Storage Devices and Media Flashcards
What is magnetic tape?
Is a very thin strip of plastic which is coated in a magnetic layer (iron oxide)- it reads, writes and stores data
What are the uses of magnetic tape storage?
- Use in applications where batch processing is used (e.g. Clearing bank cheques, utility billing and producing pay slips
- Used as a backup media where vast amounts of data needs to be stored
- Used in long-term archiving of data
What are the advantages and disadvantages of magnetic tape?
Advantages:
- They are generally less expensive than the equivalent hard disk drive for high volumes of data
- Huge data storage capacities
- The data transfer rate is fast
Disadvantages:
- Very SLOW access times
- When updating, another tape is needed to store the final updated version
- They are affected by magnetic fields- a strong magnet can corrupt data stored on the tape
Define Data Transfer Rate.
Is the rate at which data can be sent from a storage device to a computer.
Define Data Access Time.
Is the time it takes to locate specific data stored on the storage media.
What are the uses of a Hard Disk Drive?
- To store the OPERATING systems, system software and working data/files
- Storing applications software
- Used in real-time systems e.g. Robots
- Used in file servers for computer networks
What are the advantages and disadvantages of Hard Disk Drives?
Advantages:
- They have a very fast data transfer rate
- Large memory capacities
Disadvantages:
- Fairly easily damaged
- Many moving parts which can affect their whole ability in general
- Their read/write operation can be quit noisy when compared to Solid-state drives (SSD)
How does a HDD work?
- Actuators are used to move the read/write heads
- A read/write arm swings the read/write head back and forth across the platter; the platter is rotating at up to 10,000 rpm (revolutions per minute)
- Each read/write head contains a tiny magnet which allows the data on the platter to be read
- Platters are made from glass which are coated in iron oxide
- There are two read/write heads per platter
- Data is stored in circular tracks- each track is broken into sectors
- When the computer wants to store new data it looks at the file allocation table to see which sectors are free and moves the head to that location
How is a portable HDD different to a normal HDD?
Portable external hard drives are smaller and lighter than desktop drives.
When are portable HDDs used?
Used for transport as well as backup and additional storage, portable hard drives rival the capacity
What are the advantages and disadvantages of a portable HDD?
Advantages:
- The data access time and data transfer rate are very rate
- They have a large memory capacity
- They can be used as method of transferring information between computers
Disadvantages:
- They can be easily damaged
- Data transfer rate is not as fast for fixed hard drives
Define latency.
Network latency is the delay in network communication. It shows the time that data takes to transfer across the network.
What do we mean by Optical Media?
Discs (CDs, DVDS and Blue Ray) that are read by lasers
What do the following mean:
ROM ?
RW ?
R ?
ROM- Read Only Memory
RW- Can be written to or read from many times
R- Wite once only
What is the typical capacity and uses of DVD-R and CD-R?
CD-R: 700 MB
DVD-R: 4.7GB
- Home recordings of music (CD-R) and films (DVD-R)
- Used to store data to be kept for later use or to be transferred to another computer
What are the advantages and disadvantages of DVD-R and CD-R?
Advantages:
- Cheaper medium than RW disks
- Once burned( and finalised) they behave like a ROM
Disadvantages:
- Can be only recorded once; if an error occurs then the disk has to be thrown away
- Not all CD/DVD players can read CD-R/DVD-R
What is the capacity and uses of CD-RW / DVD-RW?
CD-RW: 700 MB
- Used in CCTV systems
- Can be used as a backup device for files and data
- Used to record television programmes which can be recorded over, time and time again
What are the advantages and disadvantages of CD-RW / DVD-RW?
Advantages:
- Can be written over many times
- Can use different file formats each time it is used
- Not as wasteful as R format because the files, data can be added at a later stage
Disadvantages:
- Can be relatively expensive media
- Possible to accidentally overwrite data
What are is the capacity storage and the uses of CD-ROM/DVD-ROM?
