SECONDARY STORAGE

Floppy Disk 3.5 inch floppy disks:

Floppy Disk Write protect notch: allows you to pretent a diskette being written to Write protect notch: allows you to pretent a diskette being written to Track: Data is recorded in concetric circles Track: Data is recorded in concetric circles Sector: Invisible wedge-shapes section used for storage reference purposes. Sector: Invisible wedge-shapes section used for storage reference purposes.

Floppy Disk Zip Disks: are special disks with a capacity of 100 or even 250 megabytes. Super Disks: with a capacity of 120 megabytes; the superdisk drive can also read 1.44 megabyte floppy disk. HiFD disk: Have a capacity of 200 megabytes; the superdisk drive can also read 1.44 megabyte floppy disk.

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

Optical Disks CD-ROM (read-Only) CD-ROM (read-Only) CD-R (for recording on once) CD-R (for recording on once) CD RW (reusable) CD RW (reusable) DVD-ROM(read-Only) DVD-ROM(read-Only) DVD-R (for recording on once) DVD-R (for recording on once) DVD RW (reusable) DVD RW (reusable)

Magnetic Tape Quarter-Inchcartridge(QIC) Digital audio Tape(DAT) Digital Linear Tape(DLT)

Smart card Smard card looks like a credit card but contains microprocessor and memory chip Optical cards are plastic, laser-recordable, wallet- type cards used with an optical-card reader.

Online Secondary storage

The System Unit Sytem Board Sytem Board Microprocessor Microprocessor Memory Memory Expantion Slots and cards Expantion Slots and cards Bus lines Bus lines Ports and cables Ports and cables

Electronic Data and Instructions Data and instructions are presented electronically with binary numbering system. Tree principal binary coding schemes are ASCII:(Microcomputers) Americam Standard Code for Informatin Interchange ASCII:(Microcomputers) Americam Standard Code for Informatin Interchange EBCDIC:(Large Computer) Extended Binary Coded Decimal Interchange Code EBCDIC:(Large Computer) Extended Binary Coded Decimal Interchange Code UNICODE: International Languages(16 Bit) Apple IBM UNICODE: International Languages(16 Bit) Apple IBM

Electronic Data and Instructions Bit:Each 0 or 1 is called a bit (binary digit) Byte:A group of 8 bits calaled a byte Kilo byte(KB) 1024 byte Megabyte(MB) 1,048,576 byte Gigabyte(GB) 1,073,741,824 byte Terabyte(TB)Petabyte(PB)

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

Microprocessor CPU is brain of the computer; it fallows the instructions of the software to manipulate data into information.Consist of two part. The control Unit: Tells the rest of the computer how to carry out program’s instruction The control Unit: Tells the rest of the computer how to carry out program’s instruction Logic Unit: Performs arithmetic and logical operations and controls the speed of those operations. Logic Unit: Performs arithmetic and logical operations and controls the speed of those operations.

Microprocessor Two principal architectures or designs fore microprocessors are CISC (Complex instruction set computing) CISC (Complex instruction set computing) RISC(reduced instruction set computing) RISC(reduced instruction set computing)

Memory RAM (Random Access Memory) Provides the processor with temporary storage for programs and data. Physically memory chips are installed on Single in-line memory modules(SIMM) Dual in-line memory modules(DIMM) Rambus in-line memory modules(RIMM) ROM (Read only memory) PROM (Programmable read-only memory) cahce memory

Expantion slot and Cards Connect to system board to allow expantion of sytem capabilities. Graphics cards Graphics cards Sound cards Sound cards Modem cards Modem cards Network interface cards Network interface cards PC card (PCMCIA) PC card (PCMCIA)

Bus Lines Data bus ISA bus(industry standard architecture):for ordinary low-speed ISA bus(industry standard architecture):for ordinary low-speed PCI bus(Peripheral component interconnct):for higher- speed PCI bus(Peripheral component interconnct):for higher- speed AGP bus(Accelerated graphics port): for even higher speed and 3D graphics AGP bus(Accelerated graphics port): for even higher speed and 3D graphics

Port A port provides a direct link to the PC’s comman electrical bus Serial Port: For Transmiting slow data over long distance Serial Port: For Transmiting slow data over long distance Paralel Port: For Transmiting fast data over close distance Paralel Port: For Transmiting fast data over close distance SCSI port: For transmitting fast data to up to seven devices in a daisy chain SCSI port: For transmitting fast data to up to seven devices in a daisy chain USB Port: for transmitting data to up to 127 devices in a daisy chain USB Port: for transmitting data to up to 127 devices in a daisy chain 1394 Port 1394 Port IrDA Port(Infrared): allows a computer to make a cableless connection with infrared-capable devices. IrDA Port(Infrared): allows a computer to make a cableless connection with infrared-capable devices.