10-31-2016, 10:44 AM
Most all commercial disks were produced using a duplication machine that uses the INDEX pulse as a reference for the start/stop of the write for each track. So, most all disks can be imaged/duplicated using the INDEX mode. For disks that were not created using the INDEX pulse as the start/stop reference (like anything created by the Amiga itself), those have to have at least 2 revolutions to obtain the full uninterrupted track data. There is a "write splice" that occurs when the head writing is turned off. That ends up being a "smeared" bitcell with a time that typically invalid. Finding these invalid smears is how the SPLICE mode works. It looks (starting with the last revolution and moving backwards) for the invalid flux data and uses that as the end of the track. There is some other magic involved to make sure that the write splice appears in the proper location based on the speed of the destination drive.
For "preservation", yes, you should use 5 revs. If you are concerned with only making working copies, the most you would need really is 2 revs for anything non-index'd, and just a single rev for index'd disks.
I will look to see why your disk did not make a working image in SPLICE mode. It really should have, so there is something off in my SPLICE routine - or it's just one of those rare occassions where the flux data smeared perfectly. In that case though, the disk type (Amiga) is used to locate the write splice the old fashion way, so perhaps there is a problem there.
For "preservation", yes, you should use 5 revs. If you are concerned with only making working copies, the most you would need really is 2 revs for anything non-index'd, and just a single rev for index'd disks.
I will look to see why your disk did not make a working image in SPLICE mode. It really should have, so there is something off in my SPLICE routine - or it's just one of those rare occassions where the flux data smeared perfectly. In that case though, the disk type (Amiga) is used to locate the write splice the old fashion way, so perhaps there is a problem there.