With the advent of computers, the issue of storing information, which was initially submitted in digital form, became very acute. And now this problem is very relevant, because you want to save the same photos or video for a long memory. That is why initially it is necessary to find an answer to the question of which devices and media serve for long-term storage of information. You should also fully appreciate all their advantages and disadvantages.
The concept of information and its storage methods
Nowadays on computers you can find several basic types of information data. The most common forms are text, graphic, audio, video, mathematical, and other formats.
In the simplest form, they are used to store information. hard drives computers to which the user saves the file initially. But this is only one side of the medal, because in order to view (extract) this information, you need at least operating system and related programs, which by and large are also informational data.
Interestingly, in schools, in computer science lessons, when choosing the right answer to such questions, there is often a statement that, they say, for long-term storage of information is rAM. And schoolchildren who are not familiar with the specifics and principles of its work, consider this the right answer.
Unfortunately, they are mistaken, because only information about the currently running processes is stored in RAM, and when they are completed or the system is rebooted, the RAM is completely cleared. This is similar to the principle of the action of once popular children's toys for drawing, when on the screen you could first draw something, and then shake the toy, and the picture disappeared, or when the teacher erases the text written in chalk from the chalkboard.
How information was saved before
The very first method of preserving information in the form of cave paintings (by the way, graphics) has been known since time immemorial.
Much later, with the advent of speech, the preservation of information began to be a process of, so to speak, word of mouth (myths, legends, epics). Writing led to the emergence of books. Do not forget the pictures or drawings. With the advent of photography, sound and video recording, the corresponding media appeared on the information field. But all this was short-lived.
Device for long-term storage of information: basic requirements
As for computer systems, you should clearly understand what exactly the requirements must meet modern mediaso that information is stored on them as long as possible.
The most important requirement is durability and resistance to wear and physical or other damage. And in relation to any type of media, one can speak about time intervals very relatively, because, as is known, “nothing lasts forever under the Moon”.
For long-term storage of information are what media
We now turn directly to the devices on which data of any type can be stored, if not forever, then at least long enough. So, for long-term storage of information are what types of media?
Among the most commonly used in relation to computer technology are the following:
- internal and removable hard and zip disks of computers;
- optical CDs, DVDs and Blu-ray discs;
- flash memory of any type;
- floppy disks (now used extremely rarely).
Advantages and disadvantages of carriers
As can be seen from the above list, only hard drives built into computers belong to internal storage devices. All other media are external.
But all of them in one way or another are subject to aging or external influences. In this sense, floppy disks or the same CDs or media of a different format are the most insecure, although optical media in this respect look more durable. But how long can they last? 5-10 years old? But if the information stored on them, view very often, the service life is reduced.
Flash drives and hard drives have a longer service life, but they are not insured against wear, damage and aging.
Winchesters begin to “crumble” (this is a natural process), flash drives can be exposed to the same sunlight, moisture, or even delete data if improperly extracted or software crashes. In addition, there are many additional factors that can lead to device malfunction.
Nevertheless, saying that for the long-term storage of information are the devices listed in the list above, it should be borne in mind that this classification is given solely for the current state of affairs in the computer world. Who knows, maybe even in the foreseeable future, completely new carriers using other technologies will be invented, because it is claimed that the creation of quantum computers is not far off.
"Who owns the information, he owns the world," said the great Chinese philosopher Confucius 3,000 years ago. But the incoming information had to be stored, summarized, found at the right time and used in time. From the beginning, these were rock plates and walls, where ancient people painted, then they were clay boards, birch bark, papyrus, paper, vinyl disks, magnetic tape, punched cards, floppy disks, disks and finally, a hard disk.
But when a hard disk is located in the system unit, it is always subject to various types of danger that can lead to loss of recorded information. And this is due to voltage drops and overheating. Yes, and the nature of the information may be one that is not always needed in real time, but it is still relevant for the owner. Catalog of family photos, favorite music, but also films that, of course, downloaded from a free torrent. It is beneficial to store such information not in the hard drive, but on the external hard drive. And you can carry with you, and always at hand, and less danger of losing information.
