Warning: potentially boring...

 ...at least, unless you're one of those fortunate people who have the time to spend hours (and sometimes days!) messing with computers.
As I am.
Anyway, on to the latest computer saga, revealed through (a somewhat modifed) email correspondence with a friend who is also my Linux guru:

I have a DVD that I wish to duplicate for several complex reasons involving the fact that we have too many computers featuring too many operating systems at our house. 
So I go looking for K9copy, which I've always used before, and find it unavailable in any of the Linux repositories. I subsequently find it online, but then discover I will have to "compile" the file, which is well beyond what I think I'm able to do. 
On reading the on-line forums, I discover that K3b will also serve, but there's a problem: the resulting .iso file is 7.7 gig, and my blank disks are 4.7, which is of course why K9copy (which shrinks as it extracts and then writes files)  has been so useful in the past.
I suppose I could shrink the file using DVD95, but that has created problems in the past and I'd still have to write the resulting file to a blank DVD.
Clearly, I'm meant to not copy DVDs.
On the other hand, today one can purchase two 16-gig flash drives for a mere $20, tax included.

I send, and carry on, expecting to just drop the .iso files onto the virtual flash drive now mounted on my desktop. And the saga continues in the next email, an hour or so later..:

I'd forgotten that FAT32 files (which is how most usb flash drives are initially formatted) max out at 4 gig. So I reformatted one drive to NTFS, which Linux will format and Mac will read. However, according to Dr. Google, Mac won't write to it.
So I thought I'd format the other on the Mac. Disk Utility offered several versions of "Mac OS extended (journalled)". I know from past experience that doesn't work in Linux. It also offered something called ex-FAT, which, again according to Dr. Google, does. Except that this requires installing a new repository in Linux, and when I tried to do that, my terminal assured me that such a repository could not be found.
Apparently it is possible to shut off journalling in Mac OS, but I don't know what the consequences would be so I'm not going there.
In any case, I do have the two .iso files installed on Sandy's iMac, and I do have them on a 16 Gig NTFS-formatted drive.
And I learned a bunch of stuff, some of it even useful.

That email had just been sent when I received:

Interesting. Back on 2013-04-27, in reply to my question about whether you could play (with VLC) .iso files made with K9Copy, you wrote:

K9copy seems to have disappeared from the repositories. So I used K3b
to create the iso, then DVD95 converter to create a burnable file,
then DiskCreator to burn the disk, which the VLC Media Player played
without issue. I'd prefer K9copy, but there you are.

To which I replied:

Damn. So I've been here before, and had forgotten the particulars.
Oh well, as I mentioned, USB flash drives have come down in price phenomenally, so I really no longer need to make DVDs for this purpose.