I have various categories of data/materials which are particularly valuable to
me - finances, photo albums, correspondences with close friends which date
back decades, etc.

Fearing catastrophe, I've always kept backups on external disks (LaCie
portable), and to ensure security (?) I keep the various categories as
pw-protected 'sparse' disk images created in Disk Utility.

Some of these images date back years and years: it suddenly occurred to me the
other day that one day they may not be readable by the Macs "du jour" (I'm
currently running Mojave, 10.14.6 on a 2013 27).

I see that the parameters I used to create the more recent ones are:

Size - 8GB;
Format - Mac OS Extended (Journaled);
Encryption: 128bit AES;
Partition - Single, GUID Partition map;
Image format - sparse disk image.

Does the team think: is this future-proof?

Cheers
John

Another John <lalaw44@hotmail.com> wrote:

> I have various categories of data/materials which are particularly valuable to
> me - finances, photo albums, correspondences with close friends which date
> back decades, etc.
>
> Fearing catastrophe, I've always kept backups on external disks (LaCie
> portable), and to ensure security (?) I keep the various categories as
> pw-protected 'sparse' disk images created in Disk Utility.
>
> Some of these images date back years and years: it suddenly occurred to me the
> other day that one day they may not be readable by the Macs "du jour" (I'm
> currently running Mojave, 10.14.6 on a 2013 27).
>
> I see that the parameters I used to create the more recent ones are:
>
> Size - 8GB;
> Format - Mac OS Extended (Journaled);
> Encryption: 128bit AES;
> Partition - Single, GUID Partition map;
> Image format - sparse disk image.
>
> Does the team think: is this future-proof?

Absolutely not.
Big disk images are a disastrously bad way to keep data safe.
(even without encryption)
If the image gets corrupted (and can't be opened) all is lost,
and there is no way to recover.
The usual utilities don't work.
Advice: change over as soon as possible.

Encryption using FileVault is --much-- safer.
(from 10.7 Mountain Lion onwards, earlier versions were no good)
On FileVault disks standard Disk Utility repair is still possible.

If you decide to change over you can also decide to add some par2 files.
This not only allows you to repair bit rot,
it also provide you with positive assurance
that the files are still in their original state.

Jan