Information carrier. Classification of storage media
Information carrier- an object used by a person for long-term storage of information.
Optical discs
Disk-shaped storage media that can be read using a laser. Information is stored in the form of pits (pit - pit) and lands (land - earth) on a polycarbonate layer. If the light is focused between the pits (on the lens), then the photodiode registers the maximum signal. If light hits the pit, the photodiode registers a lower light intensity.
First generation
Compact Disc(CD)- developed by Sony and Phillips in 1979, used primarily for recording audio files. They have a volume from 650 MB to 900 MB. They are divided into CD-R(Compact Disc Recordable) for single recording and CD-RW(Compact Disc ReWritable) for multiple recording. Very common so far.
Second generation
Digital Multipurpose Disc (DVD)- was announced in 1995. Due to the denser structure of the working surface and the possibility of applying it to both sides of the disc, it significantly outperforms CDs in volume from (1.46 GB to 17.08 GB). They are also divided into DVD-R and DVD-RW, DVD+R and DVD+RW, which are more advanced than the previous two, and DVD-RAM, which allows a much greater number of rewrites than DVD+RW. The most common optical discs at the moment.
Digital Multilayer Disc(DMD) is an optical disc developed by D Data Inc. The disc is based on 3D optical data storage technology, meaning the laser reads from several work surfaces at the same time. DMDs can store 22 to 32 GB of binary information. DMDs are coated with proprietary chemicals that react when a red laser illuminates a specific layer. At this point, the chemical reaction produces a signal that will later be read from the disc. Because of this, drives can potentially hold up to 100 GB of data.
Fluorescent Layered Disc(FMD)- an optical media format developed by Constellation 3D that uses fluorescence instead of reflection to store data, which allows you to work according to the principles of large optical memory and have up to 100 layers. They allow you to accommodate up to 1 TB with the size of a regular CD. The pits on the disc are filled with fluorescent material. When coherent light from a laser is focused on them, they flash, emitting incoherent light waves of different wavelengths. As long as the disk is clear, light is able to pass through many layers unobstructed. Blank discs have the ability to filter laser light (based on wavelength and coherence) while achieving a higher signal-to-noise ratio than reflection-based discs. This allows you to have multiple layers.
third generation
Blu-ray Disc(BD)- an optical disc format used for high-density recording of digital data. The modern version of this disc was introduced in 2006. It got its name (blue ray - blue beam) by the technology of writing and reading using a short-wave blue laser, which made it possible to compact the data on the disk. Can hold from 8 to 50 GB.
High capacity DVD(HD DVD)- an analogue of the previous disk format with a capacity of up to 30 GB. Not supported since 2008 to avoid format wars.
High Capacity Multipurpose Layered Disk(HDVMD)- a format of digital media on optical discs, designed for storing high-definition video and other high-quality multimedia data. Up to 5 GB of data can be placed on one layer of an HD VMD, but due to the fact that the disks are multi-layered (up to 20 layers), their capacity reaches 100 GB. Unlike the previous two formats, it uses a red laser, which allows them to be read by drives that support CD and DVD discs.
fourth generation
Holographic Multipurpose Disc(HVD)- developing perspective format optical discs, which involves significantly increasing the amount of data stored on the disc compared to Blu-Ray and HD DVD. It uses a technology known as holography, which uses two lasers, one red and one green, combined into a single parallel beam. The green laser reads grid-encoded data from the holographic layer close to the surface of the disc, while the red laser is used to read auxiliary signals from the normal CD layer deep within the disc. Estimated capacity - up to 4 TB.
Hard disks
Hard disk drive- mass storage device, the main storage device in most computers. The principle of operation is based on a change in the magnetization vectors of the domains (a small section of the disk) of a magnetic disk under the action of alternating current in the coil at the end of the read head. Widespread due to the very high capacity and speed of operation. Many hard drives make noise. Household disks usually store information in the amount of up to 1 TB. There are also external hard drives connected to the computer via a USB port, they do not provide the same speed as internal ones, but provide the same large capacity. In addition, hybrid hard drives with flash memory elements are being developed.
Media using flash memory technology
Flash memory- a kind of semiconductor technology of electrically reprogrammable memory. The principle of operation of the semiconductor technology of flash memory is based on the change and registration of an electric charge in an isolated area ("pocket") of the semiconductor structure. The advantages of such media are compactness, low cost, mechanical strength, large volume, speed and low power consumption. A serious disadvantage of this technology is the limited lifetime of media.
USB flash drive- a storage device invented in 2000. Very popular due to ease of use and versatility. Can store information without electricity for up to 10 years.
Memory card- a storage device of various types used for certain devices, such as mobile phones, PDAs, car recorders. The most common standard is microSD.
ATTENTION!Here is a very abbreviated text of the abstract. The full version of the essay on informatics can be downloaded for free from the link above.
Types of storage media
Information carrier- the physical environment directly storing information. The main carrier of information for a person is his own biological memory (human brain). A person's own memory can be called working memory. Here the word "operational" is synonymous with the word "fast". Learned knowledge is reproduced by a person instantly. We can also call our own memory internal memory, since its carrier - the brain - is inside us.
Information carrier- a strictly defined part of a particular information system, which serves for intermediate storage or transmission of information.
The basis of modern information technologies- It's a computer. When it comes to computers, we can talk about storage media as external storage devices (external memory). These data carriers can be classified according to various features, for example, according to the type of execution, the material from which the carrier is made, etc. One of the options for the classification of information carriers is shown in Fig. 1.1.
The list of storage media in fig. 1.1 is not exhaustive. Some storage media will be discussed in more detail in the following sections.
