Data And Program Storage Devices Computer Science Essay

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From the beginning, the rapidly developing computer industry continuing need that data and program storage devices (commonly known as mass storage devices) can also keep track of - computers, other elements (such as CPU, memory) development due - increased demand for storage capacity increases, and their performance (access to data and information to the media write speed) in the field. This must be implemented to achieve the security and economy not sacrifice on the altar of development.

Thesis in the background storage, the required equipment was created, and their development by presenting - especially in the last 10 years developments - I want to go far to try to determine what could be the future direction of development of the PC's built-in mass storage of and external, portable, removable With regard to media.

The data storage need and the digital data storage method by showing the moment of storage development from the beginning to the present, and perhaps the future of storage techniques are submitted, turn into account the background storage development trends, into the lyukkártyától holographic, or even the material fázisváltozásán, ie thermal állapotváltozásán based storage. The chronological presentation in addition, functional princi according to class, presented the tools and technologies that have been working with their expectations, and their way, but we present those that are different - but most non-technical, technological, but also business policy - proved to be the wrong reasons.

Then, the practical part - today even the most common - adattárolóról magnetic disk (or hard disk) try to find out the technical sense, there is still room for improvement. In practice, carried out measurements carried out specifically looking for the answer to theof performance of the technology, the nature of belonging - the speed increase due to - warming in check may be doubted whether the home computers (PCs) are available - and commonly used - cooling processes, or perhaps this may be what prevents this technology further development.


Second The Mass Storage

The computer processing of the data storage is unavoidable. Since the memory is "volatile" memory - that is, the machine switched off, the contents will be lost - and it is necessary for long-term storage devices. This serves the purpose of mass storage devices. The háttértárolón stored data can not perform operations, and the stored programs will not run. Use them, you must first load them into memory.

Modern mass storage of data to be read before the development was not an easy task. In addition to these there was a pleasure to use - for example, punch card reader and a streamer, had several major disadvantages. For example, the processor performance relative to the scanning speed was extremely slow and manual tape exchange can be very time consuming. The central unit in order to better use have called for greater efficiency when storage device.[1]

I think that is the biggest step towards the advancement of data storage on the physical and technical knowledge is, and that more information should be stored. For the first data storage means to mechanically, in addition to those data sources were relatively short-lived. These days are already in electronic circuits, mechanical parts are working together, which results in more precise operations. The man is not at rest. Always seek the right, so the storage to be improved. In this light, today's achievement of established solid state drives. In these devices have no moving parts, but also semiconductors. As a result, reduce the number of any failures. Not that kikophatna or megkarcolódhatna.

In short, as long as people will be able to think and build, while the data storage, they will be renewed. One discovery will not say what will be the representative of the next generation, can only point the way forward towards.


Third The Mass Storage GROUPING

The mass storage devices grouped according to several criteria. The group, for instance, that the media material. According to this distinguished paper or plastic, metal or plastic coated with magnetic media and semiconductor-based storage devices. But it is also possible that the operating principle of the classification that we can speak of mechanical, optical, magnetic, ormagneto-optical units, operating, or flash, or even holographic storage using the method from the background.

In my dissertation, and the operating principles - including - in chronological order of grouping chosen.

3.1 Paper or plastic-based mass storage devices

Paper or plastic-based mass storage devices comprise a hole card and its successor, the hole band. These were the first media that are no longer used, since processing is slow, cumbersome handling, easy to be damaged, and massive amounts of raw materials and demand. One advantage that may be used in an environment where magnetic media is not.

3.1.1 Hole Card

This is a medium, primarily data input device, where the information - in digital form - the position to represent the holes in a hard paper card.[2]

[1] . Figure COBOL program that contains a manual punch card

Already in the 18th century used punched cards and similar systems such as data processing or automation. Punched cards for the first time the U.S. census data processing, IBM's founder, Herman Hollerith used, intended mostly for repetitive processes were controlled. For example, there were punch card controlled looms, punch card where wood panels have been reported.

How it works: The punch card punch served in a punch card, but made of hand-punched for kártyalyukasztókat well. Then put the card is punched rávitték with the code on the cards, they are checked by a second machine. The second re-entered into the computer data, and if that card lyukasztásokkal already agreed to, the machine has been marked as checked. Served to facilitate the work - one part of the punch card - the card program, which for example, the card alphanumeric or numeric fields could also be defined. Later, the devices were also used to visualize the text can also punch card data content.

The hole cards played an important role in the creation of computers. The country's first relay computer, lime and a ( M Û E gyetemi W ámítógép) programs stored in punch cards. The computer system architecture, operation graduation, and control system developed by László Kozma. The machine design and construction began in 1955. From 1958 to nearly 10 years, used mainly in education, but also used to calculate a variety of industrial tasks.

In the '60-ies, beginning with the introduction of magnetic tape, punch card computing is gradually lost its importance. In the late 60s, IBM was planning to smaller and larger capacity cards are introduced, which ultimately did not take place because of the increased amount of computer punch cards to store information about the 80 years has become unfit. However, other areas continue to be applied to them, such as tokens or as a washing machine for storing programs. In this case the card is usually made of thin plastic sheeting. The development of electronics, specifically the so-called. chip design, this usage model is finished.[3]

3.1.2 Perforated tape

In the early mainframe tape data storage device was. The advantage was that the storage temperature and was not sensitive to the environment. Slowness, and low storage capacity due to outdated and took over the role of magnetic data storage devices. Robustness for a long time due to use of the machinery industry, NC and CNC machine tools to enter data because the environment is relatively well-oiled and dusty he could.

[4] . Figure Punched tape

The tape is relatively strong paper or plastic strips to which the data will be punched.

How it works: The holes in the tape punch tape reader mechanically or optically, as they are binary, that is interpreted as zero or as individual. Holes are punched in the tape longitudinal lines were located, they speak according to the number five, or eight-channel tape on.A small lyuksor information can be found in the holes between the media, which helps transfer the tape (mechanical tape readers). The tape is a small hole in a special climbing gear carried forward line.[4]

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It is worth mentioning that the M-3 at (Hungary's first fully electronic computer) to enter the data tape reader - as an external memory - was used. The M3 was built in 1957 by the end of autumn 1959, but will continue development of a number of tasks. The M-3 had a huge impact in the scientific and economic life. Destroyed in 1968, only a few sub-Drums and survived it.

