The format in computer science is a certain standardized structure of the information facility.
- File format - Description of the data structure in the computer file.
- - Text data storage format.
- - Formats for storing graphic information - photos and drawings.
- - Sound File Storage Formats.
- - video storage formats (also aspect ratio: 4: 3, 14: 9, 16: 9) (also see file formats list of some file formats)
- Open format - publicly available (its description is not closed) Digital data storage specification.
(Wikipedia material - free encyclopedia)
Here are more or less familiar words begin to meet, unless of course read.
What is the file format and file types?
So, will continue.
We created with you text format file which recorded information by copying it from the Internet. Now we can open this file at any time, see what is written there, can correct something or add (edit) and then save.
Christmas trees stick, you say. Well, how many can be the same to caring. It is possible further, in principle, not to chew. In principle, yes, but since I, very often, I hear the question of type, how to open file format fileAll the same in more detail I will explain this topic so that you have no questions left.
After all, if you figure it out, what is incomprehensible here? Text he and in Africa text.
For us, yes, but not for a computer. Computer on the drum, a picture of this president or a recipe for pancakes, our favorite song or the last masterpiece of cinema.
The fact is that the computer "knows" and "performs operations" only with two digits - "0" and "1" (zero and unit). Everything. More he, like a piece of wine, knows nothing. Yes, he does not need it. For him, this is quite enough. (By the way - this is digital format .)
For him, for a computer, maybe enough, but not for us. Agree that it is not interesting for us to see zeros and units. We give a meaningful text or a beautiful picture, we do not agree to the smaller. Well, it is right.
Yes, the numbers are only two - "0" and "1". But their combinations can be billions.
For example, if we take a simple text, then for a computer, each symbol is strictly defined. in binary form , i.e. any sign or letter has a certain combination of zeros and units.
For example, English (Latin) letter "a" in binary looks like "01000001" (ranks 1 byte or 8 bits), and Russian (Cyrillic) letter «
BUT «
In binary form looks like "11010000 10010000" (occupies 2 bytes or 16 bits).
Remember how much byte "weighs" our recipe for pancakes from the first part of the article? In my case it was 507 bytes (you may differ from mine, but it does not matter now).
Let's see how "see" the computer is our recipe for pancakes.
I did not post it all, there is another 5 or 6 times as much. Yes, and no need. It is important how "sees" the computer to our information and how it is recorded.
But the program (application) "Notepad" "stupidly" reads this information from where we recorded it and "stupidly" displays this information to us, transforming into a convenient view for us, on the monitor screen. Since the file is recorded simple information in the form of letters and numbers (text format), there are no problems with the perception of this information. Yes, and the rate of withdrawal on the monitor of such "smallers", you can say "mad".
The word "stupidly" I wrote not by chance and we will talk about it. But from the simple text editor "Notepad" more, to be honest, and is not required.
I hope you all understood, and questions how to open file file fileYou no longer have.
Everything. Go to more complex format .
What are the types of files and how to change the file format to another?
You probably remember that we had problems with the preservation of the picture. To do this, there are more "powerful" programs (applications) that can save both text, and pictures (images), and tables - and a lot of things they still know how.
For further explanation of the concept of "format", I will use the text editor " Microsoft Office. Word "(link to the lessons with a Word) from the Microsoft Office Office Package. This is a rather powerful and friendly "monster", which can easily keep anything (well, almost everything).
Let's go again on the site page, where we copied the recipe for pancakes and copy this fragment once again into the clipboard, as we did in the 1st part of the article.
Everything, text with the image in the clipboard and let it "sit".
Create a file Microsoft Word. (Microsoft Word). In principle, you can create it in the same way as we created a text file. But let's create a little different (in the future you will already be able to determine how it will be more convenient for you to do it).
Press the left mouse button sequentially: Start - All Programs - Microsoft Office - Microsoft Office Word 2003, as shown in the picture.
You will find the Microsoft Word text editor window (often text editor "Microsoft Word" is called the "text processor" to emphasize its great opportunities, i.e. this text editor allows you to work not only with text, but also with graphics, tables, etc. To the processor of the computer itself, this does not have a relationship ).
Now insert the file content that "languishes" in the exchange buffer. To do this, on the white field, click the right mouse button, then in the menu that appears, we bring the mouse pointer to the "Paste" menu item and clicks left button Mice, as shown in the picture.
Everything. We copied the recipe we need from the Internet, and even with the picture. And it looks like this is quite pretty.
Save all this to the desktop (I use the saving files to the desktop solely for clarity. In general, in the future I do not recommend this. It is best to create a couple of top three on the desktop thematic folders, well, for example "my recipes", "My Photos. "Moreover, you can create more folders inside folders on topics. For example, in the" My Photos "folder, create folders" on kebabs from Vasi "," As I rested on the Canaries. "And immediately keep everything in Created folders. Believe me, save the mass of time and nerves).
To save, execute the following steps. Summer pointer Mouse and sequentially press the left mouse button, the menu items, the pop-up menu items and the pop-up buttons as shown in the figure: "File" - "Save as ..." - "Desktop" - "Save".
