[paxys]

My MP3 collection has been going on for at least 25 years and still works perfectly. Same for HTML pages (I have entire websites backed up from the early 90s). I still have Wordstar and Word 1.0 files which I can open and edit. I can't think of too many pieces of software or data formats from the last 30-40 years which achieved some threshold of popularity but have no support today.

[briandoll]

MP3 is a good one. Although I had to develop a lot of perl to manage the various incantations of ID3 tags, especially when VBR became popular. MP3 files may still play, but the full experience (properly attributed w/ band, album, song title, song number, album art, etc.) is likely less than perfect over time.

Do Wordstar files open in modern Word applications, even on iOS? That's part of the access aspect over the long term -- files that can be used, everyday, with your daily-driver tools with minimal special software needed.

[jjav]

> My MP3 collection has been going on for at least 25 years and still works perfectly.

Mine as well (maybe not quite 25 but close). But music isn't written word, clearly it wouldn't be in an ASCII text file.

The key is universal, non-proprietary formats that are supported by thousands of open source applications. Those are the formats that will last a lifetime and beyond. So, plain text for the written word (HTML counts as plain text, you can read and write it in any plain text editor), JPG for pictures, MP3 for music.

For video there doesn't seem to be an answer that is fully satisfactory, that I feel confident I can still view in 50 years. So I mostly take photos, not much video, since I can't trust the longevity of video.