From: kelli217@crosswinds.not.invalid   
      
   On Fri, 03 Mar 2006 18:51:58 +0000, thewises wrote:   
      
   > dgriffi@cs.csbuak.edu (Dave Griffith) wrote in   
   > news:DLUNf.17844$rL5.17837@newssvr27.news.prodigy.net:   
   >   
   >> ditinsta  wrote:   
   >>> I collect Tandy and TRS-80 computers. Just bought an 1100FD from a   
   >>> thrift store. No disks were included. I downloaded four dsk files of   
   >>> Deskmate and MS-DOS for the 1100FD and downloaded a program called   
   >>> wfdcopy to transfer the files to disk. The transfer seems to work, but   
   >>> of course the only disks I have are 1.44 3.5" and the 1100FD doesn't   
   >>> like them. Can I somehow format a 1.44 3.5" disk to 720 so the 1100FD   
   >>> will recognize it? XP doesn't seem to allow it. Is there a better route   
   >>> to go in getting these dsk files to work with the 1100FD?   
   >>   
   >> Have you tried taping over the HD hole on a 1.44 floppy?  It's not   
   >> supposed to work, but it sometimes does.   
   >   
   > Don't do it. HD floppies are coated with different material than DD   
   > floppies are, and DD drives don't have enough current to read them. Disks   
   > formatted this way won't last long. Look on Ebay. They always have plenty   
   > of brand-new DD 3.5" disks.   
   >   
   > Windows XP only can format 1.44MB disks, if you're using Windows Explorer.   
   > But if you go to a DOS box, you can format 720k disks by typing FORMAT A:   
   > /N:9 /T:80. There's also various third-party formatter programs on the   
   > web.   
   >   
   > I never format floppies with XP, anyway. I use my two old computers(a   
   > Pentium and a 386) to format them.   
      
   HD 5.25" floppies are coated with different material than DD 5.25"   
   floppies; HD 3.5" floppies are much more compatible with their DD brethren.   
      
   In the early days of 1.4MB 3.5" floppies, manufacturers used the same   
   production lines to produce HD and DD floppies: disks that tested OK for   
   1.4MB bit density were sold as HD floppies, and those that failed or were   
   marginal were tested again at 720kB bit density and, if they passed, were   
   sold as DD floppies. When the DD market was still comparable with the HD   
   market, these manufacturers would often start a production run for DD   
   floppies and only test them at that bit density, but considering that the   
   same coating was used, many of these disks were quite capable of holding   
   an HD format. In later years, the formulation for the HD floppy coating   
   was indeed changed slightly to improve performance and reliability -- but   
   this did not have any significant impact on the performance of the disks   
   at DD bit densities.   
      
   There are many people who will tell you that it's a bad idea to format an   
   HD disk as DD. Many of them will even tell you that they have experienced   
   failures with disks so formatted. These reports are unreliable, as they   
   tend to rely on anecdotal information, and have not borne up under   
   methodical scrutiny.   
      
   Much of this 'information' about the incompatibility comes from a mixture   
   of the 5.25" problem, which is legitimate and verifiable, and the few   
   products that were sold in the early days to punch a hole in the corner of   
   a DD 3.5" floppy and make it into an HD floppy. This latter technique   
   flourished, briefly, because of the production run issues mentioned   
   earlier, which created a number of HD-capable floppies that were not   
   certified as such, but was soon discovered to be unreliable, because of   
   the lack of testing at HD bit densities.   
      
   A 5.25" HD floppy drive can reliably *format* a DD 5.25" floppy, using the   
   /4 switch, which runs the write head down each DD track 4 times. This   
   compensates for the thinner track pitch and lower magnetic field strength   
   of the HD drive mechanism. However, *writing* any actual files to a DD   
   5.25" floppy with an HD 5.25" mechanism results in very unreliable   
   storage, because of those same issues, which are not compensated for in   
   the write process. An HD 5.25" floppy formatted on a DD 5.25" drive   
   mechanism, or on an HD 5.25" mechanism with the /4 switch, is basically   
   useless, due to the different characteristics of the floppy coating, which   
   are designed to work best with HD 5.25" mechanisms in their normal usage.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)