What does it mean the file must be executable. What are executable files and what are they? EXE Openers

In order for the operating system loader to load correctly executable file into memory, the contents of this file must correspond to the one accepted in this operating system executable file format. There have been and still are many different formats in different operating systems at different times. In this chapter, we will take a look at the Portable Executable (PE) format. The PE format is the main format for storing executable files in the Windows operating system. Assemblies. NET are also stored in this format.

In addition, the PE format can be used to represent object files... Object files are used to organize separate compilation of the program. The meaning of separate compilation is that the parts of the program (modules) are compiled independently into object files, which are then linked by the linker into one executable file.

And now - a little history. The PE format was created by the developers of Windows NT. Prior to this, the Windows operating system used the New Executable (NE) and Linear Executable (LE) formats to represent executable files, and to store object files used Object Module Format (OMF). The NE format was intended for 16-bit Windows applications, and the LE format, originally developed for OS / 2, was already 32-bit. The question arises: why did the developers of Windows NT decide to abandon the existing formats? The answer becomes obvious when you pay attention to the fact that most of the team that worked on the creation of Windows NT, previously worked at Digital Equipment Corporation. They were developing tooling for the VAX / VMS operating system at DEC, and they already had the skills and code to work with executable files in the Common Object File Format (COFF). Accordingly, the COFF format in a slightly modified form was ported to Windows NT and called PE.

The .NET Framework Glossary says that PE is Microsoft's implementation of the COFF format. At the same time, it states that PE is the format of executable files, and COFF is the format object files... In general, we can observe confusion in the Microsoft documentation regarding the name of the format. In some places they call it COFF and in others PE. True, you can see that in the new texts the name COFF is used less and less. Moreover, the PE format is constantly evolving. For example, a few years ago Microsoft stopped storing debug information inside an executable file, and therefore now many fields in COFF structures are simply not used. In addition, the COFF format is 32-bit, and the latest revision of the PE format (called PE32 +) can be used on 64-bit hardware platforms. Therefore, apparently, the point is that the name COFF will cease to be used altogether.

It is interesting to note that legacy NE and LE binaries are still supported by Windows today. Executable files in NE format can be run under NTVDM (NT Virtual DOS Machine), while LE format is used for virtual device drivers (

The Linux operating system, unlike Windows, determines which files are programs not by extension, but by a special executable flag. Each file has three main flags, read, write and execute. They determine what the system can do with this file.

When you download various installers for programs from the Internet or create a script in text editor, they are set to default flags - read-only and write-only. You won't be able to run such a file as a program, there is a little more to do with it. In this article, we will look at how to make a file executable in Linux.

Much has been written about how to set an executable flag. But what happens to the file during this, what is the usability and how does it work?

A program is a set of instructions that the processor executes in turn on data to obtain a specific result. But you probably already know that.

There is really no difference for the processor between data and instructions. Both those and others consist of bytes, in other words, numbers. Once upon a time it was agreed that certain combinations of numbers would mean this or that action of the processor, but in all other respects it is the same data. Therefore, it makes no difference for the processor what to execute - executable linux file or normal text file... Both can be successfully executed, but in the second version, the instructions do not make any sense.

So that the system can determine which files need to be executed, and which ones are better not, and an executable flag was invented. In fact, the usability flag is a few bytes in file system that say whether the file should be executed or not, the file content itself does not change in any way. With scripts, everything works in the same way, only the commands from the file are executed not by the processor, but by the interpreter, for example, in bash scripts - the bash shell itself. And ordinary programs also have their own loader - this is ld-linux.so.2.

How do I make a file executable in Linux?

On Linux, the chmod utility is used to manipulate file flags. The syntax for calling the utility is:

• Category- flags can be set for three categories: file owner, file group and all other users. In the command, they are indicated by the symbols u (user) g (group) o (other), respectively.
• Action- may be + (plus), which would mean to set the flag or - (minus) remove the flag.
• Flag- one of the available flags - r (read), w (write), x (execute).

