DOSFS and the short and Long file names.

Nasir, Aliasgar ( SBU-ETS ) aliasgar.nasir at igatepatni.com
Thu Aug 4 05:15:09 CDT 2011


Hi Chris,

Thanks for the reply.

If the file name has only lower case letters, then the name in not distorted on Windows. However, on the Windows, the file name shows all characters as upper case.

If the file name has just upper case letter, the name appears distorted on Windows. Is this desired behavior?

If the file name has only upper case and a numeral (0 - 9), then the name is again seen distorted on Windows.

But still I am not able to figure out why mixed case file names are seen distorted in Windows. Do you have any idea? Or is there any solution to this problem?

Or as a rule we have to ensure that we make files names with only lower case when working with DOSFS with RTEMS4.10. Is this true? Otherwise we end up seeing distorted names on Windows.

Regards,
Ali

-----Original Message-----
From: Chris Johns [mailto:chrisj at rtems.org]
Sent: Thursday, August 04, 2011 10:05 AM
To: Nasir, Aliasgar ( SBU-ETS )
Cc: rtems-users at rtems.org
Subject: Re: DOSFS and the short and Long file names.

On 4/08/11 1:59 PM, Nasir, Aliasgar ( SBU-ETS ) wrote:
> Hi,
>
> With the RTEMS4.10, we noticed that there is concept about long and
> short file names in the DOSFS.
>
> We use the DOSFS on an SDCARD. When we try to write a file on the card,
> with file name say 'Error2.txt', the DOSFS detects this as a long file
> name and then executes the below code in function
> msdos_find_name_in_fat_file(), while creating the file.
>
> *if**(*name_type*==*MSDOS_NAME_LONG*)*
> *{*
> *int*slot*=**(((*empty_space_offset***bts2rd*)**+*empty_space_entry*)**/*
> MSDOS_DIRECTORY_ENTRY_STRUCT_SIZE*)**+*lfn_entries*+*1*;*
> msdos_short_name_hex*(*MSDOS_DIR_NAME*(*name_dir_entry*),*slot*);*
> *}*
>
> The above piece of code modifies the file name as ERR~0005.TXT. This is
> the file name seen when we see the contents of the card on a Windows
> based machine using card reader. The file name of the file as seen from
> the RTEMS shell is still 'Error2.txt'
>
> Can anyone guide as what should be done to see a the correct file name
> (Error2.txt) on the Windows machine?
>

You have used mixed case and this cannot be handled with a short file
name therefore it has used a long file name which does maintain the
case. Windows should notice this and show the short and long filenames.

> Regards,
>
> Ali
>
>
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