Let's start with the first - breakdown of a single hard disk space into smaller pieces. It is only for us, users, the hard disk looks the creature monolithic, one and indivisible. Although even from a physical point of view, this is not the case: the informational space of our hard drive is located on several physical plates? Now it turns out that on the logical level of disks on one hard drive can be somewhat! First of all, the disk can be divided into several sections. For example, on two - the main and optional. The main program necessary for the computer (operating system) must necessarily live in the main section (in practice, several operating systems can be installed on the computer). But the most interesting starts next: in each section, we can create a few more logical disks! At the same time, for us, users, and for the computer they will look like separate devices, each of which will wear its own name. It happens on the contrary - thanks to RAID technology, you can combine several physical disk into one logical disc. « winchester » . At home this method is rarely used, but on powerful servers employed, for example, video processing or in computers « libraries » , such « superdisci » there are always even around.

In most cases, when installing a new hard disk, only one partition is created on it and, respectively, one logical disk. But many users believe that it is reasonable to make it possible for the right organization of work anyway. For example, if you have a high-capacity hard drive in the system (from 100-200 GB), it can be divided at least two sections. The first, volume of about 25-30 GB, can only be removed under the operating system and application programs. And the second, more section, to give off documents, photographs, music collections or films. Why do you need it? Very simple: in the event that with « systemic » the section will happen to the section, your documents will remain in inviolability in its « reservations » .

Several logical disks will use you in the event that you want to install several operating systems on your computer (for example, Windows and Linux). True, such tricks are engaged in statistics, less than one percent of users.

So, the hard disk is divided into partitions, in the sections, in turn, logic disks are created ... It is clear that each such disk should have a name - it is more convenient and the user and the computer itself.

Disc names are the letters, for example:

| A:- floppy;

| C:- HDD;

| D:- the second hard disk or, in its absence, DVD drive ...

By the way, when you connect replaceable drives to the computer, for example, a flash keychain or an external hard drive - the computer immediately highlights them your own letter, and when you disconnect the device and remove the disk from the system, the letter will be released. So, theoretically, in the computer you can safely create at least two dozen« logical disks» - There would be enough letters. Although it is important not to overdo it - what a sense from the top ten« virtual» disks for several gigabytes each!

To break the hard disk to partitions, we can use both standard programs and individual Partition Magic utilities from Symantec.

Clusters and sectors

So, we broke the disk to sections and logical disks (or created one section and disk - no matter). So to speak, broke the field to the plots. But our work is not finished yet: after breakdown, we have to perform the formatting operation, the logical markup of the entire space of the hard drive. Such formatting is the same as plowing, turning the shapeless space to the finished field, decorated with neat furrows.

However, « furrows » already laid to us: at the physical level, the hard disk is already broken on the tracks, which in turn are divided into sectors. Sector- This is the minimum physical volume of the disk, which can be busy data: as a rule, its volume is 512 bytes. It's quite a bit - imagine that you need to crush a big file to pieces of 512 bytes, and also remember the location of each such grain! That is why, with the logical markup of the hard disk, larger logical sections are created on it - clustersuniting several sectors. The number of sectors in the cluster, and therefore, its size, depend on the volume of the hard disk and the selected type of file system.

Here, for example, cluster Sizes Table for NTFS File System:

The cluster size affects the volume occupied by your files, and the speed of the entire system. After all, the cluster partially occupied by any file cannot be placed anything else. Suppose your file is located in 10 clusters of 1024 MB, and in the last - tenth cluster it takes only ten bytes.

What happens to the remaining free kilobyte? Nothing. He just disappears for you. Such not suitable for nothing to call "Tail". A B. « tails » it is often a rather significant volume - up to several hundred megabytes!

If the volume is more important for you, the cluster size should be as little as possible. But it is also possible to reduce it to infinity too: the smaller the size of the cluster, the greater the data fragmentation on your computer (which in turn leads to a decrease in the rate of data exchange with a hard disk). The last stage of preparing a hard disk to work - Creating file Placement Tables(FAT), a peculiar table of contents in which all your files and folders will be listed, as well as their physical addresses on your hard disk. However, about files and folders - « containers » where all information is stored on your computer is to tell in more detail.

How is the information stored?

Now, if you are asked how information is stored on your computer, you can answer like this:

| Where exactly?- on the tracks and sectors of the hard disk (or, on the logical level - in the form of clusters on logical disks).

| How exactly?- in the form of logical zeros and units (bits), as well as their groups (bytes).

All this is correct ... But still incomprehensible. The computer is so, maybe, it's easier, because it is absolutely indifferent than we score Winchester - whether documents, music or pictures. For him, all this is the information that only needs to be divided into certain pieces - and at any time know where one or another piece is located. But we, users, have to deal not with bits and bytes. And even more so - not with clusters and sectors. We are also interested in another division of information - logical. Content. Therefore, we need to take a new unit, a new reference point. Such units and will be the file and folder for us.

Files

File (File)translated from English - a sheet on which some information can be recorded. It does not matter that this is the program code or the text you have created. The other is important - each such sheet is something logically completed, complete.

The file can store any information - text, graphical information, software code, and so on (although there are also some combined files, including, for example, a picture, text and program element). The main thing is that we, users, can always distinguish one « piece of information » from the other and knew exactly how we work with each type of files.

How it's done? Very simple: each file, like a person, has its own « name » and « familia » (it is called « type » file).

File namemost often can be selected arbitrarily by the user. Say, you created a file document with the text of your contract with the company - it can be called « Treaty » , « Document 4155. » or even « April theses » . Previously, in the era of DOS, the names of the files could be the maximum of eight letters of the Latin alphabet - today they can be up to 256 and there are no linguistic restrictions left. Working with the Russian version of Windows, we can give Russian names to our files, and the Chinese, for example, can easily use their hieroglyphs. Another question is that such a document can not always be opened on other computers - « american » Windows may not understand the Chinese name, but ours, the Russian version often stumbles on Western European characters.

File typeshows what kind of filling is stored in each information « container » - Does this drawing, text or program.

About the type of file tells itexpansion - Part of the name of three (rarely from four) letters separated from the main part of the title point. For example, the file in which this book is stored is called compbook.doc.

