31 Dec
2020
31 Dec
'20
11:45 p.m.
Thomas DeBellis wrote:
So I went spelunking and here is what DATE75 is all about.
Briefly, very early versions of Tops-10 could only handle dates between January 1st 1964
and January 4th 1975 ...
The DECtape directory format (on TOPS-10) used only 12 bits to store the date, and
between 1964 and 1975 are 4096 days.
Actually as I remember the rollover was sometime in March 1975, not January.
The DATE75 patch squeezed out three extra bits in the directory structure to allow for
32,768 days since 1/1/64.
Bob