[lproven]

WTF?

> I heard the first version is close to VMS.

No.

> Is it true?

No.

> Is there any material on VMS?

Tons. It came with metres of docs. It is still on sale. You can get a freebie hobbyist VM image.

> OpenVMS is open sourced

No, it isn't.

> but the version is too high.

Not true.

Always, always check your assumptions before asking a question. If you want to ask "because (a) can I (b)" then check A is true before asking. ALWAYS.