In the field "File name:" You can write any name that you like (I wrote a "recipe for thin pancakes." Extension. DOC Here you can not write here, the program itself will substitute if the "File Type:" field specified "Word Document (* .doc) ")
Here I specifically opened a list formats and the corresponding name Extensions (In the figure, the arrow indicates this button) in which the Microsoft Word program can save the file. By default, the document is saved in Microsoft Word format (- "Dock" document). This list can be "hiking" by the slider.
But you can also save the document and in another format, for example, in text, selecting the "File Type:" field "Normal text (* .txt)". For what? Well, for example, that this file can be opened and read by the program (application) "Notepad". True, however, Word can throw out the warnings that, they say, you will lose all sorts of formatting elements, pictures and something else. But if all these "screams" will not pay attention, then the usual text in the text format file it will save.
What would you understand how to change file type, let's, for clarity, will be saved in two formats. In a text format and format in which you can put on the page of the site on the Internet.
In the first case, in the "File Type:" field, select "Normal text (* .txt)" by clicking on this line with the left mouse button and then again the left mouse button, click the "Save" button. Word will save our recipe named "Recipe with thin pancakes" by adding it extension. TXT. i.e. will save in text format.
In the second case in the field "File Type: « Select "Web page in one file (* .mht; * .mhtml)" by clicking on this line with the left mouse button and then again the left mouse button click the "Save" button. Word will retain our creation with the name "Recipe for thin pancakes" by adding the expansion .MHT, t. e. Save in the format of web pages.
The desktop appeared 3 new files with the same name "Recipe of thin pancakes", but with different extensions and, accordingly, different icons (icons, pictograms).
In other words, we created three files of different format with the same (for us) information. And these three "recipe" open different programs (applications). Ie by clicking two times quickly for each of labels (Well, or opening them by the "Dedovsky method" as I described in the previous part of the article), we obtain the following:
"Recipe for thin pancakes.txt" - by default it opens, edited and saved by the program (application) "Notepad"
"Recipe for thin pancakes.doc" - by default it opens, edited and saved by the program (application) "Microsoft Word"
"The recipe of thin pancakes.mht" - by default only opens (not edited) by the program (browser) " Internet Explorer."Since this is a program only view , not editing.
Now, if that, you know how to change file format.
Comparison of sizes of different types of files?
Let's compare two files that open by default are edited and saved by different text editors- "Recipe with thin pancakes.txt" and "Recipe of thin pancakes.doc".
To do this, we will see the properties of these files (for this, as you remember, the mouse pointer must be brought to the shortcut, press the right mouse button, tie the mouse pointer to the "Properties" menu item and click on it with the left mouse button).
So, what happens (the sizes of your files from mine can differ slightly, but this is the topic of another conversation and this in our case is not fundamentally). At the "text" document, the size of 511 bytes, and the "Vordovsky" document 46,080 bytes (a picture of pancakes in the file occupies 23,226 bytes).
Calling a calculator ("Start" - "All Programs" - "Standard" - "Calculator") and begin to count.
The size of the "Vordovsky" document is more than "text" approximately 90 times. Thus, on our hard disk "G:" in 10 GB, which we took for example, will fit (rudely) 200 thousand "Vordsk" documents, unlike 20 million "text".
A comparison may be a little bit rough, but it illustrates very well how much space on the disk occupies the same information, depending on which format it is recorded.
You can smile and with sarcasm to tell me: Well, and that. Yes, I don't "stick up so many documents in my life. Yes I. hDD On my computer 500 GB, even consider reluctant, how much it will fit there. And in terms of documents you will be absolutely right.
But the place that the documents on our hard drive occupy is, is actually a thousandth or maybe even a million part of what is stored on our computer.
For example, one high quality film (HD) can occupy on a 20 GB hard disk, or even more.
And one more interesting moment. Let's try to open the file microsoft format Word program (application) "Notepad", which does not understand this format.
To do this, call the program "Notepad". By moving the mouse pointer in series with the left mouse button, click "Start" - "All Programs" - "Standard" - "Notepad".
In the program window that appears, we do the following: with the left mouse button, select "File" - "Open" - "Desktop". In the "File Type:" field, press the left mouse button on the "drop-down list" button and select "All Files".
The file we opened. But what do we see?
Yes, nothing interesting. The program "Notepad" "Stupidly" opened to us what he thought from the disk.
"Encoded" information microsoft program Word can only read the program that "understands" format.doc (there are such programs except Word_A), and our application, as you probably remember, only text format understands.
I also wanted to tell in this part of the article about graphic, Musical and Video Files . But the article turned out again a little long, and the fundamental things really wanted to bring.
As for graphic, musical and video files, there are a lot of interesting things there, and I would like to tell a little more about them. And, so that you do not tire you, I will talk about it in this article.
That's all. Good luck and creative success. 🙂
So, in today's lesson you will learn, what is file extensions, and how it is possible to change the extension. The most observant or more experienced users of the computer, probably, have already noticed that any Windows operating system file has its own name, consisting of 2 parts: the name itself, which is displayed, actually, under the file itself and extension, separated from the name of the point. Here simple scheme File name with extension:
file name. Weight
The extension is necessary so that the OS can determine how type the file relates and which program should be opened.
