[Simh] VAX emulator slow to configure extra disks

[Jonathan Welch]

A vax emulator I was configuring for a friend (MicroVAX 3900 simulator
V4.0-0 Current git commit id: ab3e07a4) needs to mount more than four
disks.

The .INI file has
set rqb enabled

and an associated attach command.

In my VMS startup disks are mounted very close to the beginning of the
boot sequence.

I discovered that when the emulator starts it is necessary to put a
$ WAIT 00:00:06
before mounting DUB0; the wait is necessary for the disk to appear.

Is this something that is expected behavior and should be documented
or a bug that can be fixed?