Information media are classified according to four parameters: the nature of the media, its purpose, the number of write cycles and durability.
By nature, information carriers are material-objective and biochemical. The first are those that can be touched, picked up, moved from place to place: letters, books, flash drives, disks, finds of archaeologists and paleontologists. The latter are of a biological nature and cannot be physically touched: the genome, any part of it - RNA, DNA, genes, chromosomes.
According to their intended purpose, information carriers are divided into specialized and general purpose. Specialized ones are those that are created only for one type of information storage. For example, for digital recording. And a broad purpose is a medium on which information can be written in different ways: the same paper, they can write and draw on it.
Depending on the number of recording cycles, the media can be single or multiple. The first one can record information only once, the second one - many times. An example of a single-use information carrier is a CD-R disc, while a CD-RW disc is already a multiple-use one.
The durability of a medium is the length of time it will store information. Those that are considered short-lived are inevitably destroyed: if you write something on the sand near the water, the wave will wash away the inscription in half an hour or an hour. And long-term ones can only be destroyed by an accidental circumstance - a library burns down or a flash drive suddenly falls into the sewer and lies in the water for many years.
Storage media are made from four types of material:
- paper, from which punched cards and punched tapes were previously made, and book pages are still made from;
- plastic for optical discs or tags;
- magnetic materials needed for magnetic tapes;
- semiconductors, which are used to create computer memory.
In the past, the list was richer: information media were made from wax, fabric, birch bark, clay, stone, bone and much more.
To change the structure of the material from which the information carrier is created, 4 types of influences are used:
- mechanical - sewing, threading, drilling;
- electrical - electrical signals;
- thermal - burning;
- chemical - etching or painting.
Of the media of the past, the most popular were punched cards and punched tapes, magnetic tapes, and then 3.5-inch floppy disks.
Punch cards were made from cardboard, then pierced in the right places so that the holes in the cardboard resembled a pattern, and information was read from them. And punched tapes appeared later, were made of paper and were used in the telegraph.
Magnetic tapes reduced the popularity of punched cards and punched paper tapes to zero. Such tapes could both store and reproduce information - play recorded songs, for example. At the same time, tape recorders appeared on which you could listen to both cassettes and reels. But the shelf life of magnetic tapes was modest - up to 50 years.
When floppy disks appeared, magnetic tapes became a thing of the past. Floppy disks were small, 3.5 inches, and could store up to 3 MB of information. However, they were sensitive to magnetic influences, and their capacity did not keep up with the needs of people - they needed media that could store much more data.
Now there are many such media: external hard drives, optical drives, flash drives, HDD boxes and remote servers.
external HDs
External hard drives are packaged in a compact case with one or two USB adapters and vibration protection. They can store up to 2 TB of information.
- easy to connect: no need to turn off the computer, mess with the power cable and sata - external hard drives have a USB0 interface, they are connected like regular flash drives;
- easy to transport: such devices are very small, you can easily take them on a trip, on a visit, you can even carry them in your pocket, and they are also quite easy to connect to a home theater;
- You can connect as many hard drives to your computer as there are USB ports.
- the information transfer speed is lower than over a sata connection;
- increased power supply is required, so a double USB cable is required;
- The case is plastic, which means that you can hear clicks or other noise during operation.
However, if the disk is in a rubberized metal case, then no one will hear the noise.
External hard drives come in portable (2.5) and desktop (3.5) types. The interface can be exotic - firewire or bluetooth, but these are more expensive, they are less common and they require an additional power supply.
Optical discs
These include CDs, LaserDiscs, HD-DVDs, MiniDiscs and Blu-rays. Information from such disks is read using optical radiation, which is why they are called that.
The optical disc has four generations:
- the first is laser, compact and mini disc;
- the second - DVD and CD-ROM;
- third - HD-DVD and Blu-ray;
- fourth - Holographic Versatile Disc and SuperRens Disc.
CDs are almost never used these days. They have a small volume - 700 MB, and the data is read from them by a laser beam. Compact discs were divided into two types: those on which nothing could be written (CD), and those on which it was possible to write (CD-R and CD-RW).
