The TI-99/4A makes use of different kinds of storage media, which are also represented in MAME.

System ROMs

ti994a consoleThe read-only memory used in the TI console or in other members of the TI family are mask ROMs / EPROMs, or GROMs, a special kind of 8-bit streaming ROM with 6 KiB capacity. To be used in MAME, the contents of the ROM chips must be put into a file ("ROM dump"), and this file must then be stored in a ZIP container and put into a directory that is located in the "ROM path".

More about system ROMs

Peripheral device ROMs

More about peripheral devices

Software modules

Also called cartridges, with ROM, RAM, or NVRAM

More about cartridges

Cassettes

More about cassettes

Floppy disks

More about floppy disks

Hard disks

More about hard disks

RAM disks

More about RAM disks

External devices

More about external devices

Single files

This is probably a bit misleading, because MAME does, in fact, not support accessing single files. I thought it would be better to mention it so that you don't have to guess whether it works or not.

More about single files