=*=*=*=*=*› Double Density vs High Density› from MEI/Micro  Center  Advertisement› Reprinted    from   The   Sourcerer's› Apprentice (MAGIC) March,  1991,  and› THE OL'HACKERS ATARI USER GROUP, Inc.› with THANKS!›› Many   computer  users  are  confused› about the difference  between  double› density  and  high density diskettes.› The basic difference is in  the  size› of  the   magnetic   particles.   The› difference  in particle sizes applies› to both 5.25" and 3.5" diskettes.›› The magnetic particles  used  in  the› coating  of  high  density  media are› smaller   than  those  found  in  the› double density media. The smaller the› particles,  the more that fits on the› surface   of   the   diskette.  These› smaller particles are what allow  the› high  density  disk  to have a higher› capacity  to  hold  data.  Since  the› particles are smaller,  they  emit  a› lower  voltage or signal strength. To› compensate for this smaller  voltage,› the  read/write head used in a double› density disk drive is less  sensitive› than  those  found  in a high density› drive. The double  density  and  high› density  sensitivities  are different› so that they  can  clearly  read  the› signal being sent.›› Interchanging  high  density  and low› density disks will often  cause  data› errors,  because the read/write heads› will either be too weak or too strong› to read the signals clearly. This can› result in data  errors,  problems  in› retrieving  the  data,   and/or   the› inability to format a diskette.›            <> end <>››