There are 14 Mdisks in total, but you need only 11 of them to unlock the achievement. Here's the full list of Mdisks.
1. Game Save Disc - You have this from the start and use it to save your game.
2. Mr. De Castellac - The mission disc you receive at the beginning before going to Black Isle.
3. The Pearl and the Currents - An information disc given to you by IRIS.
4. For Jade - A gift from Pey'j given to you at the Nutripils factory.
5. Surveillance Camera - Footage of Pey'j on the conveyor belt. It is in the cabinet next to his jetboots.
6. Hillyan Army Database - A full list of the gear used by the Hillyan Army and the Alpha Sections. Found in the security room above the area where you find the jetboots.
7. Beluga Check-Up - Found on the desk by the Beluga.
8. Animal Species - A photo album of all the species on Hillys. You receive it as a reward when you complete the photo survey.
9. IRIS 511 - An early, lackluster report from before you arrived. Pick it up in Ming-Tzu's backroom.
10. IRIS 512 - Another early report. Pick it up in Ming-Tzu's backroom.
11. IRIS 513 - Your finished report on the Nutripils factory. Pick it up from Ming-Tzu's backroom.
12. IRIS 514 - Your finished report on the slaughterhouse. Pick it up from Ming-Tzu's backroom.
13. Disc Game - On http://beyond-good-and-evil.ubi.com/beyond-good-and-evil-hd/...
, you can enter the "Internet Code" given when you save your game. Not only does it include you in a leaderboard depending on your in-game stats, but it also give you a code to get the disc from the jukebox and play Francis' disc game online. This code is unique to each player.
14. Pearl Game - A little pearl game you get as a reward from Mammago for collecting all the pearls.
List found on: http://www.mahalo.com/beyond-good-and-evil-pearl-list/