The M-3 for the first time an operational repository mágnesdob memory was initially a kszó capacity (a 31-bit word), then further developed kszóra 1.6. 1960 mágnesdob new control unit was built, which is four - is addressed - could drum magnet attached to the machine. Later, the ferritmemória (kszó a storage capacity) and fit after the arrival of the drums worked as a back-up memory.

[5] . Figure M-3 memory mágnesdob

3.2 The magnetic data carriers

The punched cards or tape marginalization came to the front of the magnetic storage devices for recording. Two typical types of tape and disk.The serial-access tape storage tanks, which means that a search of all the data before the data must go through. The advantage of magnetic disk storage, in contrast to the tape does not stretch, so in a safe place to search for relevant information. Direct access, so it can not be read at the same time all the data, but some parts can be achieved.

Characteristics:

  • The amount of data stored in the size (capacity),


  • The velocity (speed), that is what the data-access time, and


  • The magnitude of the density.

Several types are available to both storage capacity and security are different.

Before you start to magnetic tape storage ismertetésébe, a few sentences I would like to introduce the M-3 has already said magnetic drum storage is. This repository is used by digital computers. The first magnetic drum storage was made ??in 1949 and 1024 word capacity. This container is a cylindrical surface of the magnetic layer is located. The information circular ring-shaped or cylindrical ingredients are recorded simultaneously. The writing and reading of the cylinder heads in parallel with a fixed component. The organization of information can be serial or parallel. Serial organization in the case of one set of bits of a ring road, parallel to the cylinder szervezésnél is located along a creator.[5]

3.2.1 Magnetic tape streamer

The magnetic tape (magnetic tape) in a wide magnetic surface with plastic tape. One of the oldest secondary storage device which looks and storage principle is similar to ordinary cassette tapes, but the essential difference is that analog recording instead of digital recording is used. the tapes, such as computer storage prices in the functioning of any of the 70's in Colombo on film can be seen. Then these tapes are very large amounts of data could be stored. (This is approx.: 108 bits, which was roughly 10 MB). Today, 800 GB of data, you can save with LTO-4 tape (see later this year marked the LTO-5 tape storage capacity of 1.6 TB)[6] .

[6] . Figure: The HP LTO-4 tape drive

Mágnesszalagnál constant size data blocks are located, which are separated by empty areas. The beginning and end of tape for data storage areas are not used for threading. The tape indicates the end of the aluminum strip.

[7] . Figure: Magnetic Tapes

Micro-computer environment, the scope of a single magnetic tape files to archive device (streamer) functions as a storage medium.[7]

It is interesting to mention that IBM has set a new record in magnetic tape capacity: not less than 35 TB of data can be recorded, also with their newly developed magnetic tape cassette, a square inch (6.45 cm2) can store up to 29.5 billion bits. This thirty-nine times surpassed the previous highest-density magnetic tape data storage capacity.[8]

The magnetic tape units ( str eamer , "adatáramoltató") data, are used to store programs in computing. The hard drive on the files, data, programs, we can reach directly from your computer, unlike the bands from which the discs are usually only used after the restore information.

The magnetic tape cassette is placed in a similar way to the cassette tape. The tape drive is an external unit, but it can also be built into the computer, the standard location.

[8] . Figure: Magnetic Tape Operation

The magnetic tape unit ("Drive") main functions:

  • Block write,

  • Read,

  • Delete

  • Move the tape.

The magnetic tape reels driven by the read-write heads in front. The direction of transmission, one of the spindles kilyuggatott rászívják, on the other air cushion of air created kifújással sliding. The high-speed access to the tape reels while vákuumkamrákba sucked.[9] It is worth mentioning the DAT (Digital Audio Tape Digital Audio cassette =) - drives. They are also used for magnetic tape storage, but greater capacity.

Tape storage is the simple matter of the present day computing and entertainment industry. True, not analog, but the digital version. Since sequential, it is more long-term archiving and storage devices vulnerable to security copy stored information is used. The entertainment industry is primarily used on DAT tapes.[10]

[9] . FigureDAT tape drives and

3.2.2 Floppy disk (floppy) drive

In 1971, IBM introduced the magnetic disk storage. The floppy disks (floppy disk FD) were the first portable operating magnetic storage media.

A few last words, address Janosi, Marcella , who is the 3.5 "floppy ancestor of the 3" floppy disk to the inventor of the tape. The floppy disk in the Budapest Radio Technology Factory (BRG) was developed. At the time, storage is widely used in the 8 "papírtasakos floppy disk. John's had the idea that your use of plates could be placed on a rigid cartridge. A patent in 1974, was registered. The invention news of people also came to negotiate, but the BRG prohibited any trial. Trial production began in 1981 MCD-1 under the name, but the inventor's request was not manufactured nor sold. Patent fees are not paid, so from then on Janosi creations everyone was free. First, IBM's interest in the floppy After including an 8inch-est, and the Japanese made ??the most similar Jánosiéra floppy.[11]

[10] . Figure BRG MCD-produced in a floppy tape

A long time ago - while the computers were not common in hard disk drives (hard drives) -, these low-capacity built in the computer data storage media.

This proves the first widely used PC operating system DOS, which is the name (Disk Operating System) suggests that we are dealing with a disk operating system.[12]

Plates were made in different sizes, the most common are 8, 3.5 and 5.25 inch (inch) in size were.

[11] . Figure 8 ", 5.25" and 3.5 "floppy

How it works: The information in a circular disk with a magnetic layer is stored. The magnetic disk, the data in concentric rings (bands) are stored. The information then can be read if the read-write head is set to the selected track.

These areas - despite the fact that less and less from outside to inside the circumference - the same number of bits stored information. It is possible that the outer circles along the storage capacity is not utilized fully, but the disk usage of this simple solution. The disk is formatted, reading and writing the read-write heads. They are not in contact with the rotating disk, but the rotation is formed during the run cushion. Upon reading of the surface magnetic states of perception, would be altered when you write them. The only moving radially read-write head stepper motor placed above the selected track.

