While DVD's and Blu-Rays are not on topic, archiving files for the long term seems plausible to discuss. Here's what I found from Web search today. Wikipedia on M-Disc is not current. It appears from Web search, that yours.co (the Web site for the alleged owners of Millenniata intellectual property) is not accessible at least today. Neither is mdisc.com. Domain registration for yours.co was renewed Aug 2019 so it ought to be. There's some kind of kickstarter for yours.co about "transforming videos into a magical experience" for delivery Oct 2018. I conclude yours.co is dead; of course millenniata was already dead. But they sold licenses to produce and label M-DISC to several brands of drives and media. Those resources seem to be active and available. Web search seems to show that Verbatum currently offers M-DISC media in blueray and DVD. The Verbatum page notes that to write to M-DISC requires special drives; Wikipedia was not specific on brands and models but has a similar note. Verbatum says the DVD or BR drive may have a "M-DISC" brand or label. Playback should not be a problem on ordinary DVD or BR drives, both sites say. Verbatum wants about $2 per 4X DVDR M-DISC in 25 packs. I didn't price Blue-Ray media. Other sites have similar prices. Given the application I would not buy non-branded media. Sites selling DVD or BR drives may specify M-DISC models; but check the manufacturer's docs to confirm. newegg shows an LG Blue-ray M-disc drive for $60 or $100. Amazon of course shows several models but some may be "all hat and no cattle" (liars). Dig deep to confirm specific support. But apparent LG external DVD slim drives seem to be cheap ($30). Given the range of prices, it may make sense to get a Blue-Ray compatible drive even if one only writes DVD's. I searched for plausible technical or review articles on M-DISC. What I found was semi-tech blogger who talked but didn't have serious data or experience to provide. Some were incoherent, maybe they were machine-translated English. But the physical technology of M-DISC seems like sound physics; and one needs M-DISC compatible drives for their higher power during write to physically punch through the "stone" coatings. Dave McGuire's post in this thread, seems to offer similar considerations to mine and a similar experience of looking at DVD and drive technology; his views are a little sharper. He makes a fair call for saving to smaller few-TB drives and archiving physical drives, on cost and performance and reliability; and makes other considerations which one should read. This discussion suggests to me, I should look at my stored DVD's and see if they have degraded by year. I have some redundancy and hopefully a run of DVD's might provide a complete set of desired archived files. I continue to recover files from diskettes four DECADES old, with drives of similar (sometimes newer) vintage; and occasionally from ZIP disks and drives maybe two decades old. So I'm optimistic. Regards for another decade, Herb Johnson -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net preserve, recover, restore 1970's computing email: hjohnson AT retrotechnology DOT com or try later herbjohnson AT retrotechnology DOT info