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发表于 2005-12-30 23:36:15
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There are several good ways to manage integer serial numbers. The most obvious is just to use a counter: increment the serial number by one each time you modify the file. Another method is to derive the serial number from the date. For example, you could use the eight-digit number formed by YYYYMMDD. Suppose today is January 15, 1997. In this form, your serial number would be 19970115. This scheme allows only one update per day, though, and that may not be enough. Add another two digits to this number to indicate how many times the file has been updated that day. The first number for January 15, 1997 would then be 1997011500. The next modification that day would change the serial number to 1997011501. This scheme allows 100 updates per day. It also has the advantage of leaving you an indication in the zone data file of when you last incremented the serial number. h2n will generate the serial number from the date if you use the -y option. Whatever scheme you choose, the serial number must fit in a 32-bit integer. |
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