On Sun, Jun 10, 2018 at 04:07:17PM +0100, Rowland Penny wrote:

> What you are talking about doing is akin to dual-booting, just on
> different disks i.e. you will only be able to boot one distro.
>
> Rowland

Yes. In the past I've always had multiple hard drives in one machine,
each with an operating system and its own boot menu. This because I've
become paranoid over the years and always want the option of which drive
on the machine to boot.

I suspect, though, that these disks always had at least different
versions of the operating system, and what I'm doing now is trying to
install ascii 2.0 on a disk in a system that already has a disk with
ascii-rc on it. Do you know if I wouldn't have had the problem had I
tried to install devuan testing or experimental on sdc with ascii on
sda?

The suggestion to disconnect the sda drive while I install the same
version of the operating system on sdc occurred to me, but I worried
about the effect of the resulting change in drive designations. In my
case, by disconnecting sda my sdb becomes sda and my sdc becomes sdb.
Will all of this sort itself out when I reconnect the old sda drive and
boot it? After installing ascii on sdc I probably will have to select
sda as the drive to boot in BIOS and then run update-grub after it is
up.

Haines