Re: Y2K ProDOS 8 (2.0.3)

[Andy McFadden <fadden@fadden.com>]

Willi Kusche <willi@wilserv.com> wrote:
>     The year field is a 7 bit field.  So it can hold values from 0 to
> 127.  The Technical Note says that values 100 to 127 are invalid.  It
> is my contention that they should be valid and should represent the
> years 2000 to 2027.
> 
>     ProDOS versions 2.0.x will ensure that the year field is in the
> range 0 to 99 when reading the clock on a IIgs.  Earlier versions do
> not change the year field when reading the clock on a IIgs.

ProDOS 8 and GS/OS do slightly different things.  Here's a comment from
NufxLib:

/*
 * Dates and times in a NuFX archive are always considered to be in the
 * local time zone.  The use of GMT time stamps would have been more
 * appropriate for an archive, but local time works well enough.
 *
 * Regarding Y2K on the Apple II:
 *
 * Dave says P8 drivers should return year values in the range 0..99, where
 * 40..99 = 1940..1999, and 0..39 = 2000..2039.  Year values 100..127 should
 * never be used.  For ProDOS 8, the year 2000 is "00".
 *
 * The IIgs ReadTimeHex call uses "year minus 1900".  For GS/OS, the year
 * 2000 is "100".
 *
 * The NuFX file type note says the archive format should work like
 * The IIgs ReadTimeHex call, which uses "year minus 1900" as its
 * format.  GS/ShrinkIt v1.1 uses the IIgs date calls, and so stores the
 * year 2000 as "100".  P8 ShrinkIt v3.4 uses the P8 mapping, and stores
 * it as "0".  Neither really quite understands what the other is doing.
 *
 * For our purposes, we will follow the NuFX standard and emit "100"
 * for the year 2000, but will accept and understand "0" as well.
 */

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