Lesson # 66. What is removable media
Removable storage media designed to store your data outside of your computer. They are very convenient to use to transfer your files from one computer to another. I am sure you are well aware of such removable media.
The most popular removable storage media currently are flash drives, flash drives, removable hard drives and optical discs (CD and DVD). I think that using a computer and knowing nothing about them is impossible.
Quickly, this format is required. These diskettes have a stronger advantage due to their rigid packaging and metal valve to protect the magnetic part. They have another advantage, appreciated by computer scientists: they fit into a shirt pocket, and their measurements were provided for this purpose. With an initial capacity of 720 KB, the disk quickly switches to 1, 44 MB.
At first, it was limited to registering databases, it became more democratic over the years. Capacity from 500 to 700 MB allows you to record 80 minutes of music or an hour of video, even if the quality is not at a rendezvous. Fast and working with a small amount of electricity, flash memory cards quickly become inevitable. If the former had limited memory capacities, but sufficient for cameras of that time, new generations contain from 8 to 16 GB.
Let's take a closer look at each of these devices and learn how to work with them.
But before we begin, I want to talk about some of the parameters of removable media that primarily affect their cost:
- Volume - This is the main parameter of any storage media and not only removable. To measure the volume using the same unit as for measuring the amount of data (information). We know that all information on the computer is stored as files. In order to somehow measure the amount of information, a special unit of measurement was introduced, which was called - byteThere are smaller units - bitsand 1 byte = 8 bits. What are bits and why 1 byte equals 8 bits, we will not disassemble. This is absolutely optional information for regular user. But still give an example that will give an idea of what is byte. The amount of information in 1 byte - this is one letter in a text document. 1 byteAs you understand, a small amount of information is enclosed (just one character), therefore usually larger units are used.
1 kilobyte (KB) = 1024 bytes;
1 megabyte (MB) = 1024 kilobytes;
1 gigabyte (GB) = 1024 megabytes;
1 terabyte (TB) = 1024 gigabytes.
It is expensive, but it is nothing compared to what it was. Not very interesting: an external hard drive of the same capacity costs less than 100 euros. But flash memory prices remain high, as global demand is stronger than production. Rental of premises for individuals. Today, everyone uses it, sometimes without even knowing it. We no longer store our information on our devices, but we send them over the Internet to remote servers so that they can be found anywhere. The possibilities are enormous: enterprises can get rid of their bulky and expensive servers, and individuals are no longer afraid that their plant hard drives.
The prefixes “kilo”, “mega”, etc. are borrowed from ordinary life, but unlike, for example, 1 kilometer, containing 1000 meters, 1 kilobyte contains 1024 bytes. Why this happened to us is not necessary to know. The amount of information is a very conditional value and in everyday life everything has long been rounded up to 1024 to 1000.
So, the volume of information carrier is its main indicator affecting its value. The larger the volume of information carrier, the higher its cost.
This allows you to quickly and easily copy hard drives.
One no longer “buys” computer software, but “rents” a program, its parameters, and the space needed to store information. Operators are at war and ready to break prices. Data carriers are hardware components that can be used to back up data permanently or permanently. There are three categories peripheral devices: Input devices: these are devices that allow data to be entered into the central processing unit for processing. Output devices: transmitting devices are transmitted in a form understandable to the user, the results collected in the main memory. I / O devices: these are devices that allow information to be transmitted in both directions. previous next Mouse A mouse is a pointing device used to move the cursor to the screen and select, move, and manipulate objects using buttons. Previous Next You can highlight: flatbed scanners, hand scanners and a scanner by scrolling. It is connected to a sound card that acts as an interface between the microphone and the computer. The optical pen is used on the screen or a special table. It allows you to select existing objects or draw in order. Previous Next To transfer these photos to a computer, you must connect it to a computer using a digital video camera connector. The camcorder can be used to record video clips and digitize them for processing by a computer in the following order. It allows you to display information that will be processed or used by the user. screens for cathode-ray screens Printer A peripheral device for outputting data from a computer to paper or other print media, such as dot-matrix printers, inkjet printers, laser printers. Previous Next Speakers These speakers are used to play sound. Video Projector This device allows you to project the contents of the screen on the screen of large sizes. A peripheral drive that allows you to read and write to floppy disks. The modem uses a modem between two computers to exchange data over the telephone network. A magnetic tape holder is used to store a large amount of information. The disadvantage of this type of support is that the access mode is consistent. In general, a hard disk is an environment where operating systems and various software are installed, as well as your personal files. Memory card. The memory card has the same characteristics as the random access memory, but data is not lost when the power is turned off, i.e. It is a semiconductor, non-volatile and rewritable flash memory.