Here are the most common examples of extensions in any version. operating system From the Windows series:
gif; .jpg; .bmp; .png. - Formats of common graphic files
.mpg; .avi; .vob - video files (video)
.flv - Popular Flash format. The video files in this format "weigh" are much less than the video in AVI or MPG formats, which is widely used to view the rollers directly on the sites.
.pdf. - document program Adobe Reader.. Used when creating e-books and all sorts of manuals for various equipment and software, which are included on a separate CD along with products.
.exe - executable file used in Windows to directly launch the program itself. When double-clicking on a file with a similar extension, the program will be launched to which the "EXE-Schnick" refers.
.zip; .rar - Format of popular archivers WinZip and WinRar.
/; .htm. - Web pages format. You can try to save to your computer any web page on the Internet, as a rule, it will have one of the above extensions.
.sys; .dll - System and service files needed to work OS and installed applications. Deleting such files can damage Windows and its complete failure. If you are 100% sure that you do, never delete such files.
It is thanks to the Windows extension determines which information contains a particular file. We noticed when you open a file, first starts a program specifically designed to open it, which then launches the file. This is possible thanks to file extensions.
How to change file extension And how to see him?
To display extensions from files, do the following:
File expansion in Windows
Go to "My Computer \u003d\u003e Service \u003d\u003e Folder Properties \u003d\u003e View" and remove the tick "Hide extensions for registered file types" (in other Windows versions other than Windows XP, the settings may differ slightly). After you took a tick, do not forget to click OK. Now extensions will be visible.
Also to find out the file type, just bring the mouse cursor to it conductor windowsAfter which it will be possible to see all the necessary information in the pop-up clue.
Change the file extension if it suddenly has become necessary, you can use the Total Commander program that you can easily find and download using Yandex search engine.
On this, our lesson approached the end, you can ask my questions in the comments below, at the first opportunity we will try to answer them.
File name extension - This is a sequence of characters that allows you to determine the file format. File extensions in Windows are separated from the file name. For example, the full name of the text document will be viewed by filename.doc, and the music track is FileName.mp3. Certain expansion files can be tied the default programs. If once to specify in the properties of the file, that the file with such an extension should be opened with a specific program, the operating system will open the specified program all files with this extension.
For example, you want all MP3 music files to be opened by a specific player. In the File List, find any file with the mp3 extension and click on it right-click. In the context menu that appears, select "Properties". At the top of the dialog box that appears, you will have two lines: "File Type" (you can see the file extension) and "application" again (shows the current default application for all files with this extension). In the line "Appendix" there will be a "Change ..." button, it is necessary for you! When you click on it, the OS will invite you to select a program to open this type of files from the list of installed programs. Selecting the desired program, do not forget to put a check mark near the phrase "Use the selected program for all files of this type" and click OK.
What kind the most common file extensions in Windows? For example, EXE is executable files, for example, programs installers, RAR and ZIP - archives. E-books Different with the extension PDF, DJV or FB2. Audio files Usually have an extension of MP3, WAV or OGG. Files lossless audio (sound filesCompressed without loss) may have an extension FLAC, APE or WAV. Video files Different with extensions AVI, MPEG, MP4, MKV, FLV, etc. Raster images You can learn from the extension JPG (JPEG, JPE), BMP, GIF, PNG, TIFF, etc. Extension vector Images Depends on the program in which they are made - for example, CDR for CorelDRAW.
In general, file extensions in Windows often depend on the specific application, and open files with a third-party application with such an extension may be difficult or even impossible. For example, the PSD extension has files created in Adobe Photoshop graphic editor (however, this program allows you to save ready File Practically in any graphic format). Text files created in Microsoft Word can be found by extension doc. (DOCX for new versions of the program), and the OPEN Office text editor works with ODT format. Also text files May have a resolution of TXT or RTF.
How to find out, what types of files does your operating system work with? Go to the conductor, in the drop-down menu Service Select Folder properties And in the dialog that opens, go to the tab Types of files. On this tab, there will be a table in two columns - extension of the file in Windows and the corresponding file type.
How to change file extension?
Imagine: You downloaded an archive from the Internet, but for some reason the browser saved it with HTM resolution (web page permission). Naturally, you will not be able to unpack such an archive. You need change file extension On the right one. However, Windows may not show the expansion of files, including security reasons so that the user does not rename the file incorrectly.
To change the file extension, you need enable display file extensions in Windows. To do this, go to Windows Explorer (double click on My Computer icon on the desktop or Win + E). Go to the folder where the file is lying, the extension of which you want to change. In the Explorer menu Service Select Folder properties. IN Windows 7. The menu may not be; In this case, press the ALT key in the Explorer window, and it will appear. Menu item equivalent Properties of the folder in Windows 7 is called Folders settings.
In the dialog that appears, go to the tab View. IN Additional parameters There must be a string: "hide extensions for registered file types." Remove the tick standing opposite it and do not forget to click OK! Now file extensions in Windows will be displayed, and you can change the file extension. Also often expand files by default are shown in many file managers, for example, Total Commander.. We remind you that you can rename the file by pressing the F2 key or selecting the file to the context menu (it is called by right-clicking) item "Rename".
