Without knowing anything about the CBM-900 or even the SFD-1001 I'd say it's No. 2) From the specs below it looks like you should be using a 5.25" *1.2MB HD* disk drive, not a DS/DD (~360KB) drive. mike ----- Original Message ----- From: "Uffe Jakobsen" <email@example.com> To: <firstname.lastname@example.org> Sent: Friday, October 21, 2011 5:51 PM Subject: CBM-900 floppy disk format/encoding > > > Hi, > > I'm in the progress of dumping some 5.25" disks from a CBM-900 (protoype) > system - for "obvious" preservation reasons. > > The disks are labeled to contain Coherent 0.7.3 (UNIX) - (which was the OS > for CBM-900) > > From the labels both "lowres" and "highres" Coherent disk sets exists. > I guess that has to do with hw graphics modes and not the disk format. > > > My problem is that I cannot read/dump the disks. > > I've even tried dumping with the Kryoflux unit (http://kryoflux.com) > It does not recognise the disk either - and hence it can only produce a > "flux" preservation dump - which it a sort of recording of the magnetic > fluxuations on the disk surface. > > The fact that Kryoflux doesn't give me anything can mean a number of > things: > > 1) the disks are damaged - not very likely - the disks have been stored > correct all the years. > > 2) the drive I'm using with kryoflux (5.25" DS/DD 83 tracks) is not the > right type. > > 3) the disks are not encoded with either FM/MFM/GCR > > > > From various sources on the net I've read that the CBM-900 contains a > drive that is SFD-1001 compatible and an MFM disk controller. > > Quoting zimmers.net: (http://www.zimmers.net/cbmpics/c900.html) > > Addition hardware: > 1.2 megabyte 5.25" disk drive (SFD-1001 compatible) > 20 megabyte hard drive > C900 Series: Prototype UNIX System, dropped after Amiga acquisition > Zilog Z8000 CPU, Runs Coherent 0.7.3, UNIX 7 clone, > Built-In Floppy, HD, IEEE-488. MFM Disk Controller, 1MB > 9600 bps, 500 units made. Came in two versions. > > But what does the above actually mean ? > > 1) is it only the mechanical parts of the disk drive that is similar to > the SFD-1001 ? or does CBM-900 contain a complete SFD-1001 with comtroller > board etc ? (I think not) > > 2) The MFM disk controller ? is it for the harddisk or the floppy or both > ? > > Could someone give me some info on what disk format/encoding to expect on > those Coherent disks. > > Now I could take the CBM-900 apart and have a look inside - but it is kept > in a storage room - and is unaccessible at the moment. > > I'd be thankful for any information :-) > > Best regards > > /Uffe > > > > Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2011-10-21 23:09:50
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