After it was touched on briefly in a TV series called "The United States of Tara" I looked into it a little and this is far more common than originally thought. There are usually one or two IDs that are at least partially aware of the actions of some or all of the others, but most of them only know the name and have a vague awareness of their existence (usually by the IDs leaving physical evidence of their existence around, but occasionally by actually leaving each other messages, either written or through a third party).
But also, each case is unique.
That's sort of the default state before system discovery. It's possible for someone with DID to learn of all or most of their system members on their own, or often with therapy, and for them to communicate with each other freely. Sometimes it takes a lot of work to get to that state. Sometimes, it just happens when they feel safe enough to come out to each other.
We're a case of the latter.
We spent 41 years of our life unaware of our plurality/DID until the circumstances leading to our divorce and loss of career caused our symptoms to flare and become unignorable. But, the day we accepted that we were plural was the day system members started barging their way forward to say "Hi! I'm not you!"
The vast majority of us do not have names. But quite a few of us do.
You should also read
When Rabbit Howls, by the Troops for Trudy Chase, if you're interested in learning what it can be like from an internal perspective. Though, content warning for CSA and violence on that one.
I read all this but I still don't know what the subconscious mind does and what it is.
Sorry about that.
A brief run down:
Reflexes happen in the spine, as said above, and are the super quick single muscle reactions to stimulai.
The subconscious receives and processes your raw sensory inputs and does all the neurological "number crunching" to make sense of them. It can also react faster than the conscious mind. The subconscious also
creates the conscious mind. Think of it as a huge server farm that hosts the virtual reality MMO that is the conscious mind. Well, it's an MMO for us. For singlets it's a single player game. Anyway, it's hard to define exactly what the subconscious mind does because it really does pretty much everything that isn't reflexes.
The subconscious mind is everything that happens in your brain that your conscious mind is not fully aware of, including everything it takes to create the perceptions of the conscious mind.
The conscious mind does a small handful of things the subconscious mind wouldn't be able to do without it, according to theory. It is what gives you self awareness and the ability to self evaluate and override reflexes and subconscious decisions. In
theory. But our own personal experience suggests that it isn't always that special.