[kwlug-disc] question -- booting from multiple ISOs in USB stick?

[William Park]

On Sun, Sep 27, 2015 at 11:59:41AM -0400, Jason Locklin wrote:
> 
> 
> On 26/09/15 07:14 PM, B.S. wrote:
> >Are any of these persistent? i.e. you can make changes, create
> >documents, etc., and when you shut down the state is written back to
> >the stick?
> >
> >Not meaning to hijack the thread, but ... IIRC, all this stuff reacts
> >differently on external drives (which behave exactly like internal
> >drives, but slower?), than on sticks, it seems.
> >
> >So, if you used a small, 2.5", usb powered, external drive, would
> >your life be easier? Perhaps even an SSD, for speed / robustness?
> >e.g. Could use standard grub / multiple partitions?
> 
> Actually, no, there is no difference between the two types of physical
> hardware. The difference is booting ISOs vs. installed systems. For
> instance, the same dd command *could* be used to copy an ISO to a thumb
> drive or an external hard drive to boot from -- but this would only allow a
> single os at a time. Conversely you can install one or more systems to a
> thumb drive or an external hard drive, using GRUB (partitioning as normal).
> It's the same whether its one type of device or the other.
> 
> The trick is getting Grub to boot from a list of ISOs on a drive. The grub
> trick Bob mentioned or the windows scripts mentioned by Brian and
> CrankyOldButter should work on either device as well --but I gave up last
> time I tried to do it. -Jason

I tried "unetbootin".  It extracts ISO and puts the contents in a
partition.  That's why you see "supported OS/filesystem" in its
documentation.  I thought it meant the OS it will be running under.
But, it turned out to mean the OS it will extract, because it has to
find the kernel/initrd.

Initially, you only have to carry 1 USB stick.  But, when you add/update
new ISO, maintenance is much more.
-- 
William