A lot of the ideas as far as software goes, on this project are being decided on now. The first submarine won’t be completed until 2026. It is estimated that the last one will be in service till 2078. So you can only imagine how that software will contrast to what will be in 2078.
I am not a software guy, but I always found it interesting how the computing technology on a submarine such as a LOS ANGELES Class compared to what we have now.
I will ad that the radio room was always refitted with the best the military could find.
Good “old-fashioned” principles of modularity.
In the sofware design, hardware handling is separated out in an abstraction layer, i.e., a library of routines/classes/etc.
The rest of the sofware is built on that.
For hardware, at the lowest level, it “should” be just that - hardware.
Then their is “firmware” on top of that, controller devices that are actually small computers running sofware. Like a disk drive controller.
Any of those three layers should be able to be replaced, and as long as the new one supports the old interface, and works “as advertised”, the other layers need no changes. Meanwhile, it can have a new interface that it also supports. When the other layers get to supporting the new interface, which is typically required to use new features, new features can be used.
It becomes like the 150-year-old axe that was my great-grandaddy’s - it’s had 3 new heads and 4 new handles.