Date   : Thu, 23 Mar 2006 09:56:40 -0000
From   : "David Hunt" <dm.hunt@...>
Subject: Re: Web site: Mainly Master 512

> >> A curiosity I came across while doing this: You cannot enter dates into
> >> M512 DOS-Plus earlier than 1980.
> >
> > That would make sense - in the disc catalogue (FAT12/16/32) dates are
> all
> > stored relative to 1980 (7 bits, thus 2108 is going to be a painful year
> > for
> > Windows) so you'd want to clamp it to 1980 to stop negative datestamps.
> 
> Agreed. There is some logic in this.
> 
> >> However, the date stored in DOS-Plus counts from
> >> the beginning of 1978.
> >
> > That would not make sense,
> 
> I cannot see any sense in it either, which is why I asked. It is the way
> the
> date is stored, however. Look at it if you like. The value (in M512 DOS-
> Plus
> 2.1) is a word variable stored at 1197:005F
> 

Perhaps it is a remnant of CP/M i.e. 1-1-1978, isn't DOS Plus a descendant
of CP/M 86 which in turn is a descendant of CP/M. I'd imagine this was done
for compatibility with PC-DOS & MS-DOS whose dates start at 1-1-1980. ???

Dave ;)