CB>On Mon, 30 Aug 1999, Nicolas Welte wrote: CB>> Geoff Oltmans wrote: CB>> > I thought the "QD" format on 5.25" disks still used DD disks, only with CB>> > double the number of tracks (80 vs. 40)? CB>> CB>> Not exactly, real QD disks were tested and approved for that track CB>> density. I think they are physically the same as DD disks, but were more CB>> expensive. CB>The question often occurs: What is the difference between the various CB>densities since the coating seems to be the same for SD, DD and QD. Also CB>what is the difference between single and double sided since there is a CB>magnetic coating on both sides of single sided disks. CB>The best answer I have seen was in the letters column of Electronics Now CB>several years ago by a former employee of one of the manufacturers. CB>He stated that the most expensive part of disk manufacturing is the CB>testing and certification. Single sided disks are not disks that CB>failed on the second side, but disks that were never tested on the second CB>side. Double density disks are disks that were tested at double density, CB>etc. CB>- CB>This message was sent through the cbm-hackers mailing list. CB>To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org. At one time there were disks that were only coated on one side, they are rare collector's items now. Commodore in their Disk System User Reference Guide (182) says: Any 'soft-sector' single-density or double-density certified diskette will work well with Commodore disk units. However, for the 8050 and 8250 disk units, double-density diskettes are recommended. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail email@example.com.
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