[12] . Figure: Structure of the floppy

The disc is protected by a plastic cover environmental hazards (dust, mechanical effects, etc.). Against disrupting or removed, the disk can not be used. The floppy disk, you must have an in-and export unit, a floppy disk drive (FDD floppy disk drive).

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[13] . Figure Floppy Drive

Types of media disc OD and capacity, the following types are distinguished:

  • Early 8-inch drives - because of the size - units were still outside. Depending on the capacity of the disks was 160 to 500 kB.

  • 5.25 inches (1 inch = 2.54 cm) diameter discs:

    • SS SD (one-sided, single density) labeled disk capacity: 128 kB

    • The DS DD (two-sided, double density regulations) labeled disk capacity: 360 kB

    • The DS HD (two-sided, high density regulations) marked disk space: 1.2 MB

  • 3.5 inches (1 inch = 2.54 cm) diameter discs:

    • The DS DD (two-sided, double density regulations) labeled disk capacity: 720 kB

    • The DS HD (two-sided, high density regulations) labeled disk capacity: 1.44 MB

    • The DS ED (two-sided, extra density regulations) labeled disk capacity: 2.88 MB

The floppy diskette is no longer called a secure data container. Vulnerable, low capacity, slow data access, and a very short service life, but rather a short-term storage (was) should be used, for example, two independent data between computers.[13]

3.2.3 Zip drive

The zip drive breakthrough in data storage floppys in 1994 with its 100 MB and 250 MB, 750 MB and finally capacity. Barrier to the spread that was not compatible with the traditional floppy, and the price was high. Rather, small firms using daily data archiving.

[14] . Figure: Zip drive

The ZIP drive air pockets formed in the disk and the read / write head stone kept as a medium of high speed (3000 rev. / Min) spins. The floppy disk berezeghet such speed, or strike, so we need to solve the stability of the disk. The media in the ZIP cartridge mechanically recorded and only one head resting on the spring is about. 1.2 mm wide fit through a gap in the disk. Lane is one of the useful pre-recorded servo information. Each rotation of the drive 120 times to read the servo information, and thus controls the read / write head. The servo information should not be changed. If the media is a strong magnetic field, then in addition to the prescribed data is lost, the servo information is corrupted, and so the disk for data storage is no longer available.[14]

3.2.4 Superdisks

Superdisks (LS 120, A: drive): the 3.5 "floppy same size, 120-MB floppy disk to store data. The designers intend this tool to the PC world would have been used to replace the standard floppy disks, but experience has shown that highly sensitive to external influences, and is relatively slow and therefore not widely spread.[15]

[15] . Figure Superdisk drive and disk

3.2.5 Hard Disk Unit

The technique appeared to be the development of more and more limited capacity removable magnetic disks, it appeared permanently built into the computer's hard drive units, which are usually known as hard drives or hard disk drive has disk-nek/hard (HDD) is called. The "Hard" is the IBM 1973 and launched in 3340 a type of hard drive was the code name. In 1988, Conner produced a first down in the "high 3.5" hard drive, today's desktop machines are virtually the physical size of drives used.

Before I go any further, a few sentences, address the RAMAC onto the hard drives osére. The RAMAC was the 1956th on September 13 presented by IBM researchers. This device is a terrible amount, that is 5 megabytes of data could be stored for 15 pieces, a huge 24-inch plate. The data to a - plates in the radial direction, and each plate is moving vertically between - a mechanical arm on the read-write head treated. Was fast data retrieval, the read head of the band needed - regardless of which disk in place - one second he was able odatalálni. A huge advantage over the immediate, or random access to data that is unthinkable speed data access hole provided in the linear system tapes, magnetic tapes or punch card era.[16]

[16] . Figure RAMAC

The hard drives m tracking system: In one or more rigid metal plate is applied to the magnetic layer. The disk is formatted, reading and writing the read-write heads. The album moves at a constant speed by turning the head in front, so that no physical contact with him. Upon reading of the surface magnetic states of perception, would be altered when you write them. The only moving radially read-write heads to move the stepper over the selected cylinder. The head torsion springs push the plate toward the plate from air movement and rotation of lift on it, so the head - the result of two countervailing forces - the disk surface of a few tenth of a micrometer to fly.

The data storage is technically the same as the floppy disk (throat tracks and sectors on the disk), the difference in the number of tracks and sectors throat, and the density of the bits are. The higher data density to ensure that all equipment with the plates, between them and the read / write head with a dust-free air space is rare.[17]

[17] . Figure: The structure of hard

The large optical discs, flash memory and portable external HDDs appearance was common removable drawers (mobile racks) may be located using conventional hard drives.

[18] . Figure: Mobile Rack                  [19] . Figure: USB HDD

The USB ports appear in the spread of USB HDDs as well. They are smaller in size, but almost the same capacity with the built-in. Practical business people who attend all day, come to a laptop and the computer storage capacity of outgrown or do not want to store personal information about the company's device, but good, unless you have these documents. But I recommend to anyone who is not enough for a 32 or 64GB flash drive. The USB HDD has a higher power requirements than a simple flash drive has, therefore, two USB cable solved this problem by professionals. One cable for data exchange and the voltage going through the other side, however, only the voltage.

It is worth to mention some of the hard drive data density, since it greatly affects the storage capacity, size, price, and not least the performance.

The hard drive data density depends on two factors:

  • Sávsuruség: it shows that colonként (2.54 cm), number of tracks on the disk (TPI - Track Per Inch)

  • Linear density: the length of the bar shows the number of data bits stored.

