On 2011-10-22 01:09, MikeS wrote: > 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. > I may have written this in a way that that could be misunderstood but the drive attached to my kryoflux is capable of 80 tracks (83 actually) someone could argue that I should have written DS/HD than :-) /Uffe > > ----- Original Message ----- From: "Uffe Jakobsen" <uffe@uffe.org> > To: <cbm-hackers@musoftware.de> > 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 list Message was sent through the cbm-hackers mailing listReceived on 2011-10-23 00:00:07
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