The way people use “ROM” as an interchangeable term for internal storage is one of my big pet peeves in the tech world. The journalists who are writing in this manner are way too young and obviously didn’t take any computer science classes, or even read up on computers.
ROM stands for “Read Only Memory” and is memory that resides on your computer main board to store vital instruction code that almost never changes — hence “read only.” There is one ROM which has hardwired code and is used during your phone booting.This is one time programmable and is not accessible to users or your service center.
Another ROM is where our phone binary remains. This binary goes to RAM during the phone boot up and operation .This section has a phone code, boot loader core and a user can't write any data during phone operation. But when we do firmware update or we flash a new binary to the device then we are writing to this area . Otherwise the device is only reading from this area while device operation. That's why out of 16 GB internal storage of your device you can see only around 13GB to store your pictures or music or apps. This 13GB is your effective phone storage and the other 3GB is your ROM.
Examples for ROMs : BIOS,Android,IOS..etc
This is a completely different thing from storage memory, which a lot of people erroneously use the term form. Storage memory is the actual non-volatile memory of your phone used to keep your day-to-day things like photos, music, and additional apps/programs. Most phones have a core “internal storage” memory along with ways for expansion, usually by microSD cards today.
Internal Storage is actually the total storage space available on your phone sometimes it is used interchangeably with ROM but ROM is that part where programming is stored or where hardwire codes are written and this part is inaccessible.
Storage space left after this ROM is generally used for storing all other kind of data like music, photos, videos and stuff.