However, such a reception it will not allow you to change the format of the multimedia file. You can not make an APE file from the APE file or from the MKV file AVI file, simply changing the file extension. To change the format of audio and video files, we need to convert one multimedia format to another. It should also be remembered that if you incorrectly change the file extension, you will not be able to open it. We can say that file expansion in Windows is not a toy!
File expansion: What is and with what it is eaten.
The file extension is a combination of letters and numbers that stands after the last point in the file name. Most often expansion have a length of 3 characters. Extensions are used to identify the type (format) of the file. With their help, the user and software of the computer can determine the data type stored in the file.
The operating system (Windows, etc.) can put each extension in line with its program that will start when the files are opening a certain type. For example, in the Windows system, the default image opens the "Image Viewer and Faxes" program. Those. It is in line with the extensions of JPG, BMP, GIF are extensions for different types of image files.
Compliance with extensions and programs can be changed by itself if you have multiple programs for opening files with a specific extension.
The extension is usually indicated in the form of * .rar, i.e. Before the expansion symbols, an asterisk and a point are added, where the asterisk symbolizes any file name.
The extension may indicate not only on the type of information that is stored in the file (image, media file, text file), but also on the method of encoding this information. For example, * .gif, * .jpg, * .bmp, * .raw, * .png et al. - These are expanding image files, but methods for encoding an image in such files are different, and not every program that opens one type can open another.
There are no extension files, usually system files.
If you do not displays file extensions, it means that this function is disabled on your computer. How to enable it read in the article (click on the name to go to the article)
Below is a list of the most common in Windows extensions (formats) and their data types.
There is a huge number of file formats, consequently and extensions. It is impossible to remember everything, and no need. At the user level, it is enough to know a small part of the above table, to be able to recognize the audio file from the picture or type from the text. The rest are needed either for professional activities (images for designer, video for video editor, etc.), or for administrators who operate with sytene files.
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What is file extensions
And how to see them
The file name in the Windows operating system consists of two parts: in fact, the name and expansion itself, which are separated from each other by the point. This is how it looks in the general case:
file name. expansion
The extension is necessary in order for Windows to understand what type the specific file relates and what program it is created.
Here are examples of extensions of the most frequently used files:
tXT. - A simple text file.
dOC - Microsoft Word document.
jPG, GIF, BMP - The most common formats of graphic files.
mP3, WAV. - Audio files, music.
aVI, MPG. - video files.
fLV. - Video in the popular Flash format (it is in this format that the videos are most often laid out to view directly on sites).
pDF. - Document Acrobat Reader. In this format, almost all manuals (instructions, descriptions) are made to various programs and equipment that manufacturers are written to the attached CD.
eXE - This is a started file, i.e. Directly program. If you start such a file, the program will start working.
rar, Zip. - These are archives created by popular WinRar and WinZip archivers, respectively.
hTM, HTML. - And this is web pages. When you save one or another page from the browser to your computer, it, as the rules, is saved to the disk as a file with such an extension.
dLL, SYS. - Service files required for the operation of the operating system and installed programs. Never delete such files if you are not sure what you are doing.
as I said, it is the extension that helps Windows determine which information contains a particular file. Not in vain because when you click on the file twice to open it, the system first automatically starts the necessary programAnd then opens this file in it. This recognition occurs due to the file extension.
Often even the user looks at the extension to see, what type of files in this moment Displayed on the screen. But not always the expansion is visible. It often happens that only the file names are displayed, there are simply no extensions. This means that in the tinctures of your system disabled display of extensions.
To turn it on, go to "My Computer - Service - Folder Properties - View" And remove the checkbox "hide extensions for registered file types" (settings are specified for Windows XP, it may differ in other versions). Click OK. After this expansion, the files will be visible.
Try, perhaps you enjoy it. Personally, I can't work if the files do not see extensions.
Respectfully
Konstantin Forth
P.S. You can significantly reduce the time when sending a large file by email, if you pre-"compress" the file with a special program.
In order to learn how to squeeze files yourself, it is enough to view only 8 small video lessons on the use of the most popular WinRAR archival program.
Click now to find out the details -
File expansion or file name extension is a suffix at the end of the computer file. It usually has a length of two or four symbols. If you have ever discovered the document or viewed the image, you probably noticed these letters at the end of your file.
Screenshot of various extensions
File what file is suddenly you ask? And this, in our case, just a certain type of data stored on electronic media.
What is the file name extension
File extensions are used by the operating system to determine which applications are related to file types - in other words, which application opens when double-clicking.
For example, the file named "awesome_picture.jpg" has the extension "JPG". For example, when you open this document in Windows, the operating system is looking for any application associated with JPG, opens this application and downloads the file. And expansion .m4r. Applied
What are the types of extensions?
There are many different types of file extensions - too much so that they can be listed in one article, but here are some examples general extensions Files that you can see on your computer:
Doc / docx: Microsoft Word Document. Doc was the original extension used for Word documents, but Microsoft changed the format when Word 2007 debuted. Documents Word. Now based on XML format, therefore adding "x" to the end of the expansion.
XLS / XLSX: - Microsoft Excel spreadsheet.
