And yes, TI calculators have indeed been improving, apparently.
The TI-84 Plus is a graphing calculator made by Texas Instruments which was released in early 2004. There is no original TI-84, only the TI-84 Plus, the TI-84 Plus Silver Edition models, and the TI-84 Plus CE. The TI-84 Plus is an enhanced version of the TI-83 Plus. The key-by-key correspondence is relatively the same, but the TI-84 features improved hardware. The archive (ROM) is about 3 times as large, and the CPU is about 2.5 times as fast (over the TI-83 and TI-83 Plus)[citation needed]. A USB port and built-in clock functionality were also added. The USB port on the TI-84 Plus series is USB On-The-Go compliant, similar to the next generation TI-Nspire calculator, which supports connecting to USB based data collection devices and probes, and supports device to device transfers over USB rather than over the serial link port.
On my TI-83 plus, a fellow students and my calculator were matching rand(int) and it was amazing. Random wasn’t really random. I thought it’d be based on some sort of hidden internal clock.
True randomness is really really hard to do in software; bigger CPUs often have hardware random number generators that exploit some sort of quantum or otherwise non-determanistic phenomena, but in software the best you can do is pseudo-random. These are algorithms that generate a sequence of randomly distributed numbers, but in a deterministic way - from a given starting state, it will always generate the same sequence of numbers. Good algorithms are designed to make it hard to infer the starting state just by observing the sequence (if you can do that, you can run the algorithm in parallel and predict the next number), but that’s an active area of research.
At a guess, the calculator was programmed to initialise the random number generator from something that it is hard for the user to control (milliseconds since power on would be a good one) the first time you used it, but maybe TI got lazy and just initialised it to a constant value
You can set the seed, if you don’t the default is 0
You need to set the seed number.