I planned a business trip to one of the southern republics of Russia for a period of 1 year. Naturally, I went to buy an external hDD, to throw on him a photo of family, friends, favorite concerts of rock groups, and of course movies, a lot of movies! The main criteria was a capacity of 1 TB, the transfer rate is appropriate, and of strength. As a result of consultations with the manager in the store, I chose the HDD “ Western digital WDBBJH0010BBK.
During the operation of this device, it turned out its advantages: it corresponds to the declared speed. USB 3.0-2.0 support: works great with any standards. Design: not huge, with rounded edges, the upper and lower surface leaves no fingerprints. Noise: for me it is quiet. Vibration: moderate (for me not strong), rubber steps on the bottom reduce vibration by 80%. Omnivorous: a TV set took the disk without problems, the computer also took it without problems.
However, later began to appear, seemingly minor, but still significant shortcomings. And the main thing is the presence of your own power cord. Just imagine, each of you has a network filter connected at your workplace at home or at the office: a monitor, system unit, active speakers, printer, modem, router, some other very necessary and required power supply crap. And for my external disk there is no space. At the same time, another nearest outlet through 5 meters in the opposite wall. We connected, we work, and the cord hangs through half the room - we stumble! Further, during the operation of the device, a noise was heard, a vibration appeared. Of course, when a telly works in a room, there are people who don’t pay attention to it, but if you’re left alone, all these sounds are not childishly annoying! And the size of the disk began to cause confusion - after all, it is big. You cannot put it on the LCD monitor, but it interferes on the desktop, the USB cable is short, the power cord is stretched.
It’s no secret that a business trip for a man is a vent. A business trip for 1 year - this is from the beginning of a complete outlet, and then strained. Since we are not saints, we spent our free time in a joint viewing of the next new Hollywood masterpiece with the use of alcohol-containing drinks of various strengths. So, in one of these free days, my external disk is touched by a cheerful fellow, and the device falls from a height of 1.5 meters to the floor. Although the height was not great, but I was already tensed! It seems to be Lenolium, it seems to be a small height. I start with confidence to connect the drive. A computer and a TV set do not see it when connected. Hoping to fix it, I removed the outer casing and, to my great surprise, inside I found a standard hard disk, the relatives of which are inserted into the system unit. Why does Western Digital make a standard external drive portable? This is still a secret for me.
Personal attempts to run the disk to no avail. By transferring the device to his comrades from the “K” department of the Ministry of Internal Affairs (they are engaged in computer crimes) in the hope that they will be repaired, the latter also failed to restore not only the performance of the disk, but even the information on it. It turned out that when it fell, a part of the reading mechanism was separated from it and the surface of the disk itself was mechanically damaged. That's how family photos, favorite music and masterpieces of the Hollywood film industry were lost to me. As well as 57 GB of quality porn.
Considering the bitter experience of using the previous hard drive and spending some time on the Internet, I made the choice of buying in favor of external hard drive 1Tb Western Digital My Passport Essential Silver (WDBEMM0010BSL).
Its advantages: external storage of large capacity with low power consumption; the model automatically turns on and off with the computer, and after several minutes of inactivity goes into standby mode, which allows you to use the drive, both with stationary computers and with laptops. Included is an external power supply.
The 1Tb Western Digital My Passport Essential Silver external hard drive (WDBEMM0010BSL) has a stylish and ergonomic case, small size and weight, which allows you to carry it in a small bag or pocket. It turned out to be a convenient and reliable auxiliary hard drive. Just plug it into a USB port. On 1 TB of memory, you can save a huge number of files without saving space.
And as you can see, the main differences from the previous hard disk are smaller sizes, high transfer speed, the absence of its own power cord and most importantly, high reliability of the product during physical impact. This device is fully interfaced with all technical devices, it works without failures. But one thing strains - it also has a rotating element, And if you drop it, then there is a high probability of losing the stored information.
Thank God, that technical progress does not stand still, and therefore, external solid-state SSD hard drives are already on sale now. These drives are made on silicon like flash memory. And there is nothing to break, as there are no moving parts. Neither high temperature, nor water, nor pressure can destroy information. In addition - small size, high speed of information transfer, a long shelf life (manufacturers claim that up to 1000 years). The only drawback of these SSD drives - their high cost. But so far.
