Diamond Rio PMP300, with only 32 MB of flash memory, was the second portable MP3 player ever released, in 1998. Unfortunately, such a revolutionary piece of hardware is very painful to interface with: as it is connected through parallel port, highest transfer rates achieved were around 80 KB/s. And the software bundled with it was too primitive. To the luck of thousands of (un)happy Rio owners, The Snowblind Alliance released their Open-Source RIO utility, which became a starting point of several alternative Rio manager interfaces. Mine is just one of them
First of all, there's absolutely no need to write the entire file manager. Total Commander (TC for short) is one of the most feature-rich file managers ever made, and it supports a very extensible plugin API. As a result, one could use TC to manage files directly on the flash memory of his/her Rio! Actually, my plugin supports listing, uploading, downloading & deleting files from Diamond Rio PMP300 internal memory. It also displays the transfer speed and the total/remaining space. Take a look at this screenshot to see it in action. Behind the GUI, my plugin uses the source of the "RIO utility v1.07" by The Snowblind Alliance.

Installation:

Just the same as for many other FS-plugins:

1. Unzip rio.wfx & rio.cfg files to Total Commander directory
2. Choose "Configuration => Options => Operation => FS-Plugins"
3. Choose rio.wfx
4. Click OK.
5. You can now access the plugin in the "Network Neighborhood"
6. Open rio.cfg file and set the correct LPT port address (see below for more details)
   

Please note that DriverLINX Port I/O Driver by Scientific Software Tools, Inc. is required for plugin to operate. Get it below.

Configuration:

In the majority of cases, the plugin may work fine "out-of-the-box". If it doesn't work at all, probably you'll need to discover and specify your PC's parallel port hardware address. Open your system's "Device Manager" (on Windows XP, open the context menu for "My Computer", click "Properties", go to the "Hardware" tab, and click the "Device Manager"). Go straight to "Ports (COM & LPT)". Now locate the port that your Rio device is attached. On my case, it's LPT1. Double-click "Printer port (LPT1)", and go to the "Resources" tab. You need the first one of  "I/O Range" numbers:


378 is what you need. Note that this number is in a hexadecimal format. Thus, many programs (like my plugin) may accept it as 0x378. Now, open the rio.cfg file. It looks like this, by default:
Now, just update the IOPort parameter to the value you discovered.
Note all that IODelay* parameters. For the safety reasons, the delays are high by default, and, consequently, the file transfer is slow. If you comment out the default values and uncomment the turbo mode ones, you'll get a great increase in performance! But remember to only use it when your Rio battery is 100% charged, and when your Rio is turned on. It may corrupt some bits, through.