In the computer world there are countless extensions - remember everything is simple unreal.

However, the main extensions are not so much:

¦ eXE - denotes « performing » file storing the program. For example, Winword.exe;

¦ com.- Another type of program file. Usually files.com correspond to a small (up to a hundred kilobytes) programs. Often they met in the DOS era, however, today we practically got off the scene;

| Bat.- The so-called batch file designed to serial multiple programs (or commands). In fact, it is an ordinary text file in which the names of the program files that you want to perform in the manner you need are scored. Example - AUTOEXEC.BAT file that is automatically executed at the time of the computer loading;

| CFG.- a configuration file in which the program indicates the parameters of its work;

| DLL- the so-called dynamically connected data library to which several programs can immediately contact;

| HLP.- a reference file in which is stored « tips » , and sometimes a complete manual for a particular program;

| TXT., dOC- text files;

| Htm., hTML- hypertext document internet;

| XLS.- spreadsheet;

| Dat.- data file;

| Wav, mp3- sound in digital format;

| BMP., jpg.- graphic information, pictures;

| Arj., zip., rAR, 7z.- files of archives, that is, compressed using special programs "Archives » information. In one archive file, many files can actually be stored. Etc.

Working in Windows, you most often see not expanding the file, but the corresponding graphic icon. For example, a sheet with text and the letter W will show that in front of you - a document created in Microsoft Word. This, of course, is convenient - but just do not forget that the icons may vary depending on which the program is attached to one or another file type. In addition, several types of files can be designated one icon. Expansion in all cases remains unchanged. There is a file and another sign called attribute. However, in contrast to the name and expansion (and in Windows - a defined type icon), the user does not see it. But it sees great and understands the computer.

Here are just some of these attributes:

Hidden(Hidden). Files with these attributes are usually not visible to the user. For reinsurance - as a rule, these files are very important for the functioning of the system. Although the experienced yooner will not be difficult to configure the file viewing program (file manager) in such a way that all hidden files will be visible as on the palm.

Only for reading(Read-only). But these files are always open to a curious breath ... but only. Change their content cannot be - at least without a special user team, in order not to be completely sure what he does.

Systemic(System). This attribute, as a special acquaintance, marked the most important files in the operating system responsible for downloading the computer. Their damage or removal always entails the greatest consequences, so the generous computer, not sting « awards » they are at the same time and two previous attributes - « only for reading » and « hidden » .

Archival(Archive). This attribute is usually set while working with the file when it is changed. At the end of the session, it is usually removed.

Folders

If we compared files with leaves, then why should we continue the analogy further? Where are those trees on which such useful leaves grow? Comparison with wood is not accidental here. After all, the location of the files on the hard disk is called the tree structure. There are leaves. They grow on branches. Spreads in turn grow on branches. Branches ... well, let's say, on bunches. And there is a bitch ... and so indefinitely. It is clear that it is impossible to keep completely different files in one pile. They must be ordered. Each cricket is its sixth, each family - a separate apartment ... Well, and so on.

Files are combined into special structures -folders . Or -catalogs . Or -directors . Or -folders . It is completely unclear why it was necessary to create such a bunch of terms for a single item. The folder is the latest term and, in my opinion, the most successful. It is in the folder that the files are lying. The folder that can be opened at any time and find the desired sheet. The folder in which, by the way, you can attach another folder ...

Usually each software package installed on your computer occupies a separate folder. However, it happens that the program, as if a tricky bird-cuckoo, spreads its files on many folders. This is especially like to make software packages running under the Windows operating system.

How to distinguish the folder from the file? Not so difficult. First, the folders do not have extensions and are designated in Windows by special icons - just in the form of the opening folder. Secondly, the editing operations cannot be applied to the folder. Rename, move, delete - please. And, of course, the folder can be opened to see what is in it. To do this, just click on it twice with the left mouse button.

Well, now we will figure it out how the logical address of any file or folder on our hard disk looks like. The first element of this address is the name of the disk. It consists of one letter, colon and reverse braid, called computer jargon back-slash:

A: \\ C: \\ D: \\ E: \\

Disk A:most often is called a drive and until you insert a floppy disk, you will not have this disk. And God with Him: And without it there is enough disks.

Disk C:- The main hard disk of your computer (or logic disk in the main section). It is from this disk that the system is loaded, it is on it « lives » most of your programs and documents.

If your system has more than one hard disk or a single hard disk into several partitions, these sections will wear names corresponding to the following letters of the Latin alphabet. And the last letter name usually denotes a CD-ROM drive.

C: \\ Windows.

Well, the third element of the address is the name of the file itself. For example, the address

C: \\ Windows \\ regedit.exe

complies with the program for editing the Windows registry, which is located on a C: \\ disk in the Windows folder.

File system

Well, now we understand how the computer is more convenient to store the data and in what form we prefer to see them we. It remains behind the frame only one thing - in the same way the sectors and clusters scored by bits and bytes turn into convenient files and folders for us! Mystic, magic? Not at all. Simply, telling about the logical structure of the hard disk, we deliberately missed a very important stage - the creation file System . Namely, it allows you to finally streamline the data on our hard disk and at any time extract from this information pantry necessary piece.

When we write files and folders to the hard drive, the computer splits them into the clusters familiar to it and spreads through the entire space of the hard disk. The file, of course, is not placed in one cluster. He lives immediately in several, and it is absolutely not necessary that these clusters will live next to the peas in the pod. It happens more often on the contrary: the file is stored on the disk in a fragmented form - « head » in one section of the disk, « legs » in the other ... so as not to get lost in your own « bins » , computer creates a special special hard disk at the very beginning « guide » by its content - FAT, file placement table. It is in FAT that all information is stored about exactly which clusters take a particular file or folder, as well as their headlines. On the one hand, it is convenient: with this method of placement, the computer should not be feverishly searching on the hard disk a piece of this size that is suitable for a specific file. Write where he wants! Yes, and delete files and folders it becomes easier - you do not need to erase the contents of the clusters belonging to them, it is enough to simply declare them free by changing the pair of bytes in Fat. Yes, and the user has the opportunity to quickly restore them with the help of all the same pairs of bytes ...

