History of OSs?

From: Jack Peacock <peacock_at_simconv.com>
Date: Tue Mar 17 12:40:13 1998

>The dos geneology is roughly...
>
>DEC PDP-8 OS/8 (pip, stat, dir)-->
RT-11/RSTS/RSX11-->
> CPM-80-->
> CPM86-->
> dos-1.0-->
>
>The VAX OS line up VMS is off the RSX11 part fo the PDP-11
tree.
>
>DOS was a translation of 8080 CPM-80 to 8086 by seattle
computer. Unix
>has been an influence but largely not that great.
>
>UNIX has it's own tree and there are to say the least many
flavors some
>of which even resemble each other.
>Allison

To add in a bit more....
CP/M comes directly from RT-11 and the RSTS tree. Even the PIP
command (peripheral interchance program) was very similar to the
RT-11 version of PIP. CP/M had a more sophisticated file system
than RT-11, but less sophisticated device drivers.

VMS was not the first virtual memory OS that DEC wrote.
TOPS-20, for the PDP-20 (that was a PDP-10 with virtual memory)
was the first virtual system. TOPS-20 was not the same as
TOPS-10, even the system calls were invoked a different way.
(My first real systems programming job was on a 20/40, a joy to
work on, tho slow by modern standards).
        Jack Peacock
Received on Tue Mar 17 1998 - 12:40:13 GMT