// Remap sectors for Amstrad 1512 with ST225 drive. No error handling
#include <unistd.h>
#include <string.h>
int main()
{
   unsigned char b1[512*17];
   unsigned char b2[512*17];
// Shift should be second number in reported interleave
//Interleave (not checked): 0 3 6 9 12 15 1 4 7 10 13 16 2 5 8 11 14
   int shift = 3;
   int rc;
   int i;

   while (1) {
      rc = read(STDIN_FILENO, b1, sizeof(b1));
      if (rc < sizeof(b1)) {
         break;
      }
      for (i = 0; i < 17; i++) {
         memcpy(&b2[i*512], &b1[((i + shift) % 17)*512], 512);
      }
     write(STDOUT_FILENO, b2, sizeof(b2));
   }
}