File Placement Table- This is part of the file – systems responsible for storing data on our computer. File systemit is created on the hard disk at the final stage of formatting, and it is from it that such important parameters are dependent as the size of the cluster, the number (or view) of the characters in the file name, the possibility of working with folders and much more - up to the maximum size of the hard disk ...

There are several standard file systems tied to specific operating systems.

For example, ancient DOS.and the first versions of Windowsused the 16-bit FAT16 file system, in which there was no support for long names, and the volume of the logical disk could not exceed 4 GB (65536 clusters of 64 KB). In particular, this particular factor forced the owners of high-capacity Winchesters « break » its into several sections - otherwise it was impossible to work with the disk.

For Windows 95.a new modification of the file system was created - 32-bit FAT32, which made it possible to use long names to use us. The maximum cluster size decreased - up to 16 KB (the standard size was 4 KB). And most importantly, the maximum hard disk size increased - up to 4 TB! However, it turned out quite soon that FAT32 works well-work: despite the declared support of up to 4 TB of disk memory, the standard utilities allowed to create logical sections with a volume of only up to 32 GB. In addition, the file size in FAT32 could not exceed 4 GB, which extremely complicated the work to lovers of digital video (because a digitized film can take hundreds of gigabytes on the disk!). So think about changing the file system I had to rather soon, although today FAT32 is used, for example, when creating DVDs. And seven years ago, the world slowly began to go to the file system of the new type - NTFSQuantitative changes in which were much less interesting than high-quality. Yes, thanks to NTFS, it was possible to remove the restrictions on the file volume - now it can occupy at least the entire hard disk of the whole - and the maximum size of the disk partition increased to 12 TB. However, more interesting were new features: besides the usual logical NTFS logic disks, it allows you to create dynamic hard drives, supports encryption and password protection of individual sections and folders.

The main quality of the new system is the reliability of data storage: if« drop» the hard disk with FAT32 was easier, then under the protection of NTFS your data will feel much more confident. NTFS leads its own operation log, which allows you to protect data in case of failure.

Try to suddenly turn off the computer when copying or deleting a file in FAT32 - and, most likely, you pay for such a data loss. After all, the changes in the location table will not be saved, and your document will turn into a bunch « lost clusters » . Therefore, Fat is always stored in 2 copies! NTFS makes changes to the table only when the operation is successfully completed, and « magazine » helps to insure files from premature death.

Alas - for the sake of reliability you have to sacrifice compatibility:

If hard drives formatted in FAT16 and FAT32 are able to see almost all versions of Windows (as well as operating systems of the Linux family), then when using NTFS, you are tightly tied to the rulerWindows 2000 -HR -Vista .

If two operating systems fit on your computer - old Windows Me.and new Windows XP.(with the NTFS file system), - then the contents « ikspishy » the partition or a whole disk will remain invisible to ME. Moreover, you lose the ability to work with a disk, loading in mode « command line » from a compact disk or « boot » diskettes - for the DOS file system NTFS, too, no matter how exists.

Finally, if you convert the FAT32 file system to NTFS will not be difficult, even with the help of standard Windows programs, and with the full saving all information, then the reverse transformation is simply impossible without disk formatting. And, as a result, the loss of all information ...

Of course, there are special programs for working with partitions and file systems - for example, Partition Magic, which can convert NTFS disk to FAT32 without losing information. But their use is associated with considerable difficulties - especially for newcomers ... And yet, despite all the shortcomings, the use of NTFS today gives much more advantages than inconvenience. Therefore, confidently answer "Yes!" On the question of translating to NTFS - and finally, say goodbye to the past.

Programs and their types

Working with a computer, most people do not create the necessary programs independently, but only uses ready-made developments. Therefore, they are called users. However, it is also not easy to be a user. After all, you need to be able to not only handle multiple common software packages, but also to navigate « software sea » - In order to easily and quickly find the desired program and learn how to work with it. List them all? But it is almost impossible: there are hundreds of thousands, if not millions of a variety of programs, and about hundreds are added to them every day! So is it worth trying to argue the immense? Therefore, we will try to smash the entire array of programs created in the world of several basic groups.

Types of appointment programs

As you know, each program is responsible for its specific plot of work. Some helps to create text or graphics, others - to restore order on the hard disk, the third - to work on the Internet ... Sometimes it seems that how many programs can be their categories. And partly it really is. However, with some zeal, you can try to reduce all the software abundance to several main sections. We break together the classification and we, creating a small « periodic table program » in the spirit of Mendeleev.

The first and most extensive group of programs that we have to deal with the system programs.

Systemic- So necessary to ensure the normal operation of the computer, its maintenance and settings. Such programs refers primarily the operating system. And a number of auxiliary small programs - utilities.

Operating system- This is the first and chief mediator between computer « iron » and all the other programs, the soul and the heart of the computer. There is no operating system - and your computer will not be able to perceive any command - it will not even be able to boot.

Utilities. This class combines a huge number of useful programs designed to serve your computer. It is necessary to approach the choice of utilities especially thoroughly, in order not to overdo it. But also to skip something really useful is not worth it - a correctly selected utility can significantly ease your life. You can also include tests - programs for testing both software and PC hardware resources.

Of course, unfairly, the largest number of programs was created to maintain the needs of the computer, and not his host - a person ...

Application programs.The most important programs for us, so to speak, creative, work tools designed to create and process information.

The user, in contrast to the computer, is an extraordinarily whimsical being. Therefore, the types of application programs are much more than systemic. Let's call only some of them:

Office programs. The task of these programs is to create and edit documents, whether text, spreadsheet, image or a totality. Sometimes such programs are called older « editors » (Although the real editor remains a person, and the program is only its working tool). Today, individual programs of this class on the market almost never left - much more often sold « full sets » including everything you need. The most popular Microsoft Office office package consists of a text editor Microsoft Word, Microsoft Excel spreadsheet, programs for preparing Microsoft PowerPoint presentations, Microsoft Access database management programs and a number of auxiliary programs are smaller.

