Usually used to referred to
media, either
analog or
digital. For a
random access medium, any data anywhere on the medium can easily be accessed. For example, any piece of information on a
hard disk can be retrieved at any type. Whereas, say, on a
tape backup, you can't instantly jump to a
random point on the tape, you have to go through the
tape sequentially. Random access is the opposite
sequential access, when you have to read the data in
order.
This makes its way through to the API level. For example, in Unix, there are certain devices you can do an fseek() on (i.e. a move to a random location), such as hard disks, and others that you can not (e.g. serial ports).
Random Access Memory is named so because you can read any address you like at any time, You don't need to do it in a particular order. There was a time when memory wasn't random (e.g. stored on a magnetic drum, or using mercury delay lines).