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   MSGID: <719d12f3-b7a5-4f6b-95d4-d34a02dbe7c1@googlegroups.com> c0744016   
   REPLY:  8d9ff203   
   PID: SoupGate-Win32 v1.05   
   > Even SC+ is not able to make an identical copy of a   
   > certain disk. As Jim Drew explained somewhere, the true   
   > halftrack protection from Bounty Bob Strikes Back!   
   > cannot be reproduced with the native copier for the SC+.   
   > Instead Jim wrote a custom copier after he analyzed the   
   > protection.   
   > By analyzing a protection and then creating a mastering   
   > routine that will recreate that protection does mean   
   > that this is not a _copy_, but a re-master.   
      
   That is not the case.  The Bounty Bob Strikes Back! Copier is an actual   
   copier.  It is just a custom copier that knows which tracks are 1/2 tracks and   
   which are not.  Since the main copiers for Supercard+ do not support 1/2   
   tracks, a custom copier was    
   needed.  Copying Bounty Bob Strikes Back! is a two part process - first you   
   copy the disk with the GCR Nibbler and then you copy it again using the custom   
   copier.   
      
       
   > And further true copier machines (Trace duplicator) are   
   > able to create patterns that can be detected with a 1541   
   > disk drive, but cannot be written with 'em, even if you   
   > do adjust the motor speed. E.g. true Fat Tracks that are   
   > recorded over two adjacent halftracks. If you try to   
   > replicate that, then you would always overwrite one of   
   > the both halftracks due to mechanical issues. The 1541's   
   > R/W head is a so named tunnel erasing head. It write a   
   > wider track and after that the left and right side of   
   > that wide track are erased again after. This sharpens   
   > the track and it can be better reread after. In fact I   
   > never saw such a true Fat Track protection, mostly these   
   > were only precisely aligned adjacent full-tracks.   
      
   If you disable the erase head you can write a 1/2 track.  However, you need to   
   first erase the disk with a magnet.  EA used true 1/2 track protection, with   
   tracks 34, 34.5, and 35 all containing valid sectors for the entire track.   
      
       
   > Reframing btw. is no magic issue. And because Jim Drew   
   > does not explicitly tell about all the nifty tricks that   
   > he used to make the copiers work does not mean that he   
   > did not use something similar to reframing for SC+.   
   > Since no 1541 drive runs at the very same RPM as the   
   > drive the original disk was recorded for, you always   
   > have to do SYNC and GAP length reducing/increasing,   
   > maybe RPM adjustments and some sort of reframing or   
   > frame detection (perhaps tail GAP detection too) on   
   > SYNC-less tracks.   
      
   I never changed gap lengths or anything else GCR related, and I didn't   
   re-frame any data.  The only real change was a reduction of the drive speed to   
   298.1 RPMs.   
      
   --- SoupGate-Win32 v1.05   
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