Pro/Venix and Y2K
SHOPPA at trailing-edge.com
Fri Nov 27 02:50:34 AEST 1998
The following exchange recently took place on comp.sys.dec.micro/
vmsnet.pdp-11/alt.sys.pdp11. In it, I made the guess that PRO Venix
is based on 2.9BSD - does anyone know more details about its heritage?
Donato B. Masaoy III wrote:
> Came into a Pro 380 and loaded Venix as a means of tyring out Unix.
> Noticed that at 2000 it sets itself back to 1970. Is there fix for this?
> Should I bother?
The PRO 380 Time-Of-Year clock has two modes:
1. BCD mode, where the year is stored in two decimal digits.
2. Binary mode, where the year is stored as at least 7 bits (more
likely 8 bits - it's been a couple of months since the changes
were implemented the fix in RT-11's PI.SYS, PIX.SYS, and
SETUP.SAV to make it Y2K compliant.)
When in BCD mode, 31-Dec-99 rolls over into 1-Jan-00, and the
clock keeps accurately ticking. Venix evidently chokes on this
and doesn't interpret "00" as "2000".
As Unix is incapable of representing times internally outside
the range 1970-2038, the obvious fix is to interpret BCD years
in the range 70-99 as being in the 1900's, and the BCD years
in the range 00-38 as in the 2000's. This is, for example,
how BSD2.11 interprets the two-digit 11/93 or 11/94 clock year.
Of course, finding the sources to Pro 380 Venix to implement
the changes may be difficult. The PUPS archive has a version of 2.9BSD
patches for the Pro, and if you're lucky Venix may be close
enough that you can use the Pro-specific clock sources to patch
your kernel binary. In the 2.9BSD Pro patches, the clock
code is in "/sys-dev/prostuff.c", and begins:
/* These two fuctions handle the pro 300's clock
* This code is defunct at the end of the century.
* Will Unix still be here then??
Tim Shoppa Email: shoppa at trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
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