- He has much more buttons than a mouse.
- Optical pen.
- Read speed (write) information from the carrier (to the carrier). Since the volumes of removable media are increasing every year, this figure becomes important. Of course, if you purchase a USB flash drive to transfer your text documents from computer to computer, the speed in this case is practically unimportant, since text files usually have a small amount. But if you need to rewrite a large number of videos or music files on a USB flash drive, then the recording speed plays an important role, and the time after which the files are transferred to the USB flash drive will directly depend on it. The same goes for flash cards that are used in digital cameras. The faster the recording speed of such a flash card, the faster the photo is recorded on it and the faster the camera is ready to take the next frame. Let's deal with the concept of data transfer speed, as it is used very often and novice users have problems with it. The basic unit for measuring information transfer speed in the computer world was adopted bits per second, also denoted by - bit / s (english bits per second, bps). The speed of information transfer can be indicated not only as a characteristic of storage media, but also applied in networks, including the speed of connection to the Internet is indicated in bits per second.
We already know that bit, this is the minimum amount of information and basically use a large amount - byteequal to eight bits. Therefore, when you are told that the speed of your connection to the Internet is 1 Mbit / s, then this DOES NOT MEANyou download 1 megabyte of information in a second. To translate Megabits at Megabytes we need to divide the speed of your connection by 8 and in our case we will get 0.125 MB / s, which is 125 kilobytes per second. Often there is such a designation:
This is ideal when you need to copy your hard disk once, eliminating the difficulty of creating a “hard disk image for a one-time project.” The menu offers access to all value-added features that provide simple task management, for example: duplication from hard disk to second tough disk backup and restore image library and more. It also offers a number of advanced configuration options for advanced users.
The adapters in the following list have been specifically tested for compatibility with this disk duplicator. The first article in the “Don't Scare Me More” series focuses on your hard drive. The operating system, programs, our data is actually written differently to the hard disk.
Kilobits per second - Kb / s
Kilobyte per second - KB / s
Pay attention to the title or lowercase letter "B" in this designation.
- Device size. This parameter is very conditional and not suitable for all types of devices, but basically the tendency is as follows: the smaller the device, the higher its price.
Lesson # 67. Optical discs
This is the most important component of the entire computer, not only because it stores our data, but also because the overall performance of our machine depends a lot on it. The history of the hard disk is somewhat strange and contradictory. HDD It is also a component that most users-consumers know little, very little and, therefore, cares little. Of course, we do not want consumers to know about this hardware, but the market, which simply gives us almost zero information.
Question: "Why?". Why we did not provide a detailed technical map with all these strange and incomprehensible abbreviations that we could learn to read, and give us the opportunity to choose our new computer also based on hard disk performance?
CDs (Fig.197) or they are also called CDs ( CD comes from the English. Compact Disc) have almost become obsolete, although for a long time they were the main carrier for transferring information between computers. Their volume was usually about 700 MB. To read such disks, a special device is used - a CD-drive (Fig. 198).
Well, guys, it's time to change and not be afraid. They are sellers, there are several competent and very rare, which are contrary to the "business policy". If you try to ask them more technical information than four things on the board, then in 99% of cases everything happens like this.
If you had “luck” to directly understand the genius of the situation, he will remove four abbreviations and invent a healthy plant, so we don’t know, we don’t understand, but at least we have an illusion of answer. You cannot answer and interrogate your most experienced colleague. . A cool, fresh example from a couple of days to stay on your hard drive.
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| Fig. 197. Optical disk | Fig. 198. CD optical disc drive |
Data from the disk is read using a laser beam. There are drives that allow only reading data from CDs, and there are also so-called writing drivesthat allow recording to disk.
Performance Rotation Speed Access Time Interface. . Capacity or capacity is a parameter that we all know well or badly. This is the physical amount of data a disk may contain. As mentioned in the opening, mechanical hard disk data is quickly recorded on swirling plates. On each plate, two heads move dizzyingly in nanometer-sized spaces and “touch” them so many 0 and many 1, that is, information.
The rotation speed of these plates is a factor that affects the speed of writing data. The first is smaller, the second largest. Access time is the most important parameter you need to know. In fact, it determines the recording performance. This is the average time used because a resident is found at a specific point on the disk.
Blank discs intended for recording are called computer slang. a blank. There are two main groups of compact discs (blanks):
- CD-R - You can write information to such a disk only once;
- CD-RW - Discs designed for multiple recording. Information on such discs can be erased and recorded again.
