Therefore, each set has a day of data. Each block represents 16 d of data. The blocks are broken on natural time boundaries so that one block contains data for the first half of the month, and the second block contains data for the remainder of the month. Because the second block has more sets than there are days in the month, the remaining sets are filled with missing data indicators. Finally, a file holds 1 yr of hourly data.
Months begin with the first set of a block.
If a block is not 2 filied when a month is completed, the remainder of the block is filled with nulls. The collation sequence organizes the data for efficient retrieval. For one instrument over an entire record period 2. For all instruments over one time interval. Unfortunately, the ideal collation sequences for the two types of requests are mutually incompatible.