Mansion cost financialand accounting programs. Home Accounting today has not yet become fashionable, but it is only a matter of time! In the west of the expense planning program, accounting for family finance and tax calculation has always been among the most popular. In the same group - spreadsheet and auxiliary financial utilities.

Multimedia programs. "Media » translated means - « carrier » , « bulletin » , and in modern interpretation - type of information. That is, « multimedia » - This is a combination of all kinds of information. This term itself was born in the era, when the use of any information means, in addition to « naked » text, it was for a computer into a circle. Strictly speaking, « multimedia » you can call only those programs that can work with several types of information. But there are not many such programs in nature ... and so it turned out that « multimedia » today they call graphic, and sound, and video programs ... Word - those that work with the type of information other than textual.

Programs for processing and creating images. This is already quite professional programs, which is worth it to your computer only in one case - if you at least know how to draw. If not, even such a powerful program as a vector graphics editor (drawings) CorelDRAW will not help you. The same applies to programs for processing photo images - for example Adobe Photoshop. Of course, with their help you can build a magnificent photo montage or mocking a photo of a adorable wife ... But, again, is it vital for you?

Programs for working with sound.The minimum set of programs for processing and playing sounds and music is already included in your operating system. Several additional programs (for example, players, or « player » ) do not interfere. And serious, professional sound processing packages (Sound Forge, Cooledit) Leave professionals.

Players(Players) and viewers (Viewers) Unlike editors do not allow you to edit a text document, a sound file or video. Their task is modest - for example, play a music composition or display a picture.

Editors of three-dimensional graphics and animation. Thanks « Park of Jurassic period » and other fissure special effects of films, these programs have become surprisingly popular with us (although in the West the same 3D Studio Max or Softimage - purely professional programs worth dozens of thousands of dollars).

Professional programs.Extremely conditional group. In fact, the professional, highly specialized programs can be attributed to the program of any group - it depends only on its « fedoon » , in demand, relatively small circle of people and, as a result, high price. Combines these programs one - for home office and for everyday use they are unsuitable. And they are needed to specialists who know why they need, in fact, this program is needed. You can, of course, and at home in 3D-Studio play, but this is ungrateful. Of course, in addition to what is described here, there is another sea « specialized » programs, but write about all, alas, it is impossible.

Programming tools. Superchadded programming systems, professional compilers and more. For programmers, this is the number one tool, but the home user most often they are not needed. Although many modern programming systems are so simple and « visual » What allows you to create applications by designing them from finished blocks.

Automated Design Systems(CAD). These programs (for example, AutoCAD) also often put on household cars - according to ignorance, apparently, for drawing professional block diagrams The occupation is difficult and the game is not similar.

Mathematical and scientific programs- The patrimony of scientists and advanced engineers.

Commercial status of programs

In addition to the thematic division of programs, there is another classification. It is connected with the way of distributing the program and the conditions, accepting which, the consumer is able to use it. Well, of course, with its cost ... The fact that programs are paid and free, knows every user. But few people guess how many modifications « paid » and « free » did the cunning authors of the programs.

Free Software(Freeware). Initially, the principle of Freeware was distributed by small utilities or free additions to famous commercial packages. However, today the principle of Freeware is sometimes distributed and quite serious packages of well-known manufacturers, including Microsoft.

Freeware programs sometimes include applications applied on the OpenSource (open source) principle - for example, Linux operating system and applications for it. However, this is not entirely true: OpenSource postulates imply the ability to change the program code by the user by the user (what is not all the authors of Freeware programs go). And the distribution of such products does not have to be free - so, there are many in the world « commercial » versions of the same Linux. However, most often Freeware and OpenSource go hand in hand.

Conditional Free Software(Shareware). The most massive group of programs that includes almost all utilities, and often - and very serious, skillful software packages. As a rule, Shareware programs are distributed in the form of full-featured versions, limited either by time, or by the number of launches. After the time limited to you, the program (usually from 15 to 45 days), the program is either just stops running, or loses part of its functions, turning into a less functional freeware version. In the case most favorable case, the program fully maintains performance, but from time to time it bothers with urgent calls to pay - this is exactly what the popular file manager of Windows Commander.

If you still decide to purchase a program and list at the expense of the author, then in exchange you will receive a special digital code (key) to be entered into a special program registration window. As an option can be expelled special« key» the file that must be copied to the folder with the installed program.

"Advertising and paid" programs(adware). The flourishing of this type of programs fell at the end of the 90s - today their popularity decreased significantly. The Adware principle implies that he pays for the program is not a user, but an advertiser who in return is given to the placement of information about its products - in the form of banners or pop-up windows. And users have to look at this advertisement, and sometimes - also click on the pictures particularly like, going straight to the site of the company-advertiser ... The return from these travels is not too large, however, the clients can bring, for example, the online store hundreds of dollars Profit, 10-15 of which he will pay the programmer with the hunt.

Unfortunately, the creators of the programs often abused this opportunity, introducing spyware modules into their products and even viruses, so today adware programs are practically delivered outside the law.

Commercial software(CommercialWare). For these programs, you should always pay, and most often - quite significant amounts. This includes all major software packages of well-known manufacturers and a number of utilities. Programs of this type can be purchased in beautiful boxes or without it in any computer supermarket. However, today more and more often software products are sold through the Internet. You can buy them either on site manufacturers sites, or in large online software stores. You can get the goods in two ways. Large programs in the form of the most colorful boxes with a CD or documentation are delivered to you at the courier service or by mail, and you can copy small programs directly from the Internet site. At the same time, as in the case of ShaReware programs, you get a trimmed ( Demo.) or limited in time of work ( Trial) version. Trial, like a shareware program, can be turned into a full-featured option by registration, but with a demo the focus will not pass, since there are no other functions in it initially. For example, in a text or graphic editor you will not be able to save the changes made by you.

OEM version. Special options for ordinary commercial programs that are supplied at a reduced price along with ready-made computers. For example, Windows costs in the OEM supply can be cheaper several times « boxed » versions.