Usually, a read / write speed is indicated on a CD drive, for example, 24X. This is the rate at which a drive is capable of reading data from a disk or writing information to a disk. The speed is indicated as a multiple of 150 Kb / s (i.e. 153 600 bps). For example, a 24-speed drive provides a maximum read (or write) CD rate of 24 × 150 = 3600 Kb / s. This means that, for example, when copying information from a CD to your computer, in one second the drive will transfer 450 kilobytes of data. If you are copying a movie that is 650 megabytes in size, it will take about 24 minutes to copy it to a computer. Here is such a simple arithmetic.
This time is associated with the speed of rotation and the speed of the heads. Therefore, if we need a very fast disk when reading and writing data, this is the parameter that needs to be looked for in the technical data sheet of the disk. Technical data is available only on the manufacturer's website or in any case on the Internet, be sure to find it in the store.
An interface is a physical connection that connects a hard disk to motherboard. To date, we have come to revision 3 with the following speeds. If you are looking for a fast disk at all times, you will also have to look for this small element in the technical map of the disk, and you should also be prepared to spend more money on a disk with this function.
Over time, the CDs were pushed out DVD discami
DVD (dvd, eng. Digital Versatile Disc- digital multipurpose disk; also eng. Digital Video Disc - digital video disc) - has the same size as a compact disc, but uses a different technology that allows to significantly increase the amount of information that it can accommodate. For reading DVD discs use DVD drives that can also read CDs. But CD drives are unable to read DVDs.
Does the desire to have the most prestigious disc on the market? Turn on the computer and see it active and ready in 10 seconds? Open the program and tighten it to work? No need to keep up with defragmentation? The volume of modern hard drives is growing rapidly, but at the same time it quickly reduces real reliability. On the one hand, manufacturers increase the recording density and, on the other hand, struggle with strong competition. Mass patterns are cheaper, but their life cycle is reduced. In factories where they are collected, budget kits are widely used, there are savings on introductory marriages, as well as lower exit control criteria.
Currently, the most popular DVD format DVD-5 and DVD-9. 4.37 GB (Gigabyte) of information can be recorded on DVD-5 discs, and 7.95 GB can be recorded on DVD-9 discs.
The unit of speed (1x) of DVD reading / writing is 1,385,000 bits / s (i.e. about 1352 Kb / s = 1.32 Mb / s), which roughly corresponds to the 9th speed (9x) of CD reading / writing, which is equal to 9 × 150 = 1350 Kb / s. Thus, a 16-speed drive provides DVD read (or write) speeds of 16 × 1.32 = 21.12 Mb / s.
Tactile motto of manufacturers - "Everything will take effect." All this can be frequent back up data. But it takes a lot of time, takes a lot of time and money. The habit of connecting an external hard drive once a week to a backup should be considered very useful.
Not all users can boast of having a new copy stored in a safe place and are ready to replace lost or damaged files at any time. Regardless of universal backup software and “cloud” technologies that have been developed in recent years, in practice, regular backups prevent inertia and unwillingness to complicate our lives, and on the other hand, the inaccessibility of many for material costs, Internet services that provide sufficient storage space are also not free.
As with CDs, DVDs are divided into groups:
- DVD-R - designed for one-time recording;
- DVD-RW - rewritable discs.
Also, historically, another division of DVDs into “plus” ones (indicated by DVD + R and DVD + RW) and "negative" (denoted by DVD-R and DVD-RW).
"Plus" blanks appeared later and are an improved version of the "minus". The main, significant for the end user, the difference between “plus” and “minus” blanks is as follows. When rewriting DVD-RWyou must first remove the disk from it, but when you dub it DVD + RW disk information is not necessary to delete, the drive is able to record new information over the old one. But to work with “plus” discs, you need to have a DVD burner that supports this format (almost all modern DVD drives support this format).
That is why it is better not to lose data, and therefore we should strive for the hard disk as little as possible. To avoid emergencies, help choose a hard drive model, its proper installation and operation. There is no need to monitor its condition, as well as periodic prevention. For all of this, we’ll talk on the following pages, but first we need to identify the causes that lead to data loss.
According to the statistics of the seminars, they are distributed as follows. 40% - malfunction and equipment problems; 29% - errors caused by the user; 13% - software errors; 9% - deliberate damage to the data; 6% - exposure to viruses and other malware; 3% - external influences. As you can see, the widespread belief that a computer problem is mainly the culprit of the user is wrong — the most common cause is a malfunction or problem with a computer system.
