SUBROUTINE DISCO 
         COMMON/DATA/DATA(2,600),NDATA,IFLAG,NDIMAX
         LOGICAL*1 ICH(18),FILNAM(32),IAA(6),ID(10),IT(8)
         DIMENSION COL(8),A(6)
C
         DO 73 I=1,600
         DATA(1,I)=0.0
         DATA(2,I)=0.0
  73     CONTINUE
   53    WRITE (5,101)
  101    FORMAT (1X,'FILE NAME:',$)
         READ (5,103) (FILNAM(I), I=1,32)
  103    FORMAT (32A1)
         OPEN (UNIT=2, TYPE='OLD', NAME=FILNAM, ERR=14)
C
  35     READ (2,40,END=55) (ICH(I), I=1,16)
         IKY=MATCH(' DATA BEGINS NEX',ICH)
         IF (IKY.EQ.1) GOTO 45
         IKY=MATCH('DATA BEGINS NEXT',ICH)
         IF (IKY.EQ.0) GOTO 35
  40     FORMAT (16A1)
C
  45     WRITE (5,60)
  60     FORMAT (1X,'X IS COLUMN:',$)
         READ (5,75) KX
         WRITE (5,70)
  70     FORMAT (1X,'Y IS COLUMN:',$)
         READ (5,75) KY
  75     FORMAT (I1)
         NDATA=0
         DO 90 I=1,600
         READ (2,88,END=50) (COL(J), J=1,8)
         DATA(1,I)=COL(KX)
         DATA(2,I)=COL(KY)
         NDATA=NDATA+1
  88     FORMAT (1X,8(1X,E12.3))
  90     CONTINUE
  50     GOTO 160
  55     TYPE*,'HOPE OR FAITH FILE'
         NSN=0 
         TYPE *, 'INPUT SCAN NUMBER:  '
         READ (5,7)NNSN
   7     FORMAT (I4)
         REWIND 2
  10     READ (2,11,END=14) (ICH(I),I=1,16)
  11     FORMAT (16A1)
         IKY=CMPS('SCAN',ICH,18)
         IF (IKY.EQ.0) GO TO 12
         GO TO 10
  12     BACKSPACE 2
         READ (2,1)NSN,(ID(I),I=1,9),(IT(I),I=1,8)
   2     FORMAT (3X,4A1,4X,6(F7.3,3X),I2)
   1     FORMAT (5X,5X,I4,10X,9A1,10X,8A1)
         IF (NSN.NE.NNSN) GO TO 10
  21     WRITE (5,1) NSN,(ID(I),I=1,9),(IT(I),I=1,8)
         READ (2,2) (IAA(I),I=1,4),(A(I),I=1,6),IA
         NDATA=((A(2)-A(1))/A(3))-1.
  68     DO 80 I=1,NDATA
         READ (2,4) OM,TTH,CTS
   4     FORMAT (1X,2(F7.3,3X),F7.0)
 204     FORMAT (7F10.4)
         DATA(1,I)=TTH
         DATA(2,I)=CTS
  80     CONTINUE
 160     PMAX=0.0
         PMIN=0.0
         DO 180 I=1,NDATA
 167     PMAX=AMAX1(PMAX,DATA(2,I))
         PMIN=AMIN1(PMIN,DATA(2,I))
 180     CONTINUE
         CALL CLOSE(2)
 202     WRITE (5,22) NDATA
  22     FORMAT (1X,'FILE HAS ',I4,'POINTS TO PLOT')
         WRITE (5,81) PMAX,PMIN
  81     FORMAT ('  MAX VALUE  =', F7.0,'  MIN VALUE =  ',F7.0)
         RETURN
  14     TYPE*,'OPEN ERROR; TRY AGAIN!'
         RETURN
         END