIntegrated Circuit Uses

processors processors

MemoryMemory

Support circuitrySupport circuitry

Chip Chip

PackagePackage

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Processor Packages Processor Packages

DIPs (dual in-line packages)DIPs (dual in-line packages)

DIMMs (dual in-line memory DIMMs (dual in-line memory modules)modules)

PGAs (Pin-grid arrays)PGAs (Pin-grid arrays)

SECs (single-edge contact SECs (single-edge contact cartridges)cartridges)

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Microprocessor (Processor)Microprocessor (Processor)

Designed to process instructions Designed to process instructions

Largest chip on motherboard Largest chip on motherboard

Intel: world’s largest chipmaker Intel: world’s largest chipmaker (Pentiums)(Pentiums)

AMD: Cheaper chips (Athlons)AMD: Cheaper chips (Athlons)

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Motherboard Motherboard

Main circuit board Main circuit board

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Inside the System UnitInside the System Unit

The The systemsystem unitunit of a PC is the of a PC is the case that houses processing case that houses processing hardware and other hardware. hardware and other hardware.

All of the hardware contained All of the hardware contained within the system unit is within the system unit is connected to the connected to the system board system board or or motherboardmotherboard..

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CPU CPU

The The CPU (central processing unit) CPU (central processing unit) does the vast does the vast majority of processing for a computer.majority of processing for a computer.

CPUs contains a variety of circuitry and components CPUs contains a variety of circuitry and components and are connected to the motherboard.and are connected to the motherboard.

Also called the Also called the processor processor or or microprocessor.microprocessor.

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CPU, CPU, Cont’d.Cont’d.

Processing speedProcessing speed ( (clock speedclock speed) is ) is measured in measured in megahertz (MHz) megahertz (MHz) or or gigahertz (GHz) gigahertz (GHz) and measures the number and measures the number of clock ticks per second.of clock ticks per second.

A computer A computer wordword is a group of bits or bytes is a group of bits or bytes that a CPU can manipulate at one time.that a CPU can manipulate at one time.

Other factors that affect the speed of the Other factors that affect the speed of the computer include the amount of computer include the amount of RAM RAM andand cache memorycache memory,, bus width bus width, and , and bus speedbus speed..

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Memory: RAMMemory: RAM

RAM (random access memory)RAM (random access memory) is the computer’s is the computer’s main memory and is used to temporarily storage main memory and is used to temporarily storage programs and data with which it is working.programs and data with which it is working.RAM is RAM is volatile volatile (erased when the power to the PC (erased when the power to the PC goes off).goes off).RAM comes in a variety of types, speeds, and RAM comes in a variety of types, speeds, and size. Types of RAM include:size. Types of RAM include:

DRAMSRAM

SDRAM

DDR SDRAMRDRAM

DDR-II SDRAM

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Memory: Other TypesMemory: Other Types

Cache memoryCache memory—fast memory chips located on or —fast memory chips located on or close to the CPU chip (L1, L2, and L3).close to the CPU chip (L1, L2, and L3).

RegistersRegisters—high speed memory built into the CPU.—high speed memory built into the CPU.

ROM (read-only memory)ROM (read-only memory)—non-volatile chips inside —non-volatile chips inside which data or programs are stored.which data or programs are stored.

FlashFlash memorymemory—non-volatile—non-volatile memory that can be memory that can be erased and reused. Used both within the PC and for erased and reused. Used both within the PC and for portable storage media (e.g digital cameras).portable storage media (e.g digital cameras).

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BusesBuses

BusesBuses are electronic paths are electronic paths that d that data ata travels around on a computer system.travels around on a computer system.

Internal buses Internal buses move data around within move data around within the CPU.the CPU.

Expansion busesExpansion buses establish links with establish links with peripheral devices.peripheral devices.– ISA, PCI, AGP, USB, FireWire.ISA, PCI, AGP, USB, FireWire.

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ExpansionExpansion Slots and Cards Slots and Cards

Expansion for desktop PCs.Expansion for desktop PCs.– ExpansionExpansion cardscards can be inserted into can be inserted into expansionexpansion slotsslots

on the motherboard.on the motherboard.– Some external devices can be plugged into existing USB Some external devices can be plugged into existing USB

or FireWire ports without adding another expansion card.or FireWire ports without adding another expansion card.

PC cardsPC cards—used with notebook PCs.—used with notebook PCs.

Expansion for handhelds and mobile Expansion for handhelds and mobile devices—can have proprietary, PC card, or devices—can have proprietary, PC card, or SDIOSDIO slot. slot.