In pursuit of an increase in the amount of storage media, manufacturers are constantly creating something new. So another format appeared - Blu ray disc, Bd (Blue Ray, Eng. blue ray - blue ray). Format discs Blu ray have the same dimensions as the CD and DVD discs (120 mm), but differ significantly in capacity. By technology Blu ray discs are made having one or two layers for recording data. Single-layer discs can hold up to 25GB of information, and dual-layer discs can hold up to 50GB. There are discs for one-time recording - Bd-r, and for reusable recording - BD-RE.
Of course, to read and write such disks you need a special drive that supports Blu-ray technology. The write speed has also increased significantly. The unit of speed (1x) of Blu-ray read / write is 36 Mbps, which allows you to record the amount of information in 25GB on a single-layer disc at 12th speed in about 8 minutes.
Most computers are currently equipped with optical disc drives. In order to install the disk in the drive, you need to click on the button located on it (Fig.199).
After the disc is placed in the tray with a light touch, close the tray. After that, the information recorded on the disc will be available and it will be possible to read it, for example, using the program Conductor.
Lesson # 68. Flash drives
Flash drives or simply flash drives- These are the most popular and currently popular removable media. In computer stores you can find a huge selection of flash drives. They differ in color, shape and material of the case, and you can always choose a USB flash drive to your liking (fig.202). But still, the main parameter of a flash drive is its size, i.e. amount of information that can be written to it.
On sale you will find a flash drive with a capacity of hundreds of megabytes, up to several tens or even hundreds of gigabytes. Moreover, the difference in price may not be proportional to the difference in volume, so before buying a flash drive, compare the prices of devices of different volume and choose the best price-volume combination.
The flash drive connects to the computer through the so-called universal connector - USB(Universal serial bus - universal serial bus, fig. 203).
This connector has become very popular and with it a huge number of different devices are connected to the computer, starting with flash drives and ending with printers, scanners, cameras and video cameras.
Usually on the computer you can find several USB connectors (2, 4 and even 8). They are located on the back of the computer. But since these connectors became very popular, manufacturers of computer cases began to place them on the front or side wall of a computer, which allowed them to get quick access to the connectors and connect devices without unnecessary movements. Typically, these connectors are marked with a special icon (Fig. 204).
On laptops usually install two or three USB connectors (Fig.203).
USB connector, unlike other computer connectors, allows you to connect and disconnect devices while the computer is running. This means that you can turn off the device, for example, remove the USB flash drive without turning off the computer, but there are some nuances of work and we'll talk about them later.
Lesson # 69. External hard discs
Along with flash drives are used and external HDs (fig.205). They have larger dimensions than flash drives, but the amount of information stored on them is much larger. The volume of modern removable hard drives in the hundreds of gigabytes and reach several terabytes. Accordingly, the price of the hard drive will depend on its volume. In addition, the size of a hard disk is also influenced by its geometric size - the smaller the hard disk, the more money will usually have to be paid for it.
Often hard disks are abbreviated. HDD - from English Hard drive disk (HDD). In colloquial speech, you can still hear the name "Winchester" or "screw."
External hard drives are connected to the computer through the already familiar connector. USB(fig.206).
Lesson # 70. Memory cards
Memory cards or flash cards - This is a compact electronic storage devices used to store information (Fig. 207). Modern memory cards are made on the basis of flash memory, i.e. by the same principle as flash drives.
If you have a digital camera, then one of the memory cards shown in Figure 207 will definitely be installed in it. The type of memory that is installed in a specific camera model is determined by the manufacturer.
Currently most popular SD cards are Secure digital memory card (fig.208). These cards have several sizes and are used mainly in portable devices (cameras, cell phones, PDAs, etc.).
Memory cards are used specifically as storage devices, i.e. on them, the camera records the captured photos, and in a pocket computer (PDA) you can use the card as a hard disk of your computer, i.e. save your files to the card or install programs on it.
When working with portable devices Inevitably there is a need to connect the device to the computer in order to copy information to or from the device. The same with a digital camera - sooner or later there is a need to transfer photos to a computer. How to do it?
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| Fig. 209. Card reader |
It is very convenient to work with flash memory cards through a device called card readerfrom English card reader (fig.209).
Typically, the card reader is a small box with different connectors and you can simultaneously connect memory cards of various formats to your computer.
The card reader itself is connected to the computer via the USB connector.
