what is computer architecture ||computer science||technology||digital

I can give you examples of architectures, so you can try to generalise.

If you have a PC at the front end and some kind of computer behind it, there are a variety of ways you can split between front and back end, you can have the front end be completely dumb, displaying pure HTML and sending forms back to the back end. Or you can have JavaScript enabled HTML and do some validation on the front end before submitting syntactically valid requests to the back end, which then has to semantically validate them before executing them. Or you can put the major logic in the front end, and have the back end purely as something that can be queried. In the latter case, you can jump out of the browser and have an app-style front end. All variant software architectures on the same underlying hardware architecture.

But you can take that “two layer” architecture and are it into three layer: user interface at the front, business logic in the middle, and a dedicated database engine at the back end.

As you get more sophisticated, you need to think of fault tolerance. So you need to have backups and failovers. And you need to think of scaling. Do you want one big database engine, with a twin on standby? Or can you distribute across a dozen servers so that if one fails, nobody notices.

Even within a single computer, you have architectural questions. A single program, or several co-operating ones. Multi-threaded or multi-process. Perhaps an easy-to-write front end language like Python backed with some high performance number crunching libraries. Or do the whole thing in, say, Java.

An dhow do you split up your programs? Of you use OOP, who designs your Objects? Do you have separate libraries, with strict interfaces, or do you just write a heap of code that seems to solve the problem.

And how have you future-proofed the system? Is it modular, and are the module boundaries chosen so that likely future enhancements will,be restricted to one module, or can be implemented by slotting in a new module?

Does your program allow for plug-ins? If so, how? What is the interface and how is it controlled?

What is the systems fault handling strategy? Do you allow exceptions, or must all errors be returned through results. What is your policy for global variable? Do you have, or need, singletons, and if so, who manages them?

And so on, for hours.