TL;DR: Can human build a computer that lasts for a few hundred years under active maintenance with a limited spare part supply, not too bulky or power hungry, and has the performance similar to a high-end desktop PC in the near future?
I'm aware of similar questions in this site, like Preserving electronics for hundreds of years and Computers lasting for centuries. However, I couldn't come up with a reasonable enough design based on the info they provided. The former has the requirement of using regular electronics (which we don't need here). The latter has provided some good ideas, but they are mostly for large bases on Earth.
Space faring robot functioning for 1G years is also a nice source of ideas, but I don't think it puts the computing power of the machine as a priority, while we do.
Full version with background
Let's say people are sending a space probe to some solar system nearby (think of Project Longshot but a longer trip). The trip will take roughly 300 years.
Since the communication delay will be multiple decades, the probe will have to handle any situation during the trip or inside the solar system on its own. So, we have to install a powerful computer on the probe to make it smart enough, and keep it running throughout the trip (or at least preserving it in a state that can be woken up any time).
Here I'm making numbers up. Let's assume the computer's total performance is comparable to a high-end desktop PC today (e.g. i7-12700K + RTX 3080, in any measurement you like (TFLOPS?); details can be adjusted), and its tasks can be distributed/parallelized however you want. It can be custom-built using technology available in the near future (say in the 2070s), and cost isn't a problem.
We also assume that any reasonable preservation environment is possible (proper heat management, vacuum, noble gas, constant temperature, anti-radiation, etc.). We can also have some spare part supplied in the probe with reasonable ways to use them. Robots that do simple maintenance can be available if needed (methods to preserve them are not discussed here).
There are limitation on mass and power because it's on an interstellar space probe. The computer and its shielding should weigh no more than a few tons so that the probe can fly fast enough. Relying on the probe's reactor, its power consumption should be less than 100kW. The lower the mass and power consumption, the better.
Are there reasonable explanations/designs for the setting above? What will the computer look like, or what should be considered when coming up with a design of it?
Rough ideas are perfectly okay! I'm not really designing an interstellar computer, but looking for a technical starting point to design other parts of the story.
Some limitations I'm aware of:
- Diffusion and other degradation within semiconductor chips that makes transistors unusable. Running it continuously for a few hundred years makes matters worse. Is this a big problem?
It's my first time to ask a question here, so please tell me if I did anything wrong.
Edit: Explained what I expect to get nicer.