HolocronSith holocrons usually took the form of a pyramid, and the existence of the first Sith holocron predates that of a Jedi holocron by at least three thousand years. The technology to create the pyramidal holocrons common to the Sith was something gifted to the ancient Sith king Adas by Rakata warriors trying to gain his trust. He accepted their technology and made a holocron, but he saw through their ploy and rebelled against them. It can only be assumed that the Jedi also learned the secrets of the holocron by Rakatan example, possibly by studying mysterious artifacts left behind by the Infinite Empire.
The holocron was able to capture the appearance and cognitive networks of the holocron's owner, and transform this into a three-dimensional hologram. This gatekeeper acted as a guide through the holocron's store of information, as a search and recovery engine with a more personal touch. These gatekeepers could relate stories from the holocron's archives to events in the life of the one who activated the holocron. Jedi gatekeepers could sense the ability and level of a Jedi, and offer or restrict information accordingly—so that Padawans were not shown information too advanced and dangerous for their basic stage. However, Sith holocrons usually allowed the activator unlimited access to its entire dark side repository.
A great many holocrons were stored in the Jedi Archives on Coruscant; stored in a specific Holocron Chamber within the Jedi Temple. In addition to holding the holocrons created by Jedi in the field, the Archives also held the details to creating holocrons and direction on accessing them.