Especially Samsung has succeeded in manufacturing SSD drives. Such external drivesas Samsung MZ-7PD256BW and Samsung MZ-7TE1T0BW
at the end of 2013 and at the beginning of 2014 they occupy leading positions in their characteristics, the main ones being speed, reliability and durability. They will save and save information. With them you can definitely own the world as the ancient philosopher Confucius said.
2013-08-26T11: 45: 39 + 00: 00
Andrey Samkov
What a pity that summer is coming to an end! Surely you have accumulated a whole suitcase of summer impressions - someone had a graduation from a school or university, someone had a stunning vacation on a paradise beach, someone got married, someone had a baby. Photos and videos of such events want to keep in its original form for a long time, to review many years later. How to protect your “digital memories” from loss? Let's figure it out.
Computer storage
Obviously, this is the most unreliable way to store data, but, alas, most of us do just that. Especially dangerous are laptops in this sense. Judge for yourself: we carry them with us everywhere, sometimes we connect to the most diverse networks, both wired and wireless. So, our laptop is always in the "risk zone".
We can break it, they can steal it from us, if not sad to think about it. And “erratic network connections” lead to the fact that our laptop computer constantly walks under the threat of being infected with viruses, trojans and other computer infections (and reliable antivirus, unfortunately, is not a 100 percent guarantee, for the virus writers are fighting against virus-wrestlers continuously with varying success).
And there’s nothing at all if we could get problems with the loss of valuable information if there are problems with a computer that has ceased to function.
Optical discs
External drives should not be kept permanently connected to a computer: it’s no secret that even the best of computers fail from time to time. Especially dangerous when a breakdown is related to a power supply or power system. motherboardIn this case, the damaged component threatens to “take with it to the grave” everything that will be connected to the computer, including your precious electronic archive.
You do not have to hide the hard drive in the cabinet for years: the fact is that the information on it is stored as magnetized areas, and this magnetization can (and will) be lost over time, simply speaking, the disk will be demagnetized, and the data, respectively get lost. So every few months, the hard drive should still be connected to a computer so that it restores the magnetization of its “pancakes”.
Flash media
Last time there is an active transition from hard drives on solid-state carriers. So maybe the photos should be stored on the "flash drive"? There is no definite answer.
24.03.2008 Igor Korepanov
The concept of "archive" today means not dusty shelves full of documentation, but electronic systems capable of storing data for a long time. Despite all the advantages of specialized professional systems, the method of storing this or that information, especially in Russia, does not always correspond to real requirements.
In recent years, the concept of managing the life cycle of information, which is based on the principle of dividing the total data set into classes depending on the content, frequency of hits and retention period, has become widespread. In accordance with this approach, there are three key tasks for storing electronic data: online access to information, backup and archiving. Different equipment is used to solve each of them - according to specific requirements for storage and access.
Online access. A typical example is a file server, whose main task is to immediately provide the necessary data to a large number of users on the corporate network. The main requirements for such systems are continuous access and high speed operation. The ideal solution is a RAID array.
Backup. This storage phase implies a high streaming speed of writing and reading and a large storage capacity. The longevity of storage does not matter, as backups are done regularly. The best choice would be tape based systems.
Archival storage. In this case, it is supposed to store important information for a long time while ensuring quick access to it, which dictates quite specific requirements for storage technologies and equipment, in particular, long-term storage of large amounts of information in unchanged form. All these conditions are met by robotic optical disk libraries.
It should be noted that in most European countries and the USA the need for archival storage of key business information is enshrined at the legislative level. Around the world, about 25 thousand directives have been adopted, including resolutions of the governments and individual ministries of Germany, Italy, the United States, Great Britain and other countries requiring data to be kept on financial transactions, stock exchange transactions, medical research and insurance payments for five to ten years. .
Legislative standards for data storage are actively developed in our country. The planned entry of Russia into the WTO is a powerful catalyst for this process. In the near future, many companies will legally be obliged to store data for long termso that they will have to upgrade their storage systems. Therefore, the global growth rate of the archival storage market in Russia will most likely be significantly exceeded.