Both of these factors depends on what size of data bits in a "spot" represents the disk. In spots the size of hard drives with the development of decreased continuously. The density increase beyond a certain storage spots for adatbiteket change the status of a small magnetic energy is sufficient, and it is a snow patch on the environment also can record. Then the state becomes unstable spots, and the technology becomes unsuitable for storing data. This phenomenon is superparamagnetic effects , and called the limit, and it is possible that this technology will soon reach the limit of manufacturers. It is also possible, however, that for a long time reduced the size of spots before the technology reaches this limit, since it is not difficult to know where he is.[18]

(Published is 2.5 inches, so mobile devices are intended for two pieces, each with 320 GB platters with 640 GB drive, which is 507 Gb / négyzethüvelykes data density can boast. This earlier 394 Gb / négyzethüvelykes compared to a very large step forward stretching.[19] )


3.3 Operating on the principle of optical storage media

The digital data storage is currently the most widely used method for optical storage.

The optical disc of plastic sheet created recesses, holes containing disks, which are wound in order to protect the plastic coated with a layer of a second.

The optical data storage systems in the sixties began to be developed. The aim was a large amount of data, eg. the storage device to record images, which are later read out by optical means, and also to find ways to reach a density at least as much information as - you know the most - magnetic storage devices.

Raised in the '80s, beginning to a media set up, which eliminates the previous magnetic active media problems (for example, the strip elongation resulting from the run-roughness on magnetism and heat to a high degree of sensitivity, the data storage secure less secure nature , in addition to providing a high volume of small capacity and relatively slow data access speed).

How it works: When recording data, we create small pits on the surface of the optical storage, these readings of the laser beam is scattered, but azadathordozó original surface of the layer is reflected back. Upon reading the reflected light sensors, and data are converted back. High storage density optical storage devices, this is due to the laser light from the primary storage magnetic storage surface is much smaller than the surface can be focused.[20]

The optical storage is usually the CDs and DVDs are the different types mean. They are suitable for multimedia applications, large-scale storage programs, but also to archive data.

3.3.1 CD

The CD recording of the 1980s, appeared very quickly and can spread to the world of digital audio technology. The Sony and Philips company in 1980, launched the joint development after.

[20] . Figure: A compact disk bottom side of the written

Compact Disc - compact disc, or light disk, optical operating principles, random-access storage device. This was the first based on an optical data storage operation. Factory-produced by extrusion, and may contain arbitrary data. Ideal for documents or images, or modification programs do not require storage.

CD plastic plate aluminum, or gold reflective layer is located in the Designed for those bits (light or dark pits, pit-s). The data read with laser light, reflected from the measured scattered light: dark points less light is reflected back. The data center of the disc outward spiral located. The reading of data using an infrared laser. 640-900 MB of disk space.

The CD-ROM drive

The difference in host-source standard-size discs to CD-ROM drive is a constant linear velocity or constant angular turns. The drive follows the focused laser head with high accuracy the written spiral track. The motor drive with a removable tray pull the carrier within the optical system above. The optical system is the primary task of the CD stored in hole information into digital signals. Equally important, the head of the spiral turning carefully follow prescribing. The data reading out the polycarbonate substrate from the laser diode is focused with the help of light, from the inside out spiral along the line. The digital data including the pits and flat areas situated in the Land given. The disk scan is based on light interference is present. The constant wavelength laser diode detects light reflecting coating pitrendszert. The scanning beam is reflected back to the island, it's a digital signal is present. The light beam is reflected from the pits have opposite phases, the reflected light intensity is lower, it will be a digital signal 0.[21]

[21] . Figure: The CD-ROM drive lens

The CD disc types:

The physical CDs are divided into two groups according to their structure. The user is free to once or several times CD-R, and users are read-only CD.

  • CD-ROM (Compact Disc Read Only Memory): read-only. Factory-produced by extrusion and manufacture, to be inscribed on the information. Maximum capacity of 650 MB, or standard music CDs in 74 minutes.

  • CD-Recordable (CD-R = Recordable CD), also known as WORM (Write Once Read Many) disk: write once, read many times but disk. The disk is prescribed information can not be modified, or deleted. Capacity of 650 to 800 MB.

  • CD-Rewritable (CD-RW = CD Rewritable) CD-RW content can be rewritten thousands of times. The data stored in the disk more kinds of reversible techniques are used, though more expensive, so these discs are more expensive than CD-Rs.

In addition, there are so-called magneto-optical ( MO CD = Compact Disc - Magneto-Optical) disks. These writable, erasable and rewritable discs. Recording technology combines magnetic recording write signal, and deletion of the advantages of laser optics high density writing. MO disks for data storage space in the magnetic behavior of light can take advantage of the conventional optical storage against that, only the laser light reflection and extinction properties are used.[22]

The CD is not "eternal life", but the data can be stored for decades without loss of quality, of course, only if you adhere to the strict quality standards.

[22] . Figure CD-R discs

[23] . Figure CD-RW

3.3.2 DVD

The increasing amount of data storage capacity requirements necessitated by more than the CD media is established. Thus was born the DVD (Digital Versatile Disc or Digital Video Disc). The high-capacity optical storage DVD (digital versatile disc), which is best motion picture, good sound quality, and is used to store data.

The CD is capable of multiple capacity. The increased capacity is due primarily to lower wavelength laser light is used which allows for smaller size data storage application. Thus, the bits on the disk are located in more densely than the CD case. In addition, multiple, one above the other layers can be used, each one slightly different wavelengths of light are able to repel.

[24] . Figure: The CD and DVD disc structure

DVD drive

The DVDs and small holes are gaps and spiral bands of the distance is smaller, thus reducing the lézerhullámhosszt smaller hot spot of the focus. The DVD-CD compatible DVD drive in the spirit of the lens system is used in two different units of the two optical drives to read. The holographic lens surface in the middle of a long cuts, edges of the lens - where there are no incisions - resulting in a shorter focus. Some drives can read ikerlencsés solution CD and DVD.[23] [25] . Figure: The DVD-ROM drive lens

The DVD disc on each side formed of two layers of storage. The two-layer disk, disk-DL (Dual or Double Layer), the usual DVD + (-) R discs capacity (theoretical) double the recording layer to another. The first disk, writable surface (bottom of the upstream side of the recordable disc) is a polycarbonate plastic layer protects, and the subsequent write an interface, the laser light from semi-translucent, metallic reflective layer is followed. Above this is also a metallic reflecting surface we find that this time will not let on to the laser beam. The polycarbonate substrate layer is followed by the inscription.

