Storage

MemoryMemory

• RAM• Virtual Memory• Cache Memory• ROM• Motherboard

Memory:Memory: CPU’s Electronic ScratchpadCPU’s Electronic Scratchpad

Inside the System Unit

A

Module

• Memory Capacitieskilobyte (K or KB), megabyte (M or MB), gigabyte (G or GB)

• Random-Access Memory (RAM)store programs & data being usedeach memory location has an addressvolatilemore is better

Random Access Random Access MemoryMemory

Inside the System Unit

A

Module

In RAM, each memory location has an address, just like a post office box.

data

SIMMs

• you can increase your personal computer’s RAM by buying extra memory chips to install in your memory board or by purchasing a Single IN-Line Memory Module, SIMMs, a board that contains memory chips

• A SIMM board plugs into the computer’s main circuit board (cheaper and more efficient than single chips)

Virtual Memory

• enables a computer to execute programs that require more memory than is in RAM by dividing it into smaller pieces and use part of the hard disk as an extension

Cache Memory

• a specialize chip used with the computer’s memory

• faster more expensive than RAM chips

• stores most frequently used data and instructions

• newer PCs have cache (L1 and L2) within the microprocessor chip

• Usually L1 is smaller (128K) than L2 (can go up to 512K)

MemoryMemoryInside the System Unit

A

Module

• Read-Only Memory (ROM)non-volatileROM BIOS, flash BIOS

• CMOSused to store startup configuration optionseach memory location has an addressvolatile

Motherboard

• large circuit board which contains the microprocessor

• can hold expansion cards

• ports - parallel (printers) and serial (modems)

Plug and Play Plug and Play Inside the System Unit

A

Module

Microsoft and Intel created the Plug and Play (PnP) standard. This standard requires

special chips on the motherboard, compatible hardware that is expressly compatible with the Plug and Play standard, and a system

BIOS that supports Plug and Play.

Speed and Power

• speed is always associated with computers

• power is a derivative of speed plus other factors

• what make a computer go faster, there are several factors

• memory size, microprocessor speed, bus line size, cache

• Storage Concepts: The Basics

• Disks and Disk Drives: Putting a Spin on it

• Magnetic Tape: Still Useful

• Optical Storage Media: Seeing the Light

Data Storage

B

Module

Storage Concepts:Storage Concepts:The BasicsThe Basics

Data Storage

B

Module

Device Access speed Cost per MB

MEMORY Cache memory Fastest Highest

RAM memory Fast High

STORAGE Hard disk Medium Medium

CD-ROM disc Slow Low

Backup tape Very slow Lowest

Memory versus Storage

Disks & Disk Drives:Disks & Disk Drives:Putting a Spin on itPutting a Spin on it

Data Storage

B

Module

Before a disk can be used for

storage, it must be formatted

sectors

cluster tracks

Floppy DisksFloppy DisksData Storage

B

Module

A 3 1/2 inch disk

plastic casing

read/write openingsliding metal

shutter

write protection tab

linerdisk

spindle holesector hole

• How Hard Disks Work

• Storage Capacities

• Physical Performance

• Disk Caches

• Hard Disk Interfaces

• Hard Disk Maintenance

• Backup Procedures

• Removable Hard Disks

Hard Disks

B

Module

Data Storage

Magnetic Disks

• both electrical and mechanical

• FAT (File Allocation Table)

• speed

• storage capacity

Disk Drives

• interface to connect to motherboard

• IDE (Integrated Drive Electronics)

• SCSI (Small Computer System Interface)

Hard Disk InterfacesHard Disk InterfacesData Storage

B

Module

Interface type Maximum possible data transferrate (Mbps)

Original IDE 2.1

Standard SCSI 5.0

EIDE (ATA-2) 16.6

Ultra SCSI 20.0

Ultra ATA (Ultra DMA) 33.3

Ultra Wide SCSI 40.0

Removable Hard DiskRemovable Hard DiskData Storage

B

Module

Many new computers come equipped with a Zip drive, a removable hard disk that uses 100MB cartridges. The cartridges cost about $10 each.

Magnetic Tape:Magnetic Tape:Still UsefulStill Useful

Data Storage

B

Module

Quarter-inch cartridge (QIC) tape drives work with cartridges that can hold more than 10MB of

data

Optical Storage Media:Optical Storage Media:Seeing the LightSeeing the Light

Data Storage

B

Module

CD-ROM disks are prerecorded and cannot be altered. CD-ROM provides an excellent way to distribute large amounts of data at little cost.

• CD-ROM

• CD-R

• CD-RW

Optical Storage Media:Optical Storage Media:Seeing the LightSeeing the Light

Data Storage

B

Module

DVD-ROM drives are expected to replace CD-ROM drives as the standard personal

computer equipment in the near future

• DVD

• DVD-ROM

• DVD-RAM

Questions