Tape media
Magnetic tape- a magnetic recording medium, which is a thin flexible tape consisting of a base and a magnetic working layer. The working properties of a magnetic tape are characterized by its sensitivity during recording and signal distortion during recording and playback. The most widely used is a multilayer magnetic tape with a working layer of needle-shaped particles of magnetically hard powders of gamma-iron oxide (y-Fe2O3), chromium dioxide (CrO2) and gamma-iron oxide modified with cobalt, usually oriented in the direction of magnetization during recording.
Disk media
Disk media refer to machine media with direct access. The concept of direct access means that the PC can “access” the track on which the section with the required information begins or where new information needs to be written.
Disk drives are the most diverse:
- Floppy disk drives (FPHD), they are also floppy disks, they are also floppy disks
- Hard disk drives (HDD), they are also hard drives (popularly just "screws")
- Optical CD drives:
- CD-ROM (Compact Disk ROM)
- DVD-ROM
Floppy disk drives
Some time ago, floppy disks were the most popular means of transferring information from computer to computer, since the Internet was a rarity in those days, computer networks too, and CD-ROM readers were very expensive. Floppy disks are still used, but already quite rarely. Mainly for storing various keys (for example, when working with the client-bank system) and for transmitting various reporting information to state supervisory services.
Diskette- a portable magnetic storage medium used for multiple recording and storage of data of relatively small volume. This type of media was especially common in the 1970s and early 2000s. Instead of the term “floppy disk”, the abbreviation GMD is sometimes used - “floppy magnetic disk” (respectively, the device for working with floppy disks is called NGMD - “floppy disk drive”, the slang version is a flop drive, floppy, floppar from the English floppy-disk or in general " cookie"). Usually a floppy disk is a flexible plastic plate coated with a ferromagnetic layer, hence the English name "floppy disk" ("floppy disk"). This plate is placed in a plastic case that protects the magnetic layer from physical damage. The shell is flexible or durable. Floppy disks are read and written using a special device - a disk drive (floppy drive). A floppy disk usually has a write protection feature that allows you to grant read-only access to data. Appearance 3.5” floppy disk is shown in fig. 1.2.
Hard Disk Drives
As hard disk drives, hard disk drives are widely used in PCs.
Term Winchester originated from the slang name for the first 16 kV hard drive (IBM, 1973), which had 30 tracks of 30 sectors, which coincidentally coincided with the 30/30 caliber of the famous Winchester hunting rifle.
Optical drives
CD("CD", "Shape CD", "CD-ROM", "CD ROM") - an optical storage medium in the form of a disk with a hole in the center, information from which is read using a laser. The CD was originally created for digital audio storage (called Audio-CD), but is now widely used as a general purpose storage device (called CD-ROM). Audio CDs are formatted differently from data CDs, and CD players can usually only play them (you can, of course, read both types of CDs on a computer). There are discs containing both audio information and data - you can listen to them on a CD player and read them on a computer.
Optical discs usually have a polycarbonate or glass heat-treated base. The working layer of optical disks is made in the form of the thinnest films of fusible metals (tellurium) or alloys (tellurium-selenium, tellurium-carbon, tellurium-selenium-lead, etc.), organic dyes. The information surface of optical discs is covered with a millimeter layer of durable transparent plastic (polycarbonate). In the process of recording and playback on optical discs, the role of the signal converter is performed by a laser beam focused on the working layer of the disc into a spot with a diameter of about 1 μm. As the disk rotates, the laser beam follows along the disk track, the width of which is also close to 1 μm. The ability to focus the beam into a small spot makes it possible to form marks on the disk with an area of 1–3 μm. Lasers (argon, helium-cadmium, etc.) are used as a light source. As a result, the recording density is several orders of magnitude higher than the limit provided by the magnetic recording method. The information capacity of an optical disk reaches 1 GB (with a disk diameter of 130 mm) and 2-4 GB (with a diameter of 300 mm).
Widespread use as a carrier of information has also received magneto-optical CDs type RW (Re Writeble). Information is recorded on them by a magnetic head with the simultaneous use of a laser beam. The laser beam heats up a point on the disk, and the electromagnet changes the magnetic orientation of that point. Reading is performed by a laser beam of lower power.
In the second half of the 1990s, new, very promising carriers of documented information appeared - digital universal video discs DVD (Digital Versatile Disk) of the DVD-ROM, DVD-RAM, DVD-R type with a large capacity (up to 17 GB).
According to the technology of application, optical, magneto-optical and digital CDs are divided into 3 main classes:
- Disks with permanent (non-erasable) information (CD-ROM). These are plastic CDs with a diameter of 4.72 inches and a thickness of 0.05 inches. They are made using an original glass disc, on which a photo-recording layer is applied. In this layer, the laser recording system forms a system of pits (marks in the form of microscopic depressions), which is then transferred to replicated copy discs. Reading information is also carried out by a laser beam in the optical drive of a personal computer. CD-ROMs typically have a capacity of 650 MB and are used for recording digital audio programs, software for computers, etc.;
- Discs that allow one-time recording and multiple 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 drives. They are a base made of a transparent material on which a working layer is applied;
- Reversible optical discs that allow multiple recording, playback and erasing of signals (CD-RW; CD-E). These are the most versatile discs that can replace magnetic media in almost all areas of application. They are similar to write-once discs, but contain an operating layer in which the physical write processes are reversible. The manufacturing technology of such discs is more complicated, so they are more expensive than record-once discs.
Electronic media
Generally speaking, all the carriers considered earlier are also indirectly related to electronics. However, there is a type of media where information is stored not on magnetic / optical disks, but in memory chips. These microcircuits are made using FLASH technology, so such devices are sometimes called FLASH disks (popularly just a "flash drive"). The microcircuit, as you might guess, is not a disk. However, operating systems define storage media with FLASH memory as a disk (for user convenience), so the name "disk" has the right to exist.
