To give you an idea of what I am looking to, for example, I have a gsm modem connected to a serial port of my machine. I can run a program called minicom and be able to directly communicate with the firmware in the modem using the at command set. Here's an example of me communicating with that modem on my ubuntu server:
at+cgmi Enfora, Inc. OK at+cgmm Enabler-II G Modem OK
I can get all kinds of information by using at commands and most importantly I can check the status of the modem right from the terminal without going physically to the location and having to run something like memtest. I have my servers remotely, so I would like to find an equivalent program of minicom on ubuntu that will allow me to check the status of my hard drives and my RAM (since these are two critical components to my system). What are the best programs on ubuntu for doing diagnostics and interacting with the hard drive and RAM from terminal?