You can find card readers of various configurations and sizes on sale, but when purchasing a card reader, pay attention to what types of flash memory cards it supports. There are card readers that support, for example, only cards Secure digital. If you want to purchase a universal card reader, then look for the inscription “ all in one" or " all in 1". This means that this device works with all types of memory.
Lesson # 71. How to download photos from a camera
If you have a digital camera, but no card reader, then you can use the following method to transfer photos.
- Included with the camera is always a cable to connect to the USB connector. Connect the camera to the computer with this cable.
- Turn on the camera.
- The operating system will try to determine for itself what device was connected to the computer.
If you have an Internet connection, then most likely, you just need to wait about a minute until Windows will detect your camera and install the necessary driver.
Driver - This is a program that is a kind of intermediary between the operating system and the device. The driver “explains” the operating system, what kind of device is installed and how to work with it.
If you do not have an Internet connection, then most likely you will need to install the driver yourself. Included with the camera is always the disk on which the driver for the device is usually located. Read the camera manual and install necessary programs as described.
- After installing the driver, a dialog box will appear (Fig.210):
- The easiest option is to select an item. View files. A program window will open. Conductorin which you can work with photos on the flash card of your camera in the same way as on a computer. Those. You can simply copy the files and paste them into the desired folder on your computer.
The second way is to use the item Import images and videos. A window will appear Import images and videos (fig.211).
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| Fig. 211. Import images and videos |
In this window, you can configure the settings for importing images by selecting the appropriate item. A window will open Import Parameters (fig.212). In this window, you can customize the folder to which the photos will be copied from the camera. By default, photos are imported to the folder Imageswhich is in Libraries. Then you can specify the name of the folder that will be created when importing photos from the camera.
Look at Figure 212. Now selected. following settings - photos will be imported (copied) from the camera to the library Images, while in the folder Images a new folder will be created and it will be given the name as today's date.
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| Fig. 212. Import Parameters |
After you configure the import, click OK and in the window Import images and videos press the button Import (fig.211). Your photos will be copied to your computer.
Lesson # 72. We work with removable media
When working with removable media there are nuances that you should know. When we install a disk into an optical drive or connect a computer external storage device (USB flash drive, removable hard disk or card reader with a memory card) to the USB connector, then in the operating system Windows autorun works. It means that operating system automatically detects a new storage medium and, trying to predict our actions, displays a window with a list of operations that we can conduct (Fig. 213 and 214).
You can choose a convenient action from the list or close the window. Autostart and access information removable media through the program Conductor. By the way, point Open folder to view files just lead to launch Conductorin which the contents of the removable media will be displayed.
Window Autostart you may not appear. The fact is that the opportunity Windows by auto start attackers use to activate their viruses and malware on your computer. For this reason, some antivirus software and some programs designed to protect your computer may block Autostart. In this case, access to information located on the removable device can be obtained through the program Conductor.
Run Conductor and display the contents of the folder Computer (fig.215). I connected a USB flash drive to my computer, and I installed a DVD in the optical drive.
In Figure 215, you see what appears new section in folder Computerwhich is called Removable media devices. This section displays the optical drive icon (indicated by the letter E), and removable disk G - this is my flash drive.
To get me started with the information in these disks ( E and G) I need to go into them by double-clicking the left mouse button on the corresponding icon of the removable device.
Work with files located on flash devices (flash drives and memory cards) and removable hard drives, no different from working with files on the computer. This means that you can copy, move and delete information from these devices. Just be careful - when removing information from removable media, it DOES NOT FIT at Shopping cart, and immediately removed.
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| Fig. 215. Displaying removable devices in Explorer |
Files located on optical disks can only be copied or run. To delete or write information to optical discs, you need to use additional program, which we will discuss in the future.
Now let's look at how to properly remove removable storage media from the computer. There are a few rules that I follow and recommend them to you.
If you are working with information located on an optical disc, then before removing the optical disc from the drive, make sure that no file or program is running from this disc. There is nothing to worry about if you eject the disk while the file is running from it. Simply, the operating system will lose connection with this file and will ask you to install the disk again. Those. You will not cause any harm to the disk or files located on it, only you will lose some time to reinstall the disk and re-extract it after the file is closed.
The situation is different with flash drives, memory cards and removable hard drives. If you simply remove the device from the slot, then you can damage the information that is on this device, and in some cases the device itself.
Before removing the device from the computer, you must disable it. For this in Windows there is a tool called. To access it you need to Notification areas select the corresponding icon (fig.216), then click on it with the left mouse button and a menu will appear (fig.217) in which all the disks available on your computer will be listed. From the list, you must select the disk that you want to disable, i.e. our flash drive, memory card reader or removable hard drive.
