The voice recorder is required to record at least a half hour but can be longer. The data recorder has a longer requirement. Wikipedia (yes I know the warnings) states “Most FDRs record approximately 17–25 hours worth of data in a continuous loop”.
In the 777 all of the recorders are solid state chips, only older aircraft use tape.
Originally then recorders were tape , then they went with a disk system (kinda like a CD/R-W)and finally to solid state.
There are some talk of transmitting the data/voice directly to the cloud, don’t know if the newest planes are doing that currently