Path: utzoo!attcan!uunet!cs.utexas.edu!usc!apple!agate!monsoon.Berkeley.EDU!joonsong From: joonsong@monsoon.Berkeley.EDU (Suk-Hyun Song) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: Making a floppy drive ignore high density hole Message-ID: <1990Jul22.015706.16479@agate.berkeley.edu> Date: 22 Jul 90 01:57:06 GMT References: <11547@ingr.com> <1990Jul19.021714.10040@world.std.com> <803@digi.lonestar.org> Sender: usenet@agate.berkeley.edu (USENET Administrator;;;;ZU44) Reply-To: joonsong@monsoon.Berkeley.EDU (Joon Song) Organization: University of California, Berkeley Lines: 23 The source of the problem that make 3.5" disks unreadable is the disk controller. Most HD/FD controllers insist on using the hole detector on the 3.5" disk drives to determine whether the disk is high density or double density. The most notable among these is the Western Digital controllers. This can be considered a feature or an annoyance depending on your point of view. The solution to this problem is replacing the controller. I have such a controller. It is an MFM 2:1, 2HD, 2FD controller. I used it for about 6 months with no problems reading, writing, and formatting 720K and 1.44M disks irregardless of the hole. Depending on how the disk was formatted, (format a: /t:80 /n:9 || format a: /t:80 /n:18) any disk could be 720K or 1.44M. I later replaced the MFM controller with an RLL 1:1 controller which no longer lets me do this. (I lost the ability to use 720K as 1.44M disks but I got faster transfer rate and more capacity.) If anyone out there is interested in the MFM controller, I would be happy to sell it to you. Make me an offer. Reply to joonsong@ocf.berkeley.edu.