After that, in the notification area will appear announcement (fig.218):
Homework:
1. If an optical disc drive is installed on your computer, then install what disks it works with (CD, DVD, Blu-ray). This information is usually located on the drive tray (fig.199). If the drive allows you to burn discs, then it will be marked “RW” or “Recoder”.
2. If you have a memory card, for example, in a camera, then find out its size and type. You will need this information if you decide to purchase a larger card or card reader.
3. If you do not have a card reader, copy the photos from the memory card using Windows (fig. 210).
4. Connect your USB flash drive to your computer via the USB connector, launch a file from it and try to disconnect it via Safely remove hardware and drives (fig.216). A warning window should appear (fig.219). Then close the previously running file and repeat the action. An informational message should appear as in Figure 218.
In the constant pursuit of gigahertz and gigabits per second, which the CPU passes through, we very often forget that there are many other important components in the computer that need improvement, for example, RAM, as well as drives that store the processed data. The development of devices that allow information to be stored is just as important as increasing the computing power of the CPU. In this article we will talk about what the prospects are facing modern storage media, such as hard drives.
In the second part of the article we describe the future of optical disk drives, while in the third we will try to consider some of the most interesting and fundamentally new developments in the field of microelectronic mechanical systems that may be used in devices that have replaced traditional HDD and less traditional, but quite familiar CD, DVD and BlueRay.
In order to be able to compare the various types of media among themselves, it is necessary to single out some characteristics inherent in each of them. Such, for example, as the speed of reading or writing, the average search time for an arbitrary data element (Random Seek), as well as the cost of storing a unit of data. If we want to compare data drives that are not yet in nature, but they will be born in the future, then we need to try to break them all into three large groups: those that are about to be produced and will soon appear on the market; those that will become widespread in a more or less foreseeable future and, finally, those that will appear only under favorable circumstances and the successful completion of all research related to their implementation. In fact, it is difficult to compare a modern hard drive with a random access time of 9.0 ms with some drive of the distant future, which will have the same characteristic several orders of magnitude better (that is, less), but which is not on the shelves of stores yet will be in the next fifty years. Naturally, such comparisons continue to be done on the Internet, forgetting that the prototype, which appeared in the top-secret laboratory of Silicon Valley and works only at temperatures close to absolute zero, is not the same as the hard drive that you have in your computer desktop.
Trends in the development of magnetic storage media
Let's start with hard drives, because today this is probably the most common and demanded type of drive, and in the next 3-4 years there will probably not be any hard competition from other types of drives. Opponents are still clearly losing either in speed, or in capacity, or in cost, and most often - in several ways.
We all know what the hard drive is today: capacity - say, from 20 to 400 gigabytes, average search time - from 8 to 12 ms, sequential read / write speed - 30-40 Mb / s. In principle, the characteristics are not bad, although, again, it depends on what to compare: RAM will work faster (but it turns out to be more expensive, and besides, when you turn off the network, it completely “forgets” everything that was written to it, - agree, a significant drawback); rewritable DVDs are much cheaper (but in terms of the speed of work they did not lie near, besides, their capacity is relatively small).
If you remember how much data you have to read and write to the hard drive when working with multimedia, and the fact that most modern operating systems one way or another uses it as an addition to random access memoryWhen writing a swap file there, it becomes obvious that no matter how good the characteristics of the hard drives are, it would be nice to improve them. First of all, manufacturers would like to increase the mentioned read / write and search speed, as well as capacity. In second place are the dimensions, as well as power consumption and impact resistance, coupled with reliability. Naturally, in future models of hard drives these characteristics will be surely improved, only questions remain: how and when?
It is possible to achieve an increase in the speed of reading in two ways: either by increasing the information recording density, or by forcing the hard drive's “pancakes” to rotate at a higher speed. Both methods have their drawbacks. With an increase in the spindle rotation speed, the hard drives begin to warm up much more and become noisier, not to mention that the material from which the plates are made must be strong enough to withstand the corresponding mechanical loads and not be deformed. The technology of their manufacture becomes more complicated, and this is reflected in their cost: it is significantly higher. But in addition to increasing the linear reading speed, the average search time also decreases, due to the fact that the head earlier finds itself above the required sector of the track. The problem with excessive friction and noise can be partially solved by hydrodynamic bearings, which some manufacturers began to use relatively recently, but it still seems unlikely to us that the spindle speed in 3.5 "HDDs may exceed 15-20 thousand revolutions per minute, whichever "Cunning" and "fancy" bearings are not used.
