Use the .com extension for the command line executable on Windows

Jérôme Vuarand wrote on Wed, 01 August 2012 12:50

An informal convention when using that dual executable solution is to

use the same base name for the two files, but using the .com extension

for the Console executable.

There is no such convention.  Furthermore, the file name suffix ".com"

already has a specific meaning.

Quote:

My suggestion is then to simply rename the file "eaglecon.exe" to

"eagle.com".

Really bad idea.

Some other convention could be used though.  For example, I add "_w" to GUI

executables, like myprog.exe for the command line and myprog_w.exe for the

window version.  You want the command line version to be the simple name

since you have to type it.  The GUI version can be more convoluted since it

is generally run from a menu item with the actual executable name hidden

from the user.

The Eagle convention is fine too.  The point is there is no standard, just

various things people have done.  There is also little need for one.  There

is no problem to solve here.  Let's move along and stop diverting the

developer's attention on frivolous issues like this.

--

Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

Jérôme Vuarand wrote on Wed, 01 August 2012 12:50

An informal convention when using that dual executable solution is to

use the same base name for the two files, but using the .com extension

for the Console executable.

There is no such convention.  Furthermore, the file name suffix ".com"

already has a specific meaning.

Quote:

My suggestion is then to simply rename the file "eaglecon.exe" to

"eagle.com".

Really bad idea.

Some other convention could be used though.  For example, I add "_w" to GUI

executables, like myprog.exe for the command line and myprog_w.exe for the

window version.  You want the command line version to be the simple name

since you have to type it.  The GUI version can be more convoluted since it

is generally run from a menu item with the actual executable name hidden

from the user.

The Eagle convention is fine too.  The point is there is no standard, just

various things people have done.  There is also little need for one.  There

is no problem to solve here.  Let's move along and stop diverting the

developer's attention on frivolous issues like this.

--

Web access to CadSoft support forums at www.eaglecentral.ca.  Where the CadSoft EAGLE community meets.

Hi,

On 08/01/12 19:08, Olin Lathrop wrote:

Jérôme Vuarand wrote on Wed, 01 August 2012 12:50

>> An informal convention when using that dual executable solution is to

>> use the same base name for the two files, but using the .com extension

>> for the Console executable.

 

There is no such convention.  Furthermore, the file name suffix ".com"

already has a specific meaning.

 

Quote:

>> My suggestion is then to simply rename the file "eaglecon.exe" to

>> "eagle.com".

 

Really bad idea.

 

Some other convention could be used though.  For example, I add "_w" to GUI

executables, like myprog.exe for the command line and myprog_w.exe for the

window version.  You want the command line version to be the simple name

since you have to type it.  The GUI version can be more convoluted since it

is generally run from a menu item with the actual executable name hidden

from the user.

 

The Eagle convention is fine too.  The point is there is no standard, just

various things people have done.  There is also little need for one.  There

is no problem to solve here.  Let's move along and stop diverting the

developer's attention on frivolous issues like this.

 

I agree. It's difficult to make everybody happy on questions like this.

As long there is no real need to change that we keep it.

Regards,

Walter Spermann

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Walter Spermann

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CadSoft Computer GmbH

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Tel.: 08635/6989-10

www.cadsoft.de

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Geschäftsführer: Thomas Liratsch

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Olin Lathrop wrote:

Really bad idea.

Telling something is a bad idea mandates some explanation. Otherwise it's just an opinion, and I don't think your opinion matters nearly as much as the one from the Microsoft Visual Studio team.

Olin Lathrop wrote:

There is no problem to solve here.  Let's move along and stop diverting the developer's attention on frivolous issues like this.

There may be no problem for you, that's a problem for me. Anyways the forum is named "suggestions", not "bug reports", and even if there is no problem that's a place to propose improvements. So I will kindly ignore your message and continue "diverting the developer's attention" on issues like this.

Walter Spermann wrote:

I agree. It's difficult to make everybody happy on questions like this. As long there is no real need to change that we keep it.

Fair enough. My goal was just to improve consistency with other platforms where I assume a single "eagle" binary name is used, and with other applications that use a different naming convention on Windows to solve the same problem. Of course that was never meant as a high priority request, just a personal opinion.

On 08/01/2012 01:08 PM, Olin Lathrop wrote:

Quote:

>> My suggestion is then to simply rename the file "eaglecon.exe" to

>> "eagle.com".

 

Really bad idea.

I agree.  The ".com" extension is a left over from the CP/M days and

even earlier than that in the PDP-10 and PDP-11 days.  It was used to

designate a "command" other than what was built into what one could

loosely refer to as a shell.  At the time it was called a "command

interpreter".

Unlike most other file extensions, a ".com" file is expected to be

loaded at address 0x100 and the first instruction is to occur at that

address.  It's a pure binary file that contains all the code and data

objects a program needs to execute.  This was adapted for MS-DOS and the

80x86 when segment registers were introduced to expand addressable

memory beyond 64k.  In this case, the CS register was set to an

arbitrary value as determined by the OS, and the .com file was loaded en

masse at offset 0x100, providing backward compatibility with binary code

for CP/M.

More modern executables, including ".exe", have what's called a magic

number in the first few bytes of the file.  The magic number is a unique

value that identifies the format of the file's content.  "MZ" identifies

a Windows executable.  This particular format describes different

segments of the file that are to be loaded in different segments of

memory (text, data, bss, etc.).

One executable file format for unix-like systems is "ELF" (Exectucable

and Linkable Format), with the first four bytes of the file containing

".ELF".  Like the "MZ" format, ELF files contain descriptors for loading

text, data, and bss segments as well as relocation.

Another example are scripts for perl, shell, and other interpreted

languages start with a "#!".  Batch files for CP/M, MS-DOS, Windows, etc

do not contain any magic number and rely entirely on the shell to

properly identify the file's format based solely on the file's extension.

Some kernels will try to identify the format of the file image

regardless of the extension.  This, of course, has its benefits, but it

also opens a security hole should an arbitrary binary data file happen

to contain a magic number recognized by the kernel.  One could wind up

executing data.

This is by no means an exhaustive list of file formats, but merely a few

examples of more common formats.

For these reasons, it is generally considered a bad idea to rename a

.exe to .com.

HTH

    - Chuck