DVDs are similar in appearance to CDs, but have significantly more storage capacity. DVDs have several formats, the most popular being DVD-5 at 4.37 GB and DVD-9 at 7.95 GB. Such discs also come in R - for write once, and RW - for multiple write.
Blu-ray discs, being the same size as CDs and DVDs, hold much more data - up to 25 and up to 50 GB. Up to 25 are discs with one layer of information recording, and up to 50 - with two. And they are also divided into R - write once, and RE - write multiple times.
Flash drives
A flash drive is a very small device that has storage capacity of up to 64 GB or more. Flash drives are connected to a computer via a USB port; they have high read and write speeds and are made of plastic. Inside the flash drive is an electronic board with a memory chip.
The flash drive can be connected to a computer and TV, and if it is in Micro-CD format, then to a tablet or smartphone. Scratches and dust that could destroy optical discs are not scary for a flash drive - it is slightly susceptible to external influences.
HDD boxes
This is an option that allows you to use regular desktop computer hard drives as external ones. An HDD box is a plastic box with a USB controller where you can place a regular hard drive and easily transfer information directly, avoiding additional copying and pasting.
A HDD box is much cheaper than an external hard drive, and is very useful if you need to transfer a large amount of information or even almost the entire hard drive section to another computer.
Remote servers
This is a virtual way of storing data. The information will be on a remote server, which you can connect to from a computer, tablet, or smartphone, you just need to have access to the Internet.
With physical storage media, there is always a risk of losing data, since a flash drive, hard drive or optical drive may break. But with a remote server there is no such problem - the information is stored securely and for as long as the user needs it. In addition, remote servers have backup storage in case of unforeseen situations.
In this article we will skip storage drives. floppy disks, which have long become digital archaisms, as well as all types of CDs, almost never used due to their limited capacity (up to 4.7 GB - DVD discs, up to 124 GB - four-layer Blue-ray discs).
They are still used only as “resuscitation cases” to restore the functionality of the operating system or media for “native” drivers from the manufacturer of peripherals and other devices. Such discs, if they are rewritable, last about 1-3 years, and even less with intensive use.
Today, a potential buyer in any computer or virtual store will be offered to buy digital media of the following types: hard magnetic disks, external hard drives, flash drives(flash drives) and their derivatives – various memory cards for digital cameras and mobile devices. These most popular queries among the average consumer are confirmed by the results of research by marketers.
Hard magnetic disk
It is a high-tech product with all the corresponding consequences, namely: complexity of manufacture and relatively high price. The fragility and abundance of high-quality assembled moving parts will delight you for at least 5-7 years, and their capacity is steadily increasing every year. So, for example, buying hard drives in the CITY with a capacity of up to 5 terabytes (TB) is not difficult at all. It should be remembered that if the necessary information is stored on hard drives for a long time, then it must be rewritten every five years, or better yet, annually.
External hard drive
Essentially a mobile version of the previous one. Enclosed in a shockproof housing hard magnetic disk, which has a USB port for convenient connection to the device. The most popular line of their volumes: 1, 2, 3 and 4 TB. Disks equipped with a data protection system that looks like a regular combination lock are gradually gaining popularity. Their cost is slightly higher. If you need to store and process a lot of videos, work with the same information on different devices, you just need to buy an external drive.
Flash drives
The most popular and cheapest medium is a memory chip with a control controller and a USB connector. They vary widely in capacity (from 1 to 256 GB), but users often forget about one more main parameter of a flash drive - its speed. As a rule, the write speed of such drives is 5-7 MB/sec, and the read speed is 15-20 MB/sec. When choosing, you should pay attention to inscriptions such as “ultra fast” and “high-speed”. These devices have high speed. This type of media stops working mainly due to blocking of the control controller - they last for about 5 years, and it is not recommended to use them as archiving devices. A flash drive, like its “relative” - a memory card, always “dies” entirely.
The main types of memory cards are Memory Stick Pro, SD (Secure Digital), SD, SDHC and SDXC. MiniSD and MicroSD (or TransFlash) are their smaller versions, which are standard for most cell phones, communicators and GPS navigators.
It is convenient to use external media to store and transfer information from one computer to another. The storage media most often used are optical discs (CD, DVD, Blu-Ray), flash drives (flash drives) and external hard drives. In this article we will analyze the types of external storage media and answer the question “What to store data on?”