DVD types:

  • DVD -Video (movies stored);

  • DVD -Audio (audio area)

  • DVD -ROM (data, compressed, read-only): high-capacity CD-ROM's successor, at least 4.7 GB of storage space. The first applications in digital video files (movies) are stored. Pre-written, so they are written to home is not possible.

  • DVD -RAM (data, direct access, multiple writable). The DVD - RAM is a bit out of the line. Separate storage is that due to the longer reading device can be different than the others. Per can hold 4.7 GB.

[26] . Figure: DVD-RAM, which can be recognized "checkered ságáról"

The DVD - R and + R discs can only write once, while the - RW and + RW discs can be written several times. There were mini DVD + R discs (80 mm in some), which is about 1.5 GB capacity.

[27] . Figure: DVD-R and DVD-RW

The capacity of DVD discs depends on the number of pages and layers.

The DVDs are four basic types are distinguished:

  • DVD5 : DVD discs are the simplest, single-sided, single layer disc capacity of 4.7GB.

  • DVD9 : single-sided, dual-layer discs, 8.5 GB capacity.

  • DVD10 : Double sided pages per single layer DVD disc has a capacity of 9.4 GB.

  • DVD18 : double-sided, dual layer DVD disc per side, has a capacity of 17 GB.[24]

Life of an ordinary DVD, good housing conditions between 10-15 years. It is worth being protected from light, cool, fog-free place to keep them. There are archival-quality DVDs, they have a longer lifetime (100 years). Goods multiple of the normal DVD (5/6-szorosa).

3.3.3 HD DVD and Blu-ray

Further progress in increasing the density of the HD DVD and Blu-ray discs.

HD DVD

HD DVD may be composed of up to three layers. Each layer 15 GB of storage capable of high definition content, HD DVD discs so the maximum capacity of 45 GB. HD DVD discs scratch resistant. It is backward compatible with DVD discs, DVD discs still play content stored on the HD DVD players. The HD DVD data is stored as a series of microscopic holes - the same as DVD technology - which is a long spiral form on the disc.

The red-laser DVD technology, unlike the HD DVD blue-laser technology is used for greater storage capacity. Shorter wavelength of 405 nm due to - as opposed to DVD 650nanométeres wavelengths - blue laser technology, large amounts of data stored on the HD DVD discs.[25]

Blu-ray

A current, single-sided, standard DVD can store 4.7 GB of data, enough of an average two-hour, standard-definition movie and some extra data. But a high-definition film, with a much clearer picture is (HDTV - High Definition Television) as a DVD movie, about five times more space, it is essential to plates, on which much more data, fit in like a DVD Shop. In order to be added to an HDTV more than two-hour show on Blu-ray disc will be required. The BD read and write data to the blue laser, unlike DVDs, which use red lasers. The blue laser has a shorter wavelength than red lasers. The smaller fénynyalábbal exactly it focus, which allows a small gödröcskébol ("Pits"), we can also read the data, which are only 0.15 microns long - more than twice smaller than the DVD are small pits in comparison. In addition, the Blu-ray has reduced the track hüvelykméretét. The smaller pits, smaller beam and shorter track pitch together resulted in a single-layer Blu-ray more than 25 GB of information can be stored in a double-layer Blu-ray disc is about 50GB, Nyi data.

he Blu-ray Disc is a long standing HD DVD format war. The two similar-sized format, while supporters of camp managed to collect. Finally, the war on the Warner Bros. film studio was up in early 2008 when it announced in May that year, only on Blu-ray Disc movies will publish, which severe blow to the HD DVD format. After several commercial chain also announced that it would withdraw from the HD-DVD discs from the supply, but the format is probably the victory of Sony's new game console, the PlayStation 3 has also contributed greatly to the appearance. Sony's console contains a built-in Blu-ray drive, while the competing consoles like Microsoft Xbox, or Nintendo Wii called - would provide a revolutionary gaming experience - gaming machine is not one to boast. Toshiba announced in February 2008 to gradually shut down the HD-DVD development and production, which in the format war - the victory of Blu-ray - practically ended. [26]

[28] . FigureHD-DVD and Blu-ray Disc

3.3.4 Holographic storage devices

The holographic data storage virtually limitless opportunity for capacity and data transfer speeds. In 2004, the Conference of technology professionals involved in the development of three different development of holographic data storage arrangement: the storage capacity of 200GB Holographic Versatile Disc (HVD), a 100GB read-only Holographic Versatile Disc (HVD), and the credit card-sized,Holographic Versatile Card 30GB (HCV).

[29] . Figure Holographic Versatile Card 30GB (HVC)

The first functional prototype called the InPhase holographic drive meant it. The 130 mm diameter - is the CD / DVD drive using slightly larger than - 200 GB device can hold, and the data transfer rate of 20MB / s. On this record, about 40 DVD disks, CD-300 and approximately equivalent amounts of data can be stored.

[30] . FigureHolographic storage prototype

Reading and writing data in the holographic storage devices, in contrast to previous treatment with an optical drive, not least, with bit-by-bit, but the data are recorded simultaneously, or even the media is read.

[31] . Figure Holographic Disk

The new optical process huge amounts of data can be stored in a small space. Postage stamp-sized area of ??tens of gigabytes of data can be recorded, while a credit card-sized, clear plastic sheet or later, 20 to 50 gigabytes of data may be included. The American inPhase Technologies plans to later in the year prior to 2010 may appear in about 1.6 TB of capacity holographic data storage.

[32] . FigureHolographic discs

The new technology is quite high due to fault tolerance - according to the manufacturer - the media will be used 10 million times and the estimated life of 50 years.

Commercially, this technology is still only available to wealthy companies, private spread the Blu-ray Disc and the spread of commercial kifutásáig s not likely.[27]

[33] . FigureHolographic disks Reading

The previous figures inPhase Technologies applied by the "traditional" architecture, we can see a rather large form factor drives results, but there is a company developed by the Japanese Optware POLARIZED collinear technology is called, where the carrier signal and reference laser beam in an optical axis, the same effect as if for use by a single laser beam. As a result, the drives can be so thin, as is now available on CD and DVD drives.[28]

[34] . FigureCommercially available HVD drives and 300 GB disk

The micro-holographic disc storage devices, and is expected sometime in 2011-2012 are presented, and only large data storage-intensive applications such as medical institutions, data management, or movie studios will be used to store materials.


