>At 00:34 +1100 on 16/01/03, Darren wrote: > >>An 800K Mac floppy drive doesn't use a strong enough magnetic field to >>properly record data onto 1.44 MB disks. >> >>Is the glass half empty or half full? > >That's why you can't format 800K disks as 1.4MB; the reason you can't use >disks >the other way 'round is due to differences in the media. >-- > >the pickle
There are some things that are the same between the two disks, and major differences between the two disks, and the Drives. Bytes per Sector are the same, both disks have 512. The 800k disks have 8-12 Sectors per track. The 1.4 disks have 18 per track. Tracks per side are the same, 80 for both. Capacity per Side (bytes) 800k = 409,600 1.4's = 737,280 Capacity per Disk (bytes) 800k = 819,200 1.4's =1,474,560 Now then, this is one of the problems that will get you into trouble making a 1.4 disk into an 800k disk. The Rotation speeds of the two disk drives. A 1.4 drive has a constant speed of 300 rpm when formating, or accessing data. But an 800k drive has 5 (five) different speeds (rpm) for its tracks as follows: Tracks 0-15 394 rpm Tracks 16-31 429 rpm Tracks 32-47 472 rpm Tracks 48-63 525 rpm Tracks 64-79 590 rpm And then there is the problem of Media differences, as mentioned before by someone else on the list, but got it backwards, the HD disk has a thinner magnetic coating, and smaller magnetic particles. The thinner coating means that the magnetic force needed to alter the particles is much less than an 800k drive puts out for the 800k disks. The smaller particles allow data to be packed more tightly on the HD disks, this helps the HD disks able to have 18 sectors per track. Also the tracks on a 1.4 HD disk are thinner, and the sectors are longer. This info is from the book "Inside The Apple Macintosh" written by Jim Heid and Peter Norton, copyright 1989 Dan M. -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> The FAQ: <http://macfaq.org/> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
