There are 2 types of Alpha islands:
Alpha 1 islands all have a terminal and 3 outposts, this is where novice players start the game. Which island new players start on depends on the faction of their choosing during agent creation. All NPCs on this island don't attack other players unless targeted and locked (Orange NPC). These islands are Daoden, New Virginia and Attalica. Each of them is connected via teleports to two Alpha 2 islands.
Alpha 2 came at a later date during game's live development with the need for more space for players to roam, they only have one main terminal. NPCs are harder and some (Red NPCs) shoot you, if you get too close. Resources are more abundant on these islands, with a full rack of 50 production points for all facilities at their main terminal. These islands are Shinjalar, Hershfield and Tellesis.