In nine days, Microsoft will be releasing its first all-new operating system in three years. To commemorate the release of Windows 10 on July 29, we're taking a look back at some of the more notable versions of the OS over its 30-year history.

On September 30, 2014, Microsoft unveiled the successor to Windows 8, giving us all a sneak peak at Windows 10 before it appears for real. Why skip 9 and go straight to 10? Your guess is as good as ours.

Even the number 10 is suspect. By our reckoning, there are at least 13 distinct flavors of Windows, not including upgrades, service packs, special editions, home and professional versions, yadda yadda. Some are forgettable; others we wish we could forget.

Here’s how Windows 10 stacks up against some of its older (but probably not wiser) siblings, starting with the original Windows circa 1985. (Note: We excluded enterprise-centric releases from this list. Sorry Windows NT and Windows 2000 fans.)