What is PST file format ?

hie friends,

I want to know about the PST file format that is associated with Microsoft Outlook Express.
Does anybody know the details about this ?.......please provide me the information about the same.......

thanks a lot

PST stands for Personal Storage Table - A file format with .pst extension.

In computing, .pst is a file used to store local copies of messages, calendar events, and other items within Microsoft software such as Microsoft Exchange Client, Windows Messaging, and Microsoft Outlook.

In Microsoft Exchange Server, the messages, calendar and other data items are delivered to and stored on the server.
In standalone applications (Microsoft Outlook, for example), the messages, calendar and other data items are delivered to and stored locally in a Personal Storage Table (.pst) file that is located on the computer. The size of the file then no longer counts against the size of the mailbox used; by moving files from a server mailbox to .pst files users can free up storage space on their mailserver.
To use the .pst files from another location you need to be able to access the files directly over a network from your mail client.

When data files like email messages are added to a .pst file its filesize is automatically adjusted by the mail client (if necessary).
When mail is deleted from a .pst file the size of the .pst file will stay the same, creating space to hold future data items.
To reduce the size of .pst files you need to compact them. Password protection can be used to protect the content of the .pst files.

The .pst file format is fundamentally insecure for multiple reasons.

• The password (actually a crc-32 integer representation of it) is simply stored in the .pst file, and Outlook checks to make sure it matches the user specified password, and refuses to operate if they don't match. But the actual data is still there, and is readable by the libpst project code.
  
  
• MS offers three values for the encryption setting - none, compressible, and high.
  
  
  1. none : No encryption is easy - the .pst file contains your data in plain text, and a simple text editor will show the contents.
     
  2. compressible : Compressible encryption is a simple byte substitution cipher with a fixed substitution table. Of course, since the table is fixed it is also widely known, and so must be assumed to be known to any attacker. So they can simply decipher the data and see your plaintext.
     
  3. high : High (sometimes called "better") encryption moves us up to a WWII German Enigma cipher with three fixed rotors. Again, the rotors are fixed and widely known, and so must be assumed to be known to any attacker. So again, they can simply decipher the data and see your plaintext.

Note that neither of the two encryption modes uses the user specified password as any part of the key for the encryption. Using encryption in this way (with a single global fixed key) is at best obfuscation, and not really encryption.

The Personal Storage Table format is supported by several Microsoft client applications including Exchange Client, Windows Messaging, Microsoft Outlook, and Microsoft Office Outlook.

The PST file format is proprietary and cannot be read directly by third-party applications such as Eudora and Mozilla Thunderbird; many such applications are nonetheless able to import data from PST files via MAPI calls to one of the applications which can read them directly.

VERSIONS

Outlook 97
Starting with Microsoft Outlook 97 the Personal Storage Table file is encoded in ANSI format.
It has a maximum file size of 2 GB. If the file exceeds this size it will become corrupted.
This format is supported by Microsoft Outlook 97, Outlook 98, Outlook 2000, Outlook 2002, and Outlook 2003 Internet Message Access Protocol Version 4rev1 (IMAP4) accounts and HTTP accounts.


Outlook 2003

Starting with Outlook 2003 the Personal Storage file is encoded in unicode format.
It allows a user-definable maximum file size up to 33TB that exceeds the previous limit of 2GB.
This format is supported by Microsoft Outlook 2003 and Outlook 2007. A file that is created in the personal folders format in Outlook 2003 or Microsoft Office Outlook 2007 is not compatible with earlier versions of Microsoft Outlook and cannot be opened by using those older versions.

To store emails, calendar data, contacts, etc, all versions of outlook use PST files. By default, the PST file is located in the following path: C : \ Documents and Settings \ User \ Local Settings \ Application Data \ Microsoft \ Outlook. This folder is hidden, so to open it in Windows Explorer, you need to show hidden folders. To do this in Windows Explorer, it should be noted the option View / Options / Files or Folders / Hidden files and folders / Show hidden files and folders .

You can move the PST file at any place convenient for you. To do this, log out of Microsoft Outlook, and drag the file into a new folder. It is better not to perform a transfer, instead it should be copied, then the next time you start Microsoft Outlook, then it will not issue a warning that the PST file was not found. You will only need to select a file from the new location, and Microsoft Outlook will continue to work. You can create multiple PST files and store them on your local disk or a flash drive or a CD. PST files are a universal repository, which is very convenient to use, including for the transfer of data from one computer to another.

PST stands for Personal Storage Table. This file format helps you to store various stuff like messages, events, etc. If this file is corrupted there is a pstfix tool that can be used to recover its content. Also it is possible to password protect this file. You must also remember that the maximum file size limit of .pst is around 2GB. If that exceeds you will face a error of maximum file size limit reached.