PPDD is a Linux device driver.
The 1.2 version of PPDD is specific to the device driver and only works with 2.0 and 2.2 series of Linux kernels. In contrast, the later versions, which work with the 2.4 series, use the loop device driver, reducing PPDD's dependence on kernel revisions. Moreover, PPDD has been made secure and foolproof through a lot of effort in developing it.
The 2.0 version of PPDD is still in beta, meaning undiscovered bugs could potentially erase user data or create security holes. However, the 1.2 version is very stable, and there are no reported security problems. Though both versions have their limitations on liability, they're fully compatible, and the data format on disc is precisely the same.
The 2.0 version of PPDD is designed to work on Intel-86, but PPDD has been modified to replace the assembler routine with a C version. As such, PPDD's performance issues are the same regardless of the hardware platform it's running on. While the 2.0 version of PPDD can handle very large discs (38Gb being the maximum tested), switching back to version 1.2 may prevent them from working. Additionally, version 1.2 has its limitation; users can only work with ext2 and 1024-block sizes.
Version 2.0 of PPDD works with ext2, ext3, and reiserfs. The real data file can be kept on a software raid device without any complications, and the loop device can be used with a real data file on a ppdd device.
Installing and using PPDD as an average user is one of the driver's design objectives. This is reflected in the new software revisions which include extensive documentation such as "man" pages. PPDD's make macros have been modified to check the user environment more comprehensively, and success is almost guaranteed when users follow the instructions.
PPDD also features the ability to encrypt the root filesystem and swap files to minimize accidentally leaving sensitive material on disc. However, at its current development stage, this feature requires prior knowledge of Linux, mainly the booting process, on the sysadmin's part to implement effectively.
Version 2.0: N/A