Here are a few of my rambling thoughts about rationalizing how Traveller computers relate to real computers. Though in the end, I mostly just go with the "it's scifi, not reality" approach.
IMTU (which is MgT flavored), I assume that a Starship computer has effectively unlimited "long term memory", and the Rating is more about what it can keep accessible at any one time. I make the possibly naive assumption that computers will continue to have short- and long-term memories as distinct pools.
There are practical limits to long-term memory size, but frankly I tend to hand-wave that part. (Such as, "You can't store Regina's whole Internet in your computer." and "Your passengers have access to a few hundred movies during the trip, but you may want to try to buy some more recent ones; those have been in circulation for quite a while....")
As an aside, I also consider "Library Data" to be both a database and a web-browser of sorts. You can often get more detailed Library Data about a world you are currently visiting and often about neighboring worlds, at least if you are visiting a TL-8+ world or one with a Class-C+ starport. If the Starport provides the data, you will probably have to pay for it. A Scout base will sell the best quality data, and will give it to Scouts for free. Otherwise, the local government determines access restrictions and fees (as well as content
).
A model/1 is equivalent to a 70's or early 80's supercomputer in performance (that is, pretty much a modern desktop machine) but as a starship computer, it has multiple redundant systems and various fail-safes built in. Naturally, it's not just "a laptop plugged into the Ship's USB jack", but more like a rack-mount server farm. Since in MgT computers don't take up tonnage, I imagine each bridge has a dedicated space for the "computer rack" with access to the data feeds of all ship systems, and most likely the entire bridge's construction is modular to make repairs easier.
I view model/2 as being "the most reliable and performant computer we could imagine with current computer architecture". It should be just beyond what we can reliably manufacture today, but not into any "alternative" techs, like quantum or molecular.
From my experiences with dedicated hardware, in the end general purpose hardware always catches up and surpasses it. But to save money and time, specialization is very useful. Hence, "bis" - you don't *need* quantum computer technology to compute a Jump/2 if you build a special purpose J-Drive interface module, but a real Model/2 computer will be more useful, if you can get one.
Model/3 appears around the same time as synaptic computers are available, so presumably they incorporate some of that technology. Higher models probably follow from integration with quantum and other technologies. This is "beyond the Singularity" (in the strict sense of the term, not the "apocalyptic" sense used by Kurzweilites), so it's hard to guess what they will actually work like.
I toyed with the idea that Traveller computers are really NOTHING like modern computers, using some sort of handwave like "Transition to Jump Space causes an EMP, so silicon is actually a dead-end technology, so Starship computers use XXX processors, which have some odd properties." In the end, I was too lazy to follow up on that too much.
