Recently I saw a talk from a twenty-something programmer who as a child didn't believe "real" computers (desktop PCs) could be programmed at all, that was something you could do only with "old" computers like the Apple II. He hacks lisp now for some networking company, so maybe the kids will be all right. :)
When I retire and I have more time, I'm going to fill my house with Cromemco-era gear and do all the things I always wanted to do back then.
But first, I have to convince my wife that S-100 bus machines are mid-century modern, so she'll allow them in the door.
Stuff is pretty expensive even now, depending on what you want, what you can get, and such. Or, maybe you'll get lucky - several years ago I scored an Altair for $200 from a local electronics junkyard; later I went back and scoured it for a bunch of S-100 cards (as is, it came with a full complement).
Later I got some things off ebay, and even some free items from some other collectors - all I had to pay for was shipping. One strange beast was a 6502 cpu PCB (unpopulated) - I am not sure if it is compatible with the Altair's S-100 bus layout, or if it is meant for some other machine (the bus wasn't as standard as one would like, unfortunately).
Anyhow, good luck with your dream - just collecting the stuff can be fun enough!
It was for so-called "hard sectored" drives.
If you know about floppies, you know they have a timing hole near the hub ring; as this flies past a sensor, the controller can use it to keep the speed of the motor constant, as well as determine what sector on a track is currently under the head of the drive. Depending on timing and other factors, it can allow for varying size sectors - this is known as "soft sectors".
Hard sector drives had a similar sensor, but the floppies had - instead of a single hole - multiple holes spaced around the hub - one hole for each sector, hence "hard sectored"...
It was mainly a difference with the media and controller, not so much the drive itself, IIRC.
The problem is that, if I ever could even find an actual drive for the system, I'd probably never find any media; as it is, it's getting more difficult to find 5.25" media in the old 8-bit era "low-density" format - at least, anything new (similarly, low-density 3.5" floppies are difficult to find - which stinks for Amiga owners).
High density floppies in both 5.25" and 3.5" sizes are much easier to find - though the 5.25" drives can be an issue (not that they are hard to find, but sometimes the prices are thru the roof - mainly because of demand from industrial controllers that used PCs for CNC control needing replacements).