Flash memory (eng. Flash-Memory) - a kind of solid-state semiconductor non-volatile rewritable memory. Flash memory can be read as many times as desired, but it can only be written to a limited number of times (usually about 10,000 times). Despite the fact that there is such a limit, 10 thousand rewrite cycles is much more than a floppy disk or CD-RW can withstand. Erasure occurs in sections, so you cannot change one bit or byte without rewriting the entire section (this limitation applies to the most popular type of flash memory today - NAND). The advantage of flash memory over conventional memory is its non-volatility - when the power is turned off, the contents of the memory are saved. The advantage of flash memory over hard drives, CD-ROMs, DVDs is that there are no moving parts. Therefore, flash memory is more compact, cheaper (including the cost of read-write devices), and provides faster access.
Data storage
Data storage It is a way of disseminating information in space and time. The method of storing information depends on its carrier (a book is a library, a picture is a museum, a photograph is an album). This process is as ancient as the life of human civilization. Already in antiquity, man was faced with the need to store information: notches on trees so as not to get lost while hunting; counting objects with the help of pebbles, knots; images of animals and episodes of hunting on the walls of caves.
The computer is designed for compact storage of information with the ability to quickly access it.
Information system- this is a repository of information, equipped with procedures for entering, searching and placing and issuing information. The presence of such procedures is the main feature of information systems that distinguish them from simple accumulations of information materials.
From information to data
People have different approaches to storing information. It all depends on how much it is and how long it needs to be stored. If there is little information, it can be remembered in the mind. It is not difficult to remember the name of your friend and his last name. And if you need to remember his phone number and home address, we use a notebook. When information is stored (stored) it is called data.
Data in a computer has a different purpose. Some of them are needed only for a short period, others must be stored for a long time. Generally speaking, there are quite a few "tricky" devices in the computer that are designed to store information. For example, processor registers, register cache, etc. But most of the "mere mortals" did not even hear such "terrible" words. Therefore, we will confine ourselves to consideration of random access memory (RAM) and permanent memory, which includes the information carriers we have already considered.
Computer RAM
As already mentioned, the computer also has several means for storing information. Most fast way to remember data is to write them into electronic microcircuits. This memory is called RAM. RAM is made up of cells. Each cell can store one byte of data.
Each cell has its own address. We can assume that this is like a cell number, so such cells are also called address cells. When a computer sends data to RAM for storage, it remembers the addresses where the data is placed. Referring to the address cell, the computer finds a byte of data in it.
RAM regeneration
An address cell in RAM stores one byte, and since a byte is made up of eight bits, there are eight bit cells in it. Each bit cell of the RAM chip stores an electrical charge.
Charges cannot be stored in cells for a long time - they "drain". In just a few tenths of a second, the charge in the cell decreases so much that data is lost.
Disk memory
Data carriers are used for permanent data storage (see section "Types of information carriers"). Compact discs and floppy disks are relatively slow, so most of the information that needs constant access is stored on the hard drive. All information on a disk is stored as files. There is a file system to control access to information. There are several types of file systems.
Data structure on disk
So that data can not only be written to HDD, and then read it again, you need to know exactly what was written and where. All data must have an address. Each book in the library has its own hall, rack, shelf and inventory number - this is, as it were, its address. The book can be found at this address. All data that is written to the hard disk must also have an address, otherwise they cannot be found.
File systems
It is worth noting that the structure of data on a disk depends on the type of file system. All file systems are made up of the structures needed to store and manage data. These structures typically include the operating system boot record, directories, and files. The file system also performs three main functions:
- Tracking used and free space
- Support for directory and file names
- Keeping track of the physical location of each file on disk.
- FAT (File Allocation Table)
- FAT32 (File Allocation Table 32)
- NTFS (New Technology File System)
- HPFS (High Performance File System)
- NetWare File System
- Linux Ext2 and Linux Swap
FAT
The FAT file system is used by DOS, Windows 3.x and Windows 95. The FAT file system is also available in Windows 98/Me/NT/2000 and OS/2.
The FAT file system is implemented using the File Allocation Table (FAT - File Allocation Table) and clusters. FAT is the heart of the file system. For security, FAT has a duplicate to protect its data from accidental erasure or malfunction. A cluster is the smallest unit of the FAT system for storing data. One cluster consists of a fixed number of disk sectors. The FAT records which clusters are in use, which are free, and where the files are located within the clusters.
FAT-32
FAT32 is a file system that can be used by Windows 95 OEM Service Release 2 (version 4.00.950B), Windows 98, Windows Me, and Windows 2000. However, DOS, Windows 3.x, Windows NT 3.51/4.0, earlier versions of Windows 95 and OS/2 do not recognize FAT32 and cannot load or use files on a FAT32 drive or partition.
FAT32 is an evolution of the FAT file system. It is based on a 32-bit file allocation table, which is faster than the 16-bit tables used by the FAT system. As a result, FAT32 supports much larger disks or partitions (up to 2 TB).
NTFS
NTFS (New File System Technology) is only available on Windows NT/2000. NTFS is not recommended for drives smaller than 400 MB because it requires a lot of space for system structures.
The central structure of the NTFS file system is the MFT (Master File Table). NTFS keeps many copies of the critical part of the table to protect against malfunctions and data loss.
HPFS
HPFS (High Performance File System) is a preferred file system for OS/2 that is also supported by older versions of Windows NT.
Unlike FAT file systems, HPFS sorts its directories based on filenames. HPFS also uses a more efficient directory structure. As a result, file access is often faster and space is used more efficiently than with the FAT file system.
HPFS distributes file data in sectors, not in clusters. To store a track that has sectors or is not in use, HPFS organizes the disk or partition into 8 MB groups. This grouping improves performance because the read/write heads don't have to return to track zero every time the OS needs to access information about the available space or the location of a needed file.
NetWare File System
The Novell NetWare operating system uses the NetWare file system, which was designed specifically for use by NetWare services.
