All memory is accessible. Buster is the new version of Rasbian. There is not a plan to update Rasbian in the near term to 64 bit per Simon Long (senior principal software engineer at RPi) who says at this link it will be changed when:
someone comes up with a convincing improvement resulting from a move to 64-bit which justifies the loss of backward compatibility which it entails. Which no-one has yet managed to do.
There are other flavors of Linux which may well implement 64 bit. See discussion at link above.
All memory is accessible. Buster is the new version of Rasbian. There is not a plan to update Rasbian in the near term to 64 bit per Simon Long (senior principal software engineer at RPi) who says at this link it will be changed when:
someone comes up with a convincing improvement resulting from a move to 64-bit which justifies the loss of backward compatibility which it entails. Which no-one has yet managed to do.
There are other flavors of Linux which may well implement 64 bit. See discussion at link above.
