stever@videovax.tv.Tek.com (Steven E. Rice, P.E.) (06/22/89)
In article <741@lakesys.UUCP>, Joe Pantuso (joe@lakesys.UUCP) writes: > I recieved some ds/hd (pc type) disks courtesy of Adobe a few months back > and I attempted to format and use them, out of six disks only ONE of them > worked. Is there really that much of a physical difference between dd and hd > disks? . . . The "HD" floppies hold twice as much data as "DD" floppies by doubling the data clock rate. This makes the magnetic domains on the HD disks one-half the size of the domains on the DD disks. To ensure they won't self-erase (two "1" bits surrounding a "0" bit causing the "0" to become a "1", or vice versa), the magnetic material used in HD disks has higher coercivity (just what it sounds like -- you have to work harder to coerce [force] the magnetism to change direction). HD disk material requires higher write currents because of the higher coercivity of the oxide. Your chances of correctly writing an HD disk in a drive designed only for DD disks are pretty small. . . Steve Rice ----------------------------------------------------------------------------- * Every knee shall bow, and every tongue confess that Jesus Christ is Lord! * new: stever@videovax.tv.Tek.com [phone (503) 627-1320] old: {decvax | hplabs | uunet | uw-beaver}!tektronix!videovax!stever
dwi@manta.NOSC.MIL (Steve Stamper) (06/23/89)
Although it may not be recommended, I have used HD diskettes in my Amiga drive many times and have had no problems. I can read/write them just fine. I imagine it is better to use DD disks, especially since they are so much cheaper as well. -Roger Uzun
thad@cup.portal.com (Thad P Floryan) (06/24/89)
Restating Steven E. Rice's answer in "more common" terms ... attempting to use a HD disk on a drive not designed for it is akin to an attempt to use "metal particle" audio cassettes on a drive not designed for them. In the audio cassette world, you have "metal particle", chromium dioxide (CrO2) Ferrichrome (FeCr2), and the ol' rusty iron on plastic run-of-the-mill ferric oxide formulations. Each requires special treatment in regards to bias, head current, etc. for optimum performance. Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]
sneakers@heimat.UUCP (Dan "Sneakers" Schein) (06/25/89)
In Message <850@manta.NOSC.MIL>, dwi@manta.NOSC.MIL (Steve Stamper) writes: >Although it may not be recommended, I have used HD diskettes in my >Amiga drive many times and have had no problems. I can read/write >them just fine. I imagine it is better to use DD disks, especially >since they are so much cheaper as well. I also use HD drisks in heimat - I did however have to change from the Matashuta (sp?) drive to a Chinon - Reason I use (some) HD disks is simply because their free - I read alot of Messy-DOS magazines and weekly/monthly newspapers where somone is always offering a *FREE* demo disk - I look at the demo and then format the disk for Amiga use ;-) Sneakers -- ___ Dan "Sneakers" Schein //// BERKS AMIGA BBS Sneakers Computing //// 80+ Megs of software & messages 2455 McKinley Ave. ___ //// 12/2400 Baud - 24 Hrs West Lawn, PA 19609 \\\\ //// 215/678-7691 \\\\//// {pyramid|rutgers|uunet}!cbmvax!heimat!sneakers