Linux Ext2 and Linux Swap
The Linux Ext2 and Linux file systems were developed for the Linux OS (UNIX version for free distribution). File Linux system Ext2 supports a disk or partition with a maximum size of 4 TB.
Directories and file path
Consider, for example, the structure of the disk space of the FAT system, as the simplest.
The disk space information structure is a user-oriented external representation of disk space and is defined by such elements as volume (logical disk), directory (folder, directory) and file. These elements are used when the user communicates with the operating system. Communication is carried out using commands that perform file and directory access operations.
Information sources
- Informatics: Textbook. - 3rd revision. ed. / Ed. N.V. Makarova. - M.: Finance and statistics, 2002. - 768 p.: ill.
- Wolf V.K. Study of the functional structure of the memory of a personal computer. Laboratory practice. Tutorial. Publishing house of the Kurgan State University, 2004 - 72 p.
What did the first man know? How to kill a mammoth, bison or catch a wild boar. In the Paleolithic era, there were enough walls in the cave to record everything studied. The entire cave database would fit on a modest megabyte flash drive. In the 200,000 years of our existence, we have learned about the African frog genome, neural networks, and we no longer draw on rocks. Now we have disks, cloud storage. As well as other types of storage media capable of storing the entire library of Moscow State University on one chipset.
What is a storage medium
A storage medium is a physical object whose properties and characteristics are used to record and store data. Examples of storage media are films, compact optical discs, cards, magnetic disks, paper, and DNA. Storage media differ according to the principle of recording:
- printed or chemical with paint applied: books, magazines, newspapers;
- magnetic: HDD, floppy disks;
- optical: CD, Blu-ray;
- electronic: flash drives, solid state drives.
Data storages are classified according to the waveform:
- analog, using a continuous signal for recording: audio compact cassettes and reels for tape recorders;
- digital - with a discrete signal in the form of a sequence of numbers: floppy disks, flash drives.
The first media
The history of recording and storing data began 40 thousand years ago, when Homo sapiens got the idea to make sketches on the walls of their dwellings. The first rock art is located in the Chauvet cave in the south of modern France. The gallery contains 435 drawings depicting lions, rhinos and other representatives of the Late Paleolithic fauna.
To replace the Aurignacian culture in the Bronze Age, a fundamentally new type of information carrier arose - tuppum. The device was a clay plate and resembled a modern tablet. Recordings were made on the surface using a reed stick - a stylus. To prevent labor from being washed away by rain, tuppums were burned. All tablets with ancient documentation were carefully sorted and stored in special wooden boxes.
The British Museum has a tuppum containing information about a financial transaction that took place in Mesopotamia during the reign of King Assurbanipal. An officer from the prince's retinue confirmed the sale of the slave Arbela. The tablet contains his personal seal and records of the progress of the operation.
Kipu and papyrus
From the III millennium BC, papyrus began to be used in Egypt. Data is recorded on sheets made from the stems of the papyrus plant. The portable and lightweight form of storage media quickly supplanted its clay predecessor. Not only the Egyptians write on papyrus, but also the Greeks, Romans, and Byzantines. In Europe, the material was used until the 12th century. The last document written on papyrus is a papal decree of 1057.
Simultaneously with the ancient Egyptians, at the opposite end of the planet, the Incas invented the kippah, or "talking knots." Information was recorded by tying knots on spinning threads. Kipu kept data on tax collections, population. Presumably, non-numeric information was used, but scientists have yet to unravel it.
Paper and punch cards
From the 12th century to the middle of the 20th century, paper was the main data storage. It was used to create printed and handwritten publications, books, and mass media. In 1808, punched cards began to be made from cardboard - the first digital storage media. They were sheets of cardboard with holes made in a certain sequence. Unlike books and newspapers, punched cards were read by machines, not by people.
The invention belongs to an American engineer with German roots Herman Hollerith. For the first time, the author applied his offspring to compile mortality and birth statistics at the New York Board of Health. After trials, punched cards were used for the 1890 US Census.
But the idea of punching holes in paper to record information was far from new. Back in 1800, Frenchman Joseph-Marie Jacquard introduced punched cards to control a loom. Therefore, the technological breakthrough was the creation by Hollerith not of punched cards, but of a tabulation machine. This was the first step towards automatic reading and calculation of information. Herman Hollerith's TMC tabulating machine company was renamed IBM in 1924.
OMR cards
They are sheets of thick paper with information recorded by a person in the form of optical marks. The scanner recognizes marks and processes the data. OMR cards are used to compile questionnaires, tests with optional choice, bulletins and forms that must be completed manually.
The technology is based on the principle of compiling punched cards. But the machine does not read through holes, but bulges, or optical marks. The calculation error is less than 1%, so government agencies, examining bodies, lotteries and bookmakers continue to use OMR technology.
Perforated tape
A digital storage medium in the form of a long paper strip with holes. Perforated ribbons were first used by Basile Bouchon in 1725 to control a loom and mechanize the selection of threads. But the tapes were very fragile, easily torn and at the same time expensive. Therefore, they were replaced by punched cards.
Since the end of the 19th century, punched tape has been widely used in telegraphy, for entering data into computers of the 1950s-1960s, and as carriers for minicomputers and CNC machines. Now bobbins with wound punched tape have become an anachronism and have sunk into oblivion. Paper media have been replaced by more powerful and voluminous data storages.
Magnetic tape
The debut of magnetic tape as a computer storage medium took place in 1952 for the UNIVAC I machine. But the technology itself appeared much earlier. In 1894, Danish engineer Voldemar Poulsen discovered the principle of magnetic recording while working as a mechanic for the Copenhagen Telegraph Company. In 1898, the scientist embodied the idea in an apparatus called the "telegraph".
