SECONDARY STORAGESECONDARY STORAGE

Floppy Disk Floppy Disk 3.5 inch floppy disks3.5 inch floppy disks: :

Floppy DiskFloppy Disk

• Write protect notch:Write protect notch: allows you to pretent allows you to pretent a diskette being written toa diskette being written to

• Track:Track: Data is recorded in concetric circlesData is recorded in concetric circles

• Sector:Sector: Invisible wedge-shapes section Invisible wedge-shapes section used for storage reference purposes.used for storage reference purposes.

Floppy Disk Floppy Disk

Zip DisksZip Disks: are special disks with a capacity of : are special disks with a capacity of 100 or even 250 megabytes.100 or even 250 megabytes.

Super Disks: Super Disks: with a capacity of 120 with a capacity of 120 megabytes; the superdisk drive can also megabytes; the superdisk drive can also read 1.44 megabyte floppy disk.read 1.44 megabyte floppy disk.

HiFD disk: HiFD disk: Have a capacity of 200 Have a capacity of 200 megabytes; the superdisk drive can also megabytes; the superdisk drive can also read 1.44 megabyte floppy disk.read 1.44 megabyte floppy disk.

Hard DisksHard Disks

Hard DisksHard Disks:Thin but rigid :Thin but rigid metal platters covered metal platters covered with a substance that with a substance that allows data to be held in allows data to be held in the form of magnetized the form of magnetized spots.spots.

Optical DisksOptical Disks

• CD-ROMCD-ROM (read-Only) (read-Only)

• CD-R CD-R (for recording on once)(for recording on once)

• CD RW CD RW (reusable)(reusable)

• DVD-ROMDVD-ROM(read-Only)(read-Only)

• DVD-R DVD-R (for recording on once)(for recording on once)

• DVD RW DVD RW (reusable)(reusable)

Magnetic TapeMagnetic Tape

Quarter-Inchcartridge(QIC)Quarter-Inchcartridge(QIC)

Digital audio Tape(DAT)Digital audio Tape(DAT)

Digital Linear Tape(DLT) Digital Linear Tape(DLT)

Smart cardSmart card

Smard card Smard card looks like a credit card but looks like a credit card but contains microprocessor and memory contains microprocessor and memory chipchip

Optical cards Optical cards are plastic, laser-recordable, are plastic, laser-recordable, wallet-type cards used with an optical-wallet-type cards used with an optical-card reader. card reader.

Online Secondary storageOnline Secondary storage

The System UnitThe System Unit

• Sytem BoardSytem Board• MicroprocessorMicroprocessor• MemoryMemory• Expantion Slots and cardsExpantion Slots and cards• Bus linesBus lines• Ports and cablesPorts and cables

Electronic Data and Electronic Data and InstructionsInstructions

Data and instructions are presented electronically with Data and instructions are presented electronically with binary numbering system. Tree principal binary binary numbering system. Tree principal binary coding schemes arecoding schemes are

• ASCII:(Microcomputers) ASCII:(Microcomputers) Americam Standard Code Americam Standard Code for Informatin Interchangefor Informatin Interchange

• EBCDIC:(Large Computer) EBCDIC:(Large Computer) Extended Binary Coded Extended Binary Coded Decimal Interchange CodeDecimal Interchange Code

• UNICODE: UNICODE: International Languages(16 Bit) Apple International Languages(16 Bit) Apple IBMIBM

Electronic Data and Electronic Data and InstructionsInstructions

Bit:Bit:Each 0 or 1 is called a bit (binary digit)Each 0 or 1 is called a bit (binary digit)

Byte:Byte:A group of 8 bits calaled a byteA group of 8 bits calaled a byte

Kilo byte(KB) Kilo byte(KB) 1024 byte1024 byte

Megabyte(MB) Megabyte(MB) 1,048,576 byte1,048,576 byte

Gigabyte(GB) Gigabyte(GB) 1,073,741,824 byte1,073,741,824 byte

Terabyte(TB)Terabyte(TB)

Petabyte(PB)Petabyte(PB)

Sytem BordSytem Bord

System board is main circuit board in system System board is main circuit board in system unit. Mainboard offers slots or sockets for unit. Mainboard offers slots or sockets for removable components:microprocessor chip, removable components:microprocessor chip, RAM chips and various expantion cardsRAM chips and various expantion cards

MicroprocessorMicroprocessor

CPU is brain of the computer; it fallows the CPU is brain of the computer; it fallows the instructions of the software to manipulate data instructions of the software to manipulate data into information.Consist of two part.into information.Consist of two part.

• The control Unit: The control Unit: Tells the rest of the computer Tells the rest of the computer how to carry out program’s instructionhow to carry out program’s instruction

• Logic Unit: Logic Unit: Performs arithmetic and logical Performs arithmetic and logical operations and controls the speed of those operations and controls the speed of those operations.operations.

MicroprocessorMicroprocessor

Two principal architectures or designs fore Two principal architectures or designs fore microprocessors aremicroprocessors are

• CISC (Complex instruction set computing)CISC (Complex instruction set computing)

• RISC(reduced instruction set computing)RISC(reduced instruction set computing)

MemoryMemory

RAM (Random Access Memory)RAM (Random Access Memory)Provides the processor with temporary storage for programs Provides the processor with temporary storage for programs

and data. Physically memory chips are installed on and data. Physically memory chips are installed on Single in-line memory modules(SIMM)Single in-line memory modules(SIMM)Dual in-line memory modules(DIMM)Dual in-line memory modules(DIMM)Rambus in-line memory modules(RIMM)Rambus in-line memory modules(RIMM)ROM (Read only memory)ROM (Read only memory)PROM (Programmable read-only memory)PROM (Programmable read-only memory)cahce memorycahce memory

Expantion slot and CardsExpantion slot and Cards

Connect to system board to allow expantion of Connect to system board to allow expantion of sytem capabilities. sytem capabilities.

• Graphics cardsGraphics cards• Sound cardsSound cards• Modem cardsModem cards• Network interface cardsNetwork interface cards• PC card (PCMCIA)PC card (PCMCIA)

Bus LinesBus Lines

Data bus Data bus

• ISA bus(industry standard architecture):ISA bus(industry standard architecture):for for ordinary low-speedordinary low-speed

• PCI bus(Peripheral component interconnct):PCI bus(Peripheral component interconnct):for for higher-speedhigher-speed

• AGP bus(Accelerated graphics port): AGP bus(Accelerated graphics port): for even for even higher speed and 3D graphics higher speed and 3D graphics

PortPort

A port provides a direct link to the PC’s comman electrical busA port provides a direct link to the PC’s comman electrical bus• Serial Port: Serial Port: For Transmiting slow data over long distanceFor Transmiting slow data over long distance• Paralel Port: Paralel Port: For Transmiting fast data over close distanceFor Transmiting fast data over close distance• SCSI port: SCSI port: For transmitting fast data to up to seven devices For transmitting fast data to up to seven devices

in a daisy chainin a daisy chain• USB Port: USB Port: for transmitting data to up to 127 devices in a for transmitting data to up to 127 devices in a

daisy chaindaisy chain• 1394 Port 1394 Port • IrDA Port(Infrared): IrDA Port(Infrared): allows a computer to make a cableless allows a computer to make a cableless

connection with infrared-capable devices. connection with infrared-capable devices.