IIcx Time Problem — #20

Post #20 by Mac128

Source Forum	IIcx Time Problem — #20
Category	Hardware
Post Date	Mon, 9 Feb 2009 - 04:50
Original URL	https://68kmla.org/bb/threads/iicx-time-problem.8740/

Post

Its definately true...i've experimented with my older Macs, and they have no problems recognising any time between 1920 and 2019. The only thing is that after 2019, all our old Macs will roll back over to 1920.

Isn't that based on the operating system? My understanding is from this rather confusing Apple tech article:

All Mac OS date and time utilities have correctly handled all issues related to the year 2000 since the introduction of theMacintosh. The original date and time utilities, introduced with the original Macintosh 128K in 1984, used a 32-bit value

to store seconds, starting at 12: 00: 00 a.m., January 1, 1904. Since Apple used a 32-bit value to store seconds, this

means that the last date represented in this 32-bit value is 6: 28: 15 a.m. on February 6, 2040. The current date and

time utilities, documented in Inside Macintosh: Operating System Utilities , use a 64-bit signed value. This covers dates

from 30081 B.C. to 29940 A.D. For further reference, see Inside Macintosh: Operating System Utilities , Chapter 4, or

its predecessor, Inside Macintosh Volume II .

The Date & Time control panel constrains user entry to dates between January 1, 1920 and December 31, 2019. This

feature was added for compatibility with the original Macintosh System 6 General control panel, which limited dates so

there would be no ambiguity about a 2-digit year (which was all that was normally displayed on a US system). The Date &

Time control panel uses the Script Manager function ToggleDate. ToggleDate was enhanced in 1989 to have an

option that limited dates to the 1920-2019 range so that it could be used by the General control panel and other control

panels that wanted to have a date widget that operated in the same way. You can set a date beyond 2019, up to the year

2040, by using the Macintosh Toolbox call SetDateTime().

That all Macs since the 128K have the capability of running the date up to 6: 28: 15 a.m. on February 6, 2040. The caveat is that from System 6.0.3, the control panel limited the maximum date to December 31, 2019 (with an option to extend to 2040). That persisted until an update to System 8 extending the maximum date to to 29940 A.D.

Doesn't this mean that Macs running System 1.0 through 6.0.2 will have a maximum date of 2040? Is it possible to confirm? Under System 3.2 setting the clock ahead to 20 does not guarantee it is not 1920.

I wouldn't have thought it before, but if not, that means the 68K Macs only have about 10 years of useful life left. I would feel much better about it if I knew the useful end date would last at least as long as I do.