Here's a guide on how to find all of the hidden terminals in every stage of Halo Combat Evolved Anniversary.

Also be sure to check out this Youtube channel with videos of how to find all the terminals.

Terminal 1
Location: Pillar of Autumn
Look for a red computer console on the bridge after you talk to Keyes and get control again.

Terminal 2
Location: Halo
Near the underground tunnel, search the side of the tunnel for this terminal.

Terminal 3
Location: Truth and Reconciliation
Defeat the Elites on the bridge, then look for the terminal on the raised central platform.

Terminal 4
Location: Silent Cartographer
After fighting two hunters in the center of the island, the terminal is on the outer wall of the central structure.

Terminal 5
Location: Assault on the Control Room
After you come across a pyramid-shaped Control Room you will see a large structure leading into crevasse in the ground. The terminal down is located below.

Terminal 6
Location: 343 Guilty Spark
When you are reaching for the elevator leading outside the facility, turn around and look above the door for an elevator. To reach that room, you will have to jump off the elevator as it moves up.

Terminal 7
Location: The Library
On the third floor of library with the index platform above you, go right from the entrance and jump over the barrier. You will enter a room that contains the terminal ahead of you.

Terminal 8
Location: Two Betrayals
Look around the circular chamber in the control room at the start of the level and to find this terminal.

Terminal 9
Location: Keyes
After you find Keyes absorbed by the flood, defend yourself in the room. There are two crevices by your sides and there is a terminal down in one of these two crevices.

Terminal 10
Location: The Maw
You will find this terminal by the wall in Cyrogenic Storage Bay.