"Conditional" programs(Donation Ware). The author of such a program hints that, in principle, he would not refuse to pair-other coins for his brainchild, but he does not force anyone and the functionality of the program does not limit. A desire will appear - pay, it will not appear ... Well, no, there is no court! It is clear that such « altruists half » among programmers are a bit. And honest payers among users - and less.

"Cut out" versions(Cardware). A very exotic kind of programs, as a remuneration for the use of which you are asked to send the author a beautiful postcard.

Versions of programs

Programs, as you know, write live people. And people have a habit of mistake. And in error programs, there are perhaps more often than in all other types of human activity together. There are many reasons for this, but the main is the complexity of modern computers: no person can track all the commands performed by the computer during the operation of the program, there is a lot of things there are involved. I do not even talk about the wild diversity of all sorts of glands, settings and installed programs, with which the creation of any programmer is found, published « in light » . Well, of course, about the mistakes of the programmer itself - both in the algorithm, and in its implementation - too, you should not forget ...

In order to understand where the implementation errors come from, you can take a typical example - division to zero. Suppose you decided to write a program that will consider the average growth rate of a person (I do not know why, but let's say). The user introduces the date of his birth and its height, and the program deducts from today's date of birth, counts your age in the days and divides growth to the number of your days. Such a program will work perfectly for you and your relatives, but if you are her « lay in people » , I will definitely have someone who will introduce today's number as a birthday. And ready - age zero days, an attempt to divide on zero and the program crashes with an error. Of course, this is the easiest example. In real life, everything is more complicated and depends not only on the data entered by the user (which can be, or rather, you need to check before use in the program), but also from the installed system files, drivers and heaps of other things, to predict which is impossible, and their influence on The performance of the program is not obvious. As a rule, errors « the first type » calculate and corrected very easily, for 10 minutes. « Second Type » - more difficult, but it affects a relatively small number of users. Usually, the correction of such errors leads to a change in the second or third digit in the version number (or, the author does not change the version at all, but simply posts the updated file).

If you see that instead of version 2.1, I appeared, say, 2.11, it makes sense to look at the program website and see if there was no description of the changes to understand, you need it or not. Well, if the program is small, you can simply download the updated version ...

Another thing is to introduce new features to the program. After all, after the program output, the author receives some number of letters from users with requests to add or change something in the program, advice on its improvement and the like. If many people are asking for something one, the author often listens to their opinion and adds the corresponding function. In addition, he himself can come up with something new and interesting and embed a program. Usually, such changes lead to an increase in the second digit in the version number, that is, 1.2 appears instead of 1.1.

Such updates in most cases are documented and their description is placed in the History.txt or whatsnew.txt file. To such a version, it is worth looking more closely - there is a high probability that there is something that you did not have ...

The detected errors or non-optimal pieces in the program algorithm, as a rule, are the most unpleasant for the author, as they require rewriting large pieces of code or even the entire program « from scratch » . At the same time, their correction brings the greatest benefit to those who use this program - significantly increase the possibilities of the program, the speed of its operation, often changes the appearance, many new features appear ... on the other hand, the data storage format may change. will require some special actions when moving to a new version; The name of the program can change, its price and some other things that will require a careful study of documentation (which, in general, never interferes). Similar « global » changes usually lead to an increase in the first digit version of the program, that is, from 1.x it turns into 2.0.

Unfortunately, the rules for changing versions are not described anywhere and are not formalized; What I described is averaged description. Many authors as a version number use the program output date. Someone does not use« minor» versions in general, increasing number per unit with any small update. Someone changes the program without changing the versions. Sometimes there are cases when the version changes, but there is no mention of the changes made. All in the hands of the authors ...

Alpha(Alpha) - the very first version of the program, draft sketch. Status « alpha. » it guarantees you that the downloaded program will be installed and even starts, but its further actions are unpredictable. Most often « alpha version » it is stuffed by errors like a bun raisin, many of its capabilities and functions simply do not work. That is why to use « alpha. » only the most impatient and desperate experimenters, thus performing the role of testers. The rest is worth waiting for the appearance of a more stable and reliable version - « beta » .

Beta(Beta) - already quite suitable product. Rough mistakes are removed, the basic tasks program performs successfully. Only small shortcomings, which may disappear already in the following « betah » . In status « beta » many programs are most of life, remember at least Winamp player, the Bat post program! and a number of other programs « bethod » which does not prevent you from using millions of users.

After the errors found in the alpha and beta versions of the program are corrected, and the functions are added, the queue comes RC (Release Candidate)- Candidate for the final version. This program is already considered stable and used to identify the most hidden errors - such a program, practically without fears, can download and install even those users who are weakly understand computers. And since such - most, then the number of users is increasing, which means an increase in the number « testers » . Errors in RC versions are calculated quite rare, so when switching to « basic » the version of the program practically does not change.

Finally, after all torments and finishes to the light appear release (Release) - fully finished, final version of the program.

The main type of device that is used to store files are disk drives. The hard disk consists of one or more glass or metal plates, each of which is covered with one or two sides by a magnetic material. Thus, the disk in the general case consists of a package of plates (Fig. 7.4).

Fig. 7.4. Hard disk device diagram

Thin concentric rings are marked on both sides of the plates - tracks (tracks),which are stored data. The number of paths depend on the type of disk. Numbering tracks begins with 0 from the outer edge to the disk center. Recording and reading data from the track is performed by a magnetic head.

The totality of the tracks of one radius on all surfaces of all package plates is called cylinder.Each track is divided into fragments called sectors (blocks).All tracks have an equal number of sectors in which you can save the same number byte as much as possible. The sector has a fixed size for a particular system, most often 512 bytes. Since the paths of different radius have the same number of sectors, the record density rises to the disk center.

Sector - The smallest addressable unit of data exchange of the disk device with RAM. In order for the controller to find the desired sector on the disk, it is necessary to set all the components of the sector addresses: the cylinder number, the surface number and sector number. A typical query includes reading several sectors.

The operating system when working with a disk uses, as a rule, its own unit of disk space called cluster. The size of the cluster is keen the size of the physical sector and, depending on the size of the section, can be from 1 to 128 sectors (from 512 bytes to 128 KB). The cluster size is set automatically or manually when the disk is formatted.

