Storage Hardware Devices

Presented byHector Arreola

Valentin KifumbiKeely Ritchie-Boland

Storage Hardware

Hardware that saves data and programs

Nonvolatile Memory Memory that preserves data contents

without power Very reliable However, they do occasionally fail

Storage Hardware Devices

Magnetic Disks Hard Drives

Optical Disks CDs DVDs

Universal Serial Bus (USB) Storage Devices

Magnetic Disks

Use magnetism to store data on a magnetic surface

Hard Disks

A type of magnetic storage Records data onto platters coated

with a thin layer of magnetic material

Usually installed inside the computer's case

Hard Disks Cont.

Rotational delay The faster the disk spins, the shorter

the rotational delay Seek time

Determined by the make and model of the disk device

Optical Disks

Circular disk made of plastic and coated with a photosensitive material

Tiny pits store data Digital data (1’s and 0’s) read by

reflection

2 Different Optical Disks

CD Data layer is near the top of the disc

DVD Data layer is in the middle of the disc Can have data in two layers Have greater capacity and speed than

CDs

2 Different Optical Disks

Three different types of CDs & DVDs Read-only Memory (ROM) Recordable (R) Rewritable (RW)

CDs & DVDs can be used as storage but main use is entertainment

USB Storage Devices

A of flash memory storage Solid-state devices (no moving

parts) Read and write data electrically Memory stored on a small printed

circuit board Advantages over other storage

hardware devices

Magnetic Disks Long term nonvolatile data Rotation delay: Time it takes for the data

to rotate under the read/write head. Seek time: Time it takes to read/write arm

to position the head over the correct circle. Faster spinning disk means shorter time

delay. Channel: Common standard is the ATA-

100, transfers rate is 100MB per second

Optical Disks Some are read only memory CD: Maximum capacity of 700MB DVD: Maximum capacity of 4.7 GB

with a Transfer rate is 10 times faster

than CD. Today every computer should at

least have a CD-ROM

Hard Disks Capacity: The number of bites it can

hold. Its between 10 and 40 gigabytes. Data rate: The data rate is the number

of bytes per second that the drive can deliver to the CPU. Rates between 5 and 40 megabytes per second are common.

Seek time: The seek time is the amount of time between when the CPU requests a file and when the first byte of the file is sent to the CPU. Times between 10 and 20 milliseconds are common

Brand Names

- IBM- Toshiba- San Disk - Sony- Philips- Seagate- Macromedia

Price Range

Summary of Storage Capacity Media Good for Capacity