A steel wire passed between the two poles of an electromagnet. Recording of information on the carrier was carried out by means of non-uniform magnetization of electric signal oscillations. Voldemar Poulsen patented his invention. At the 1900 World Exhibition in Paris, he had the honor of recording the voice of Emperor Franz Joseph on his device. The exhibit with the first magnetic sound recording is still kept in the Danish Museum of Science and Technology.
When Poulsen's patent expired, Germany began to improve magnetic recording. In 1930 steel wire was replaced by flexible band. The decision to use magnetic stripes belongs to the Austrian-German developer Fritz Pfleimer. The engineer came up with the idea of coating thin paper with iron oxide powder and recording through magnetization. Using magnetic film, compact cassettes, video cassettes and modern storage media were created for personal computers.
HDDs
Winchester, HDD or hard drive is a hardware device with non-volatile memory, which means that information is completely saved, even when the power is turned off. It is a secondary storage device consisting of one or more plates on which data is recorded using a magnetic head. HDD are inside system block in the drive bay. They are connected to the motherboard using an ATA, SCSI or SATA cable and to the power supply.
The first hard drive was developed by the American company IBM in 1956. The technology was used as a new type of storage media for the IBM 350 RAMAC commercial computer. The abbreviation stands for "method of random access to accounting and control."
To accommodate the device at home, it would take an entire room. Inside the disc were 50 aluminum plates, 61 cm in diameter and 2.5 cm wide. The size of the storage system was equal to two refrigerators. Its weight was 900 kg. RAMAC capacity was only 5MB. Ridiculous number today. But 60 years ago it was regarded as the technology of tomorrow. After the announcement of the development, the daily newspaper of the city of San Jose released a report titled "Machine with Super Memory!".
Dimensions and capabilities of modern HDDs
A hard drive is a computer storage medium. Used to store data, including pictures, music, videos, text documents and any created or uploaded materials. In addition, contain files for the operating system and software.
The first hard drives contained up to several tens of MB. Constantly evolving technology allows modern HDDs to store terabytes of information. That's about 400 medium-length films, 80,000 songs in mp3 format, or 70 Skyrim-like computer role-playing games on one device.
Diskette
The floppy, or floppy disk, is a storage medium created by IBM in 1967 as an alternative to the HDD. Floppy disks were cheaper than hard drives and were intended for storing electronic data. Early computers did not have a CD-ROM or USB. Floppy disks were the only way to install new program or backup.
The capacity of each 3.5-inch floppy was up to 1.44 MB, when one program "weighed" at least one and a half megabytes. Therefore, the version of Windows 95 appeared immediately on 13 DMF diskettes. The 2.88 MB floppy disk appeared only in 1987. This electronic storage medium existed until 2011. Modern computers do not have floppy drives.
Optical media
With the advent of the quantum generator, the popularization of optical storage devices began. Recording is carried out by a laser, and data is read out due to optical radiation. Examples of storage media:
- Blu-ray discs;
- CD-ROM discs;
- DVD-R, DVD+R, DVD-RW and DVD+RW.
The device is a disk covered with a layer of polycarbonate. There are micro-pits on the surface, which are read by the laser during scanning. The first commercial laser disc appeared on the market in 1978, and in 1982 the Japanese company SONY and Philips launched CDs. Their diameter was 12 cm, and the resolution was increased to 16 bits.
Electronic media in the CD format were used exclusively for the reproduction of sound recordings. But at the time, it was cutting-edge technology, for which Royal Philips Electronics received an IEEE award in 2009. And in January 2015, the CD was awarded as the most valuable innovation.
In 1995, digital versatile discs or DVDs appeared, becoming the next generation of optical media. To create them, a different type of technology was used. Instead of red, the DVD laser uses shorter infrared light, which increases the storage capacity. Dual layer DVDs can store up to 8.5 GB of data.
Flash memory
Flash memory is an integrated circuit that does not require constant power to store data. In other words, it is a non-volatile semiconductor computer memory. Memory devices with flash memory are gradually conquering the market, displacing magnetic media.
Advantages of Flash technology:
- compactness and mobility;
- large volume;
- high speed of work;
- low power consumption.
Flash storage devices include:
- USB flash drives. This is the simplest and cheapest storage medium. Used for multiple recording, storage and transmission of data. Sizes range from 2 GB to 1 TB. Contains a memory chip in a plastic or aluminum case with a USB connector.
- Memory cards. Designed to store data on phones, tablets, digital cameras and other electronic devices. They differ in size, compatibility and volume.
- SSD. Solid state drive with non-volatile memory. This is an alternative to a standard hard drive. But unlike hard drives, SSDs do not have a moving magnetic head. Due to this, they provide quick access to data, do not emit squeaks, like HDDs. Of the shortcomings - the high price.
Cloud storage
Online cloud storages are modern information carriers, which are a network of powerful servers. All information is stored remotely. Each user can access data at any time and from anywhere in the world. The disadvantage is complete dependence on the Internet. If you don't have a network or Wi-Fi connection, you won't be able to access your data.
Cloud storage is much cheaper than its physical counterparts and has a large volume. The technology is actively used in the corporate and educational environment, development and design of computer software web applications. On the cloud you can store any files, programs, backups, use them as a development environment.
Of all the listed types of information carriers, the most promising are cloud storage. Also, more and more PC users are switching from magnetic hard drives on solid state drives and flash media. The development of holographic technologies and artificial intelligence promises the emergence of fundamentally new devices that will leave flash drives, SDDs and disks far behind.
To store and transfer information from one computer to another, it is convenient to use external media. The most commonly used storage media are optical discs (CD, DVD, Blu-Ray), flash drives (flash drives) and external hard disks. 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 a relatively small amount of information. Also, the convenience of using an optical disc leaves much to be desired, besides, discs can be easily damaged, scratched, which leads to loss of readability of the disc. However, for long-term storage of media information (movies, music), optical discs are more suitable than any other external media. All media centers and video players still play optical discs.
