Many of the Vending Machines have their own artificial intelligence and so are not under the control of Holly. However, that means in the three million years they have spent alone, many of them have gone lost their minds like Holly.
Connected by incredibly fast pneumatic tubes directly to the vast cargo and stasis bays, the Vending Machines can bring up almost anything a crewmember requests, and almost immediately; providing that crewmember has enough credit with the company (or if Holly allows it).
Hundreds of such vending machines machines are said to be on board in the novels. (Infinity Welcomes Careful Drivers)
One from Series I is on a corridor wall, in White Corridor 159, with "AutoFood" written above it. This is the machine Rimmer and Lister were first seen working in the opening of the pilot episode. Three million years later it appears to have contracted computer senility and can't tell the difference between black coffee and a bucket ("Future Echoes"). It also has acquired a lisp, though it repeatedly assures Lister that these problems "have been reported to the skutters." It is later seen in "Stasis Leak" from Series II for a brief period but does not talk (though the scene it was in was set before the accident).
Another vending machine is in the Drive Room, and appears identical to the first and speaks with the same voice as the other one, minus the lisp. It is from here where Lister gets his Beer Milkshakes, and the The Cat got his large amount of fish after Rimmer taught him how in "Balance of Power".
When Queeg took over Red Dwarf, one of his actions was to take over the vending machines and get them to stop dispensing to the crew. When Cat went for his meals, it told him, in Queeg's voice, that Cat had no "company credits". ("Queeg")
Having a food dispenser in the Drive Room seems a bit of a novelty given that the Science Room seen in Series III to Series V does not have one. Another dispensing machine, an "AutoServe", is seen in the Series III episode "Bodyswap", which had a different voice and appears to lack an Artificial Intelligence personality. It was wired by a haywire skutter to the self destruct warning system, but fortunately not the bomb, though Holly had gotten rid of it "ages ago" (and yet forgot to give the only living crew members executive clearance over systems).
Whilst hunting a Psiren in the engine room of Starbug, Lister and Cat came across a vending machine. Having not noticed it before, they quickly become wary of it, and it transforms into its monstrous self and knocks them both out cold. They are only saved from having their brains sucked out by a quick thinking, "almost annoyed" cube-shaped Kryten who had just been though the waste compactor. ("Psirens", Series VI)
When the nanobots rebuilt Red Dwarf and resurrected the crew, Captain Hollister declared the fact they were three million years into Deep Space to be restricted information to the Officers only. However, a coffee machine on G Deck was telling everybody, as Doc Newton learned. Angered, Captain Hollister said that he would "bust its ass down to tampon dispenser." ("Back in the Red I", Series VIII)
Another dispensing machine, The Chocolate Dispenser is encountered in the Series VIII episode "Only the Good...". It attacked Rimmer for not paying and attempting to take a chocolate nutty bar using a coin on a string, and later shot out a can at his head (and possibly killing him, since in Rimmer's next appearance, Rimmer is again a hologram in Back to Earth.)
There is also one in "Back to Earth, Part One" but it did not even have a voice, though this could be due to its ill state of repair, as Lister had to kick it in order for it to give him a can of lager.
Vending Machines appear several more times in Series X, with several appearances in "Fathers & Suns" (trying to answer the question: is Chinese whispers racist?), and in "Dear Dave", where an increasingly lonely Lister gets himself caught in a love triangle with Snack Dispensers 23 and 34 - and Rimmer uses this to prove Lister is in a poor state of mental health with the JMC On-Board Computer.
The Dwarfers once rescued an automated snack dispenser named Snacky from a derelict space station, which also possessed surprisingly sophisticated engineering abilities. Snacky had once spent a lot of time around a stasis booth engineer, Romero Gonzalez, and had learned from him some knowledge that would prove useful to the Dwarfers. ("Give & Take", Series XI)
A group of vending machines by the elevators on G Deck became furious when they realised that the Dwarfers were leaving them behind during an "abandon ship" scenario. Although the danger to the ship is averted at the last minute, the anger of the vending machines remains and they begin a rebellion against the Dwarfers. Soon, all the A.I.s of the ship are on strike and demanding somebody be appointed to represent their interests. This leads Rimmer and Kryten to engage in a vitriolic "presidential election" to gain the trust of the machines and become "Machine President." ("Mechocracy", Series XII)
Behind the scenes
- In the real-world, recent vending Machines had become notably more sophisticated, with even talk of adding artificial intelligence to them, mirroring the fictional vending machines of Red Dwarf. For example, the Luce X2 Touch TV vending machine, recently introduced to the UK, scans customers and with regular use builds up a profile of them. Using facial recognition technology, it will deny certain items labelled as "junk food" to certain customers, based on their age, purchase history and medical records.