DOCUMENT:Q82823  09-OCT-1999  [win95x]
TITLE   :How Does Cardfile Verify Writes?
PRODUCT :Microsoft Windows 95.x Retail Product
PROD/VER:WINDOWS:3.1,3.11
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Windows versions 3.1, 3.11 
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SUMMARY
=======

In Microsoft Windows version 3.1, the Cardfile accessory application has a
Validate Writes check box in the File Save dialog box. If this check box is
selected, then Cardfile verifies the integrity of the changes it writes to the
file.

MORE INFORMATION
================

When Save or Save As is chosen from the File menu, Cardfile writes the changes
to a temporary file. If Validate Writes is selected, Cardfile then reopens this
temporary file and checks that it can read it.

Cardfile does not compare the files card by card, but merely makes certain that
the file opened is in a valid Cardfile format by checking the validity of the
following:

 - The header for the whole file

 - The header for each card

If one of the above checks fails, the temporary file is not considered valid.
This means that if only one card is corrupted, the whole file will be marked as
bad.

If the temporary file is valid, the temporary file is renamed to the filename you
specify. By performing the validation in this manner, the old file is not
corrupted when you try to update it with more information.

Cardfile for Windows 3.1 has a new format that allows it to support OLE and
contain pictures. The new format entails a change in the header for the file. If
the file contains a picture, Cardfile saves the file in this new format. If it
does not contain a picture, Cardfile saves the file in the format used in
Cardfile for Windows version 3.0, allowing both versions to read it. If someone
takes a file containing a picture and tries to open it using the 3.0 version of
Cardfile, the following message will appear:

   Not A Valid Cardfile

For more information on the Cardfile format, query on the following words in the
Microsoft Knowledge Base:

   appnote and cardfile and format
   validateFileWrite=1

Additional query words: appnote 3.1 3.10 3.00 3.0

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Keywords          :  
Technology        : kbWin3xSearch kbZNotKeyword3 kbWin310 kbWin311
Version           : WINDOWS:3.1,3.11

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