Just curious, do the stories that pop up now and then about Sony converting the Columbia analog tape archive they acquired in the big merger in 1988 to DSD as purely an archival format ring true? See for example the Dr. AIX columns such as
https://www.realhd-audio.com/?p=3779. Clearly DSD was not intended at that time as a consumer format, nevertheless it was chosen about a decade later for SACDs.
I had a long career at a particle physics (“high energy physics”) laboratory where hundreds of petabytes of data (many thousands of petabytes by now) from both our lab and the CERN CMS experiment were written to tape, not disc, and we were under regulatory obligations to preserve those data and products derived from them. That meant that about every 3 to 5 years, every tape had to be read from an old format, and written to whatever was the chosen new format, ensuring that no bits were changed. From 8mm helical scan, to Storage Technology “Redwood”, “Eagle”, and “Beagle”, through DLT, and then all the LTO generations. Not my main responsibility, but data integrity and preservation of the ability to interpret those data were nevertheless part of life. Thank goodness for virtualization and the ability to preserve old operating systems and programs.
For my own multichannel and stereo archives, every physical disc is ripped to an image format (ISO for DVD, BluRay, SACD, compressed wav for CD) on the first or nearly first access. Those files get written to copy-on-write filesystems that can detect and correct single bit errors on any read (I use ZFS, BTRFS would suffice). Every filesystem gets backed up regularly. The ISO and wav formats are well documented and will always be readable as new computer hardware becomes available. The PCM formats, or PCM derived from DSD, will always be playable. Unfortunately the proprietary formats written to some of those ISO images (Atmos in TrueHD, Auro-3D, DTS:x) are vulnerable to loss of the knowledge of how to interpret and render them.
For Atmos, on a Mac using Loopback or Blackhole, the built-in Atmos renderer, and Audacity, a 7.1.4 render of any E-AC3-JOC file that streams on that platform can be recorded. Sadly it’s just a digital render, not the preservation of the Atmos object information. Likewise renders can be recorded of Atmos in TrueHD if the DRP is available. A Realiser A16 with the Dante 16-channel digital interface should be able to do the equivalent with DTS:x, Atmos, and Auro-3D, but I don’t have the funds to try that, and frankly the renders are not sufficient.