As the recording density increases, there are also some negative side effects, but it is still easier to deal with them. But the advantages include an increase in storage capacity, and this is for manufacturers of hard drives in many ways a far more important parameter than the average search time. After all, the average buyer pays more attention to it. Therefore, hard drive companies often try to improve their products in this way.
Superparamagnetic limit
Interference in achieving ultra-high recording density
The plate of a modern hard disk consists of a glass or aluminum substrate with a magnetic coating applied from above. Some areas of this coating can be magnetized by one of two possible ways, which denote zero and one (i.e. 1 byte). This magnetized area is called a magnetic domain, and is a miniature magnet with a specific orientation of the south and north magnetic poles. If you set the domain magnetization, the information will be recorded. Ultimately, the information recording density determines the size of this domain itself. It would seem that reduce the size of your domains to health, and the hard drives will be as capacious as you can imagine, but not everything is so simple.
Those of us who have not forgotten the school physics can strut and remember that all substances are divided into paramagnetic, diamagnetic and ferromagnetic. Diamagnetic are those substances that, being outside the magnetic field, do not have magnetic properties - it is clear that they are not suitable for creating storage media. Atoms and molecules of paramagnetic substances, on the contrary, by themselves, even before an external magnetic field began to act on them, are elementary magnets - however, they are also not very suitable for creating storage rings. And only ferromagnets, in which magnetic grains of sufficiently large size act as elementary magnets, are suitable for long-term storage of information.
To record one bit of information, the head of the hard drive creates a certain directional magnetic field, which orients all the elementary magnets of the domain mainly in one direction. This orientation is safely maintained for a long time after the head ceased its effect on the ferromagnet. However, even after multiple recordings, such magnetic grains always remain in the domain, the magnetic orientation of which does not coincide with the orientation of the entire domain; moreover, the relative content of "bad" grains is the greater, the smaller the grains in the domain, that is, the smaller its size. If you try to make the domain too small, then the relative amount of "bad" grains will be so large that the information signal cannot be distinguished from the noise. From this situation, there are two ways out - the search for new paramagnetic materials with small and mostly homogeneous magnetic grains and the development of algorithms that allow us to isolate the useful signal even with a low signal-to-noise ratio. However, there is a limit to its possibilities. If the magnetic grain is too small, then the thermal energy of the environment is more than enough to spontaneously change its magnetization. Roughly speaking, in this case we will get a substance that is very close in properties to paramagnetic - the hard drives made of such materials can work only when cooled with liquid nitrogen or, worse, with liquid helium. Because of this quasi-transition of a ferromagnetic substance into a paramagnetic one, the described restriction is called the superparamagnetic limit.
Well, besides a purely physical limitation in the form of a superparamagnetic limit, there is also a technical one associated with the process of recording and reading information, for which, as already mentioned, a special head is used. In the very first models of winchesters the head was universal - the same tiny inductor was used both for reading and for recording information. Modern heads consist of two parts: the recording (coil inductance) and the reading (magnetoresistive head, which changes its resistance depending on the magnetic field strength). Naturally, the size of the head is finite, and today it is they who largely determine the size of the minimum magnetized area - the domain. However, in modern hard drives, the domain size is so small that to further reduce it, manufacturers will need to step over the superparamagnetic limit.
That is why experts from leading companies developing hard drives have long been struggling with the problem that has arisen, and I must say, quite successfully. The ways of development of technologies and own know-how, allowing in the future to overcome the superparamagnetic limit, developed by each of them. Moreover, some are already used in mass production of hard drives, some are used only in prototypes, but from day to day will be used in conveyor assembly, some may never get to mass use.
AFC
Perhaps the first sign that foreshadowed a quick victory over the superparamagnetic limit was the technology of creating magnetic-compensated films proposed by IBM. The essence of the idea is to apply a three-layer antiferromagnetic coating called AFC (antiferromagnetically-coupled, antiferromagnetic pair) to the hard drive, in which a pair of magnetic layers is separated by a special insulating layer of ruthenium.
Due to the fact that the magnetic domains located under each other have antiparallel orientation of the magnetic field, they form a pair that is more resistant to spontaneous magnetization reversal than a single "flat" domain. Trial batches of the winchesters using the AFC technology appeared in 2001, but its mass use began only now. However, AFC is not an absolute panacea - it is only a small improvement in the old technology, which allows to increase the capacity of hard drives by 4-8 times, but not more.
