Ivan Stewart's Super Off Road

[sean_skroht]

Hi all,

I have a retail copy of Ivan Stewart's Super Off Road and having a hell of a time trying to get it backed up to another floppy.

I have tried splice with 2 and 5 revolutions as well as index. The images that are created work fine in WinUAE but when writing those images to a backup disk, the backup doesn't work. It either doesn't boot or it will get to the splash screen and not go any further. Also any images made from the backups do not work either.

I have tried on 3 drives, all aligned and have clean heads. The original retail disk is clean and works fine and it has also been used to install the WHDLoad version. Tried backing up on various new condition blanks. They tested fine without errors.

I'm at my wits end. Does this particular game have a particularly difficult copy protection? If anyone wants to have a look at it, let me know, and I will upload it to FTP. I'm not exactly sure what to look for when examining the image, so maybe someone might know what's going on.

Thanks for that.

[admin]

Sounds like the disk was not created using the index as a reference. This is no problem for WinUAE using SPLICE mode as it "rotates" the disk and will retry when the write splice is wrong. The problem is that the SPLICE mode is not finding a write splice in the correct location.

Send me an image, done in SPLICE mode with 5 revs to: data@cbmstuff.com and I can look at the disk and determine why the write splice detection is not working correctly.

[sean_skroht]

Sounds like the disk was not created using the index as a reference.  This is no problem for WinUAE using SPLICE mode as it "rotates" the disk and will retry when the write splice is wrong.  The problem is that the SPLICE mode is not finding a write splice in the correct location.

Send me an image, done in SPLICE mode with 5 revs to: data@cbmstuff.com and I can look at the disk and determine why the write splice detection is not working correctly.

Thank you very much for having a look at it. Sending it now so hopefully it makes it through ok.

[admin]

I believe your image works fine.  You need to write back your image with the override button checked, and set the mode to INDEX.  I did that and the copy loads all of the tracks and then crashes I believe due to the Vampire accelerator I have in my A2000.  I need to break out a stock A500 to test it with.  Track 0, head 1 looks odd - its the protection track, but the rest of the tracks are definitely indexed.  You would only need to use INDEX mode to duplicate this disk (like most all disks).

[sean_skroht]

Thank you for that advice. Yeah writing back to disk in Index mode did indeed work, and I was also able to re-image that backup disk I made, with the subsequent image also working.

I just wanted to ask some questions in regards to this and hopefully you can clear some things up for me:

Preservation of my own Amiga retail disks is quite important for me and I've read online that for true preservation it is best to image in splice mode for at least 5 revolutions (which I have been doing). Is this sound advice and does it have an advantage over imaging with single revolution Index mode?

When writing the image back to a disk you mentioned overriding and writing in Index mode. If I hadn't done that then how would the write and been made? If all my images were created in 5 rev. splice mode, should I be overriding in Index mode for all images that I want to write back to disk?

Sorry for the dumb questions, just trying to get a handle on things. The reason why I ask is that, if it is actually possible, I'd like the backup disk that I create to be just as good as the original to the point that even a working image can be made from the backup. Once again thanks for your help and am certainly glad I got this card.

[admin]

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.