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PortsPorts

Connectors to which devices Connectors to which devices can be attached.can be attached.

Common ports:Common ports: Serial

Parallel

SCSI

USB

FireWire

Network

– KeyboardKeyboard

– MouseMouse

– MonitorMonitor

– ModemModem

– MIDIMIDI

– IrDAIrDA

– GameGame

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How the CPU WorksHow the CPU Works

The CPU is a collection of electronic The CPU is a collection of electronic circuits and components.circuits and components.

Impulses from an input device passes Impulses from an input device passes through RAM and enters the CPU via a through RAM and enters the CPU via a system bus.system bus.

Within the CPU the impulses move Within the CPU the impulses move through the circuits and components to through the circuits and components to create new impulses.create new impulses.

Eventually, a set of electronic impulses Eventually, a set of electronic impulses leaves the CPU for an output device.leaves the CPU for an output device.

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Typical CPU ComponentsTypical CPU Components

Arithmetic/Arithmetic/logic unit logic unit (ALU)(ALU)

Control unit Control unit

RegistersRegisters

Prefetch unit

Decode unit

Internal cache

Bus interface unit

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The System Clock and the The System Clock and the Machine CycleMachine Cycle

The The system clocksystem clock synchronizes synchronizes the computer’s operations.the computer’s operations.The The machine cyclemachine cycle is the series of is the series of operations involved in the operations involved in the execution of a single, machine-execution of a single, machine-level instruction.level instruction.– FetchFetch– DecodeDecode– ExecuteExecute– StoreStore

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Making Computers Faster Making Computers Faster Now and in the FutureNow and in the Future

Speeding up your system todaySpeeding up your system today..

– Add more memory.Add more memory.

– Perform system maintenance.Perform system maintenance.

– Buy a larger or second hard drive.Buy a larger or second hard drive.

– Upgrade your Internet connection.Upgrade your Internet connection.

– Upgrade your video card.Upgrade your video card.

– Upgrade your CPU.Upgrade your CPU.

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Processor ComponentsProcessor Components

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Processor PerformanceProcessor Performance

Speed: processor clock set clock Speed: processor clock set clock speed (MHz or GHz )speed (MHz or GHz )

Word Size: number of bits the Word Size: number of bits the processor can manipulate at one processor can manipulate at one time (32-bit or 64-bit)time (32-bit or 64-bit)

Cache: high speed memory Cache: high speed memory (kilobytes)(kilobytes)

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Processor PerformanceProcessor Performance

Instruction Set Type: Instruction Set Type: – CISC (Complete instruction set computer)CISC (Complete instruction set computer)– RISC (Reduced instruction set computer)RISC (Reduced instruction set computer)

Processing Technique:Processing Technique:– Serial Serial – Pipelining Pipelining – ParallelParallel

Look at benchmark testing to Look at benchmark testing to comparecompare

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Memory Types Memory Types

Random Access Memory Random Access Memory (RAM)(RAM)

Virtual Memory Virtual Memory

Read-Only Memory (ROM)Read-Only Memory (ROM)

CMOSCMOS

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RAMRAM

Temporary (volatile) holding area for data, Temporary (volatile) holding area for data, application software and operating system application software and operating system Expensive chip set Expensive chip set CircuitryCircuitryLess storage than disk Less storage than disk Capacitors hold bits Capacitors hold bits Capacity measured in MB (64 - 512 MB)Capacity measured in MB (64 - 512 MB)Speed in nanoseconds Speed in nanoseconds Makes the most noticeable differenceMakes the most noticeable difference

Random Access MemoryRandom Access Memory

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RAM Types RAM Types

SDRAM SDRAM – Synchronous Dynamic RAMSynchronous Dynamic RAM– fast and cheap fast and cheap – DIMMS DIMMS – Most popularMost popular

RDRAM RDRAM – Rambus Dynamic RAMRambus Dynamic RAM– faster and more expensive faster and more expensive – RIMMs AND SO-RIMMsRIMMs AND SO-RIMMs

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Virtual Memory Virtual Memory

Disk based Disk based

Stores parts of programs and Stores parts of programs and data until they are needed by the data until they are needed by the processorprocessor

Works with RAM, but is slowerWorks with RAM, but is slower

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ROMROM

Permanent on a chip from Permanent on a chip from manufacturermanufacturer

Holds computer start up routine, Holds computer start up routine, which are hard-wired instructionswhich are hard-wired instructions– Only way to change is to replace ROM Only way to change is to replace ROM

chipchip

ROM BIOS (basic input/output ROM BIOS (basic input/output system)system)