Now optical discs are gradually fading into the background, and this is understandable. Optical discs allow you to record relatively small amounts of information. Also, the ease of use of an optical disc leaves much to be desired; moreover, discs can be easily damaged and scratched, which leads to loss of readability of the disc. However, for long-term storage of media information (movies, music), optical discs are suitable like no other external media. All media centers and video players still play optical discs.
Flash drives
Flash drives, or simply “flash drives,” are now in greatest demand among users. Its small size and impressive memory capacity (up to 64GB or more) allow it to be used for various purposes. Most often, flash drives are connected to a computer or media center via a USB port. A distinctive feature of flash drives is their high read and write speed. The flash drive has a plastic case, inside of which an electronic board with a memory chip is placed.
USB flash drives
A type of flash drive includes memory cards, which with a card reader are a full-fledged USB flash drive. The convenience of using such a tandem allows you to store significant amounts of information on various memory cards, which will take up minimal space. In addition, you can always read the memory card of your smartphone or camera.
Flash drives are convenient to use in everyday life - transfer documents, save and copy various files, watch videos and listen to music.
external HDs
External hard drives are technically a hard drive housed in a compact case with a USB adapter and anti-vibration system. As you know, hard drives have impressive amounts of disk space, which, coupled with mobility, makes them very attractive. You can store your entire video and audio collection on an external hard drive. However, an external hard drive requires more power to operate optimally. One USB connector is not able to provide full power. This is why external hard drives have a dual USB cable. In terms of dimensions, external hard drives are quite small and can easily fit in a regular pocket.
HDD boxes
There are HDD boxes designed for use as a storage medium with a regular hard drive (HDD). Such boxes are a box with a USB controller to which the simplest hard drives of a desktop computer are connected.
This way, you can easily transfer information directly from your computer's hard drive directly, without additional copying and pasting. This option will be much cheaper than buying an external hard drive, especially if you need to transfer almost the entire partition of the hard drive to another computer.
Electronic storage media
The technology of recording information on magnetic media appeared relatively recently - approximately in the middle of the 20th century (40s - 50s). But several decades later - in the 60s and 70s - this technology became very widespread throughout the world.
Magnetic tape consists of a strip of dense material onto which a layer of ferromagnetic materials is sprayed. It is on this layer that information is “remembered”. The recording process is also similar to the process of recording on vinyl records - using a magnetic induction coil, instead of a special apparatus, a current is supplied to the head, which drives the magnet. Sound recording on film occurs due to the action of an electromagnet on the film. The magnetic field of the magnet changes in time with sound vibrations, and thanks to this, small magnetic particles (domains) begin to change their location on the surface of the film in a certain order, depending on the effect on them of the magnetic field created by the electromagnet. And when playing back a recording, the reverse recording process is observed: the magnetized tape excites electrical signals in the magnetic head, which, after amplification, go further to the speaker.
Compact cassette (audio cassette or simply cassette) is an information carrier on magnetic tape; in the second half of the 20th century, it was a common media carrier for sound recording. Used to record digital and audio information. The compact cassette was first introduced in 1964 by Philips. Due to its relative cheapness, for a long time (from the early 1970s to the 1990s) the compact cassette was the most popular recorded audio medium, however, starting from the 1990s,
was supplanted by compact discs.
Nowadays there are many different types of magnetic media in the world: floppy disks for computers, audio and video cassettes, reel-to-reel tapes, etc. But new laws of physics are gradually being discovered, and with them new possibilities for recording information. Just a couple of decades ago, many information carriers appeared based on new technology - reading information using lenses and a laser beam.
The development of material carriers of documented information generally follows the path of a continuous search for objects with high durability, large information capacity with minimal physical dimensions of the medium. Since the 1980s, optical (laser) disks have become increasingly widespread. These are plastic or aluminum disks designed to record and reproduce information using a laser beam.
Based on application technology, optical, magneto-optical and digital compact discs are divided into 3 main classes:
1. Discs that allow single recording and repeated playback of signals without the possibility of erasing them (CD-R; CD-WORM - Write-Once, Read-Many - recorded once, counted many times). They are used in electronic archives and data banks, in external computer storage devices.