3.4 Flash-based storage

Today, more and more gaining ground in the flash-based storage devices. This category includes a variety of sizes, types of memory sticks, memory cards, and SSDs.

The compact flash memory - usually plastic tube receiving position - read-write, nonvolatile circuits, ie, retain their content without power. Such as flash memory used in digital photography, MP3 music files on it. In addition, the flash fast read access times for (50ns) - although not as fast as volatile, ie after switching off nonvolatile RAM, DRAM, or SDRAM memory, which is the main memory is used as an example of PCs - as well as it contains no moving parts , are more resistant to mechanical stress (eg vibration) than the hard drive. These characteristics explain the popularity of Flash. A further advantage is that if they are packed in memory, it is almost indestructible physically as resistant to high pressure and hot water as well.

The flash chip manufacturing technology, manufacturers are working steadily, thanks to the gradually increasing capacity of flash memory chips. Already been presented to the world's first 25-nanometer process inserts made of NAND flash, which begin mass production this summer, also manufactured. The 64 Gb presented, ie 8MB chip area occupies a somewhat smaller than the previous generation 4 GB, that is the order of twice the cost of manufacturing the same memory will be able to produce such. for the SSDs.

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3.4.1 Memory

Technological point of view there are basically two types of memory:

  • semiconductor (eg, Smart Media, Compact Flash), it is widespread, according to besorolásunknak flash memory-based technology,

  • Magnetic (eg, IBM Microdrive), becoming less common, in contrast with the classification is actually miniature hard drive, flash memory beginning of the legitimacy of a relatively small storage capacity and high price was justified.

[35] . Figure 1-GB memory card

The flash memory-based operating principles:

The type of memory chip EEPROM memory actually. (EEPROM - Electronically Erasable and Programmable ROM: electrically erasable and programmable read-only memory. Including electricity to be rewritten. Typical uses for the BIOSes today, and so does the memory game consoles as well.)

The chip is a grid structure, where the grid points to represent bits. Each bit in the corresponding row and column intersection can be achieved. The rows and columns on both sides of a meeting at the site of a transistor-transistor vezérlokapunak basis of one and the other is called the follower. The only post-gate transistor constituting the control gate connected to the lines. The two transistors in a very thin oxide layer lies. While the oxide layer between the two transistors to neutral (ie, the gate is open), the connections between transistors, the first bit in question To change it to 0, after the gate voltage to be sent through the column representing the bits in question. The gate voltage is applied to the post about starting to function as an electron gun: the negative oxidrétegnek töltésuvé make and break the connection between the two transistors. The interruption in the more powerful the more negative the oxide layer. A sensor measures the cell after passing through the gate between the control and charge size. If this value drops below 50%, the sensor cell 0 is returned as the value of the bit. Changing back to the bits are not too complicated: the individual bits passing through the strong charge is completely re-open them. The operation, however, quite slow because of the positioning. The deletion in order to increase the speed of the flash chips simultaneously for a block (or the entire data area) will be deleted and then re-enter the controller chip area of ??the previously deleted.

Memory cards are very reliable storage, hours of the order of 1 million guarantee (of course, much less unreliable). This is roughly 100 years of continuous usage.[29]

3.4.2 USB flash drive (memory stick)

While this does not mean anything any real threat to the 3.5 "floppy drive. True, less and less used, but the majority of machines are included. In a letter, a picture, it could easily make smaller files, and put it away as a backup or transfer to another machine.

Well, it looks like it's over. The flash drive smaller physical size, faster connection, only one USB port to be added, and the capacity is much higher, 64 MB to 256 GB-ranging. Writing the life of one million, and have a deletion (more manufacturers 10 year warranty on product). Transmission speed up to 20MB / s can be read and the write operations, as well, but there is 30MB / s over-speed drives for read operations, but these drives, the write operation speed of "only" 15MB / s.[30]

Birth is still debated since the first of several development companies also own attributes. In any case, no sooner than 1999 and no later than 2000 was.

The USB flash drive (USB flash drive) is a built-in USB flash memory. Alone are not able to exchange data, only when connected to a PC, it guided. A separate power supply is only if you also have other services, such as an MP3 music player, voice recorder function.

[36] . FigureThe Kingston 256 GB of storage capacity USB flash drive

The memory stick is a small printed circuit board includes a metal connector attached, usually in a plastic sleeve exposed. The housing needs of users, depending on variety: there is dust-and splash-proof, and highly impact-resistant design as well.

While the cards, cameras, mobile phones, multimedia devices, PDAs or PNAs are used in memory sticks up to the USB port on your computer by placing all kinds of data storage, and handling. Advantages: small size, high capacity, portability, resistance to external influences.

3.4.3 Solid State Drive (SSD)

It seems that the hard domination of the past can be released since the SSD. This development is thegoal was to eliminate the disadvantages of hard drives. What are they? Quite large in size and weight, due to the mechanics of vulnerability, sensitivity to vibrations, and the slowness of data management.

SSD: Solid State Disk Drive, or in Hungarian solid-state drive, a solid-state, no moving parts, data storage, a hard drive connected to your computer. We semiconductor-based, it is not inside the discs, but also memory chips are located. Basically, two types of SSD can be distinguished: the DRAM and flash-base path. Thenon-volatile flash memory, DRAM-based memory, the machine is actually made ??up of identical memory modules, which we know only that power remains in the data during this type of SSDs are made ??in a separate battery. Today, virtually n-SSD flash memory-based SSDs for us. However, the storers within the flash-based technology also can distinguish between two types, one of the SLC (Single Level Cell ð a single level cell) and the other in the MLC (Multi Level Cell ð multi-level cell) technology.