Flash drives
Flash drives or simply "flash drive" is now in the 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 through USB port. A distinctive feature of flash drives is a high read and write speed. The flash drive has a plastic case, inside which is placed an electronic board with a memory chip.
USB flash drives
A variety of flash drives include 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 a minimum of space. In addition, you can always read the memory card of your smartphone, 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 chassis 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, for optimal performance of the external hard drive more power is required. One USB connector is not able to provide full power. That's why external hard drives have a double USB cable. External hard drives are small in size and can easily fit in a regular pocket.
HDD boxes
There are HDD boxes designed to be used as a storage medium for a conventional hard disk drive (HDD). Such boxes are a box with a USB controller, to which the simplest hard drives of a desktop computer are connected.
Thus, you can easily transfer information directly from your computer's hard drive directly, without additional copy and paste. This option will be much cheaper than buying an external hard drive, especially if you need to transfer almost the entire hard drive partition to another computer.
Story
The need to exchange information, preserve written evidence of one's life, etc., has always existed with a person. Throughout the history of mankind, many information carriers have been tried. Since the carrier has a number of parameters, the evolution of the information carrier was determined by what requirements were imposed on it.
Ancient times
Ancient people depicted on the rocks the animals they hunted. However, coal, clay, chalk drawings were washed away by rain, and to increase the reliability of information storage, primitive artists began to carve the silhouettes of animals on the rocks with a sharp stone. Although the stone improved the safety of information, its recording and transmission speed left much to be desired. A person began to use clay for recording, which had the properties of a stone (preservation of information), and its plasticity, ease of recording, made it possible to increase the efficiency of recording.
The ability to write effectively contributes to the emergence of writing. More than five thousand years ago (the achievement of the Sumerian civilization, the territory of modern Iraq) writing on clay appeared (no longer drawings, but icons and pictograms similar to letters). The Sumerians squeezed out signs on wet clay tablets with a reed stick pointed in a “wedge” (hence the name - cuneiform) . The boxes (“folders”) contained large documents of dozens of clay “pages”.
Clay was heavy for large texts, the need for which was growing. Therefore, another carrier had to appear to replace it.
Egypt: papyrus
At the beginning of the third millennium BC. e. in Egypt, a new carrier appears, which has some improved parameters compared to clay tablets. They learned how to make almost real paper from papyrus (a tall herbaceous plant). From the word "papyrus" came the name of the paper in some languages: fr. papier- in French and German, English. paper- in English, Spanish papel- in Spanish, Belarusian. paper- in Belarusian. A bundle of papyrus leaves looks like the rays of the sun (the god Ra), the cut of the trihedral stem has the shape of a pyramid, so the plant was considered royal.
The disadvantage of this carrier was that over time it darkened and broke. An additional disadvantage was that the Egyptians imposed a ban on the export of papyrus abroad.
Asia
The shortcomings of information carriers (clay, papyrus, wax) stimulated the search for new carriers. This time, the principle “everything new is well forgotten old” worked: in Persia, defter was used for writing since ancient times - dried animal skins (in Turkish and related languages, the word “defter” still means a notebook), which the Greeks remembered.
The inhabitants of the Greek city of Pergamum (the first to adopt the ancient technology) improved the process of dressing skins and in the 2nd century BC. e. began the production of parchment. The advantages of the new medium are high reliability of information storage (strength, durability, did not darken, did not dry out, did not crack, did not break), reusability (for example, in a surviving prayer book of the 10th century, scientists found several layers of records made up and down, erased and cleaned, and with the help of X-rays, the oldest treatise of Archimedes was discovered there). Books on parchment - palimpsests (from the Greek παλίμψηστον - a manuscript written on parchment according to a washed or scraped text).
As in other countries, many different ways of recording and storing information have been tried in Southeast Asia:
- burning on narrow bamboo plates with fastening with cords into “bamboo books” (the disadvantage is that they take up a lot of space, low wear resistance of the cords);
- letter to:
- silk (the disadvantage is the high cost of silk),
- palm leaves sewn into a “book” (a paper sheet of a modern book is called so in memory of its palm prototype).
Due to the shortcomings of the previous carriers, the Chinese emperor Liu Zhao ordered that a worthy replacement be found for them, and one of the officials (Cai Lun) in 105 AD. e. developed a method for producing paper (which has not changed much to this day) from wood fibers, straw, grass, moss, rags, tow, plant waste, etc. Some historians claim that Cai Lun spied on the process of making paper from a paper wasp ( builds a nest from wood fibers chewed and moistened with sticky saliva). However, evidence has now been found that paper began to be made even earlier.
Europe
On the territory of Europe, highly developed peoples (Greeks and Romans) groped for their own ways of recording. Many different media are replaced: lead sheets, bone plates, etc.
Starting from the 7th century BC. e. the recording is made with a sharp stick - a stylus (as well as on clay) on wooden planks covered with a layer of pliable wax (the so-called wax tablets). Erasure of information (another advantage of this medium) was carried out by the reverse blunt end of the stylus. Such boards were fastened together in four pieces (hence the word “notebook”, since the ancient Greek τετράς translated from Greek means four).
However, inscriptions on wax are short-lived, and the problem of preserving records was very urgent.
America
In the 11th-16th centuries, the indigenous peoples of South America came up with the knot letter "kipu" (quipu translated from the language of the Quechua Indians - knot). From the ropes (rows of laces were tied to them) “messages” were compiled. The type, number of knots, colors and number of threads, their location and weave was the "encoding" ("alphabet") of the kipu.
Native American tribes of North America encoded their messages with small shells strung on cords. This type of writing was called "wampum" - from the Indian word wampam (short for wampumpeag) - white beads. The interlacing of cords formed a strip, which was usually worn as a belt. A combination of colored shells and drawings on them could compose entire messages.