When creating a file, the location on the disk is highlighted by clusters. For example, if the size of the file is 2560 byte, and the cluster size in the byte file system is 1024, then the file will be highlighted on the cluster disk.

* Sometimes the cluster is called a block (for example, in UNIX OS), which creates confusion.

Tracks and sectors are created as a result low-level (physical) Disk formatting. Low-level formatting does not depend on the type of OS, which this disk will use.

Disk marking for a specific type of file system occurs as a result high-level (logical) formatting. With high-level formatting, the cluster size is determined and the information required for the file system is recorded on the disk. On the disc is recorded also operating system bootloader - A small program that begins to initialize the operating system after turning on the power or restart of the computer.

Before forming a disk to a specific file system, it can be divided into partitions. Section -this is a continuous part of the physical disk that the operating system represents the user as logical device(logical disk, logical section). In many operating systems, the term " tom» (VOLUME).In different OS, the interpretation of this term has its own nuances, but the bowl of all indicates a logical device, formatted under a specific file system. The logical device functions as if it were a separate physical disk. It is with logical devices that the user works, referring to them by symbolic names, for example, A, B, C, SYS, etc.

Different OS use a single view of sections, but create logical devices specific to each OS type. Therefore, logical devices and file systems created in various OS are generally not compatible.

As a result, only one file system can be created on a single logical device. On different logical devices of one physical disk, file systems of different types can be located, for example: sections C and E have the NTFS file system, section D - FAT file system.

After low-level formatting, all partitions of the disk have the same cluster size. However, as a result of high-level formatting, file systems can be installed on different sections of this disk, with clusters of different sizes.

The logical structure of the hard disk is the division of disk space on areas that store various service (MasterBoot Record), Br (Boot Record), Fat1 and Fat2 et al., Root Directory) and user information.

If with user information (data), in general, everything is clear, then the terms in the service area require explanations.

MBR or master Boot Record. - This is the main boot sector, most often the first physical sector on the disk, with reading its contents, the computer starts when you turn on or reboot (you need to load the operating system). The MBR consists of two parts: the first part of the IPL1- initial Program Loading 1 is recorded, when running the computer explores the contents of the second part of the MBR-table partition table partitions, in which the numbers of the first and last sectors of each of the disk partitions are indicated. Partition Table also stores information about the type of file system of the partition and the sign that is loaded or not. Each of the hard disk partitions contains the BR sector (Boot Record), two copies of File Allocation Table (FAT) - FAT1 and FAT2, root directory root directory and data area.

The MBR - "transition" function to the partition of the hard disk from which the "Further Code" should be executed (usually download OS). At the "MBR" stage, the disk partition selection, the loading of the OS code occurs at the later stages of the algorithm. In the process of starting the computer, after the end of the initial test (Power-On Self-test - POST), the basic I / O system (BIOS) loads the "MBR code" into the RAM (in IBM PC is usually from the address 0000: 7C00) and transfers control located in the MBR boot code.

The BR sector (Boot Record) is the first sector of the section in which the Boot Record Program is recorded, which is part of the operating system and intended for running the rest of the operating system software stored on the disk. BR is available in all sections of the hard disk, although not all sections contain the operating system files, i.e. Not all sections are "system".

The FAT Table (File Allocation Table) is the file posting table, stores a record of 16 or 32 bits that store the location information on which each file is recorded. If the FAT is damaged, the computer loses access to the file and "lost clusters" appear on the disk - i.e. Sectors with useless information that cannot be read.

Root Directory is the root directory of the disk, contains records with information about each file - the name, type, volume, date and time of creation, the file attribute (system, hidden, read-only, archive) and stores the pointer to the first cluster of the file. The root directory is the most "main" directory in the disk section, all other directories and files are located on the hierarchy below it.

Data Area - area for data- The main area of \u200b\u200bthe disk partition, stores the files themselves.

Each of us is confronted daily with various computer terms, knowledge of which is superficial, and some of the terms we are unfamiliar at all. Yes, and why something to know about what we do not concern or not bother. Is not it? Famous truth: While any equipment (including a hard disk) is normal and smoothly functions, then no one will ever beat their head with the subtleties of his work, and this is nothing.

But, at the moments when, during the work of any system unit, failures begin, or just suddenly needed help with a computer, very many users immediately take a screwdriver and the book "Aza computer literacy, or how to reanimate the computer at home." And they are trying to solve the problem independently without resorting to the help of a specialist. And most often it ends very smoothly for their computer.

• Concepts "Hard Disk" or "Winchester" and their occurrence

Definition and appearance of the concept of "Winchester"

So, the topic of our regular article will this time there will be such a spare part of the system unit as a hard disk. We will consider in detail the very meaning of this concept, briefly remember the history of its development, and let's stop in more detail on the inner structure, we will analyze its main types, interfaces and details of its connection. In addition, a little bit into the future, and maybe even almost and now, and tell me that it gradually comes to replace the old good screws. Running forward, let's say that these are solid-state drives working on the principle of USB flash drives - SSD devices.

The world's first hard disk, this type, as we used to see it now and how used to use, IBM invented Kenneth Hoton in 1973. This model was called a mysterious combination of numbers: 30-30, just like a caliber in the entire well-known Winchester rifle, it is not difficult to guess that from here and one of the names went - Winchester, which is popular in the Aytichnik environment so far. And, perhaps, someone has now read it at all for the first time.

Let us turn to the definition: Hard disk (A, if it is convenient for you, then hard, hard drive, HDD or screw) is a storage device of a computer (or laptop), to which the information is recorded using special read / write heads, is stored and deleted as needed .

"And what is all different from simple floppy disk or CD-DVD?" - ask you. And the thing is that, unlike flexible or optical media, here the data is recorded on the rigid (hence the name, although someone can already guessed himself) aluminum or glass plates on which a thin layer of ferromagnetic material is applied, most often For these purposes, chromium dioxide is used.

The entire surface of such rotating magnetic plates is divided into tracks and sectors of 512 bytes each. In some drives there is only one such disk. Others contain eleven or more plates, and the information is written on both sides of each of them.