FEATURES OF ARCHIVE STORAGE
The first and most important requirement for an electronic archive is the exclusion of the physical possibility of deleting or changing data both by negligence and by malicious intent. In other words, information carrier must provide a single write for multiple reads (True Write Once Read Many, True WORM). As a result, data protection from deletion should not be software, but hardware. In addition, the key requirements include durability and high capacity storage media. This can significantly reduce the total cost of ownership of the system (TCO) and satisfy requests for storage capacity from the largest companies, including state and industrial enterprises.
From the listed conditions, it follows that neither RAID arrays, nor tape drives can cope with the task of archiving data storage. Despite this, in Russia the bulk of information resources are stored on hard drives or RAID arrays. Hard drives they even trust information that requires durable and reliable storage. Meanwhile the principle itself work hard the disk implies a constant mechanical movement, which implies a malfunction of the device and periodic loss of information. Warranty of hard disk for decades, manufacturers do not give. Trusting the most valuable data to RAID arrays, users sometimes do not attach importance to the fact that RAID technology was created to compensate for the unreliability and fragility of a hard disk.
Similar questions arise when trying to build an archival storage of data based on tape drives: the fragility of the carrier forces periodically to transfer data from the old tape to the new one. In addition, the tape needs to be serviced - if it is not used, it must be rewound regularly to prevent demagnetization. This technology has other disadvantages, in particular, it is impossible to directly access an arbitrary file on the tape.
To solve the problem of archival data storage, a new class of specialized devices was developed - archival drives. These robotic optical disk libraries running specific software allow you to build a reliable storage system to support automatic information lifecycle management.
STATUS DISCUSSION OF HARD DRIVES
Google Inc. conducted an independent analysis of statistics of failures of hard drives. The accumulated database (more than 100 thousand copies of HDD) is many times larger than any other similar study that has been published.
The results clearly demonstrate the inefficiency of using hard drives in long-term archival storage systems: by the end of the fourth year of operation, the cumulative percentage of failures of hard drives reaches 25% (see Figure 1). As a result, hard disk-based systems must have redundancy, support transfer infrastructure and reserve copyand also subject to frequent maintenance. This explains the high total cost of ownership of archives based on hard drives.
To build large information storage systems, it is essential that in a multi-disk array (more than 10 hard drives), continued maintenance without maintenance becomes unlikely a few years after the start of operation (see Tables 1 and 2), and more than half of the failures cannot be predicted from using modern embedded technologies for predicting failures (SMART).
Even with constant maintenance, backup and replacement of disks in the system, users should take into account that, according to statistics, more than a third of all HDDs fail in the fifth year of operation. Given obsolescence, this leads to significant difficulties in ensuring timely replacement. Thus, to reduce the risk of data loss, it becomes most appropriate to completely replace the drives after three to four years of operation, which entails additional costs.
RELIABILITY OF STORAGE OF INFORMATION ON OPTICAL DRIVES
According to the Enterprise Strategy Group (ESG), of all existing technologies, the best for long-term data storage are robotized drives on optical discs (DVD / BD libraries), using which the total cost of storing information is much lower than in the case of alternative technologies.
The constancy of data stored on optical media is guaranteed at the physical level, since the recording process is an irreversible change in the disk structure as a result of crystallization of the amorphous layer, which corresponds to the True WORM write-once standard. The stored data cannot be erased or modified - it is read only.
The most common type of optical media used for modern archive storage is dVDs. DVD manufacturers produce discs with a special hard surface, which guarantees the safety of information and fully complies with the international standard ECMA, while the service life of the media exceeds 30 years.
Thus, optical technologies provide the following benefits:
They guarantee exclusively safe storage data for decades;
The specification of True WORM is maintained at the physical level, since during the recording process there is an irreversible change in the aggregative state of the substance;
The capacity of one carrier is now 50 GB. This allows you to create a data warehouse of a significant amount and increase them if necessary;
Technology Blu-ray Disk provides random access to data, and the speed of positioning the laser head on the disk is the same as that of hard drives.
RESEARCH TECHNIQUE
To confirm the lifetime of the discs, their samples are tested according to the method of artificial aging. The disks will meet the standard if for 95% of samples the predicted shelf life exceeds 30 years.
