At 06:51 AM
7/12/2012, Johnny Billquist wrote:
What
31-DEC-99 gives you from TECO:
.R TECO
*^B==$$
16375
(12 * 32) + 31) * 8 = 3320
(1999 - 1970) & 7 = 5
3325 DEC, 6375 OCT plus 4096 gives 16375.
You can't tell what this really means (it could be 1983, 1991, or 1999)
but that's an OS/8 failure, not TECO.
No. That is a failure in TECO. OS/8 obviously knows if it is 1975,
1983, 1991 or 1999. The information is not preserved in TECO. TECO fail.
It's also a failure in OS/8. 12 bits gives you potentially 11 years of
date range (4096 days at 365 days per year); the 14 bits they're using
could have given almost 45 years of date range if DEC had decided to
change the date format to be days since 1-jan-1970. It would have made
sense given that the current format has so many problems (can't be
compared using simple arithmetic, for example).
Ultimately, it was a failure in DEC to allow for the continued use
of these operating systems under discussion for a large number
of years. So while RT-11 was easily extended to support dates
until 2099, some of the other operating systems which ran on
16 bit (or fewer) hardware systems had date support for a
much shorter number of years.
So pointing out the failures might be a first step. Fixing the
code is the next step and I have yet to note any such proposal.
Prior to 1990, it was easily justified at the time in almost all
companies to support dates (and almost everything else) for
as limited a time as the customer would accept for the next
few years. So the attitude was not limited to DEC.
Even today, there does not seem to be any interest by hobby
users of RT-11 to supports dates after 2099 (on the basis
that they will be dead in most cases), let alone any of the
other PDP-11 operating systems.
Jerome Fine