Internal structure

The design of the hard disk itself consists not only from the immediate drives of information, but also the mechanism reading all this data. All together this is the main difference of hards from floppy disks and optical drives. And unlike RAM (RAM), which requires constant nutrition, the hard drive is a non-volatile device. It can be safely disconnected from meals and take with me anywhere. Data on it is saved. It becomes especially important when you need to restore the information.

Now we will tell you a little directly about the inner structure of the hard disk. The Winchester itself consists of a hermetic unit filled with the usual disturbed air under atmospheric pressure. Open it at home we do not recommend, because This can lead to a breakdown of the device itself. No matter how quietly you are, but the dust in the room is always there and it can get inside the housing. In professional services that specialize in data recovery, there is a specially equipped "clean room", inside of which and opened the hard drive.

Also, the device includes a board with an electronic control circuit. Inside the block there are mechanical parts of the drive. On the spindle of the drive rotation drive, one or more magnetic plates are fixed.

The housing also contains the preamplifier switch magnetic heads. The magnetic head itself makes reading or record information from the surface of one of the sides of the magnetic disk. The speed of rotation of which reaches 15 thousand revolutions per minute - it concerns modern models.

When power is turned on, the hard disk processor begins with the fact that it tests the electronics. If everything is in order, the spindle engine is turned on. After a certain critical rotation speed has been achieved, the air layer density of the air incoming between the surface of the disc and the head becomes sufficient to overcome the force of climbing the head to the surface.

As a result, the read / write head "freezes" over the plate on the tiny distance is only 5-10 nm. The work of the read / write head is similar to the principle of action of the needle in gramophone, only with one difference - she does not have physical contact with the plate, while in the gramophone, the needle head comes into contact with the record.

At the moments when the computer is powered off and the discs stop, the head is lowered to the non-working surface of the surface of the plate, the so-called parking zone. Therefore, it is not recommended to complete the operation of the computer alarm - simply pressing the shutdown button or pulling the power cable from the outlet. This can lead to the failure of all HDD. Early models had special software that initiated the operation of the heading of the heads.

In the modern HDD, the output of the head in the parking zone occurs automatically when the rotation speed is reduced below the nominal or when the command is fed to power off. Back to the working area of \u200b\u200bthe head is displayed only when the nominal speed of rotation of the engine will be achieved.

Surely in your inquisite mind, the question has already been matured - how sealed the discs itself and what is the likelihood that dust or other small particles can be leaked there? As we have already written above, they can lead to a crash in the work of the Hard or at all to his breakdown and loss of important information.

But you should not worry. Manufacturers have long provided long ago. The engine discs with the engine and head are located in a special hermetic case - the humbling (chamber). However, its content is not fully isolated from the environment, it is necessary to move air from the camera outside and vice versa.

It is necessary to align the pressure inside the block with external to prevent the body deformation. This equilibrium is achieved using a special device, which is called a barometric filter. It is placed inside the germoblock.

The filter is able to capture the smallest particles, the magnitude of which exceeds the distance between the read / write head and the ferromagnetic surface of the disk. In addition to the above filter, there is another - recirculation filter. It catches the particles that are present in the air flow inside the block itself. They can appear there from sinking magnetic pollination of the disks (for sure you heard someday the phrase that "Hard fell apart"). In addition, this filter catches those particles that "missed" its barometric "colleague".

HDD connection interfaces

To date, to connect a hard drive to a computer. You can use one of three interfaces: IDE, SCSI and SATA.

Initially in 1986, the IDE interface was developed only for connecting HDD. Then it was modified into an extended ATA interface. As a result, it is possible to connect not only hard drives, but also CD / DVD drives.

The SATA interface is faster, modern and productive than ATA.

In turn, SCSI is a high-performance interface that is capable of connecting various kinds of devices. This includes not only information drives, but also different peripherals. For example, faster SCSI scanners. However, when a USB bus appeared, the need to connect the periphery through SCSI disappeared. So, if you are lucky enough to see him somewhere, then consider what you're lucky.

Now let's tell a little about connecting to the IDE interface. The system may have two controllers (primary and secondary), each of which you can connect two devices. Accordingly, we get a maximum of 4: primary master, primary subordinate and secondary master, secondary subordinate.

After you have connected the device to the controller, you should select the mode of its operation. It is selected by installing a special jumper (it is called jumper) to a specific location in the connector (next to the IDE plume connector).

It should be remembered that faster equipment to the controller is connected first and called Master. The second is called Slave (subordinate). The last manipulation will be connected to the power, for this we need to choose one of the power supply cables. This information will be useful to you if you have a very, very old computer. Since in the modern need for such manipulations disappeared.

Through SATA, connect much easier. The cable for it has the same connectors at both ends. SATA disk has no jumpers, so you do not need to choose the device mode - even a child can cope. Power is connected using a special cable (3.3 V). However, it is possible to connect through an adapter to a conventional power cable.

We give one useful advice: if friends often come to you with your hard drives to rewrite new movies or music (yes, friends you have so harsh, which are not external HDD, and the usual inner), and you are already tired all the time to unwind System block, we recommend purchasing a special pocket for a hard disk (it is called Mobile Rack). They are with IDE, and with SATA interfaces. To connect another additional hard to your computer, just insert it into such a pocket and ready.

SSD discs - a new stage in development

Already today (and maybe already yesterday) the next stage began in the development of device drives. A new type comes to replace hard disks - SSD. Next, we will tell about it in more detail.

So, SSD (Solid State Disk) is a solid-state drive that works on the principle of USB flash memory. One of the most important distinguishing features from conventional hard drives and optical drives - its device does not include any moving parts and mechanical components.

Drives of this type, as often happened, were initially developed exclusively for military purposes, as well as for high-speed servers, since older hard hard hards for such needs were not sufficiently fast and reliable.