For example, to make an executable script in linux for the owner of the file, just run:

chmod u + x file_address

This is enough in most cases, but if we want other users to execute the file, we need to specify other categories as well: g and o:

chmod ugo + x filename

You can view the flags in the terminal using the ls utility:

ls -l file_directory

This means that all flags are enabled for all categories. The first rwx is the owner flags, the second is the group, and the third is for everyone else. If the flag is not set, a dash will appear in its place.

It is very easy to uncheck an executable file. The same command is used only with a minus sign:

chmod u-x file_address

How to install executable file in GUI

You can make a file executable on linux not only through the terminal. This functionality is available in all file managers. It may be easier for you at first. Let's consider an example file manager GNOME, Nautilus. Click right click by our program or script file to open context menu then select properties:

Then go to the rights tab and check the box Allow the file to run as a program:

Done, the linux executable can be launched by the system, right from the file manager.

conclusions

That's all, now you know how to make a file executable in linux. And if you need to run a script or installer from the Internet, you won't have any problems. If you have any questions, ask in the comments!

Executable files are files that contain computer programs that are ready to run.

An executable file is a phrase that is quite common, mainly in the documentation. In live communication (including virtual), to denote this type of files, users use less cumbersome terms that more accurately reflect what they mean.

So what is hidden behind this phrase? Executable files are files that contain computer programs that are ready to run. Depending on the form in which the program is written in the executable file, two large subgroups of files of this class are distinguished. The first subset is binaries; they contain a program record in the form of special machine codes, which, most often, are transmitted directly to the processor. Such files are also abbreviated as binaries. In contrast to them, there are executable files in which the program is written in the form of text - that is, in the same form in which the programmer who created it worked with it. Such executable files are called scripts. Also, this term is often used in relation to the programs themselves, which are stored in such files.

To execute programs from most binary executable files, only the operating system that supports them is sufficient. To execute scripts, you need an interpreter that will translate the program text sequentially into processor instructions. Some binary executable files also need interpreters to run.

On Windows, the most common binary executable files. The most common type of them is the application. Applications have EXE extensions and can run on their own. In addition to them, there are dynamic libraries (their extension is DLL), which contain functions common to different applications. There are also drivers (DRV or VXD) - special programs needed so that the system can interact with specific models of certain devices. Executable files (especially in Windows) can depend on each other: for example, to run any application, certain system dynamic libraries are needed, and they, in turn, need drivers.

It should be noted that executable files contain not only the programs themselves, but also various additional data. These can be various graphic resources displayed by the program, texts of inscriptions, descriptions of dialog boxes, etc. A striking example of this can be self-extracting archives, which contain inside themselves large volumes of packed in order to reduce its volume when transferring or storing information.

Vadim STANKEVICH

Vkontakte is undoubtedly a very common social network, where people not only correspond with each other, but also exchange various files. In this regard, many users of this social network they often encounter a problem when, while trying to attach a file to a message, an error appears with the text “Failed to load the file. The file must not be executable, and its size must not exceed 200 MB. "

If everything is clear with the file size, then not everyone knows what "The file must not be executable" means.

In this article, we will explain what an executable file is and what to do to get around this warning.

An executable file - what is it?

An executable file is a file that contains a ready-made set of commands for the computer, which can be loaded into memory and started to be executed.

As a rule, these are files with the extensions .exe, .bat, .com.

Also, sometimes VKontakte does not want to download archives in which .exe files are packed, referring to the same error.

This is due to security issues, because .exe files are the first in popularity in the ranking in terms of susceptibility to virus infection. And in order to somehow reduce the risk of proliferation computer viruses Through VKontakte, the developers decided to simply prohibit transferring to each other the file type most susceptible to infection - the executable file.

How to get around the error?

It is quite easy to get around this limitation. You just need to send one of the allowed ones, for example .doc, to the addressee and tell him to change the extension back to the one that the file had originally after downloading the file.

File extension change

From alternative ways you can mark the upload of a file that VKontakte refuses to upload to any cloud storage such as Yandex disk or Google disk, and then sending a link to it to the addressee of VKontakte.