Flash media read/write speed is probably optimized by the factory format, which uses larger clusters (also called allocation units) than comparably sized magnetic media, for reasons related to the internal organization and control of the memory cells. Typically this is 32KB for SDHC cards, or 8 times larger granularity than equivalent hard drive volumes.

Since each file occupies at least one cluster, the default format wastes a lot of space when large numbers of small files are involved (as in maemo-mapper 1.x). Some of us choose to maximize capacity by minimizing the cluster size for this specific storage pattern, despite the penalty in access speed (which can be substantial).

fanoush posted the Windows command line syntax. The same options are also available through the GUI:

Control Panel -> Administrative Tools -> Computer Management (Local) -> Storage -> Disk Management. Right-click the drive letter in the Volume table or the graphical map. Selecting "Format..." lets you specify the Volume label, File system and Allocation unit size, or perform a quick format (which sets up the data structures without overwriting the media).

Windows Explorer gives you a similar dialog, but only enables the Default allocation unit size, presumably to deter casual users who might not understand the consequences.

To restore the format to SD Card Association standards, download Panasonic's SDFormatter V2.0.0.2 (Windows only) from here:

http://panasonic.jp/support/global/c...formatter.html

[Note: This version is newer than the one posted on sdcard.org]