PNG.: Portable Network Graphics, image format without loss.
HTM / HTML.: Hypertext markup format for creating web pages on the Internet.
PDF.: The format of the portable document created by Adobe and used to support formatting in distributed documents.
EXE: Executable format used for programs that you can run.
And, as we have already talked, it is just a small number of file extensions. There are them, literally thousands.
It is also important to know that there are types of files that are inherently dangerous and can be dangerous. As a rule, these are executable files that can run certain types of code when you try to open them.
Do not open files if they are obtained from an unreliable source.
Under spoiler You will find 50+ file extensions that are potentially dangerous for Windows.
Programs
EXE is an executable program file. Most applications running in Windows are.EXE files.
PIF is a program information file for MS-DOS programs. Although files. PIF should not contain executable code, Windows will process files .pif just like files.exe if they contain executable code.
Application is an application installer deployed using Clickonce technology from Microsoft.
Gadget - Gadget File for Gadget Technology for desktop computers Windows presented in Windows Vista.
MSI - Microsoft installation file. They establish other applications to your computer, although applications can also be set by files.exe.
MSP - Windows Installer Correction File. Used to correct applications deployed in files.msi.
COM is the original type of program used by MS-DOS.
SCR - Windows screen saver. Windows screensavers May contain executable code.
HTA - HTML application. Unlike HTML applications running in browsers, files. HTA are launched as reliable applications without sandboxes.
CPL - control panel file. All utilities found in the panel windows managementare files.cpl.
MSC - Microsoft Management Console console file. Applications such as editor group Policy And the disk management means are.MSC files.
JAR - .jar files contain executable Java code. If you have a Java execution environment, files.jar will be launched as programs.
Scenarios
Bat - batch file. Contains a list of commands that will run on your computer if you open it. Originally used MS-DOS.
CMD - command file. Like .Bat, but this file extension was entered in Windows NT.
VB, .vbs - VBScript file. Performs your enabled VBScript code if you run it.
VBE is an encrypted VBScript file. Like the VBScript file, but not easy to determine what the file will do if you run it.
Js - JavaScript file. .Js are usually used by web pages and secure when running in web browsers. However, Windows will run files.js outside the browser without sandbox.
JSE is an encrypted JavaScript file.
WS, .wsf - Windows script file.
WSC, .wsh - Windows Script and Windows Script Host scripts. Used with Windows scripts.
Ps1, .ps1xml, .ps2, .ps2xml, .psc1, .psc2 - windows script PowerShell. Performs PowerShell commands in the order specified in the file.
MSH, .msh1, .msh2, .mshxml, .msh1xml, .msh2xml - MONAD script file. Monad later renamed PowerShell.
Labels
SCF - command windows file Explorer. Can transmit potentially dangerous teams in Windows Explorer.
INF - text file used by Autorun. In case of launch, this file can potentially run hazardous applications with which it comes, or transmit hazardous options for Windows programs.
Other.Reg - Windows registry file. .Reg files contain a list of registry entries that will be added or deleted if you run them. Malicious .reg file can delete important information From your registry, replace it with unwanted data or add malicious data.
Macros Office.
Doc, .xls, .ppt - Documents Microsoft Word, Excel and PowerPoint. They may contain malicious code Macro.
Docm, .dotm, .xlsm, .xltm, .xlam, .pptm, .potm, .ppam, .ppsm, .sldm. New file extensions presented in Office 2007. M At the end of the file extension indicates that the document contains macros. For example, the file.docx does not contain macros, and the file.docm may contain macros.
This is not an exhaustive list. There are other types of file extensions - for example.pdf - which have a number of security problems. However, for most types of files above they are not above. They exist to start an arbitrary code or commands on your computer.
What if I do not see file extensions on your computer?
By default, Windows shows file extensions. For some time - in Windows 7, 8 and even 10 - it was incorrect, but fortunately, they changed the default settings.
We say that the display of file extensions is not only useful, but also safer. Without displaying extensions is difficult to determine whether this PDF file that you are looking (for example), really pDF filerather than a malicious executable plot.
If file extensions are not displayed in Windows, it is easy to return this information. In any file of the File Explorer, you simply select "View" ⯮ "Parameters" ⯮ "Change Folder" and Search Parameters.
screenshot, how to manage the visibility of file extensions in Windows
In the "Folder Settings" window on the View tab, select the "Hide Extensions for Known File Types" checkbox.
MacOS file extensions are not displayed by default. The reason for this is that MacOS does not really use extensions as Windows does (and we will talk more about this in the next section).
However, you can do the extensions of MacOS files and it is probably not so bad. Opening the Finder, just go to Finder⯮ Preferences⯮ Advanced, and then turn on the Show All File Extensions checkbox.
How does MacOS and Linux use file extensions?
So, we talked about how Windows uses file extensions to find out what type of files it is dealing, and what application to use when opening a file.
Windows knows that the file named readme.txt is a text file due to this TXT file extension, and it knows how to open it using the default text editor. Delete this extension, and Windows will no longer know what to do with the file.
Although MacOS and Linux still use file extensions, they do not rely on them like Windows. Instead, they use something type MIME and creator codes to determine what a file is. This information is stored in the header of the file, and both MacOS and Linux use this information to determine what type of files they are dealing with.
