WFWG Mail: DoubleSpace and Highest Security Options

• Microsoft Windows for Workgroups version 3.11

SUMMARY

In version 3.11 of Microsoft Windows for Workgroups, 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." The following new choices are available:

   DoubleSpace
   Highest Security

MORE INFORMATION

DoubleSpace is considered to have less encryption (resulting in less security) but better performance (that is, increased speed) than the Highest Security option. DoubleSpace is available with MS-DOS version 6.0 or later only.

The Highest Security option uses the same Mail message file (.MMF) encryption algorithm that Microsoft Mail for PC Network uses. Highest Security is not as fast as DoubleSpace because time is used to encrypt and decrypt the .MMF file.

The DoubleSpace encryption is built into DoubleSpace itself. A file cannot be copied from a DoubleSpace drive, imported to a different computer, and easily read. Since 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.

MORE INFORMATION

Additional information about DoubleSpace can be found on pages 118-136 in the MS-DOS "User's Guide" and in Chapter 3 of the MS-DOS "Technical Reference Manual."