Read-Only MemoryRead-Only Memory

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CMOSCMOS

Battery powered Battery powered More permanent than RAM; less More permanent than RAM; less permanent than ROM permanent than ROM Stores basic computer Stores basic computer configurationconfigurationMust be updated via CMOS setup Must be updated via CMOS setup program when configuration program when configuration changedchanged

Complementary Metal Oxide SemiconductorComplementary Metal Oxide Semiconductor

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Computer AdsComputer Ads

Includes: capacity, speed, and Includes: capacity, speed, and type of RAMtype of RAM

Also maximum RAM that can be Also maximum RAM that can be installedinstalled

Example:Example:

512 MB 400 MHZ SDRAM512 MB 400 MHZ SDRAM

capacity speed type

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Computer File CharacteristicsComputer File Characteristics

A collection of data on a storage A collection of data on a storage medium medium

Filename conventions Filename conventions

Filename extensionFilename extension

.txt.txt.txt.txt .jpg.jpg.jpg.jpg .exe.exe.exe.exe .doc.doc.doc.doc

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File Locations File Locations

Device drive letters A: C: D:Device drive letters A: C: D:

Directory Directory – Root Directory (C:\)Root Directory (C:\)– Subdirectory or folder (C:\Documents)Subdirectory or folder (C:\Documents)– File specification or Path File specification or Path – File size and dateFile size and date

Filename extensionFilename

Secondary folder

Primary folder

Drive letter

C:\Music\Reggae\Marley One Love.mp3 C:\Music\Reggae\Marley One Love.mp3

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Deleting FilesDeleting Files

Move to Recycle Bin in Windows Move to Recycle Bin in Windows

UndeleteUndelete

Empty Bin Empty Bin

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File Management File Management

Helps you organize your Helps you organize your computer files computer files

File/Save and File/Open File/Save and File/Open

Utilities like Windows Explorer or Utilities like Windows Explorer or MAC Finder MAC Finder – list, find, move, copy, delete, renamelist, find, move, copy, delete, rename

Save vs. Save AsSave vs. Save As

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Logical File Storage Logical File Storage

Filing cabinet or tree Filing cabinet or tree modelmodel

Metaphors to help Metaphors to help you visualize files on you visualize files on a storage device a storage device

Windows ExplorerWindows Explorer

Folder hierarchyFolder hierarchy

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Using Files Using Files

Start application (open Word)Start application (open Word)

Create file (type text)Create file (type text)

Save file (File/Save)Save file (File/Save)

Close file and application (File/Exit)Close file and application (File/Exit)

Open file again for editing (File/Open)Open file again for editing (File/Open)

Edit file Edit file

Save file (with changes, or rename)Save file (with changes, or rename)– File/SaveFile/Save– File/Save AsFile/Save As

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Organizing FilesOrganizing Files

On your computer:On your computer:– Give files and folders descriptive namesGive files and folders descriptive names– Keep file extensions so files open with Keep file extensions so files open with

correct softwarecorrect software– Group similar files into foldersGroup similar files into folders– Organize folders from top-down to make Organize folders from top-down to make

retrieval and backup easierretrieval and backup easier

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Physical File Storage Physical File Storage

Storage medium formatted Storage medium formatted into tracks /sectors into tracks /sectors electronicallyelectronicallyFile system keeps track of File system keeps track of names and file locations.names and file locations.– Windows uses FAT32 OR NTFSWindows uses FAT32 OR NTFS– Backup your index fileBackup your index file

Clusters: a group of sectors Clusters: a group of sectors that speeds up storage and that speeds up storage and retrievalretrieval

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Physical File Storage Physical File Storage

FAT (File Allocation Table) on FAT (File Allocation Table) on each disk keeps track of where each disk keeps track of where all files are and which clusters all files are and which clusters are empty. If damaged, you lose are empty. If damaged, you lose everything.everything.

Defragmentation Utility Defragmentation Utility rearranges files to be stored in rearranges files to be stored in contiguous clusters.contiguous clusters.

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Tech talk: How a processor Tech talk: How a processor executes instructions executes instructions

Instruction Set is built into Instruction Set is built into processor processor

Instructional Cycle is the execution Instructional Cycle is the execution of a single instructionof a single instruction

Fetch InstructionInterpret Instruction

Execute Instruction

Increment Instruction Pointer

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Digital Electronics Digital Electronics and File Managementand File Management

EndEnd