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Can't set year 2020

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Just wiped the HDD and installed System 7.1, and for some reason I can't set the year to 2020? Up til 2019 is fine, then it skips back to 1920. Anyone knows what that's about? I don't have a battery installed at the moment. I can't recall that I've had this issue on my other Macs.

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What a stupid idea to even have 1920 as a date. Who has files from 1920-1970?? The computers werent even out then.  They should have programmed it so it 1990-2070 or something. What a weird idea.  Yoy know mabie theres a reason for it but seriously.

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1 hour ago, Papichulo said:

What a stupid idea to even have 1920 as a date. Who has files from 1920-1970?? The computers werent even out then.  They should have programmed it so it 1990-2070 or something. What a weird idea.  Yoy know mabie theres a reason for it but seriously.

I've wondered about this too. With such constraints on space, why allow dates back to 1920? It seems like they had picked the present day as the approx midpoint of the range rather than the start. The 1970 unix epoch makes a heck of a lot more sense. 

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If they had picked 1984 as the epoch, one wouldn’t be able to write programs using standard Toolbox calls that manipulate data sets incorporating past years for eg Multiplan spreadsheets tracking economic trends, or whatever. 
 

Choosing a year reasonably far in the past made sense at the time. 80 years probably felt like more than enough without being excessive. And nobody though we’d be using these computers 36 years in the future. 

Edited by Crutch

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3 hours ago, Crutch said:

If they had picked 1984 as the epoch, one wouldn’t be able to write programs using standard Toolbox calls that manipulate data sets incorporating past years for eg Multiplan spreadsheets tracking economic trends, or whatever. 
 

Choosing a year reasonably far in the past made sense at the time. 80 years probably felt like more than enough without being excessive. And nobody though we’d be using these computers 36 years in the future. 

Thanks, this makes sense and paints the 'midpoint' decision as logical, being a general date structure vs simply for system clock and filesystem timestamps. 

 

Unix time is signed so the unix epoch is functionally a midpoint as well. (Not sure about the Toolbox's internal representation.)

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SetDate is a lifesaver and is currently on or will be on all of my classic Macs. 

 

When I was still running my lab, pre-pandemic, I hadn't yet deployed SetDate to all of the machines. It will be something I do this summer when I do my annual maintenance on them. If you want days of the week to line up with 2020, simply set your calendar to 1992. It was the most recent leap year whose calendar matches up with 2020. (Leap years are on a 28 year cycle; other years are every 6 or 11 years, depending on the calendar cycle. The World Almanac has a good explanation of how this works.)

 

By the time 2040 rolls around, we'll likely just set our clocks back to dates the Macs were new anyhow, much like how some classic car enthusiasts keep 1950s calendars in their garages to add to the "period appropriateness". 

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For 2040, we could write an INIT to patch the traps _Date2Secs and _Secs2Date to reinterpret years in the range (say) 1904-1974 as 2040-2110.

 

Should buy us another 70 years of use without actually interfering with the interpretation of almost any dates on files etc.  Yes, it would break a Multiplan spreadsheet tracking macro economic trends for the full 20th century. :)  And it would confuse apps that don’t call _Date2Secs properly but instead manipulate DateTimeRec records directly.  It also wouldn’t help in cases where an old UI widget (like the Control Panel in the 2020 case, as been well documented elsewhere) is itself imposing restrictions on date ranges.

Edited by Crutch

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