Since file extensions are not in fact not required in MacOS or Linux, you can easily have a valid file without extension, but the OS can still open the file using the correct program due to the file information contained in the file header.
What happens if I change the file extension?
Based on what we just spoke about in the previous section, what happens when you change the expansion of your file depends on which operating system you use.
In Windows, if you delete the file extension, this operating system no longer knows what to do with this file. When you try to open a file, Windows will ask you which application you want to use. If you change the extension, tell me that you renamed the file from "coolpic.jpg" in "Coolpic.txt" -Windows will try to open the file in the application associated with the new extension, and you will receive an error message or open, but useless file.
In this example, a notebook (or any other default text editor) opened our "Coolpic.txt" file, but this is just a distorted indiscriminate text.
By this the cause of Windows Warns you when you are trying to change the file extension, and you must confirm the action.
If you use MacOS, something similar happens. If you try to change the file extension, you will receive a warning.
If you change the extension to something else, MacOS will try to open the file in the application associated with the new expansion. And you will receive an error message or a distorted file - like in Windows.
Unlike Windows, if you are trying to delete the file extension in MacOS (at least in Finder), MacOS simply adds the same extension back using the data from the MIME file type.
If you really want to change the type of file - for example, you would like to change the image from the JPG format in PNG - you will need to use softwarewhich can actually convert the file.
How to change the program that opens the file
Whenever you install an application that can open a specific file type, this application and file extension are recorded in your operating system. It is possible that several applications can open the same file.
You can start the application and then download to it any supported file type. Or you can right-click the file to open its context menu and select the available application there.
For example, in the image below you can see that we have several images for images in our Windows system that can open the "Coolpic.jpg" file, which we right-click.
However, there is also the default application associated with each expansion. This application opens when double-clicking, and in Windows, this application that appears at the top of the list you get when you click the file with the right mouse button (in the image above).
And you can change this default application. Simply select "Parameters" ⯮ "Applications" ⯮ "Default applications" ⯮ "Select default applications by file type". Scroll through a list (very long) file types to find the one you want, and then click the applied application on the right to change it.
And you can do the same in MacOS. Simply select the type file that you want to change, and select File\u003e "Get information" in the main menu. In the "Information" window that appears, go to the "Open C" section, and then select a new application in the drop-down menu. Easy enough.
Now you know what is the extension of the file, and how to change it.
In operating rooms windows systems (With FAT32 and NTFS file systems), the full name should not exceed 255 characters. The name fit users at their discretion, and the file extension usually consists of just three or (less often four) symbols of the English alphabet, and these character sets for extensions are standardized and show what type of file in question. For example, the file "house.jpg" based on the name, contains information about the house, and proceeding from the extension - this is some image of the building.
Standard and popular file extensions:
dOC - Text Document editor Word.,
xLS. – spreadsheet excel programs,
tXT. - a simple test document,
jPG, PNG, GIF - Images,
aVI, JPEG, MP4, MKV - video files,
mP3, WAV. - Audio files.
eXE - executable file.
Types of files: executable files, archived, files with attributes. The possibilities of archivers. Types of file attributes. SFX - Archive. Search and launch programs from different modes Works: team, from shells, graphic.
The executable files are called files containing ready-to-start computer programs.
The archive file is a specially organized file containing one or more files in a compressed or uncompressed form and service information about file names, date and time of their creation or modification, sizes, etc.
file attributes - These are the parameters for which the file differs from many other files. Attributes include the date and time of file creation, the file name, the name of the owner of the file, size, the right, and the file access method. Attributes indicate the system that can be done with this file.
Types of attributes
For each file corresponding to it entry in the directory (directory item) contains attributes file. DOS and Windows 3.1 can handle four file attributes: "Read-only)," Hidden "(Hidden)," System "(System) and" Archive "(Archive). Each of these attributes can be either installed or not.
Assigning attributes
The purpose of these attributes is:
The read-only file attribute protects the file from changes: To change or delete a file with this attribute, it is necessary to pre-remove this attribute. Files on CDs also have a read-only attribute to show that it is impossible to change these files;
The attribute "hidden" and / or "system" is used by some system files (for example, the main MS DOS files - io.sys and msdos.sys, they have both of these attributes). Files with an attribute "System" are not moved by program optimization software on a disk (type Speed \u200b\u200bDisk), and usually not copied to a compressed disk when creating a compressed disk from ordinary DRIVE SPACE types;
The attribute of the file "Archive" is set when creating a file and is reset by programs. reserve copy To refer to the fact that a copy of the file is placed in the archive. Therefore, the presence of an attribute "Archive" usually means that it was not done for the file backup.
Thus, most files have only the "Archive" attribute installed. The remaining attributes ("only for reading", "hidden" or "system"), as a rule, are not installed.
The main functional features of WinRar are:
10-15% more efficient compression of Fa Ylov than in similar archival programs, allowing more effectively to distribute information and save space on hard disks and removable media;
128-bit protection with the use of cryptication, which is considered one of the best degrees of data protection;
Support for most of the formats used today: ZIP, RAR, ARJ, CAB, LZH, 7-ZIP, Z, BZIP2, GZIP, ISO, UUE, ACE and TAR.;
Automatic recognition of compression file format and determining the most effective size searches;
Automatic division of very large volumes of files on a volume with subsequent copying to discs;
Ability to work with different platforms and languages;
The licensed version of the program provides 40-day free archiver testing.
