PC WFW: Mail DoubleSpace and Highest Security Options

• Microsoft Mail for Windows for Workgroups, version 3.11

SUMMARY

In version 3.11 of Microsoft Windows for Workgroups Mail, there are additional menu items not supplied in the retail package of Microsoft Mail for PC Networks.

Under the Mail Options menu, there is a section titled Optimize Local Mail File. There are two choices listed:

   DoubleSpace
   Highest Security

MORE INFORMATION

DoubleSpace is considered to have less encryption (less security) but better performance (speed) than Highest Security. DoubleSpace is only available with MS-DOS version 6.0 or higher.

The Highest Security option uses the same Mail Message File (MMF) encryption algorithm used by Microsoft Mail for PC Networks. Highest Security is not as fast as DoubleSpace because time is taken to encrypt or decrypt the .MMF file.

The DoubleSpace encryption is built into DoubleSpace itself. You cannot copy a file off of a DoubleSpace drive, import it to a different computer, and easily read the file. Because the file allocation table (FAT) system is cluster based, DoubleSpace uses its own FAT [which is called the Microsoft DoubleSpace FAT (MDFAT)] to achieve sector allocation. This encryption option is fast; however, it is not as secure as the encryption algorithm used in the Highest Security setting.

For more information on DoubleSpace, see pages 118-136 in the MS-DOS "User's Guide" and Chapter 3 of the MS-DOS "Technical Reference."