User talk:Yutsi/Flippy disk

Did the original IBM Personal Computer use use index sync?

The first PC shipped with IBM PC DOS 1.0 (known internally at Microsoft as MS-DOS 1.0) which supported the PC's 5.25" single-sided double-density disk drive. Curious if it was necessary to cut an index hole to make a flippy disk for this computer.  Of course, given the high price consumers paid for this PC, it's not likely that many would have pinched pennies by using flippies, but nonetheless I'm curious.  64.128.111.166 (talk) 23:12, 2 January 2011 (UTC)

I think the index hole synch requirement may be based on whether the system used Group code recording or Modified Frequency Modulation. Apple and Commodore used GCR, and thus didn't require the second index hole to be cut, while IBM used MFM, which did require the second index hole. If someone can research and confirm, this would be nice information to be added to the article. Wbm1058 (talk) 17:16, 16 April 2011 (UTC)