Self-inspiring or self-recovery archive (eng. self-Extracting Archive, Abbreviated "SFX Archive") - a file, a computer program that combines the archive and executable code for unpacking it. Such archives, in contrast to the usual, do not require separate program To unpack them (obtaining the source files from which they are created), if the executable code can be performed in the specified operating system. It is convenient when it is unknown, whether the user who passes the archive corresponding to the unpacking program.
The main way to use self-extracting archives is the creation of software installation programs without using package management systems.
The executable code attached to the archive may be a full-fledged unpacking program. Since there is a possibility of performing a unpacking code, a self-expanding archive or a file disguised under it can be used to spread malicious software.
Basic and Additional computer system files. Functions of system files. Registry, registry work program, program for working with initialization files. Stages of computer loading stages. Methods and stages of rebooting computers.
System file. - Computer file required for the operation of the operating system. Depending on the context may mean:
- .sys - file extension Microsoft Windows. For files used by the system
- System Storage Mac Os.
- Any file with the specified "system" attribute.
- sYS - root directory in sysfs
System files are hidden by default. To prevent accidental changes or delete system files, it is best to leave them hidden. For more information about viewing system files, see Displaying hidden files.
It is not recommended to change system files, i.e. rename, move or delete them, as this can lead to incorrect operation of the computer. If the change in the system file is not immediately reflected in the computer, the next time you start the Windows OS or the computer can work incorrectly.
Registry (system registry) is a hierarchical database containing records that define the parameters and settings of the operating microsoft systems Windows. The registry as it looks like when viewing the registry editor is generated from the data, the sources of which are the registry files and equipment information collected during the download process. In the description of the registry files on english language The term "hive" is used. In some works, it is transferred to Russian as "hive". Microsoft in their documents translates it as a "bush". Registry files are created during the installation of the operating system and stored in the folder % Systemroot% \\ System32 \\ Config (Usually C: \\ Windows \\ System32 \\ Config). For Windows 2000 / XP operating systems, these are files with names.
default.
sam
Security
Software.
System.
. In the process of loading, the system receives monopolized access to these files and, therefore, standard means You can't make anything with files with them (open for viewing, copy, delete, rename). To work with content system registry Special software is used - registry editors (regedit.exe, regedt32.exe), which are standard components of the operating system. To start the registry, use "Start" "Run" - regedit.exe
Initialization files
In Visual FoxPro, FoxPro.ini and Config.fpW initialization files are used to automatically install the work environment.
Experienced users of the PC can with confidence to say that it is a particular file - a picture, music, program. It is not difficult if you know about such a thing as the file extension. Using these knowledge is the most common way to determine the type of data that was saved in the file, and additional opportunity Mustoke yourself from viruses. In essence, the extension is a few characters added to the file name that are used to identify its format.
In OS. Windowsfile display is disabled by default. Of course, it eliminates the need to view some unnecessary information, but many users are oriented only on the name of the file, open everything without thinking about possible danger. You can enable extension display in the control panel.
To do this, go to the "folder parameters" and remove the checkbox in the "View" tab near the corresponding string.
The best protection for your computer is a good antivirus program. However, even the most high-quality antivirus can be mistaken or just do not have time to put the virus in their filters. Therefore, in addition to special programsFor computer security, you must use your own knowledge. For example, if you are on email A letter came with a file from a person unfamiliar to you before opening it, be sure to check the extension. If it is not included in the Safe List - it must be checked antivirus program. In dangerous types of files, viruses or spyware, which are capable of damageing to both your computer programs and important information stored on it are possible. The most dangerous extensions are considered .exe - Files of programs and macros. Of course, if you sent an expected letter to email, there is nothing to fear. But when receiving a letter from an unreliable source, it is better to be renewed and pre-check the file for the presence of viruses.
In order to protect your computer from viruses, you need to know exactly what is this or that extension. The programs use such formats as:
| .exe | software extension that is used in most Windows applications; |
| .com. | program format for MS-DOS; |
| .Application | file type for installing applications that support ClickONCE technology; |
| .msi | the type of file that starts installing programs on the computer; |
| .msp. | updates already installed applications. |
| .gadget. | services that are displayed on the desktop in Windows 7 and Vista operating systems; |
| .scr | extension for screensaver files; |
| .hta. | web application files; |
| .msc. | expansion of Microsoft Management Console Files; |
| .cpl | format of all control panel elements; |
| .jar | It is an executive code for the Java environment. |
| .pif. | this is a special extension containing information for DOS programs. There are no executable code in them, however, they can be dangerous. |
Script files are also executable files, but their difference is that they are not launched independently, but by any program or service. The most dangerous scripts are files with expansion. .cmd., .vbs. and .bat.. For example, even without special software using the usual notepad, you can write a script with extension.Bat, which will be connected when starting to the FTP server, download and run the virus, while by the protection of some antivirus programs.
