It's not so much about going from full-height drives to half-height drives, but about finer details.

Disk rotation drive - when and how was the belt replaced with a direct drive and a flat motor? Who owned the patents and who launched the first major series?

Head positioning drive - what options existed besides the early "snail" and the stepper with metal tape winding on the shaft? How have the types of motor steppers changed over time?

When did the standard analog transistors and chips, as well as the digital logic of the 74 series, begin to be changed to more integrated solutions?

And further, deeper, including the electromechanical features of DEC dual drives and Japanese exoticism in the spirit of SHARP used in the X68000 line of computers.

PS Something like this could have been used as the starting material for the wanted review ...

  • 3
    That is a lot of questions in one question. It could be a good idea to split this up a bit.
    – UncleBod
    Sep 15 '20 at 4:52
  • 2
    It seems the OP assumes a straight and singular line of development with discrete steps when it was (like always) a continuous development in multiple parallel tracks.
    – Raffzahn
    Sep 15 '20 at 8:57
  • 1
    IMHO, you can try to form a single timeline of inventions, implementations and borrowings. And it's strange that such work is not googled ... The competition was very intense in those years. And the attitude towards protectionism and patent law, especially between the US and Japan, was different then. Sep 15 '20 at 17:22
  • 2
    Just take the belt issue. At a time when direct drive was already a thing new belt driven ones were developed and sold. A technology to use is always a factor of the targeted market, not available technology. Similar for head movement, track zero detection and other electromechanical parts. The same works for logic integration. for one, when does 'more integration' start? by using some odd chip, some custom, or only when whole device interfaces wandered into a single IC? Here, as well, different manufacturers and different markets implemented changes at different speed and in different order
    – Raffzahn
    Sep 15 '20 at 17:49
  • Please, do not use the question for discussion. Also, if you already got a starting point, why not research it from there?
    – Raffzahn
    Sep 15 '20 at 18:47

Browse other questions tagged or ask your own question.