[37] . FigureIntel's SLC technology St SSD (Intel ® X25-E), without cover

SLC-based storage, a memory cell egybittárolható, while the MLC-based 2 or 4 bits can store. As a result, higher capacity and cheaper products can be produced, whereas the faster SLC based, long-lived (hundreds of thousands of write cycles for MLC compared to the tens of thousands), but much more expensive.

The SSDs eventually take over the leading role in the everyday data storage, as quieter, faster, more durable and less energy consuming than traditional hard drives, but the unit of storage capacity per price, and the available storage size for still probably a long time lags are their relative . The SSD's life is an important issue. The new SSDs begin to approach the life expectancy of conventional hard drives. It is worth mentioning that there is a manufacturer of a certain SSD ire up to 10 years warranty company, but we should keep in mind that the warranty does not bring back the lost, perhaps irreplaceable our data, that is a guarantee regardless - as today's hard disks can recommended that (would) - Back up your important data regularly to be prepared.

In summary:

Benefits:

  • Speed - there is no spin-up, the access time to an order of magnitude smaller than the hard drive (about a hundred-fold difference)

  • Much more able to IOPS (Input / Output Operations Per Second - input and output operations per second)

  • Mechanically reliability - capable of withstanding the shock, vibration, pressure, temperature

  • The file fragmentation does not slow down the operation

  • Smooth - no moving parts

  • Less warm

  • Lightweight and compact

  • Low power consumption - the mobile hard disk is negligible compared to the benefits

[38] . Figure: 64 GB Samsung SSD

Cons:

  • Honey, is still the price / storage ratio is worse in the HDD kénél.

  • Low capacity (because there are already 512 GB of instance, but the goods are still astronomical heights).

  • Lifetime. The life span of flash memory is expected weaker than the hard drives.

    • Writing is slow. This is just a flash memóriáknál, including only the older and cheaper than MLC based storage occurs.

    • Quite sensitive to sudden power cuts for the magnetic and electric fields.

As one can see that the hard drives are still in the tournament, but are losing heavily. The speed, small size and weight, low power consumption is very desirable to make the SSD's, especially in portable equipment point of view, but it is likely that desktop owners do not have much to wait for the disadvantages of the technical development has sufficiently reduced.[31]


3.5 The material fázisváltozásán based mass storage devices

3.5.1 PRAM

The data stored in the PRAM (Phase-change Random Access Memory) chips fázisváltozásán the material, that is based on thermal állapotváltozásán. This technology is based on the physical phenomenon that certain material will be different in the crystal structure when cooled to the melting point above or below the state occurs. The PRAM into the writing of the change in crystal structure of the storage cell material, which influences the electronic conduction properties. The material can take two different states, or the resistance will be low, that will be a good leader (this condition is the zero), or an increase in the resistance and becomes quasi szigetelové (this is the one). As one of the status quo does not require energy, and therefore - like the flash memory - preserves the contents of PRAM off.

The material fázisváltozásán based memory transistors instead of diodes that are designed to take up less space demand, so production - the band width technology, - the PRAM chips higher data density and capacity to provide, such as flash and DRAM chips, and also much faster as well. Since this type of memory does not store an electrical charge, is much more resistant to electromagnetic radiation, such as flash memory, in addition to the fatigue is an order of magnitude slower, and the research shows that up to 100 million write cycles can reach the service life.

[41] . Figure: The prototype of PRAM chips from Samsung

The PRAM NAND RAM much as an order of magnitude even greater reading speed promises, which is a PRAM technology SSD is now 1 GB / s over the transfer rate would mean, when the - is yet to spread - SATA 3.0 specification would be the bottleneck .[32], the tech company's chief technology officer, one - California Santa Clara, going - flash memories related conferences that reflect the speed difference, that if a certain amount of data reading out a day keeps the PRAM from, the same flash memory 17 days it takes , hard drive is only nine years of data will arrive. The PRAM technology combines the advantages of flash and DRAM, fast, high capacity and retain data even after power off.

For now, however, the PRAM has still not started the mass production, despite the fact that the experimental technology companies in the semiconductor industry's largest, such as Intel and Samsung. The PRAM is a pre-production cost is much higher (up to ten times) of flash memóriáénál, but the semiconductor manufacturing processes with the development of this problem is resolved. This cutting-edge technology company, Numonyx plans to end the 45-nm band width of up to 1 Gb of samples can also be.

The advance is expected to have at least 3-5 years is necessary to start the PRAM able to spread widely (by then is expected that the production of flash memory technology has limitations). The Numonyx is now working jointly with Samsung PRAM, the reason for expanding and standardization of interfaces, so that they begin their commercial application. The first one interested in the Finnish Nokia, the mobile phone company in the NOR and NAND flash chips are planning to replace a single PRAM memory technology. This will significantly speed up the operation of the so-called smart phones, but these phones because of a significant penetration of the PRAM cost of production is a beneficial effect. The technology - characteristics of - time displayed on the desktop and mobile computers, or servers, whilst also replace the flash memory cards, but with the - with flash-based SSDs are still competitive - it would be hard pensionable.[33]

[42] . Figure: The Samsung 512 megabit, or 64 megabyte PRAM chips

4th The increase in storage capacity

In the computing world the strong development of the background is typical prices. The manufacturers almost daily drop in the mass storage market with new types of tools and a completely new storage system. The storage capacity and speed of rising prices, while goods is declining.

The first data storage (punched cards, punched tapes) are very primitive in today's technological advances than expected, although it had to start somewhere. The age at the time it was within reach.

The development compared to other industries is very fast, powerful interventions are among the újabbnál new data storage.

The table shows the storage capacity or rapid growth rates. The oldest of data storage technology - is still the most widely used magnetic-disk technology, too - even in the magnetic tape, which is still used today, because at the company level, large amounts of data, it is the cheapest backup, data recovery form.

The mass storage prices continue working on strengthening the capacity of the manufacturers. The SSD capacity within a few years to reach the traditional HDD capacities, but it is questionable whether price / performance ratio will be able to converge within a reasonable time (£ / GB ratio is unlikely to catch up to the hard disk, but the SSDs performance advantage can be as much to make you forget the price difference).

The following table shows the different mass storage capacity growth presents.

