Newsgroups: comp.sys.ibm.pc Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!hellgate.utah.edu!hellgate!jacobs From: jacobs@cs.utah.edu (Steven R. Jacobs) Subject: Re: Formatting 1.2 Meg disks to 360K question Message-ID: In-reply-to: jacobs@chocolate.it.udel.edu's message of 9 Jan 90 00:12:47 GMT Organization: University of Utah CS Dept References: <3226@ucrmath.UCR.EDU> <7715@nigel.udel.EDU> Date: 9 Jan 90 09:33:59 In article <7715@nigel.udel.EDU> jacobs@chocolate.it.udel.edu (michael jacobs) writes: >In article <3226@ucrmath.UCR.EDU> lulu@ucrmath.UUCP (david lu) writes: >=>I just tried to format some 1.2 Meg, high density disks in my >=>360K drive (as 360K), and I got the following error message: >=> >=> Invalid media or Track 0 bad - disk unusable >=> >=>Now, I know that I can't format 360K disks to 1.2 Meg in a >=>1.2 Meg drive, but why can't I format 1.2 Meg disks to 360K >=>in a 360K drive? I thought that "blank" disks are just that >=>-- blank. They can be reformatted as long as the density is >=>"thick" enought, right? > >Having just had this problem, I asked around and it seems that High Density >disks and Double Density disks (used for 360k) do have physical differences. >On the High Density disks, there are only certain places for the sectors >while the DD's are more flexible since there's less stuff to squeze >together. The person that told you this was either joking or making it up to disguise their ignorance. Physically, the two types of disks are similar, with oxide covering the entire surface of the disk. The difference is in the oxide itself. On the high density disks, the oxide is a different material which requires a stronger magnetic field to record information. The heads in many 360K drives are not designed to produce a strong enough magnetic field to record data on the high density floppies. -- Steve Jacobs ({bellcore,hplabs,uunet}!utah-cs!jacobs, jacobs@cs.utah.edu)