I'm trying to make copies of several 8 "floppy disks that contain the Texas Instruments DS990 Model 1 operating system. They are very rare floppies, this system is almost impossible to find and I want to be sure to make right dumps.
I connected the original disk drive to kryoflux by Dbit FDADAP as recommended in other posts.
I dumped a couple of disk in "preservation mode" but I wanted to know if it was better to set some known parameters and if I can write the dumps back on other floppies to try to boot from the copies.
Note that preservation streams also preserve any "noise" present on a disk. I've found that marginally damaged disks may decode OK with Kryoflux/HxC/PCE tools, but just writing the stream back to a new disk will write the "noise" and may result in a disk that is not readable at the same area where there was damage.
Basically, try it and see what happens.
It may be desirable to first reduce the preservation stream to a "lowest common denominator" format, in this case probably an ImageDisk format and then create a fresh noise-free stream file. HxC is really good with this - just open the Stream file, if it shows no decoding errors, save to ImageDisk, load the ImageDisk file, then save to a Kryoflux Steam format. (Note that the HxC software tool is a third party tool and is not made by or supported by the Kryoflux folks)
If in doubt, post a sample stream file and let the folks here pick over it to see if there is anything that could cause issues.
here some dump I made. II was unable to convert them to any format that allows me to understand if there is readable data inside
https://www.dropbox.com/s/ob6mu9k76x7d6 ... d.zip?dl=0
Also, manually decoding a sector from the mill-dump shows the format is non-standard such that DTC simply can't decode it.
It's MFM, uses only single 4489 syncword, 0x0A ID for sectorheader and 0x0B ID for data. Sectorsize is weird 288 bytes. 26 sectors per track. Checksums are standard tho.
It might help to tell us a little more about the drive(s) you are using. Is the drive you are reading from a drive from the machine in question? What model of drive is it/are they?
Roughly where about are you located? There could be someone in your area that might be set up for that. (Assuming that there is nothing else wildly non-standard about the drives that wrote these disks).
For these disks I'd use maybe 50/50 mix of water with isopropyl alcohol and microfiber cloth to clean the surface, which will make reading the disks more safe if the surface is flaky. Tho spinning the 8" is kind of difficult while wiping along the surface unless the sleeve is cut open (I use a 3D printed holder to spin the platter).
The aim would be to get more or less three clearly separated lines in the scatter plot. If the drive is not making a very distict squeaky sounds while reading a disk and the surface doesn't look "groovy" like an old record the heads are likely clean and the problem is somewhere else. Else any further attempts to read without cleaning the heads and the disks should not be attempted.