PMR
Perpendicular recording (PMR, Perpendicular Magnetic Recording) promises a significantly greater gain. This technology is known for a long time, its research was actively engaged already 20-30 years ago, but then it didn’t work to bring it to a working and inexpensive device. Now PMR has been recalled again, the development of new hard drives based on this technology is very fruitful for Seagate. In August 2002, in Pittsburgh (USA), she organized a special research center, whose plans included a thorough study of not only PMR, but also other problems associated with the creation of promising storage media on magnetic media. As the name suggests, PMR, in contrast to the classical recording technology, uses magnetic domains with a perpendicular (rather than parallel to the disk surface) magnetic field.
This allows you to reduce the longitudinal size of the domain, while slightly increasing its height. In addition, in the case of PMR, the neighboring inverted bits (1 and 0) no longer look at each other with the same poles, which, as is well known, repel each other, this reduces the size of the interdomain space, as compared with the classical recording technology, which further increases the capacity winchesters.
It is clear that for the implementation of PMR it is necessary to apply both a completely different design of the read / write head and a new structure of the magnetic surface of the disk. A PMR recording head should have only one core core core, the other pole will be auxiliary. The main pole of the core creates a strong magnetic field whose lines extend perpendicular to the magnetic surface of the disk; passing through a special internal magnetic layer, they close at the wide auxiliary pole of the core. Naturally, the strongest field will have the strongest field at the main pole - the domain will be re-magnetized, the wide auxiliary pole will have too weak a field to affect the disk surface, and it will remain unchanged when recording. Like AFC, PMR is a technology ready for use in mass production. Winchesters using it should appear, if not in this, then in the next 2005.
HAMR and SOMA - technology of 2010
Among the most promising technologies of the future, the task of which is to supplement PMR, when it exhausts its resources and approaches the next limit, we can include thermomagnetic recording (HAMR, Heat Assistant Magnetic Recording) and self-organizing magnetic grids (SOMA, Self-Organized Magnetic Array) . Dieter Weller, director of media research at the Seagate Center, believes that HAMR is intended to change the principle of reading and writing data once again, and SOMA is the process of producing magnetic sputtering for disks.
A special feature of HAMR is the use of magnetic materials with high coercivity, which ensure the high thermal stability of the recorded surface areas. To record information, the magnetic domain is preheated using a focused laser beam. The beam diameter determines the size of the area corresponding to one bit of information. With an increase in the temperature of the domain, a significant change in its magnetic properties occurs (the coercive force decreases), and thus the heated regions become capable of magnetization. Naturally, for the introduction of HAMR into mass production it is necessary to solve many problems, such as the development of low-cost and miniature lasers with a very small wavelength (otherwise it will be impossible to create a focusing system), it is also necessary to provide an effective heat dissipation from the plates (remember, What will happen if they are also heated by a laser, like food in a microwave?) and a number of others. However, the fact that Seagate experts have already assembled an existing experimental setup that implements the recording using the HAMR technology says that these problems will most likely be successfully resolved. The company promises that HAMR will be used in commercial products as early as 2010.
However, as already mentioned, to further increase the recording density, it is also necessary to change the manufacturing technology of the magnetic disks themselves, achieving uniformity and uniformity of the layer of particles that make up its surface. If this is not done, neither the HAMR nor any other tricks with the recording head will help. Modernization of reading / writing mechanisms should go hand in hand with the improvement of materials and the quality of deposition of the magnetic layer. Here, experts see a way to use the already mentioned SOMA technology, which provides for the formation of a self-organizing magnetic arrays on a disk surface from a tiny homogeneous iron-platinum conglomerate about 3 nm in size (3 nm is 10-15 solid atoms laid out in a row ).
The use of this "nanotechnology" will significantly reduce the level of instability of individual magnetic grains and reduce the size of the magnetizable area to record data bits. In Seagate believe that all this may allow to produce drives in tens, and maybe even hundreds of terabytes. And this will happen not in the transcendental future, but by the beginning of the next decade.
Instead of conclusion
As we can see, the improvement of hard drives on their way to achieving the superparamagnetic limit can lead to the fact that they will infuse some properties of their closest competitors - optical storage media, such as CDs and DVDs. Naturally, all this will lead to a sharp increase in their complexity, and therefore cost. At the same time, optical devices devoid of any superparamagnetic limits will develop, capturing more and more new frontiers, gaining successive victories, and probably in ten or fifteen years will surpass all the main characteristics magnetic drives. In the second part of the article we will try to deal with the future CD and DVD, as well as their numerous modifications and successors.
