Storage Hardware Devices Presented by Hector Arreola Valentin Kifumbi Keely 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