I can't point to a single specimen of that stuff that's survived the test of time. Some PS/2 models allowed for formatting HD media as ED. The whole mess continued into the ED 2.88M arena later. In fact, I've got one oddball setup where the HD media formatted as DD outperforms the native DD stuff. Back in the day, I consulted the 3M NML people on this subject and they weren't very optimistic about the survival rate of DD media formatted as HD. It isn't just the coercivity of the coating that matters (something that's often erroneously cited as evidence of no difference in the media), but it's also the oxide particle size and coating thickness. I still occasionally receive the PS/2 DD disk formatted as HD-time has not been kind to these. For a brief time, there were kits offered to do just this. Of course, the disks couldn't be read in "media sense" drives on non-PS/2 systems without punching or boring a hole in the drive jacket to inform the drive that this was high-density. PS/2 users quickly discovered that pennies could be saved by simply formatting the DD disks as HD. When HD 3.5" media first came onto the scene, it was perhaps 4x more costly than the DD disks. The IBM PS/2 thing, in my opinion was a grave error that we still are dealing with. However, almost all clones and third-party PCs use "media sense" for 3.5" media. 1.2MB 5.25" disks, for example are always "host select" as there is no distinguishing physical indication of the density. As for the PS/2, most of the line employed "host density select" the LSI FDCs (see the Intel 82077 datasheet, section 7.0 for an example) could be configured as "media sense" or "host select".
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