2. Reversible optical discs that allow you to repeatedly record, play back and erase signals (CD-RW, CD-E). These are the most versatile disks, capable of replacing magnetic media in almost all applications.
3. Digital universal video discs DVD (Digital Versatile Disk) such as DVD-ROM, DVD-RAM, DVD-R with large capacity (up to 17 GB).
The name of optical discs is determined by the method of recording and reading information. The information on the track is created by a powerful laser beam that burns depressions on the mirror surface of the disk, and is an alternation of depressions and reflective areas. When reading information, the mirror islands reflect the light of the laser beam and are perceived as one (1), the depressions do not reflect the beam and, accordingly, are perceived as zero (0). This principle makes it possible to achieve a high density of information recording, and therefore a large capacity with minimal dimensions. A CD is an ideal means of storing information - it is ridiculously cheap, practically not subject to any environmental influences, the information recorded on it will not be distorted or erased until the disk is physically destroyed, and has a capacity of 700 MB.
Magneto-optical disk is an information carrier that combines the properties of optical and magnetic storage devices. The disk is made using ferromagnets. Magneto-optical disks, for all their advantages, have serious disadvantages: relatively low write speed, caused by the need to erase the contents of the disk before writing, and after writing - a read test; high energy consumption - to heat the surface, lasers of significant power are required, and therefore high energy consumption. This makes it difficult to use MO burner drives in mobile devices.
DVD (Di-vi-dim, English Digital Versatile Disc - digital multi-purpose disk) is an information carrier in the form of a disk, externally similar to a CD, but with the ability to store a larger amount of information due to the use of a laser with a shorter wavelength, than for regular CDs. The first discs and DVD players appeared in November 1996 in Japan and March 1997 in the USA. They were intended for recording and storing video images. It’s interesting that the first 3.95 GB DVD discs cost $50 apiece back then. Currently, there are six varieties of such disks with capacities from 4.7 to 17.1 GB. They are used to record and store any information: video, audio, data.
Working with information in our time is unthinkable without a computer, since it was originally created as a means of information processing and only now it began to perform many other functions: storage, transformation, creation and exchange of information. But before it took on its now familiar form, the computer underwent three revolutions.
The first computer revolution has come to an end
50s; its essence can be described in two words: computers appeared.
They were invented no less than ten years earlier, but it was at that time that serial machines began to be produced; these machines ceased to be an object of research for scientists and a curiosity for everyone else. A decade and a half later, no large organization could afford to do without a computer center. If you talked about a computer back then, you immediately imagined computer rooms filled with racks, in which people in white coats were thinking intently. And then the second revolution took place. Almost simultaneously, several companies discovered that the development of technology had reached a level where it was not necessary to build a computer center around the computer, and the computer itself had become small. These were the first minicomputers. But a little more than ten years passed, and the third revolution arrived - in the late 70s, personal computers appeared. In a short time, having gone from a desktop calculator to a full-fledged small machine, PCs took their place on the desktops of individual users.
At the very moment when the first computer processed a few bytes of data for the first time, the question immediately arose: where and how to store the results obtained? How to save calculation results, text and graphic images, arbitrary data sets?
First of all, there must be a device with which the computer will store information, then a storage medium is required on which it can be transferred from place to place, and another computer must also easily read this information. Let's take a look at some of these devices.
1. Punched card reader: designed for storing programs and data sets using punched cards - cardboard cards with holes punched in a certain sequence. Punch cards were invented long before the advent of the computer; with their help, very complex and beautiful fabrics were produced on looms, because they controlled the operation of the mechanism. Change the set of punched cards and the fabric pattern will be completely different - it depends on the location of the holes on the card. In relation to computers, the same principle was used, only instead of a pattern of fabric, holes were given commands to the computer or sets of data. This method of storing information is not without its drawbacks: - very low speed of access to information; - a large volume of punched cards for storing a small amount of information; - low reliability of information storage; - in addition, small circles of cardboard were constantly flying from the puncher, which fell on their hands, in their pockets, got stuck in their hair, and the cleaning ladies were terribly unhappy. People were forced to use punch cards not because they particularly liked this method, or because it had some undeniable advantages, no, it had no advantages at all, it’s just that at that time there was nothing else, there was nothing to choose from , I had to get out.