Ancient Rus'
As a carrier, birch bark (the upper layer of birch bark) was used. The letters were cut through with writing (a bone or metal stick).
By the end of the 16th century, Rus' had its own paper (in Russian, the word “paper” most likely came from Italian, bambagia - cotton).
Types of storage media: (if asked!!!)
- Hard magnetic disk, ZhMD, HDD (hard disk, HD). It is used as the main stationary storage medium in computers. Large capacity, high speed access. Sometimes there are models with a removable disk that can be removed from the computer and hidden from the safe. This is what an HDD looks like.
- Floppy disk, GMD (floppy disk, FD) or floppy disk (diskette). The main removable media for personal computers. Small capacity, low access speed, but the cost is also low. The main advantage is portability.
- Laser CD (CD, CD-ROM). Large capacity, medium access speed, but there is no possibility of recording information. Recording is done on special equipment. This is what a CD drive looks like.
- Rewritable laser CD (CD-R, CD-RW). In some cases, only writing is possible (without rewriting), in others - also a limited number of data rewriting cycles. Same specifications as for regular CD.
- DVD. Similar to CD-ROM, but has a higher recording density (5-20 times). There are devices both for reading only and for writing (rewriting) DVD.
- Removable magnetic disk type ZIP or JAZZ. It looks like a floppy disk, but has a much larger capacity. This is how a ZIP disk and a drive for it look like.
- Magneto-optical or so-called. floppy disk. High capacity removable media. It looks like a magneto-optical disk and a drive for it.
- A tape cassette is a removable media for a streamer, a device specially designed for storing large amounts of data. Some computer models are adapted for recording information on ordinary tape cassettes. The cassette has a large capacity and a high write-read speed, but slow access to an arbitrary point on the tape. This is what a streamer and its cassettes look like.
- Punched cards are almost never used today.
- Perforated tape - currently almost never used.
- Cassettes and ROM chips (read-only memory, ROM). They are characterized by the impossibility or complexity of rewriting, small capacity, relatively high access speed, as well as high resistance to external influences. Usually used in computers and other electronic devices for specialized purposes, such as game consoles, control modules for various devices, printers, etc.
- Magnetic cards (stripes). Small capacity, transportability, the ability to combine machine-readable and plain text information. Credit cards, passes, IDs, etc.
- There are a large number of specialized media used in various rare devices. For example, magnetic wire, hologram.
The beginning of the beginnings (the evolution of information carriers)
XVIII century, France, the city of Lies. Textile master Basile Bouchon developed an elegant way to operate the loom. He first installed a roll of paper with holes made in the right places in the drum, after which the machine was able to reproduce the given pattern on the fabric. The invention made it possible to create very intricate weaves in automatic mode.
Here it is necessary to make a lyrical digression. Monsieur Bouchon was the son of an organ collector, these musical instruments work on a similar principle. Watching the work of his father, the young man came up with a technology that later turned the world upside down. Bouchon was the first to find a way to save commands on a separate medium with the possibility of replacement and reuse.
Time passed, the invention was further developed. First, Jean-Baptiste Falcon suggested using rectangular sections connected together instead of a roll of paper, then Jacques Wacanson improved the Bouchon-Falcon machine and made it automatic - human participation became unnecessary. By the way, the hands of the resourceful inventor belong to the world's first robots (robot flutist and duck). Unfortunately they were lost...
Worldwide success and fame came to the textile loom in 1801, when Joseph Marie Jacquard refined the technology once again. Why do we spend so much time talking about textile machines? The fact is that the Jacquard machine went down in history as a prototype of a computer. The mechanical design, of course, could not perform calculations, but the change in operating modes using punched cards formed the basis of programming technologies. In the context of our study, the method of saving commands on a carrier - paper (in the form of a punched card) is primarily interesting.
The next stop of our time machine is the 30s of the XIX century. The legendary mathematician, analytic philosopher and engineer Charles Babbage lived at this time. He is known as the first computer system architect. In 1822, he set about assembling the difference machine (computation automation). As conceived by Babbage, the machine must calculate the values of polynomials (polynomials) - this process took a lot of time and led to a large number of errors. Unfortunately, technical difficulties did not allow us to finish what we started.
Another Babbage project, the Analytical Engine, was to use punched cards to load a program. The inventor proposed a concept that was unheard of at that time: the program was drawn up on a paper punched card, installed in a machine, and it performed further actions. By the way, Ada Lovelace, who went down in history as the first programmer (in the 1970s, a programming language was named after her), helped create programs on punched cards. The ingenious idea could not be realized technically, only at the beginning of the 20th century, followers assembled an analytical engine according to Babbage's drawings.
The subsequent fate of data carriers is closely connected with the activities of Herman Cholerit. The next census was scheduled for 1890 in the United States. It took seven years to sort the results of the previous census. The government decided to optimize the process and try out the method proposed by Cholerite. Herman assembled a mechanism for reading and processing data recorded on a punched card. Using the new approach made it possible to complete the census in just 2.5 years.
Cholerit subsequently founded the Tabulating Machine Company and moved into sales. The business turned out to be profitable, in 1911 three more companies joined Herman to form the Computing Tabulating Recording Corporation, later renamed IBM.
By 1937, 32 machines at the IBM plant in New York were printing 5-10 million punched cards daily. Paper carriers were used everywhere and received the status of official documents. It is quite possible that punched cards would have gone down in history earlier, but the world was swept by the Second World War.
The tape era
At this time, the German engineer Fritz Pflumer created a magnetic film. The new carrier consisted of a thin layer of paper coated with an iron oxide powder. Pflumer sold the technology to AEG, which developed the world's first recording and playback device, the Magnetophon. The invention was carefully concealed until the surrender of Germany. Only in the early 1950s did magnetic tape break out of the country.
