Flashcards in Book Two- Chapter Two- Digital Media Deck (8)
For what purpose are magnetic tapes most often used, and what features makes them ideal for this purpose:
A magnetic tape is a recording medium that consists of a thin plastic strip with a coatin of a fine magnetic material. It is generrally used for recording audio, video, and digital data.
The magnetic layer consists of a magnetic pigment suspended within a polymer binder. As the name imples, the binder holds the magnetic particles and tape backing together.
Data is stored in frames across the width of a tape. The frames are grouped into blocks, or records, which are separted by gaps.
A magnetic tape is a serial access medium. If someone wants to find a particular piece of data on a tape, the tape drive has to start at the beginning of the tape and search until it finds that data. However, large amts of information can be stored on a magnetic tape. This feature has made it an excellent choice for the regular backup of hard disks.
Describe the 3 sizes of floppy disks and their storage capacities:
A floppy disk is a small, portable magnetic disk that is used to store and transfer computer data. AKA floppy, or diskette. The access speed of a floppy disk is slow when compared to that of a hard disk. The storage capacity of a floppy disk is lower than that of a a hard disk, but floppies are not as expensive as hard disks.
The following are the basic sizes of floppy disks:
1. 8-inch: Created in 1971, this type of floppy consists of a magnnetic storage medium enclosed in a cardboard case. it is capable of storing up the 1 MB of data.
2. 5 1/4-inch: Created in 1974, this type of floppy has types capable of storing from 100KB to 1.2 MB of data.
3. 3 1/2-inch: Created in 1987, this type of floppy is enclosed in a rigid plastic envelope. It is also called a micro-floppy. Despite is smaller size, it stores a larger amount of data, generally between 720KB and 1.4 MB.
Describe the physical specifications of a Blu-ray disc:
Blu-ray is the next-generation optical medium patented by Sony. A blu-ray disc holds a large amt of data and is generally used to store high-definition video and audio. The laser used to read the data is focused on smaller areas, so more data can be stored on a disc that is the same size as a CD or DVD. Blu-ray discs are not readable on standard CD and DVD players and readers.
The following are speciications for Blu-ray:
*Recording capacity: 27 GB***********
*Laser wavelength: 405 nm (blue-violet laser)
*Lens numbercial aperture (NA): 0.85
*Data transfer rate: 36 Mbps**********
*Disc diameter: 120 mm
*Disc thickness: 1.2 mm
*Protection layer thickness: 0.1 mm
*Minimum pit length: 0.15 microns
*Track pitch: 0.32 microns
*Recording format: Phase change recording
*Tracking format: Groove recording
*Video recording format: MPEG2 video
*Audio recording format: AC3, MPEG1, and Layer 2
*Video and audio multiplexing format: MPEG2 transport stream
A single layer Blue-ray disc holds 27GB of data, and a dual-layer Blue-ray disc holds 50 GB of data. The format offers interactive features that allow users to connect ot the Internet and directly download subtitles and other movie features.
The following are the advantages of Blu-Ray:
*A user can record high-definition television (HDTV) without any quality loss
*A user can instantly skip to any spot on a disc
*A user can record one program on a disc, even if he or she is watching another one
*It generates playlists
*It edits or reorders the programs that are recorded ona disc
*It automatically searches for a unfilled space on a disc to avoid recording over a program
*A user can access the Web to download subtitles and other additional features
Compare and contrast the different kinds of compact discs
A CD compact disk is a polycarbonate plastic disc with one or more metal layers that is used for storing digital data. It is a standard medium for distributing large quantities of information in a dependable package. The diameter of a standard CD is 120 mm, and the diameter of a mini CD is 80 mm.
common types of CD's:
CD-ROM: Compact disc read-only memory- This is the most basic type of optical dic used with computers. The most common CD-ROM format holds 700 MB of data. When a user purchases a CD-ROM, it already has the data on it. A user cannot write new data to the disc.
CD-R: compact disc-recordable- This type of compact disc can be written to once. The user must have a CD recorder to write data to the disc. The CD recorder uses a laset to write data onto a blank data track.
CD-RW- compact disc-rewritable- This type of disc can be written to many times. As with a CD-R, a user must have a CD recorder to write data to the disc.
A CD drive is used to read data-whether it is audio, video, or application data-from a CD. A device is made up of the following main parts:
Drive motor- This rotates the disc at speeds between 200-500 rpm.
Laser and lens system- This reads the bumps on the disc.
Tracking mechanism- This moves the laser assembly to follow the spiral track.
Describe the physical structure of a DVD:
A DVD (digital versatile disc) or a digital video disc, is used for storing digital data and has a much higher storage capacity than a CD. A single-sided, single-layer DVD, DVD-5 can hold up to 4.7 GB of data and a double-sided, dual-layer DVD (DVD-18) can hold up to 17 GB of data. DVD's are commonly used to store movies, as they have enough space to hold video and multiple audio tracks. A DVD has the same dimensions as a CD. As with a CD, data are encoded in the form of small pits and bumps in the data track of a DVD.
A DVD is composed of many layers made of plastic, all adding up to a thickness of 1.2 mm. Each layer is formed through an injection-molding process using polycarbonate plastic. This forms a disc that contains microscopic bumps arranged in a single continuous spiral track of data. A thin aluminum (reflective) layer is applied to the polycarbonate layer to form the inner layers of the disc. A semi-reflective gold layer, used for the outer layers, allows the laser to focus on either the outer or inner layers. All the layers are coated with lacquer and compressed together under infrared light.
The label of a single-sided disc is printed on the non-readable side. The label of a double-sided disc is printed only on the non-readable area that is near the hole in the middle.
Every writable layer of a DVD consists of a spiral track of data. On single-layer DVD's, the track always spirals from the center of the disc to the outside edge. The extended bumps that make up the track are 320 nanometers wide, 400 nanometers long, and 120 nanometers high.
Discuss the uses of flash memory cards:
Flash memory cards are solid-state electronic flash memory data storage devices. They are used in digital cameras, cell phones, handheld devices, laptop computers, digital music players, video game consoles, and other electric devices. Each sector of flash memory can be erased and written to only a limited number of times. There are various types of flash memory cards all with different storage capacities and features.
Types of flash memory cards:
*SD- Secure Digital: GPS receivers, Bluetooth adapters, Ethernet adapters, FM tuners that are compatible with the SD standard
*CompactFlash- CF- older flash memory type
*Memory Stick (MS)- typically used with digital cameras, PDA's, and Playstation PSP
*MultiMedia Card (MMC)- SD is the successor of MMC
*xD-Picture Card (xD)- typically used in Olympus and Fujifilm digital cameras that provide certain photographic features such as a panoramic function.
*SM SmartMedia- used with PCC Card slots, CF Type II slots, and 3 1/2 floppy drives using adapters. It's larger size makes it impractical for use in most modern devices.
Describe the physical structure of a USB flash drive:
USB flash drives are NAND-type flash memory data storage devicces integrated with a USB 1.1 or 2.0 interface. They are small in size, lightweight, easily detachable, and rewritable. The storage capactities of
USB drives typically range from 8 MB to 64 GB. They are usually used for relatively quick, portable storage and have replaced the floppy disk for this purpose.
a USB flash drive consists of a small printed circuit board enclosed ina robust plastic or metal casing. The USB connector is usually protected by a detachable cap. A USB drive does not require batteries and instead gets it power from the device it is connected to. The access the data that is stored on a flash drive, a user must connect the drive to a USB port or USB hub attached to a computer or some other device. .
The following are the components of a USB flash drive:
*Male type-A USB connector
*USB mass storage controller
*Jumpers and test pins
*NAND flash memory chip