A question about multiple boot options and live boot iso images

[Brian]

On Thu 31 Oct 2019 at 22:30:25 +0000, Bret Busby wrote:

> On 31/10/2019, Brian <ad44 at cityscape.co.uk> wrote:
> > On Thu 31 Oct 2019 at 20:00:26 +0000, Bret Busby wrote:
> >
> >> On 31/10/2019, Liam Proven <lproven at gmail.com> wrote:
> >> > On Thu, 31 Oct 2019 at 16:53, Brian <ad44 at cityscape.co.uk> wrote:
> >> >
> >> >> 1. Make a partition on the drive to hold GRUB's files and install GRUB
> >> >>    to the MBR of the drive.
> >> > [...]
> >> >> 6. Repeat for other ISOs.
> >> >
> >> > Sounds like a lot of work to me.
> >> >
> >> > This device does the same thing, entirely automatically with zero
> >> > intervention.
> >> >
> >> > http://www.zalman.com/contents/products/view.html?no=212
> >> >
> >> > As I said in my blog post, and spelled out in my last message.
> >> >
> >>
> >> So, I assume from that, that you are saying that it can not be done
> >> with a common USB thumbdrive?
> >
> > Did it enter your mind to try it yourself and come to a decision? After
> > all, the full instructions should help. :)
> >
> 
> 
> "not always as easy as it sounds"
> 
> Original query -
> "whether something like a removable USB drive can
> be easily set up, ..."
> 
> Your response indicates a complicated possible solution, that you
> assessed as "not always as easy as it sounds".

I was writing for a general audience. You are an experienced user who
would likely navigate the waters when they get choppy.

You precisely specified:
  
 > I am seeking to be able to write/copy multiple iso's to a removable
 > USB drive, and, thence to be able, via a bootloader, such as GRUB, to
 > select which iso on the removable USB drive, to boot.

That is exactly what you have been given.

If, having tested the technique, the process is found not to be suitable,
you would have learnt something rather than relying on my off-the-cuff
remark to make a decision.

> What I was hoping to be the level of simplicity, was something like
> copy a set of iso's to a USB thumbdrive, and either run a utility (if
> such a utility exits) that writes a GRUB instance to the thumbdrive,
> and that does a thing like update-grub, to configure GRUB to provide
> boot options for the iso's on the thumbdrive, thence, for one of the
> iso's booted from the thumbdrive, to be able to copy and add another
> iso (or, more iso's) to the thumbdrive, and, to be able to run again,
> update-grub on the thumbdrive, to provide options to boot the added
> iso's.

Copying the ISOs to a single partition is an option. The grub.cfg
entries would likely have to use GRUB's loopback feature and a user
would still be faced with extracting boot options for the kernel and
the initrd from the ISO. In terms of ease of use - nothing changes.

-- 
Brian.