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[541] [[ProDOS]] の[[日時形式]]。

[6] 関連: [[西暦2000年問題]]

- [542] [CITE@en[Time formatting and storage bugs - Wikipedia]], [TIME[2023-11-24T03:13:21.000Z]], [TIME[2023-11-25T07:09:30.539Z]] <https://en.wikipedia.org/wiki/Time_formatting_and_storage_bugs#Year_2040>
- [543] [CITE[ProDOS 8 Technical Note #28]], [TIME[2009-04-30T19:44:01.000Z]], [TIME[2023-11-25T07:09:44.626Z]] <http://www.1000bit.it/support/manuali/apple/technotes/pdos/tn.pdos.28.html>

[544] [CITE@en-US[ProDOS 2.5 Alpha 8]], [TIME[2023-01-21T22:14:08.000Z]], [TIME[2023-11-25T07:10:33.840Z]] <https://prodos8.com/releases/prodos-25/>

[3] >>544

>Year has been expanded from 7-bits (127 years) to 10-bits (1,024 years) to allow date support until the year 2924.
[I[There is still a year 2040 problem where the 24-bit timer on the Apple IIgs will wrap around to 1900.]]

[5] >>544

>year = 0-4095

[2] >>544

>
-    The [B[Legacy]] data format uses 4 bytes [I[(32-bits)]] to store the date and time.
-    The [B[Extended]] data format uses 4 bytes [I[(32-bits)]] to store the date and time for [B[directory listings]].
-    The [B[Extended]] data format uses 6 bytes [I[(48-bits)]] to store the date and time for [B[global entries]].

[1] >>544

> milliseconds*4

>    milliseconds = 0-249

[4] >>544

>    month = 2-13

>
    month +1 keeps top 3 bits from being 0,
    differentiating it from pre-2.5 format

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