(recode.info)Display Code

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Control Data's Display Code
===========================

   This code is not available in `recode', but repeated here for
reference.  This is a 6-bit code used on CDC mainframes.

     Octal display code to graphic       Octal display code to octal ASCII
     
     00  :    20  P    40  5   60  #     00 072  20 120  40 065  60 043
     01  A    21  Q    41  6   61  [     01 101  21 121  41 066  61 133
     02  B    22  R    42  7   62  ]     02 102  22 122  42 067  62 135
     03  C    23  S    43  8   63  %     03 103  23 123  43 070  63 045
     04  D    24  T    44  9   64  "     04 104  24 124  44 071  64 042
     05  E    25  U    45  +   65  _     05 105  25 125  45 053  65 137
     06  F    26  V    46  -   66  !     06 106  26 126  46 055  66 041
     07  G    27  W    47  *   67  &     07 107  27 127  47 052  67 046
     10  H    30  X    50  /   70  '     10 110  30 130  50 057  70 047
     11  I    31  Y    51  (   71  ?     11 111  31 131  51 050  71 077
     12  J    32  Z    52  )   72  <     12 112  32 132  52 051  72 074
     13  K    33  0    53  $   73  >     13 113  33 060  53 044  73 076
     14  L    34  1    54  =   74  @     14 114  34 061  54 075  74 100
     15  M    35  2    55      75  \     15 115  35 062  55 040  75 134
     16  N    36  3    56  ,   76  ^     16 116  36 063  56 054  76 136
     17  O    37  4    57  .   77  ;     17 117  37 064  57 056  77 073

   In older times, `:' used octal 63, and octal 0 was not a character.
The table above shows the ASCII glyph interpretation of codes 60 to 77,
yet these 16 codes were once defined differently.

   There is no explicit end of line in Display Code, and the Cyber
Record Manager introduced many new ways to represent them, the
traditional end of lines being reachable by setting `RT' to `Z'.  If
6-bit bytes in a file are sequentially counted from 1, a traditional
end of line does exist if bytes 10*N+9 and 10N+10 are both zero for a
given N, in which case these two bytes are not to be interpreted as
`::'.  Also, up to 9 immediately preceeding zero bytes, going backward,
are to be considered as part of the end of line and not interpreted as
`:'(1).

   ---------- Footnotes ----------

   (1) This convention replaced an older one saying that up to 4
immediately preceeding _pairs_ of zero bytes, going backward, are to be
considered as part of the end of line and not interpreted as `::'.