2. Magnetic tape drive (streamer): based on the use of a tape-type device and cassettes with magnetic film. This method of storing information has been known for a long time and is successfully used today. This is explained by the fact that a fairly large amount of information can be placed on a small cassette; the information can be stored for a long time and the speed of access to it is much higher than that of a punched card reader. On the other hand, the streamer is only suitable for accumulating, storing large amounts of information, and backing up data. It is almost impossible to process information using a streamer: a streamer is a sequential data access device: to get the 5th file we must scroll through four. What if you need a 7529?
3. Floppy magnetic disk drive (FMD - disk drive). This device uses flexible magnetic disks as a storage medium - floppy disks, which can be 5 or 3 inches. A floppy disk is a magnetic disk, like a record, placed in a cardboard envelope. Depending on the size of the floppy disk, its capacity in bytes varies. If a standard 5"25" floppy disk can hold up to 720 KB of information, then a 3"5" floppy disk can hold 1.44 MB. Floppy disks are universal, suitable for any computer of the same class equipped with a disk drive, and can be used for storing, accumulating, distributing and processing information. The drive is a parallel access device, so all files are equally easily accessible. The disadvantages include small capacity, which makes long-term storage of large amounts of information almost impossible, and the not very high reliability of the floppy disks themselves.
4. Hard magnetic disk drive (HDD - hard drive): is a logical continuation of the development of magnetic information storage technology. They have very important advantages: - extremely large capacity; - simplicity and reliability of use; - the ability to access thousands of files simultaneously; - high speed data access.
5. CDs and DVDs we have already reviewed.
But since the flow of information is only increasing, it is necessary to develop more and more new means and devices for its creation, processing, storage and transmission.
We have already discussed above storing data on CDs and DVDs. Despite their convenience, due to the need to use the largest possible amount of information, the process of replacing them is already beginning. In the coming years, flash memory will be a formidable competitor to hard drives in personal computing devices such as computers.
6. Flash memory is a type of solid-state semiconductor non-volatile rewritable memory.
Due to its compactness, low cost and low power consumption, flash memory is already widely used in portable devices that run on batteries and rechargeable batteries - digital cameras and camcorders, digital voice recorders, MP3 players, PDAs, mobile phones, and smartphones. In addition, it is used to store embedded software in various peripheral devices (routers, PBXs, communicators, printers, scanners). It does not contain moving parts, so, unlike hard drives, it is more reliable and compact.
The main weak point of flash memory is the number of rewrite cycles. It can be read as many times as desired, but it can only be written to such memory a limited number of times (usually about 10 thousand times). Despite the fact that there is such a limitation, 10 thousand rewrite cycles is much more than a floppy disk or CD can withstand. Flash memory is best known for its use in USB flash drives. Thanks to their high speed, capacity and compact size, USB flash drives are already displacing CDs from the market.
Information carrier (information carrier) – any material object used by a person to store information. This can be, for example, stone, wood, paper, metal, plastics, silicon (and other types of semiconductors), tape with a magnetized layer (in reels and cassettes), photographic material, plastic with special properties (for example, in optical disks) and etc., etc.
An information carrier can be any object from which it is possible to read (read) the information on it.
Storage media are used for:
- records;
- storage;
- reading;
- transmission (distribution) of information.
Often the storage medium itself is placed in a protective shell, which increases its safety and, accordingly, the reliability of storing information (for example, paper sheets are placed in a cover, a memory chip is placed in plastic (smart card), magnetic tape is placed in a case, etc.) .
Electronic media include media for single or multiple recording (usually digital) electrically:
- optical discs (CD-ROM, DVD-ROM, Blu-ray Disc);
- semiconductor (flash memory, floppy disks, etc.);
- CDs (CD – Compact Disk, CD), on which up to 700 MB of information can be recorded;
- DVDs (DVD - Digital Versatile Disk, digital universal disk), which have a significantly larger information capacity (4.7 GB), since the optical tracks on them are thinner and placed more densely;
- HR DVD and Blu-ray discs, the information capacity of which is 3–5 times greater than the information capacity of DVDs due to the use of a blue laser with a wavelength of 405 nanometers.
