Y2K problem for days-between-dates for TI-84 series calcs

[Don Shepherd]

The TI-83/84 series calculators days-between-dates function has always had a very limited range: years 1950 to 2049. TI is apparently not worried about this, I suppose because 30-year mortgages begun this year would terminate in 2047. But in three years, things may get dicey for them. I doubt that very many financial-types use TI calculators for their work, but if they did they will run into a Y2K-type problem in the near future for the 83/84 series.

I doubt that the TI financial calcs have this problem.

Fortunately for us, HP always got this right.

[Maximilian Hohmann]

(05-07-2017 01:02 PM)Don Shepherd Wrote:  I doubt that very many financial-types use TI calculators for their work...

Whenever I was visiting a bank or insurance company about a loan or pension or other capital building scheme (not very often), they did not use a calculator, but either an Excel spreadsheet or some dedicated software running on a notebook computer. Which I think is due to the fact that they have to hand out in print whatever they offered you. The last time he burnt everything on a CD and gave me that.

[Dave Britten]

(05-07-2017 01:29 PM)Maximilian Hohmann Wrote:  

(05-07-2017 01:02 PM)Don Shepherd Wrote:  I doubt that very many financial-types use TI calculators for their work...

Whenever I was visiting a bank or insurance company about a loan or pension or other capital building scheme (not very often), they did not use a calculator, but either an Excel spreadsheet or some dedicated software running on a notebook computer. Which I think is due to the fact that they have to hand out in print whatever they offered you. The last time he burnt everything on a CD and gave me that.

Personally, I'd go for a 19BII and 82240 printer.

[matthiaspaul]

Don, if you can document this in better details, this might be interesting info to be included in this Wikipedia article:

https://en.wikipedia.org/wiki/Time_forma...orage_bugs

Greetings,

Matthias

[Don Shepherd]

(05-08-2017 12:13 AM)matthiaspaul Wrote:  Don, if you can document this in better details, this might be interesting info to be included in this Wikipedia article:

https://en.wikipedia.org/wiki/Time_forma...orage_bugs

Greetings,

Matthias

Thanks Matthias.

That widipedia page already contains this:

Follow-on problems caused by certain temporary fixes to the Y2K problem will crop up at various points in the 21st century. Some programs were made Y2K-compliant by continuing to use two digit years, but picking an arbitrary year prior to which those years are interpreted as 20xx, and after which are interpreted as 19xx.

For example, a program may have been changed so that it treats two-digit year values 00–68 as referring to 2000 through 2068, and values 69–99 as referring to 1969 through 1999. Such a program will not be able to correctly deal with years beyond 2068.

I wouldn't exactly call TI's method a "bug"; it does calculate days between dates correctly within its abbreviated range. I think it could more accurately be described as "shortsighted." If TI intends to continue the TI-84 line into the future, I suspect they will have to change this method in the next few years.

[Dieter]

(05-07-2017 01:02 PM)Don Shepherd Wrote:  The TI-83/84 series calculators days-between-dates function has always had a very limited range: years 1950 to 2049. TI is apparently not worried about this, I suppose because 30-year mortgages begun this year would terminate in 2047.

Fourty years ago the TI58/59 Master Library ROM included a calendar program that worked with any valid Gregorian year between 1582 and (I suppose) 9999.
Sic transit gloria mundi.

Dieter

[Don Shepherd]

(05-08-2017 07:05 AM)Dieter Wrote:  Fourty years ago the TI58/59 Master Library ROM included a calendar program that worked with any valid Gregorian year between 1582 and (I suppose) 9999.
Sic transit gloria mundi.

Dieter

Thanks Dieter, that is interesting.

I guess TI didn't see a need for including an extended date range in the dbd() function on the 83/84, possibly because they didn't think that students would require that in what is primarily a graphing calculator. And I guess they would have been correct because I am not aware of this being raised as an issue before.

Perhaps sometime between now and 2049, assuming the TI-84 is still being produced at that time (and given how technology is moving so quickly, that is a large assumption), they may add a dbdx() function with an extended date range.

[Dave Britten]

(05-08-2017 10:48 AM)Don Shepherd Wrote:  Perhaps sometime between now and 2049, assuming the TI-84 is still being produced at that time (and given how technology is moving so quickly, that is a large assumption), they may add a dbdx() function with an extended date range.

It wouldn't be difficult for them to extend/shift the year range in an OS update. I think every model that's had date functions uses flash ROM for firmware. I'll have to test my 89 and 84 CE, though. I could have sworn they use 4-digit years.

[Eddie W. Shore]

(05-07-2017 01:02 PM)Don Shepherd Wrote:  The TI-83/84 series calculators days-between-dates function has always had a very limited range: years 1950 to 2049. TI is apparently not worried about this, I suppose because 30-year mortgages begun this year would terminate in 2047. But in three years, things may get dicey for them. I doubt that very many financial-types use TI calculators for their work, but if they did they will run into a Y2K-type problem in the near future for the 83/84 series.

I doubt that the TI financial calcs have this problem.

Fortunately for us, HP always got this right.

Yes - TI needs to update their code to allow for four digit years, their days between date function is slightly outdated.

[pier4r]

(05-08-2017 10:48 AM)Don Shepherd Wrote:  Perhaps sometime between now and 2049, assuming the TI-84 is still being produced at that time (and given how technology is moving so quickly, that is a large assumption), they may add a dbdx() function with an extended date range.

Would you have thought that the ti84 would have been in the 2017 market in 2000, or in 2005, or in 2010? Sure, say, 2030 seems far away but we never know, especially due to lobbying and market forces.

[Don Shepherd]

(08-11-2017 03:31 PM)pier4r Wrote:  Would you have thought that the ti84 would have been in the 2017 market in 2000, or in 2005, or in 2010? Sure, say, 2030 seems far away but we never know, especially due to lobbying and market forces.

TI-84's continue to sell at ridiculous prices for one reason: schools strongly recommend them in part because the textbook manufacturers feature them. Schools get some price breaks when they order them, and nobody wants to buck TI. TI trains the teachers!

As long as TI keeps selling them, the system won't change. And I won't hold my breath waiting for TI to update the DBD range; students don't use that.