In the process of testing, indicators of disc reading errors are determined. If the corresponding critical levels are exceeded, then read errors become unrecoverable and the sample becomes unusable, after which the time to failure is calculated. Based on the results obtained, the expiration date is determined under normal conditions.
During testing, the disks are placed in a special chamber with an elevated temperature, while the diffusion processes in the carrier are activated, which simulates the natural aging of the material. In addition, the disks are tested in conditions of high humidity, corrosive media, the effects of microorganisms and dust, mechanical effects.
First, disk performance is measured at high temperature. In each subsequent experiment, the temperature is lowered by 50 ° C and brought to 600 ° C. With each step the life of the disk increases. Data for room temperature is approximated based on the shape of the resulting health curve. Thus, for a polycarbonate substrate, the shelf life of disks at room temperature reaches 133 years.
Special hard coating ensures long-term preservation of the recorded information on DVD thanks to better protection from scratching. This is confirmed by tests on the HEIDON-14 tester: scratches are applied with a steel ball with a diameter of 7 mm and a non-woven lining at a speed of 1000 mm / min (see Figure 2). In addition, the antistatic component of the coating quickly removes static electricity from the disk surface and prevents dust from sticking during its use and storage (the relevant tests were carried out in a dust-filled chamber for 24 hours). The oil-repellent surface reduces the risk of data loss if someone accidentally touches the surface of the disk, and makes it easier to erase fingerprints (see Figure 3). A hard-coated DVD fully complies with all performance standards and maintains high stability during testing at elevated temperature and humidity (temperature 800 ° C, relative humidity 90%).
Tests conducted by ECMA International confirm that robotic libraries are based on certified dVDs with hard coatings provide reliable storage of archival data for 30 years and fully meet the standards of archival information storage.
IMPROVING STORAGE TECHNOLOGIES
The problem of archival storage is becoming more urgent as the volume of stored data increases, increasing avalanche. Globally, the amount of archival information is growing much faster than all other information. At the same time, quick access is required only to 20-30% of the information. By 2010, its total volume will reach one zetabyte, i.e. 1021 bytes.
At the moment, DVDs can store 9.4 GB on one media, and drives based on Blu-ray technology - up to 50 GB on a single BD disc. In the coming years, it is planned to increase the capacity of mass-produced optical discs to 100 GB, and further to 200 GB (see Figure 4). This will make optical technology even more affordable.
The continuity of technology is important: modern optical drives support compact discs released
25 years ago. In the future, the form factor of optical discs will not change, which makes it possible to count on the compatibility of optical discs with future drives.
BLU-RAY TECHNOLOGY
Modern optical technology Blu-ray provides a high density of archiving on media with a capacity of 25 or 50 GB each, in the future a capacity of 100 or even 200 GB is achievable. Single-sided media can have one or several recording layers of 25 GB each, support single (BD-R) and repeated (BD-RE) recording and provide high-performance sector error correction. The Blu-ray disc has a diameter of 120 mm and a hard surface.
Blu-ray drives are read / write compatible with CD / DVD media. The technology is supported by all major manufacturers of drives and media, as well as file system UDF. Modern Blu-ray drives provide 2x data writing speed (72 Mbps) and 5x read speed (for single-layer media).
APPLICATION ARCHIVAL DRIVE
Archive drives are used in the infrastructure of an enterprise information system when long-term, reliable data storage is needed (see Figure 5). Governing software performs automatic data migration from the network or from the server according to predetermined rules. It is estimated that approximately 80% of the data stored on the first level media do not require frequent access, and 20% of them will never be in demand. It is reasonable to store such data on optical archive drives, thereby freeing costly disk space RAID array.
When choosing an archival storage system, preference should be given to DVD and BD optical technologies. Only they ensure that all storage requirements are met, including such parameters as high reliability and long-term storage, data authenticity and immutability, fast random access to data, high storage capacity, expandability. Optical technology has been tested for decades and thousands of installations around the world.
Igor Korepanov - Marketing Director of the Electronic Archive Company. You can contact him at the following addresses: [email protected] and http://www.elar.ru.
