Storage Devices and Media Flashcards
What are storage devices?
Storage devices refer to the devices recording the data onto a storage media.
Why is backing storage needed in a computer?
Backing storage is needed because RAM is expensive and loses its contents when power is switched off. Backing storage provides non-volatile storage for programs and data that are not immediately required and serves as a backup in case the originals are lost or damaged.
What are magnetic backing storage media?
Magnetic backing storage media are those types of media where data is stored by writing a magnetic pattern onto the magnetisable surface of the media. Examples are magnetic disk and magnetic tape.
What is the difference between a magnetic hard disk and a magnetic hard disk drive?
A magnetic hard disk is the storage media itself, while a magnetic hard disk drive includes all components, such as read/write heads, that read and write data on the disk. The terms are often used interchangeably.
What are fixed hard disks and how are they used?
Fixed hard disks are non-portable storage devices consisting of magnetic disks and read/write heads. They store operating systems, application software, and user data, allowing fast access and storage. They are commonly used in PCs, laptops, and web servers for online processes, such as hosting websites. In networks, fixed hard disks serve as central storage in file servers, ensuring high-speed data access for multiple users.
Advantages and disadvantages of fixed hard disks.
Advantages -
1. A very high access speed
2. High transfer rate and high storage capacity
Disadvantages -
1. Fixed hard drives cannot be transferred between computers, unlike a portable hard disk
2. The hard disk cannot be taken out; raising security issues
What are portable hard disk and drives (HDD)?
Portable hard disks and drives are storage devices used to store and transport large files between computers. They have a large storage capacity, high access speed, and fast transfer rates, making them a preferred choice despite being more expensive than other removable media. They are also used for purposes beyond data backup, such as by professionals who work in multiple locations.
Advantages and disadvantages of portable hard disk and drives (HDD).
Advantages -
1. Large storage capacity meaning large files can be transferred between computers
2. Can be attached and used by any computer with a USB port
Disadvantages -
1. Size and portability makes them easier to steal
2. Their use with lots of different computers can mean there is a danger of viruses being transferred
What is magnetic tape?
Magnetic tape is a storage medium that records data on a plastic tape coated with a magnetic layer. It has a huge storage capacity and is mainly used for backing up data stored on hard disks. Magnetic tape provides serial access, meaning data must be accessed in sequence, which makes it slower than disk storage. Despite this, it is still used for large-scale backups, batch processing applications, and tasks like reading bank cheques, payroll processing, and stock control.
What is serial access?
Serial access is a method of retrieving data in which records are accessed in a sequential order, one after another, until the required data is found. It is useful for when every record on the tape needs to be accessed or stored in turn on the tape
Advantages and disadvantages of magnetic tapes.
Advantages -
1. Large storage capacity hence ideal for backup purposes where all data needs to be stored
2. Less expensive as compared to similar capacity magnetic hard disk drives
Disadvantages -
1. Low access speeds
2. In order to update data you have to make a new tape.
What are optical drives?
Optical drives are storage devices that use lasers to read data from optical disks like CDs and DVDs, which store data as a series of bumps.
What is a CD-ROM (Compact Disc Read-Only Memory)?
A CD-ROM (Compact Disc Read-Only Memory) is an optical storage disc used mainly for distributing software and music. It has a storage capacity of 700 MB, stores data as an optical pattern, and is read-only, meaning data cannot be modified or erased. While DVD drives can read CDs, CD drives cannot read DVDs.
Advantages and disadvantages of CD-ROM (Compact Disc Read-Only Memory).
Advantages -
1. One written, data cannot be erased; making it useful for the distribution of of software/music or backing up
Disadvantages -
1. Data transfer rate and access rate ae lower than for a hard disk drive
What is a DVD-ROM (Digital Versatile Disc Read-Only Memory)?
A DVD-ROM is an optical disc used mainly for distributing movies, computer games, and multimedia encyclopaedias. It is read-only, meaning data cannot be modified, and a DVD-ROM drive can also read CDs.
Advantages and disadvantages of DVD-ROM (Digital Versatile Disc Read-Only Memory).
Advantages -
1. High storage capacity, allowing full length movies to be stored
Disadvantages -
1. User cannot store files on the disk
2. Older computers may not have a drive capable of reading DVDs
What are CD-R (CD recordable) and DVD-R (DVD recordable)?
CD-R and DVD-R are optical discs that allow data to be written only once but not erased. They are ideal for archiving data, storing music, and recording TV programs. DVD-Rs, with their larger capacity, are especially useful for video storage.
What is CD-RW (CD rewritable)?
A CD-RW (Compact Disc Rewritable) is an optical disc that allows data to be written, erased, and rewritten multiple times. It is useful for updating files but has a slower transfer rate and access time compared to a hard drive.
Advantages and disadvantages of CD-RW (CD rewritable).
Advantages -
1. Rewritable so can be reused
2. The stored data can be altered
Disadvantages -
1. Data transfer rate is lower than for a MDD
2. Optical drives are more easily damaged than hard drives
What is DVD-RW (DVD rewritable)?
A DVD-RW (Digital Versatile Disc Rewritable) is an optical disc that can be written, erased, and rewritten multiple times. Also known as a DVD burner, it is ideal for storing data that needs frequent updates, with storage capacities ranging from 4.7 GB to 8.5 GB.
What is DVD-RAM (DVD random-access memory)?
DVD-RAM is a rewritable optical disc that allows fast and efficient data storage and overwriting, similar to RAM. With a typical capacity of 10 GB, it is commonly used for recording TV or films while simultaneously watching another program. It is faster and more reliable than DVD-RW, making it ideal for frequent data updates.
Advantages and disadvantages of DVD-RAM (DVD random-access memory).
Advantages -
1. Can read and write at the same time
2. Fast transfer and access rate
Disadvantages -
1. The devices are expensive as compared to others
What is Blu-Ray?
A Blu-ray disc is a high-capacity optical disk used for storing HD video and data with much larger storage capacity as compared to a DVD. With capacities of 25 GB, 50 GB, and 100 GB, it can store up to 2 hours of HDTV or 13 hours of standard definition TV. It also allows video playback while recording HD content. Blu-ray drives are now common in newer computers and are expected to become the standard for data storage.
What is solid-state backing storage?
Solid-state backing storage is a small, robust form of removable storage with no moving parts. It is rewritable, retains data without electricity, and includes devices like memory sticks, pen drives, and flash memory cards. It is robust because it has no moving parts and no removable media to damage.
What are memory sticks/pen drives?
Memory sticks or pen drives are portable storage devices with large capacities, ideal for storing photos, music, and data files. They are more expensive per GB than CDs, DVDs, or hard disks and consist of printed circuit boards enclosed in a plastic case.
Advantages and disadvantages of memory sticks/pen drives.
Advantages -
1. Small and lightweight
2. Can be used in all computers with a USB drive
3. Large storage devices
Disadvantages -
1. Small size = easily stolen
2. Often left in the computer by mistake and lost
3. Slower access speeds than a hard disk
What are flash memory cards?
Flash memory cards are small, thin, removable storage devices used for storing digital images in cameras. They are also used in computers, laptops, mobile phones, and MP3 players. Card readers in stores allow users to print photos directly from these cards.
What is a backup and why is it important?
A backup is a copy of data and program files kept for security. It protects against data loss due to corruption or destruction. Backups are often stored on removable media and taken off-site to prevent loss from fire or disasters. Many systems now automate backups, sending data to specialised storage companies via the internet.
