<P> ROM and successor technologies such as flash are prevalent in embedded systems . These are in everything from industrial robots to home appliances and consumer electronics (MP3 players, set - top boxes, etc .) all of which are designed for specific functions, but are based on general - purpose microprocessors . With software usually tightly coupled to hardware, program changes are rarely needed in such devices (which typically lack hard disks for reasons of cost, size, or power consumption). As of 2008, most products use Flash rather than mask ROM, and many provide some means for connecting to a PC for firmware updates; for example, a digital audio player might be updated to support a new file format . Some hobbyists have taken advantage of this flexibility to reprogram consumer products for new purposes; for example, the iPodLinux and OpenWrt projects have enabled users to run full - featured Linux distributions on their MP3 players and wireless routers, respectively . </P> <P> ROM is also useful for binary storage of cryptographic data, as it makes them difficult to replace, which may be desirable in order to enhance information security . </P> <P> Since ROM (at least in hard - wired mask form) cannot be modified, it is really only suitable for storing data which is not expected to need modification for the life of the device . To that end, ROM has been used in many computers to store look - up tables for the evaluation of mathematical and logical functions (for example, a floating - point unit might tabulate the sine function in order to facilitate faster computation). This was especially effective when CPUs were slow and ROM was cheap compared to RAM . </P> <P> Notably, the display adapters of early personal computers stored tables of bitmapped font characters in ROM . This usually meant that the text display font could not be changed interactively . This was the case for both the CGA and MDA adapters available with the IBM PC XT . </P>

Which type of data is stored in rom
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