The innovation was picked up by record and television companies, who began to use tape for recording audio and video. The technology entered the world of computers in 1951, when Eckert-Mauchly released the UNIVAC I system. First of all, the computer got into the very bureau from which the history of IBM began - the Census Bureau. The magnetic film used in UNIVAC stored much more information than paper punched cards (10,000 punched cards = 1 reel of film). IBM did not stand aside and switched to a new type of media. To translate data from accumulated punched cards, Eckert-Mauchly and IBM introduced automatic converters.
Over time, the reels of film were wrapped in plastic boxes, and it is in this form that the “cassettes” have survived to this day. Film has become the de facto standard for recording data, video, and music.
The year was 1967, and IBM commissioned one of its engineers to develop a fast, compact media to send software updates to customers. David Noble's team has developed a flexible 8-inch (20 cm) 80 KB disc with write-once capability. The product was fragile and attracted a lot of dust. The modified version was wrapped in cloth, sealed in plastic and named FD23. The development was called “floppy” or “floppy disk” (the plastic packaging was thin and flexible, the carrier, as it were, “flapped its wings” when it was carried in the hands or shaken in the air - hence the name floppy, from the English word flop - to clap). Computers began to be equipped with floppy disk drives, but the path to success was not easy. The drive cost on a par with the computer itself, many continued to use film cassettes.
In 1972, Alan Shugart left IBM for Memorex. There, the engineer developed the Memorex 650, a 175 KB rewritable floppy disk. 8-inch floppy disks were further developed, bringing the volume up to 1000 KB.
However, 8 inches is a bit much for a mobile carrier. One day, two employees from Shugart Associates (founded by Alan Shugart) were sitting in a bar with An Wang of Wang Laboratories discussing the appropriate size for a floppy disk. Then the idea was born that a floppy disk should not be larger than a napkin (5.25 inches or 13 cm). The first samples of 5.25-inch floppy disks contained up to 98 KB of data. It was the first format that was not promoted by IBM. Over time, the size of the floppy increased to 1200 KB.
Optical technology wins
In 1979, Philips and Sony joined forces to create a revolutionary media based on optical technology. Research was started back in 1977 by Philips engineers, the first compact disc (CD) was born in 1982.
The recording method was based on the concept of heating the disk surface and forming dots on it at strictly defined intervals. A change of point to a flat surface means one, the absence of a change means zero. There are different legends about the size of the disk. They say that the diameter of 120 mm was not chosen by chance - exactly 74 minutes of audio is placed on a disc of this size with 16-bit encoding and a quality of 44.1 kHz. Well, 74 minutes is the duration of the 9th symphony of Ludwig van Beethoven ...
On August 17, an album by the Swedish band ABBA on CD was released at the Philips factory, at the same time players appeared on the market. By 1985, many record companies switched to CD, the prices of turntables were falling. No wonder, after all, a compact and lightweight disc weighing only 16 g had a thickness of 1.2 mm, while accommodating 74-90 minutes of high-quality sound.
It became clear that a CD can also be used to record data. In 1985, Sony and Philips developed the CD-ROM (Compact Disk Read Only Memory) standard, which allows data to be written to a disc. Only manufacturers in factories could record CDs. Despite the advantages of CDs, floppy disks remained popular.
The limitations and disadvantages of 5.25-inch floppy disks are obvious - the media is quite large and fragile, dirt easily penetrated the slots. Several companies have taken up the development of new standards. As a result, a variety of modifications appeared that were incompatible with each other. Sony solved the problem by introducing a relatively simple 3.5-inch floppy disk with a sliding shutter. Several companies, including Apple, supported Sony's development. Over time, the volume of floppy disks increased from 400 KB to 1.44 MB.
In 1991, Insite Peripherals entered the arena with Floptical. Engineers combined a standard floppy drive with an infrared diode for positioning the read head, which made it possible to increase the size of the floppy disk to 21 MB. At the same time, the drive could read ordinary floppy disks. The only drawback of Floptical is the connection via an expensive SCSI interface. Three years later, Iomega introduced Zip. Despite the similar format and dimensions of 3.5 inches, the new drives could not read regular floppy disks. Iomega introduced floppy disks with a capacity of 100, 250 and even 750 MB, but technical problems and the high cost of media did their job, no one remembers Zip anymore.
CDs became more popular than ever in the mid-1990s, when special formats for recording video (Video CD, Super Video CD) and photos (Photo CD, Picture CD) appeared. In the early 90s, Sony and Philips introduced CD-R (Compact Disk Recordable) - compact discs with the ability to record once. The next starting point is 1998, when the same pair of Sony and Philips developed the CD-RW (Compact-Disk Rewritable) disc. At the same time, the DVD format loomed on the horizon...
laser disc
The first optical storage medium was the so-called Laserdisk (LD), demonstrated by Philips and MCA in 1972. A huge 30-centimeter disk was tried to be pushed through as a replacement for VHS video cassettes. Laserdisk was an almost entirely analog media with digital audio, discs could hold up to 60 minutes of video. Typically, producers released movies on dual media.
Initially, the disk had to be turned over after 60 minutes to the other side. Then, technology manufacturers released players in which the reading head learned to move from one side to the other, while the viewer still had to wait for the reading to begin. Movies on two or more discs are a different story. Especially for such sets, Pioneer released a player with two trays.
The technology was renamed several times, but it was never saved. Players with LD support appeared until 2003. Now it is a rarity.
Instead of an epilogue
Everyone knows what happened next - recordable and rewritable DVDs, large flash drives, etc. appeared. Around 2000, the last stronghold of the era of magnetic tapes, video cassettes, finally went down in history. There is a fierce war going on in the media market right now between HD-DVD and Blu-ray, the next generation technologies. And in the future, we expect holographic discs with a capacity of 300 GB per disc...
