• Preparing MPCs (Info)

  • Packed Dates

    Dates of the form YYYYMMDD may be packed into five characters to conserve space.

    The first two digits of the year are packed into a single character in column 1 (I = 18, J = 19, K = 20). Columns 2-3 contain the last two digits of the year. Column 4 contains the month and column 5 contains the day, coded as detailed below:

       Month     Day      Character         Day      Character
                         in Col 4 or 5              in Col 4 or 5
       Jan.       1           1             17           H
       Feb.       2           2             18           I
       Mar.       3           3             19           J
       Apr.       4           4             20           K
       May        5           5             21           L
       June       6           6             22           M
       July       7           7             23           N
       Aug.       8           8             24           O
       Sept.      9           9             25           P
       Oct.      10           A             26           Q
       Nov.      11           B             27           R
       Dec.      12           C             28           S
                 13           D             29           T
                 14           E             30           U
                 15           F             31           V
                 16           G
    
    Examples:
    
       1996 Jan. 1    = J9611
       1996 Jan. 10   = J961A
       1996 Sept.30   = J969U
       1996 Oct. 1    = J96A1
       2001 Oct. 22   = K01AM
    
    This system can be extended to dates with non-integral days. The decimal fraction of the day is simply appended to the five characters defined above.
    Examples:
    
       1998 Jan. 18.73     = J981I73
       2001 Oct. 22.138303 = K01AM138303