Is ROM Hard Disk?

How ROM can be Hard Disk? ROM isn't a Hard Disk.

ROM stands for Read Only Memory. This type of memory is used for things like BIOS, and firmware(like from your hard drive that tells your computer what manufacturer, model and size it is), where the memory is only read from to keep it from being corrupted.

RAM is your working memory where all the calculations are carried out. RAM stands for Random Access Memory.

Your hard drive is sort of like your ram but it's not acted upon...typically it's just called storage.

Say you're doing school work in the library. The desk you are sitting at is your RAM, where you write and read.  The book case is your hard drive, you go there to get a variety of materials and bring them back to your desk to utilize them. The reference books you keep on your desk are your ROM, this is the set of rules you use to be able to utilize the information on your desk and in the book shelves.

Hope this helps