Gramps Unit

Gramps Unit is the name given to an ambiguous and antique computer.

First Design
Originally, he was shown to take up an entire basement as Whirlwind and Univac era mechanical computers do. He requires extensive electricity which explains one reason why Mom Unit is concerned about fuel. Starting up Gramps Unit is very complex and requires many buttons and levers. This was a rhythmic theme spoken by children in the background. By season 2 episodes, there were no more children speaking in the background during the title cards, and that means this theme was forgotten about as well. When Gramps Unit was started up, he required data to analyze and was unable to communicate unless data was manually fed to him. The calculations were later printed out and also spoken by him. He does not seem to be completely conscious, but he does have a belief that Robots are superior and coexisting with humans is impossible. Gramps Unit often burned out some of his relays and some of his parts were knocked loose, leading to Robot Jones to consider that "Gramps Unit is just an old bucket of bolts.".

Second Design
The next design showed him to be much more active and holding the capabilities of a Cray or D.E.C. supercomputer. He is also shown to run the house and act as a security system. He displays the same eccentric behaviour as Dad Unit around humans and will try to zap them. This design was so sophisticated that he needed as many buttons and levers to push to be taken offline as the earlier version needed to be put online. When he was restarted, he noticed humans inside the house but that they were invited by Robot Jones. Together, Robot Jones and Gramps Unit told Dad Unit and Mom Unit that Robot wanted to study humans and that Gramps Unit invited some over.

Third Design
This third design resembles a rack server with his signature magnetic tape reels and is now able to fit inside the family motorhome. He is able to run with a single electrical wire instead of the first design, which requires numerous electrical wires. The newest design of Gramps Unit enables him to run off of batteries when this single electrical wire is not plugged in.

It is unsure who Gramps Unit is supposed to be the parent for. But since there are inconsistent designs with Gramps Unit, it is possible that there is a Gramps Unit being a parent of Dad Unit as well as a Gramps Unit being a parent for Mom Unit. It could be that the first two designs are the same Gramps Unit who received upgrades to be able to run continuously and automatically. It could also be that the second and third designs are supposed to be the same Gramps Unit, with the capability of barely fitting inside the family motorhome. It could also be that each design is completely separate, meaning that the first Gramps Unit is supposed to be the Great Grandfather for Robot Jones. Based off of the similarities with the very first Gramps Unit requiring numerous electrical wires and the need of fuel conscious Mom Unit to supply fuel, it is possible that this Gramps Unit is the father for Mom Unit; and also since the second design's personality is very similar to Dad Unit, the second design is supposed to be the father for Dad Unit.

Personality
In "House Party" Gramps Unit seems to be against humans, more so than Mom Unit and Dad Unit. He doesn't show much understanding for them, calling them 'oxygen-breathers'. He views humans as simplistic and inefficient. He usually is strict on all intruders, as seen in House Party. Despite this, he is shown to care for his grandson, Robot Jones, since he made up an excuse to get him out of trouble.

Due to him being an antique computer, he can't always identify Robot, and occasionally can't work efficiently. Gramps Unit also seems to love other machines, like an ice machine in Family Vacation. In the same episode he appears to have mellowed out. He doesn’t attempt to hurt Socks.

Robot Jones
Gramps Unit always cares about him, and made an excuse in "House Party" to get him out of trouble. They had a history together, evidenced when Gramps Unit said that they used to play chess before the humans came into Robot’s life. Robot also acts kindly towards him. Other times, Robot calls him a "bucket of bolts".

Humans
Gramps Unit is known to struggle to trust humans. He said that they are inefficient, and wanted to stand up and take control from them. Gramps Unit is also tough upon human intruders. He didn't try to hurt Socks in "Family Vacation".

Season 1

 * Vacuum Friend (1st model)

Season 2

 * Family Vacation (3rd model)
 * House Party (2nd model)

Trivia

 * Out of all the members of the Jones family, he appeared the least amount of times, with only 3 appearances.
 * It's unknown if there are actually 3 Gramps Units, or if there's only 1 Gramps Unit which is regularly upgraded.
 * His name might also be Robot Jones like his grandson. This is hinted in "House Party".