Question

why study computer architecture and organization

Answer 1

It may seem irrelevant and useless studying something which has already been accomplished and done, but improvements can still be done.

For example, you will be studying adder circuits from basic gates, and the measure of efficiency will be the total delay. Only if you know what is existing already, you can improve it if you are so interested. One of the best adder circuit available today is the carry select adder, and it has not been proved that a better adder cannot exist.

Moreover if you want to build a compiler for a new language which may come up, say in a startup, you will need to know how to interact with the hardware. Compilers convert the given code to assembly language and to build one you should know the assembly language thoroughly.

Hackers exploit holes in the hardware too to achieve what they want along with bugs and vulnerabilities in the code, and new fixes have been recently made with hardware for certain bugs. Cache memory can be used in covert channels for communication between processes which may not be intended by the user.

Simply put, you cannot get the whole picture unless you know about the organization and architecture too.