Scripts
The scripts files include extensions such as:
Labels
As for shortcuts, such formats are used here as:
Additionally
In addition, it should be carefully related to such formats as .dotm, .docm, .xlsm, .xlam, .xLTM, PPSM, .PPAM, .sldm, .potm and .pptm.. The presence of the letter "M" in the end indicates that the document contains macros. It is also worth being attentive and to expand the Windows registry files - .reg, so as not to lose the important information that is in it, and do not add dangerous data there.
To the formats of such, at first glance, secure files, as .txt (text files) as well .jpg, .png. and .gif. (Image files), still it is worth exercising caution. Some viruses use double extension files so that malicious formats seem safe. For example, if a letter with a Foto.jpg.exe file came to your email, then when opening, the operating system will select the extension located right. In this case, the File.exe will open, which is an executed program that can infect the computer with a virus. Remember that legal files extremely rarely have a double extension, so it is better not to open and not upload data in such formats.
This information is very important, as it will help to protect your computer from infection with viruses, and you are from extra problems!
Window Advanced File Anti-Virus Settings
Show all | Hide everything
In the File Types block, you can select the type of files to check the file antivirus. The parameter values \u200b\u200bset by default in this block depend on the selected security level.
All files
File Antivirus checks all files without exception (any formats and extensions).
Files checked by format
If this option is selected, the File Anti-Virus checks only the files in which the virus can be deployed. Before you start searching for viruses in the file, it is analyzing its internal header for the file format (TXT, DOC, EXE and so on). When checking, the file extension is also taken into account.
Files without expansion File antivirus considers executable. File antivirus checks them always, no matter what type of files you have chosen to check.
Extension Files
In this case, the file antivirus checks only potentially infected files. In this case, the file format is determined on the basis of its expansion.
Files without expansion File Anti-Virus considers executable and checks them always, regardless of whether you selected files to check.
Block The verification methods is designed to select methods that the file antivirus should use when checking the computer. The parameter values \u200b\u200bset by default in this block depend on the selected security level.
Alarm analysis
When signature analysis uses bases Kaspersky FREE.containing descriptions of well-known threats and methods to eliminate them. Protection using signature analysis provides the minimum allowable security level.
Heuristic analysis
Slider
Changes the level of heuristic analysis. The level of heuristic analysis provides a balance between threat search care, the degree of loading of the operating system resources and the test time.
There are the following levels of heuristic analysis:
- Surface. The heuristic analyzer performs less actions contained in the executable file. In this mode, the probability of detecting a threat is reduced. Check requires less system resources and passes faster.
- Middle. The heuristic analyzer performs the number of instructions in the executable file, which is recommended by the Kaspersky Lab specialists.
- Deep. The heuristic analyzer performs more actions that are contained in the executable file. With this mode, the probability of finding a threat increases.
Check requires more system resources and takes longer.
The scan optimization unit is designed to select methods that allow you to reduce checking time. The parameter value set by default in this block depends on the selected security level.
Check only new and modified files
Checkbox Enables / disables the check mode of only new files and files that have changed since their previous analysis. File antivirus checks both simple and composite files.
The block checking compound files contains a list of compound files that the file antivirus analyzes to the presence of viruses. The parameter value set by default in this block depends on the selected security level.
Check archives
Checkbox Enables / disables the scan of RAR, ARJ, ZIP, CAB, LHA, JAR, ICE formats.
Check installation packages
Checkbox Enables / disables checking installation packages.
Check nested OLE-objects
The checkbox turns on / off the function when using Kaspersky Free checks the OLE objects attached to the file (for example, Microsoft Office Excel® tables or macros embedded in the Microsoft Office Word file, an email attachment file).
When you click on the button opens the Compound Files window. In the window, you can configure the settings for checking compound files.
In the Check Mode block, you can select a condition at which the file antivirus begins to check the file.
Intellectual
Check mode in which the file antivirus checks the object based on the analysis of operations performed above the object (this mode is used by default).
For example, when working with microsoft document® Office Kaspersky Free checks the file at the first opening and in the last closure. All intermediate operation of the overwrite file from the check is excluded.
When accessing and changing
Check mode at which the file antivirus checks objects when you try to open / change them.
When access
The check mode at which the file antivirus checks objects only when you try to open them.
While doing
The check mode at which the file antivirus checks the objects only when trying to run them.
In the verification technology block, you can select file verification technology.
ISWIFT technology
Technology, which is the development of ICECKER technology for computers with the NTFS file system.
ISWIFT technology has a limit: it is tied to a specific location of the file in the file system and applies only to objects located in the NTFS file system.
Checkbox Enables / disables the use of ISWIFT technology.
ICECKER technology
Technology that allows you to increase the check speed by excluding some files from it. Files are excluded from the check by a special algorithm that takes into account the date of release of the Kaspersky Free database, the date of the previous file check, as well as changing the check parameters.
ICECKER technology has a limit: it does not work with files large sizes, and besides, applies only to files with a well-known program structure (for example, to EXE, DLL, LNK, TTF, INF, SYS, COM, CHM, ZIP, RAR format files).
Checkbox Enables / disables the use of iChecker technology.
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