rmay635703
Veteran Member
Sounds like a Herne data systems maxi disk image.
My guess it’s just a Unix binary of a disk image
My guess it’s just a Unix binary of a disk image
dd if=doc.img of=doc.img.test bs=1 skip=484 count=1474560
file doc.img.test
If you want, email it to vcfblackhole at protonmail.com. This is my line of business--I routinely handle sensitive data.I'd love to post the entire file and be of better help. the only problem is that the files i'm attempting to rescue may have other people's information and I am working on the careful side.
Not really; witness XDF and DMF disks. Even the original fastback used its own format.If it uses a non standard disk geometry that means OP's machine had a non standard drive to begin with, which should be noted in the first place.
while recently getting a new box of Olivetti branded "2MB" floppies)
Why the quotes around "2MB"? That's the standard "unformatted" capacity of the diskettes people usually format to 1.44 MB "formatted" data capacity. (And yes, you really can store close to 2 MB on them if you're willing to use different format. This was frequently done for multi-disk installation sets; around 1.8 MB formatted capacity was popular for those.)(while recently getting a new box of Olivetti branded "2MB" floppies)
Thanks Zare!!
dd if=doc.img of=header.bin bs=1 count=500
Why the quotes around "2MB"?
Oh, I get it now.Because in my case I've literally held the 2 MB labeled floppy in hand recently, formatted it to 1.44MB for normal DOS use, knew what was it all about, and still posted here that having image larger than 1.44 smells of a non-standard floppy.
I suggest that posting the first 8 KB would be better. That should avoid any personal data possibly on the image, but also work even if this is a standard 1.44 MB diskette image with a 4 KB header. (As I mentioned earlier, the size of the .IMG file is 4096 bytes larger than the data capacity of a 1.44 MB diskette....To extract first 500 bytes and post the file here....
Has it? My calculation was based on the original message:I think that size difference has been misreported...
So: 1478656 bytes - (2 heads * 80 cylinders * 18 sectors * 512 bytes) = 4096 bytes.
- The file size is 1.478.656 bytes, which makes me believe it's a floppy disk image, although the IMG file itself won't fit in a floppy disk.
Ah, I see. I missed that. So that's where the "484 bytes" thing was coming from.@cjs Yes, but I later corrected the file size to 1.475.044.
If you dd bs=1 skip=484 the file, do you get a new file starting with a DOS boot sector? (The file command will immediately tell you this.) If so, you can simply loopback mount that file on Linux (see any tutorial on how to mount file images) and see what's on the image, if the rest is indeed an image of a floppy with a filesystem.Today I plan to devote some time to this again and test Norton for Windows, and other versions, then move back to manually adjusting the file if Norton doesn't do the trick.
Nothing to do with FAT per se, it's just a local modification typically coupled with last access timestamps (AT) embedded in a medium's root directory. The rumor has it that the last 3 letters stand for "CHICAGO" spelled backwards, which is the codename for the earliest Win95 release. Not sure why it spanned beyond Win95, though. Also, this behavior is not limited to Win9x alone and is present in at least all of NT-based OSs from 3.51 (presumably) to 5.1. I've had some of my dumps modified by WinXP exactly the same way. The bottomline is, this will eventually happen in pretty much any Windows version as of 1995 if a disk is not write-protected. While it may take some time for OEM ID to change (seems to depend on multiple disk access or scanning) the AT will stick to the root directory instantly on file access. A simple file copy procedure is enough to make it happen. At first only executable (.EXE, .COM) and 30kb+ file entries are targeted, but eventually all of them will meet the same fate. Again, depends on what you do.
dd if=doc.img of=doc.img.test bs=1 skip=484 count=1474560
Yeah Herne data systems had software that added a header to its floppy images because it could technically image non-dos floppies with odd parameters that were stored there by the software.Updates, updates:
I tried with Norton Disk Doctor for Windows, but no luck with that either, although I admit it was a lot of fun running that software again after so many years. And it did seem to be a logical choice. So I then moved on to the next step of the plan, and:
That was exactly it.
As it turns out, by removing that 484 byte header, the file matched a regular image file that was easily opened by Winimage and by virtualbox as well.
I am going through the recovered files now, It all seems good. Unbelievable.
I guess I'll never know which software created that strange image back then, or why did it add that 484-byte header on top of it.
I want to thank you all. Everyone who chipped in. I would have never recovered that floppy without your help and the whole process was a fun trip down the memory lane. Happy to be here, happy for your help.
yours,
Rod