jsr $ffc9 ;CHKOUT
               ldy #$00
         loop  lda u1cmd,y
               jsr $ffd2 ;CHROUT
               iny
               cmp #$0d
               bne loop
               jsr $ffcc
               ldx #$0f  ;input error code
               jsr $ffc6 ;CHKIN
               jsr $ffcf ;CHRIN
               sta $fb   ;store first error code to 251
               jsr $ffcf
               sta $fc   ;store second error code to 252
         loop1 jsr $ffcf ;read until you receive a  character
               cmp #$0d
               bne loop1
               jsr $ffe7 ;close all channels ;CLALL
               rts
         pound byt "#"
         u1cmd byt "u1: 2 0 01 00"
               byt $0d

      This M/L routine can be stored at $C000 (49152) and called from
      BASIC as follows.
      
         10 OPEN15,8,15,"I":CLOSE15
         20 SYS49152
         30 IF PEEK(251)<>ASC("2") AND PEEK(252)<>ASC("2") THEN PRINT
          "DATA BLOCK NOT FOUND!":END:REM PROTECTION PASSED
         40 PRINT "DATA BLOCK WAS FOUND":REM PROTECTION FAILED
         
         
         
                         < < < Protection Scheme # 2  > > >
         
      This protection scheme is guaranteed to defeat ANY non-hardware-
      assisted nybbler on the market; including Fast Hack'em and our very
      own set of comprehensive nybblers. The physical protection involves
      placing a set of GCR bytes in the tail gap of a sector on disk.
      Drive memory limitations prevent a software-only nybbler from
      copying these bytes, which are located after the end of the GCR
      bytes that make up the sector on disk. Only extra drive RAM and
      software to support it can copy these bytes. To better illustrate
      this, let's look at a typical sector on disk.
      
      Format a work disk, then load the GCR Editor (GCRED) from the
      Hacker's Utility Kit.  With your work disk in the drive, input 1
      for the track number and press  twice. The GCRED will
      display a summary of all the header/data blocks on the track. Both
      
            K.J. REVEALED TRILOGY    PAGE [145]    (C)1990 K.J.P.B.