Understand HC-05

Hello, I am trying to understand HC-05. In the AT command, I set the HC-05 as a master AT+ROLE=1.
Then none of my computers sees it. But once I re-set it to slave, both Mac and Linux see it right the way. Why is this? I only need the computer and the Arduino to communicate wirelessly, should the HC-05 be a master or slave device? Thanks.

Slave is fine. You only need to be in master when you want to initiate comms but about the only time you want to do this is when HC-05 is talking to another HC-05. Most HC-05 users can get through life without ever using an AT command.

Just a guess, but your computers failing to see bluetooth may be because it is still in AT mode.