There are 6 lore codex entries on Ziost. Two are required for the Ziost Archivist achievement.
The Death of a World codex entry obtained from a cutscene.
Codex type: Lore
Codex location: Ziost: GSI Orbital Station
Codex coordinates: 2082, 205
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission 'The End of it All' to gain access to this codex entry
The Galactic History 94: The Sacking of Coruscant codex entry Ziost Archive Holocron.
Codex type: Lore
Codex location: Ziost
Codex coordinates: 607, -81
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: Ziost Archivist
Special Requirements: You must progress the mission 'The End of it All' to gain access to this codex entry
To reveal the Ziost Archive Holocron you must first interact with the Exposed Walker Wiring. Doing this will trigger the walker to fire its cannons at the rocks in front of it, and expose the holocron for the whole world for several minutes. Note that if you interact with the Exposed Walker Wiring while the holocron is revealed then the walker will fire again and destroy the holocron. If this happens you must wait a few minutes for the rock, and holocron, to reset before activating the Exposed Walker Wiring again.
Exposed Walker Wiring.
Item: Exposed Walker Wiring
Item location: Ziost
Item coordinates: 585, -38
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
The Galactic History 95: A Cold War Begins codex entry Ziost Archive Maintenance Droid.
Codex type: Lore
Codex location: Ziost
Codex coordinates: 1191, 385
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: Ziost Archivist
To interact with the Ziost Archive Maintenance Droid, you must first collect two supplemental items from Ziost. There is a small clickable Ziost Archive Data Cartridge in a computer bank, it does not glow blue, but your mouse will turn into a clickable hand when you hover over the data cartridge. The second item is the Ziost Archivist's Datapad, which is found in a crate facing a wall. Once both items have been collected on a character you will be able to interact with the Ziost Archive Maintenance Droid.
The Revolt on Ziost codex entry obtained from a conversation.
Codex type: Lore
Codex location: Ziost: People's Plaza: People's Tower: Floor 2
Codex coordinates: -2295, 73
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission 'Dead Center' to gain access to this codex entry
The Emperor's Eye codex entry obtained from a mission.
Codex type: Lore
Codex location: Ziost
Codex coordinates: 1354, 144
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission 'Eyes in the Past' to gain access to this codex entry
The Invasion of Ziost codex entry obtained from a conversation.
Codex type: Lore
Codex location: Ziost: Military Outpost: Administration Office
Codex coordinates: 2088, -496
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission 'Powerless' to gain access to this codex entry