We list the most important advantages of SSD:

• First, the record of information on SSD and reading from it is much faster (dozens of times) than with HDD. The work of the usual hard drive is very much slows down the movement of the read / write head. And because In SSD it is not, then there is no problem.
• Secondly, due to the simultaneous use of all memory modules installed in the SSD drive, the data transfer rate is significantly higher.
• Thirdly, not so susceptible to shocks. While hard drives can lose when they hit part of the data or generally fail, which happens most often - be careful!
• Fourthly, consume less energy, which makes them convenient to use in devices running from batteries - laptops, netbooks, ultrabooks.
• Fifth, this type of drives during operation practically does not produce no noise, whereas when the hard drives we hear the rotation of the disks and the movement of the head. And when they fail, and in general, a strong crackling or a knock of the heads.

But we will not hide: perhaps there are two shortcomings of SSD - 1) for its definite container, you pay much more expensive than for the hard disk of the identical amount of memory (the difference will be several times, although every year it becomes less and less); 2) SSD have a relatively small limited number of read / write cycles (i.e., initially limited service life).

So, we met with the concept of "hard disk", considered its structure, the principle of operation and the features of various connection interfaces. We hope proposed information turned out to be simple for perception, and most importantly, useful.

If you have any difficulties with the choice, if you can not determine which type of hard drives your motherboard is supported, which interface is suitable or what amount of HDD will more comply with your needs, you can always ask for help in computer service Compolarhip throughout our territory Services.

Our specialists will help you with choosing and replacing the hard disk. In addition, you can order the installation of a new device in your system unit or laptop.

Call masters

Structure of a hard disk (surface, cylinder, sector).

Rigid magnetic discs are several metal or ceramic discs coated with a magnetic layer. The discs together with the magnetic head unit are installed inside the sealed hull of the drive on rigid magnetic disks (HDD), commonly referred to as Winchester.

The term "Winchester" originated from the Zarnogan name of the first model of the hard disk of 16 KB (IBM, 1973), which had 30 tracks of 30 sectors, which accidentally coincided with the caliber 30 "/ 30" of the famous Hunting rifle "Winchester". The hard disk is a very complex device with high-precision mechanics and an electronic board, controlling the disk.

The structure of hard drives has in general the same structure as flexible magnetic discs.

Magnetic plates mounted in the drive are placed on the same axis and rotate with high angular velocity. Both sides of each plate are covered with a thin layer of magnetized material recording is carried out on both surfaces of each plate (except extreme).

Each magnetic side of each plate has its own magnetic read / write head. These heads are connected together and move radially (by radius) relative to the plates. So it provides access to any track any plate

Repetition is the mother of the teaching!

Structure of a hard disk

Sectors

Any hard disk can be represented as a huge "blank sheet", which you can write the data and where then can be considered. To navigate on the disk, all its space split into small "cells" - sectors. The sector is the minimum data storage unit on the disk, usually its size is 512 bytes. All sectors on the disk are numbered: each of the N sectors receives a number from 0 to n-1. Thanks to this, any information recorded on the disk receives the exact address of the corresponding sectors. So the disc can still be represented as a very long line (ribbon) from the sectors. You can calculate how many sectors on a disk size in N gigabyte.

Sections

Present a hard disk as a single "list" is not always convenient: sometimes it is useful to "cut" it into several independent sheets, on each of which you can write and wash anything, without fear of damaging written on other sheets. The most logistic is to record separately the data of greater and lesser importance or simply relating to different things.

Of course, no physical, but logical cut, should be made above the hard disk, and the concept is introduced for this. section Partition). The whole sequence (very long ribbon) sectors is cut into several parts, each part becomes a separate partition. In fact, we will not have to cut anything (and it would hardly have been possible), it is enough to declare, after which sectors on the disk are the boundaries of sections.

Table sections

Technically, the disk partitions are organized as follows: a predetermined part of the disk is given under table sectionsin which it is written how the disk is broken. Standard partition table for IBM-compatible computer disk - HDPT ( H.ard. D.iSK. P.aRTITION T.able) - located at the end of the first disk sector after preloader (M.aster B.oot. R.ecoRD, MBR) and consists of four types of type " a type start end", One for each section. Start and end - These are the numbers of those sectors of the disk where the section begins and ends. Using such a table, the disc can be divided into four or fewer sections: if the section is not, a type Installed in 0.

However, four sections rarely when it happens enough. Where to place additional folding table fields? The creators of IBM PC offered a universal method: one of the four main sections is declared extended (Extended Partition); he usually is the last and takes everything The remaining disk space.

Advanced section can be divided into subsections in the same way as the entire disc: at the very beginning - this time is not a disk, but section - start table sections, with records for four partitions, which can be used again, and one of the subsections may be, again, expanded, with its subsections, etc.

Sections referred to in the section table diskCall called basic Primary Partition, and all subsections of extended sections - additional SECONDARY PARTITION. So the main sections may be no more than four, and additional - as much as you like.

In order not to complicate this scheme, two rules are followed when the disc mark is followed: first, extended partitions in the partition table disk May be no more than one, and secondly, the partition table expanded section It may contain either one record - a description of the additional partition, or two - a description of the additional partition and the description of the nested extended partition.

Type of section

In the partition table for each section indicates a typewhich defines file Systemwhich will be contained in this section. Each operating system recognizes certain types and does not recognize others, and, accordingly, refuses to work with a section of an unknown type.

You should always follow the partition type set in the partition table correctly indicated the type of file system actually contained within the section. Not only the kernel of the operating system can rely on the information specified in the partition table, but also any utilities whose behavior in the event of an incorrectly specified type can be unpredictable and damaged data on the disk.

For more information about file systems, see section File System Types.

Logic volumes (LVM)

Working with sections, it must be borne in mind that the actions produced above them are associated directly with the markup of the hard disk. On the one hand, partition breaks is the most traditional for PC method of a logical organization of disk space. However, if a need to change the logic of breaking the disk or dimensions of the areas (i.e. when the task occurs scaling), Working with sections is not very effective.

For example, if necessary, create a new section or increase the size of the existing one, you can encounter a number of difficulties associated with restricting the number of additional sections or redistribution of data. It is very easy to avoid them: you only need to abandon the "binding" of data to a certain area of \u200b\u200bthe hard disk. In Linux, this feature is implemented with manager of logical volumes (LVM - L.ogical. V.olume. M.anager). LVM organizes an additional abstraction level between sections On the one hand and stored on them danis On the other hand, building your own hierarchical structure.