650MB
- Permanent method of data storage
- Used to store music files and to store software
- DVD-ROM has much larger storage and is used in store films
What are the advantages and disadvantages?
Advantages:
They are less expensive than hard disk drive systems
Disadvantages:
- The data transfer rate and access time is slower than for hard disk drives
What are is the capacity storage and the uses of Blu-ray?
25-50 GB
- Home video consoles
- Storing and playing back movies
- For data storage in computers
What are the advantages and disadvantages of Blu-ray?
Advantages:
- Very large storage capacity
- Very fast data transfer rate
- The data access speed is also greater than with other typical media
- Automatically come with secure encryption code
Disadvantages:
- Relatively expensive discs
- Encryption problems
What is a Solid state drive (SSD)?
A solid-state drive (SSD) is a new generation of storage device used in computers. SSDs store data using flash-based memory, which is much faster than the traditional hard disks
What are the advantages of SSD compared to HDD?
- They are more reliable depending on how it is used
- They are considerably lighter- more portable and suitable for mobile phones
- They do not have to ‘get up to speed’ - you have to wait for them to start spinning and get up to operational speed before they work properly
- They have a lower power consumption (as there are no moving parts)
- They run much cooler than HDDs
- Because of no moving parts, they are very thin and more durable so do not break easily
- SSD data access time is much quicker compared to a HDD
- Data transfer speed for SSDs is also much faster than for HDDs
- Suitable for mobile devices as they have lower power consumption and no moving parts
- Not as affected to magnetic interference
What is another name for a pen drive?
Memory sticks
What are the disadvantages of SSD?
The longevity of the technology: most SSD storage devices are rated at only 20 GB. For this reason SSDs were not used in large servers e.g. write large operation take place everyday. as to take place everyday, more expensive per megabyte, megabyte, terabyte when compared to HDD
Give 2 uses of pen drives?
Transporting files between computers or using a backing store. Used as a security device to prevent software piracy
What are the advantages of pen drives?
Very compact and portable media
Very robust
Does not need additional software to work on most computers
They are not affected by magnetic fields
What are the disadvantages of pen drives?
Cannot write protect the data/files by making it ‘read only.’
Easy to lose
The user needs to be very careful when removing the stick from a computer otherwise it will corrupt the data on the memory stick and make it useless
List the 3 types of memory card.
SD - (secure digital card)
The SD card is a type of very small card with a very high-capacity memory. SD
cards are primarily used in portable devices such as digital video recorders,
digital cameras, audio players, smartphones and tablets.
xD - (extreme digital card) The XO card is a type of removable memory card designed for use in digital cameras. They can be written to or read from the camera or other suitable XO card reader (the card readers can often be attached to a computer to allow the memory card to be read directly). Cfast - (compactfast card). A (Fast card is a memory card format which was developed to allow solidstate technology to be used in a very small portable·device. It has no moving mechanical parts and does not need a battery to retain data. (Fast cards are primarily use
Give 4 uses of memory cards.
Storing photos on digital cameras, Used as mobile phone memory cards, Used in MP3 layers to store music files, Used as a backing store in hand-held computer devices
What are the advantages of memory cards?
Very compact
They are very durable because they are solid-state memories
They can hold large amounts of data
Digital devices are able to read and write memory card
What are the disadvantages of memory cards?
Expensive per gigabyte of memory when compared to hard disk drives
Have a lower storage capacity than hard disks
Have a finite life, regarding number of times they can be read from wand written to
Memory cards, specifically the micro SD card are the smallest deb=vices available; able to be lost or damaged
Not all computers come with memory card readers built in; have to purchase one
Why might optical media become obsolete?
Optical drives tend to take up a lot of space, making computers big and unattractive. Because of the advancement of better data management methods and storage technologies and popularity of streaming surfaces.
Why might DVD & Blu Ray players become obsolete?
Many televisions sets are now set up as smart televisions- this means that it is now possible to possibly stream on demand
