To check your Samsung drive look for that small pin which detects if a DD floppy is inserted, right at the bottom. A DD will push this pin down, HD won't because of the whole at that position. It turns out that many newer revisions don't have that pin anymore, these are HD only. You can remove a solder bridge to make them DD only, but I tried this with several new and never used drives with not much success.
Such a HD only drive seems not to be able to perform the media test in SCP. When I first tried this, I got really frustrated, as it looked like all my NOS sealed floppy disks are defective, even HD ones.
On the other Hand, a SDF-321B which is DD capable seems to be the best choice ever. Rev. S1 is such a drive and Rev T1-T5. I do have a T3 which gives the best results = sharp lines in the flux display and honest results with the media test in SCP. A T6 and newer lacks the DD pin, so these are not recommended.
Such a HD only drive seems not to be able to perform the media test in SCP. When I first tried this, I got really frustrated, as it looked like all my NOS sealed floppy disks are defective, even HD ones.
On the other Hand, a SDF-321B which is DD capable seems to be the best choice ever. Rev. S1 is such a drive and Rev T1-T5. I do have a T3 which gives the best results = sharp lines in the flux display and honest results with the media test in SCP. A T6 and newer lacks the DD pin, so these are not recommended.