[43] . Figure: Storage capacity growth comparisons between types of mass storage

5th THE GROWTH RATE DATA ACCESS

Most of our data is still stored on hard disks, as these are the mass storage devices, which are the most reliable, compact, more precisely, the compactness and reliability, they have the lowest share price. However, the hard drive can also receive a return of more advanced system performance, you are no longer able to perform adequately to meet the needs of the processor.

When someone thinks about buying a new hard drive, the capacity of the chosen product - and the price per unit of storage capacity - above the speed, reliability, and more recently, more and more noise trying to keep in mind.[34]

The hard drives are likely to be more and more, but the hard drive size is still far in, but it is faster to mechanical stresses more resistant and less power consumption and completely silent - flash memory used - solid state drives, and can take the first portable computers and desktop machines in as well. Some argue that the effect of rapidly expanding mobile computers, desktop computers, the days are time well.

The SSD and the HDD has a major advantage compared to its speed. Tests based on a traditional hard drive twice or three times faster than reading, while the cheaper SSD write speed slower than hard disks from, but in the mid-range SSDs can catch up, and sometimes leelozik the HDDs peak representing every minute 10,000 round plates are working hard (Although they are also included at a similar level).[35] The solid-state drives, average access time to turn around. hundred times shorter than the hard disk, and therefore the NAND Flash technology SSDs enable faster boot and using the computer - the program due to a faster start - never before seen, you can run more smoothly. The solid-state drives have no moving parts, so should not be felpörögniük platter and the read / write heads do not have to beállniuk to the point where the data is physically located on disk. As already mentioned there is hardly any delay in reading or writing data to the initiation, and therefore of no concern to the location of files as they are not fragmentation.[36]

The magnetic hard disk drives operating for decades served the long-term (archival purposes, but not necessarily) as a primary means of data storage. Developed standards for speed, capacity, interfaces, users will know what to expect from the individual devices. The fifty years of development, however, plenty could not respond to several emerging problems such as decrease in size due to the spread of portable computers, or an increased resistance to shock, but to shorten the access time or data transfer rate of increase did not find satisfactory answers.

6th HARD DISKS TEMPERATURE (TEST)

The hard drives - the result of technology - to read and write speed of the plate can be placed in a standard size sheet of data in excess of the disk rotation speed the most. For this reason, manufacturers have greater data density and higher rotational speed drives releasing attempt to meet the market demands. The higher speed is more air resistance, friction from, and therefore more noise and more warming also has been mentioned.

The following tests of some popular, commonly used hard drive tested to find an answer to these drives - continuous stress exposure - how much heat, this heat - by the manufacturers of the equipment specification in the specified operating temperature in comparison with - do not obstruct the driver integrity , life, making the data stored on them. In practice, the measurements of additional drives installed in your computer (fan) air cooling and without cooling is carried out. The test and measurement of the temperature of the Hard Disk Sentinel[37] , a hard disk drive control, monitoring and diagnostic applications to perform. This program is able to monitor the status of hard disks in the background acting warn of possible hard disk problems, or the expected defects. But including a test can be done - eg. the Random Access Time Test , which is present in our test we use - which means it can be examined, that the hard way you respond to prolonged load above, changes to its performance and to what extent the rise in operating temperature.

The rating takes into account that the study by Google[38] According to the hard drive life - a general belief, in contrast - is not reduced from that at higher temperatures are in operation, namely 20 and 45 ° C for roughly the same rate of failure, only extremely high temperatures broke significantly more drive. The company has more than one hundred thousand, 80 and 400 GB, retail is also available, commonly used in hard disk failure observed szerverparkjukban their willingness to fix the above.

6.1 Test Environment

The test has a roughly constant temperature (22 ± 1 ° C), living room done.

The test configuration used in desktop computers

  • Motherboard: Gigabyte GA-S2L M68SM

  • Processor: AMD Athlon 64 X2 Dual Core 2200 MHz

  • Memory: 1GB Kingmax DDR2800 MHz

  • Monitor Controller: NVIDIA GeForce 7025 (onboard)

  • House: 81 KM Mercury 400W PSU

  • Operating System: Windows XP Professional SP2

  • test program: Hard Disk Sentinel Pro 3.10

The test used a portable computer, or notebook

  • Manufacturer: Micro-Star Int'l Co., Ltd.

  • Type: MSI-GX610PX 059HU

  • Chipset: ATI RX690 + SB600

  • Display: 15.4 "WXGA TFT (1200 x 800)

  • Processor: AMD Athlon 64 X2 2 GHz

  • Memory: 4 GB DDR2 SDRAM

  • Monitor Controller: ATi HD2600 Graphic with 256MB GDDR3 VRAM

  • Operating System: Microsoft Windows XP Server Pack 3

  • Test program: Hard Disk Sentinel Pro 3.10

The hard drives in the test

First hard disk

  • Manufacturer: Western Digital Corporation

  • Model Number: WDC WD2500AAJB-00WGA0

  • Serial Number: WD-WCARY0481374

  • Format: 3.5 "

  • Capacity: 250 GB

  • Number of Discs: 2

  • Number of heads: 3

  • Rotational speed: 7,200 r / min

  • Interface: IDE / ATA

  • The manufacturer's specified operating temperature[39] :

    • Minimum: 0 ° C

    • Maximum: 60 ° C

Second hard drive

  • Manufacturer: Seagate Corporation

  • Model Number: Maxtor 2F040L0

  • Serial Number: F1B40W3E

  • Format: 3.5 "

  • Capacity: 40 GB

  • Number of discs: 1

  • Number of heads: 1

  • Rotational speed: 5,400 r / min

  • Interface: IDE / ATA

  • The manufacturer's specified operating temperature[40] :

    • Minimum: 41 ° F (5 ° C)

    • Maximum: 131 ° F (55 ° C)

3rd Hard Drive

  • Manufacturer: Seagate Corporation

  • Model Number: MAXTOR STM3160215A

  • Serial Number: 9RA89KTJ

  • Format: 3.5 "

  • Capacity: 160 GB

  • Number of discs: 1

  • Number of h