Electronic media have significant advantages over paper media (paper sheets, newspapers, magazines):
- by volume (size) of stored information;
- by unit cost of storage;
- on the efficiency and efficiency of providing relevant (intended for short-term storage) information;
- whenever possible, providing information in a form convenient for the consumer (formatting, sorting).
There are also disadvantages:
- fragility of reading devices;
- weight (mass) (in some cases);
- dependence on power sources;
- the need for a reader/writer for each media type and format.
Hard magnetic disk drive or HDD (hard (magnetic) disk drive, HDD, HMDD), hard disk is a storage device (information storage device) based on the principle of magnetic recording. It is the main data storage device in most computers.
Unlike a “floppy” disk (floppy disk), information in a hard disk drive is recorded on rigid plates coated with a layer of ferromagnetic material – magnetic disks. HDD uses one or more plates on one axis. In operating mode, the reading heads do not touch the surface of the plates due to the layer of incoming air flow that forms near the surface during rapid rotation. The distance between the head and the disk is several nanometers (about 10 nm in modern disks), and the absence of mechanical contact ensures a long service life of the device. When the disks do not rotate, the heads are located at the spindle or outside the disk in a safe (“parking”) zone, where their abnormal contact with the surface of the disks is excluded.
Also, unlike a floppy disk, the storage medium is usually combined with a storage device, a drive and an electronics unit. Such hard drives are often used as non-removable storage media.
Optical (laser) discs are currently the most popular storage media. They use the optical principle of recording and reading information using a laser beam.
DVDs can be double-layered (8.5 GB capacity), with both layers having a reflective surface that carries information. In addition, the information capacity of DVDs can be further doubled (up to 17 GB), since information can be recorded on two sides.
Optical disk drives are divided into three types:
- without recording capability - CD-ROM and DVD-ROM (ROM - Read Only Memory, read-only memory). CD-ROM and DVD-ROM discs store information that was written to them during the manufacturing process. It is impossible to write new information to them;
- with write once and read many times – CD-R and DVD±R (R – recordable, writable). On CD-R and DVD±R discs, information can be written, but only once;
- rewritable – CD-RW and DVD±RW (RW – Rewritable, rewritable). On CD-RW and DVD±RW discs, information can be written and erased many times.
Key characteristics of optical drives:
- disk capacity (CD – up to 700 MB, DVD – up to 17 GB)
- data transfer speed from the media to RAM - measured in fractions of the speed of 150 KB/sec for CD drives;
- access time – the time required to search for information on a disk, measured in milliseconds (for CD 80–400 ms).
Currently, 52-speed CD drives are widely used - up to 7.8 MB/sec. CD-RW discs are written at a lower speed (for example, 32x). Therefore, CD drives are marked with three numbers “read speed x CD-R write speed x CD-RW write speed” (for example, “52x52x32”).
DVD drives are also marked with three numbers (for example, “16x8x6”).
If the storage rules are observed (stored in cases in an upright position) and used (without causing scratches or contamination), optical media can retain information for decades.
Flash memory refers to electrically reprogrammable memory (EEPROM) semiconductors. Thanks to technical solutions, low cost, large volume, low power consumption, high speed, compactness and mechanical strength, flash memory is built into digital portable devices and storage media. The main advantage of this device is that it is non-volatile and does not require electricity to store data. All information stored in flash memory can be read an infinite number of times, but the number of complete write cycles, unfortunately, is limited.
Flash memory has its advantages before other storage devices (hard drives and optical drives), as well as its shortcomings, which you can familiarize yourself with from the table below.
| Drive type | Advantages | Flaws |
| HDD | Large amount of stored information. High speed. Cheap data storage (per 1 MB) | Large dimensions. Sensitivity to vibration. Noise. Heat dissipation |
| Optical disc | Ease of transportation. Cheap information storage. Possibility of replication | Small volume. You need a reader. Restrictions on operations (read, write). Low operating speed. Sensitivity to vibration. Noise |
| Flash memory | High speed data access. Economical energy consumption. Vibration resistance. Ease of connection to a computer. Compact dimensions | Limited number of write cycles |
