My Results of copying Amiga Disks so far
#11
(12-24-2013, 06:46 PM)admin Wrote: The new beta (.93) will let you create images now with blind mode turned off.

So when I start copying my Amiga disks I should copy them with blind mode turned off?
Reply
#12
I would recommend trying everything with Blind mode turned on. Right now, there are a couple of quirks with blind mode off with 3.5" disks (Amiga/PC/ST). I will resolve those after the Christmas holiday. Once the blind mode off is working properly you could technically copy/image everything in that mode, but its a lot slower and generates files 2-3 times the size.
Reply
#13
You are correct, MK2 is a PDOS format disk, which holds about 9% more data per track, while Project X is a standard copylock protection.

There's a list of some games and their associated protections and disk formats as part of the disk-analyse utility:

https://github.com/keirf/Disk-Utilities/...se/formats

Looks like Psygnosis went all-out on Armour-Geddon with no less than 5 different track formats across 3 disks.
Reply
#14
(12-24-2013, 06:46 PM)admin Wrote: The new beta (.93) will let you create images now with blind mode turned off. I just changed the number of revolutions to 2 (from 3) to keep the file size <32MB which is the reason for the issue.

Ok, I just sent you the images of GuySpy and Mortal Kombat II in SCP (blind off) as you requested.
Reply
#15
Ok, I just did a few more tests copying my Amiga disks and I found something that I was not expecting:

I remembered that "Nitro" from Psygnosis was a little bit special because back in the Amiga days, it could be copied with a hardware supported copier (e.g. Super Ami-Backup, etc) but if you tried to make a copy of a "working copy" disk, it always failed... always... So, I tried with Super Card Plus thinking that it would make an identical copied disk and a copy of that disk would probably work... well, the first copy of the original disk (using blind copy), works perfectly but if you try and make a copy of that disk, using the same settings (blind copy, etc), it does not work... it fails just like the old copiers did back in the Amiga days...

Was that expected? Any thoughts on why the second copy fails?

Besides that interesting and unexpected result, the good news are that I was able to make working backup copies of the following Psygnosis Games without issues:

- Walker
- Shadow of the Beast III
- Barbarian
- Nitro (only from the original as stated above)
Reply
#16
I'd have figured you could do 2 or 3 generations of copies before it had troubles loading. AmigaDOS disks probably more. Otherwise, not too surprising.

You're basically transferring data back and forth between digital and analog domain. Floppy disks and drives are imperfect. Even though you tell it to write a flux transition 4.00us from the last one, it may not come out exactly like that as the speed of the drive isn't exactly 300RPM all the time, among other factors. So the next time you sample that flux transition timing, it likely won't read back as 4.00us. The more you repeat the process, the greater the drift becomes.

Some of this can be corrected for with write pre-compensation. You could even get fancy and write the track to disk, read it back, compare timing differences, adjust accordingly, write back again.

Or you can just write all copies from the same source image file, since it will never change Wink
Reply
#17
When I add the post read normalization routine, copies of copies of copies of copies, etc. will work. However, it should be noted that every drive reads and writes data a little bit differently. I can make numerous copies of Nitro before the copy won't load. I am working on the verify routine and that will solve the issue completely because it compares the flux data times bit for bit and adjusts the bit cell times so the track comes out the perfect length with every bit cell the correct length, based on the rotational speed of the drive. This lets you also do things like use an image created by a 360 RPM drive with a drive that is 300 RPMs.

Supercard Ami III used a PEEL to actually change the data post read to minimize the issue.

If you are curious how much change occurs, use the Display Flux option and look at the original vs. a copy.
Reply
#18
I continued backing up my Amiga originals and got some pretty good results (although not perfect):

- Unreal - Copied easily with blind on (I was pretty impressed as I remember it was a pretty tough protection)

- Rise of the Robots - Copied easily with blind on (also pretty impressive as I remember I could not make a good copy back in the day, even with the Sybil copier)

- The Plague - Copied easily with blind on

- Dungeon Master - Copied easily with blind on (I remember this was also tough to copy correctly)

Now the games where I could not make a back up:

- Sword of Sodan - can't copy (Tough protection but I was able to copy back in the day with Sybil)

- NightHunter - can't copy (Tough protection but was able to copy with Sybil back in the day)

- Mortal Kombat II - can't copy (I tried again just to see if any change. Still no luck copying. I have never ever been able to make a copy of this game with anything... not Sybil back in the day and not SCP as of yet)

So... overall pretty happy as I was able to copy some tough protections and in the case of Rise of the Robots, I don't remember ever copying it right before...

I think the ones I can't copy are probably not using the index... although not sure about Sword of Sodan... hopefully, with a later software update I will be able to copy and image them.
Reply
#19
These can be copied, but need to have blind mode off because they were not written with the index. I have Sword of Sodan, so I will look at it again.

We have already copied MKII with SCP. Supercard Ami could copy this too, but SYBIL never could because it uses a variable track timing that requires exact flux timing. I will have to see if I have Night Hunter. I don't remember it. You can always send me any image files (blind mode off, 2 revolutions) to data@cbmstuff.com and I can look at them.
Reply
#20
These can be copied, but need to have blind mode off because they were not written with the index. I have Sword of Sodan, so I will look at it again.
(03-03-2014, 09:11 PM)admin Wrote: We have already copied MKII with SCP. Supercard Ami could copy this too, but SYBIL never could because it uses a variable track timing that requires exact flux timing. I will have to see if I have Night Hunter. I don't remember it. You can always send me any image files (blind mode off, 2 revolutions) to data@cbmstuff.com and I can look at them.

Great to hear that you have already copy MKII...How did you do it? with the copier or using other tools? I could not copy it either with blind on or blind off... Is there something I need to do?

I sent you the image file of night hunter...
Reply




Users browsing this thread: 2 Guest(s)