From: Marko Mäkelä (marko.makela_at_hut.fi)
Date: 2003-11-02 15:37:32
Wolfgang Moser asked me to forward the message (originally posted to comp.emulators.cbm) to the list. I'm impressed, but it's a pity that 5.25" DD drives are very difficult to obtain these days. Marko Subject: ANN: Disk2FDI 0.95a, importing CBM 1541 disks with PC floppy disk drive Date: Sun, 02 Nov 2003 01:52:14 +0100 From: Wolfgang Moser <firstname.lastname@example.org> Hello newsgroup, today morning, Vincent Joguin informed me, that a new version of his tool Disk2FDI is out. 2 years ago he developed a technique to completely trick out the standard PC floppy disk controller, so that some foreign disk formats (not beeing MFM or FM encoded) can be read out with standard PC equipment. A long time only nonstandard Amiga-MFM disks could be read out this way, but with version 0.95a some things changed... and I got really shocked! Disk2FDI 0.95a now claims to import GCR encoded Commodore 1541 floppy disks with a standard IBM PC/XT/AT floppy disk controller. But there are some requirements (hard to reach?): * Your PC must contain _two_ floppy disk drives both connected to the same floppy disk controller (USB floppy disk drives don't work) * One of the drives must be a _low_density_ 5,25" disk drive (360KB capacity drive) * The software does only work under plain DOS, probably under Win95/98/ME Vincent told me about the 360KB low density disk drive requirement, that these drives are rotating at only 300rpm. High density 5,25" (1,2MB capacity) got a rotation speed of 360rpm. Because C1541 disks contain four different speed zones Disk2FDI requires a 300rpm drive in combination with the two bitrates of 300 and 250 KBit/s of the floppy disk controller. Only with this setup all the four speed zones can be read out correctly. After I got such an old drive I made some first tests. And yes, in general it works. I was able to read out one of my 1541 disks and transfer it to a D64 disk image file. But currently there seem to be some reliability problems. I read out the same disk several times and compared them against each other. With each image file 20 to 30 byte differencies (out of 170KB) occured (only using images, that were imported without any error messages shown up). Take note that this problem may not be caused by Disk2FDI if my hardware setup doesn't work properly. You all should do independent tests for your own. Conclusion: Although some reliability problems showed up, Vincent put up the proof with Disk2FDI, that reading/importing Commodore GCR encoded disks definetly is possible with a standard PC floppy disk controller. Therefore I apologize publicly for telling people, that such a software method would be impossible ;-) If you want to download and test this thing or want to read into the very interesting tech docs, go to: http://www.oldskool.org/disk2fdi/ http://www.oldskool.org/disk2fdi/shareware.html Womo -- ------ to obtain more infos about me, look up the page ------ ---- http://www.wmsr.de pwnah (at) d81 (dot) de ---- Message was sent through the cbm-hackers mailing list
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