RAM Random Access Memory / memory is commonly referred to, as an intermediary for a computer RAM is required for cpu read speed, but the power is not saved, if you want to save the information, it is necessary to use ROM
ROM read-only memory, long-term preservation of information, said read-only, so from the computer's point of view, they are not the same ROM with hard disk, ROM is mainly used to store information about your computer, start the program BOIS panels, etc.
From the point of view of the mobile phone, ROM to store information about the phone, more than that, there will be a lot of open storage software startup like, write once read for life, for example, reinstalling the computer and mobile phone Brush, does not change the phone or fixed computer information storage, such as storage rom computer model
Well, this time, ROM with hard disk, what difference does it make?
First, the material is not the same, the material is a semiconductor memory, a storage unit, while the disk drive is the external memory, a hard disk of a computer main storage medium, the one or more discs made of aluminum or glass composition. These outer cover discs with a ferromagnetic material. The vast majority of hard drives are fixed, it is fixed permanently sealed hard disk drive. Second, the workplace is not the same, the memory device is in the workplace, and the hard disk is stored temporarily unused data. If you want to use, then loaded into memory