I've always wanted to know more about the SDS 940 project since its a relative to my SDS Sigma 9. If you know of any of the papers on the hardware, and OS they created I'd appreciate some pointers to where I could read them. Thanks!
On Wed, May 4, 2016 at 2:00 PM, Mark Kahrs <[email protected]> wrote: > Al mentioned the 940 so I thought I would fill in the details: > > Lichtenberger and Pirtle extended the hardware to include a page map: 14 > bits of VA was divided into 3 bits of page # and 11 bits of offset. The 8 > pages were held in 2 x 24 bit words divided into a 8 x 6 bit page numbers. > The high order bit of the mapped page number served as the Read Only bit. > This meant that "subsystems" (a.k.a. applications) could be shared between > users. > > Additionally, the instruction set was protected against users with specific > prohibition against using the I/O instructions. > > This was described in FJCC 1965 with modifications done in 1964. >
