Computer storage
There are 2 different types of storage device. Primary/Main/Internal memory for instance ROM and RAM. Another one is Backing memory it job is to store data. For example, Harddisk/drive, USB, CD, SD card, DVD, external/portable hard drive and pen drive.
The difference between storage devices and media.
This can also be separate in to 2 types of computer storage instead of the 2 above, which are:
- Storage Media, they are hardware that stores data, but it can't read/write the data. For example thumb drive and CDs.
- Storage device, they are hardware that reads and write data to the storage media.
* Sometimes the storage device and the storage media are together like hard drive.
Accessing stored data
we refers to a collection of data that is stored in a computer as a file. files are organised into folders.
When we click ' Save ' application, copy data, burn files or drag and drop a file onto memory stick. All of these actions means that you are using storage devices- devices that can store and retrieve data.
Serial/ Sequential Access
A serial ( or sequential ) access storage device is one one that stores files one-by-one in a sequence. There are some non-computer serial access device that might be familiar to you is a VHS video tape.
Since the video is stored on a long piece of tape, when tv shows are recorded onto the tape. It will go on one-by-one in order.
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| Inside the hard disk/ drive |
Accessing stored data
we refers to a collection of data that is stored in a computer as a file. files are organised into folders.
When we click ' Save ' application, copy data, burn files or drag and drop a file onto memory stick. All of these actions means that you are using storage devices- devices that can store and retrieve data.
Serial/ Sequential Access
A serial ( or sequential ) access storage device is one one that stores files one-by-one in a sequence. There are some non-computer serial access device that might be familiar to you is a VHS video tape.Since the video is stored on a long piece of tape, when tv shows are recorded onto the tape. It will go on one-by-one in order.
If you want to watch a show in the VHS videotape, you have to rewind/fast-forward through all other shows until you reached the one you want. However this will take alot of time till you find the show, if you have gone to far back you will need to fast forward back.
The shows are only accessible in the order that you recorded them. This type of one-by-one storage and access is called serial access.
Direct / Random Access
A direct (or ‘random’) access storage device is one that
stores files so that they can be instantly accessed - there is no need to
search through other files to get to the one you want.
An example of a direct access device would be a DVD movie.
Unlike the VHS videotape movie, you can jump to any scene on a DVD.
All parts of the DVD are directly accessible. This type of
file storage is called direct access.
Some storage media can only store a very limited amount of data, here are some list of them.
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| A chart to compare how big it is for each of the storage media |
Even a very basic storage devices like a floppy disc can
storage over a megabyte of data - that's over 1 million letters or numbers!
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| WoW !! look how large is our modern storage devices in nowadays. |
TIPS
From the graph above, yes the colourful one.I have separate them in to 3 types;
Pink = Magnetic storage media and devices store data in the form of tiny magnetised dots. These dots are created, read and erased using magnetic fields created by very tiny electromagnets.
In the case of magnetic tape the dots are arranged along
the length of a long plastic strip which has been coated with a magnetisable
layer (audio and video tapes use a similar technology).
In the case of magnetic discs (e.g. floppy disc or
hard-drive), the dots are arranged in circles on the surface of a plastic,
metal or glass disc that has a magnetisable coating.
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| This is a magnified view of the dots on the surface of a CD |
Blue=Optical storage devices save data as patterns of dots that
can be read using light. A laser beam is the usual light source.
The data on the storage medium is read by bouncing the
laser beam off the surface of the medium. If the beam hits a dot it is
reflected back differently to how it would be if there were no dot. This
difference can be detected, so the data can be read.
Dots can be created using the laser beam (for media that is
writable such as CD-Rs). The beam is used in a high-power mode to actually mark
the surface of the medium, making a dot. This process is known as ‘burning’
data onto a disc.
Orange=The term ‘solid-state’ essentially means ‘no moving parts’.
Solid-state storage devices are based on electronic
circuits with no moving parts (no reels of tape, no spinning discs, no laser
beams, etc.)
The importance of data backup :
Storage devices and media may be used for transferring information from one place to another, adding additional storage space to a computer system or for selling musics, films, software and games as downloadable files or on discs.
Backups have two distinct purposes. The primary purpose is to recover data after its loss, be it by data deletion or corruption. Data loss can be a common experience of computer users. The secondary purpose of backups is to recover data from an earlier time. Therefore you won't need to re-type the document again.
This session will look at the importance of baking up data and the various methods available.
What should be backed up ?
In an ideal world, if the cost of storage space was no object, every system would be backed up.A backup copy of a home computer would include operating system, program files, personal documents, devices driver and everything else on you computer.Unfortunately you can't backed up everything since it might used up all the storage's capacity, therefore we must make a choice about what to backup.
Operating System can be re-installed from discs and program can be downloaded again, although they must cost you if you have lost the discs. However, photographs, video and your school report that you wrote could not be replaced without being re-created.
This is event more imortant for some organisations. Hospital and banks, for example they would store important, private information and if they are became lost or corrupted, then lives and business could be at risk.
Storage devices and media may be used for transferring information from one place to another, adding additional storage space to a computer system or for selling musics, films, software and games as downloadable files or on discs.
Backups have two distinct purposes. The primary purpose is to recover data after its loss, be it by data deletion or corruption. Data loss can be a common experience of computer users. The secondary purpose of backups is to recover data from an earlier time. Therefore you won't need to re-type the document again.
This session will look at the importance of baking up data and the various methods available.
What should be backed up ?
In an ideal world, if the cost of storage space was no object, every system would be backed up.A backup copy of a home computer would include operating system, program files, personal documents, devices driver and everything else on you computer.Unfortunately you can't backed up everything since it might used up all the storage's capacity, therefore we must make a choice about what to backup.
Operating System can be re-installed from discs and program can be downloaded again, although they must cost you if you have lost the discs. However, photographs, video and your school report that you wrote could not be replaced without being re-created.
This is event more imortant for some organisations. Hospital and banks, for example they would store important, private information and if they are became lost or corrupted, then lives and business could be at risk.
Extra
After reading that whole paragraph about backing up, you might wondered " why can we just back up everything" since it is much easier. However it would not be as easy as you think. When you are backing up everything it will used a lot of storage, this means that you will need to buy more storage and it's expensive. In addition the more capacity that is needed to be back up, the more time it takes.
This Prezi will explain the topic: Backup Solutions used today.
The Prezi below will be going to explain the backup model that are used today
NICE BLOG.