Message: 17 Date: Mon, 7 Jun 2010 16:45:00 -0400 From: Brad Parker <brad at heeltoe.com> Subject: Re: yet another pdp-8 in a fpga, but this time running tss/8 To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Message-ID: <D71821FC-0C2B-4891-ACF6-C4835EF9DBDE at heeltoe.com> Content-Type: text/plain; charset=us-ascii On Jun 6, 2010, at 7:02 AM, Jerome H. Fine wrote: with the PDP-8, how PDP-11? Just a rough estimate um. I already did that. It took a few years, but I only worked on it sporadically. It currently boots (in simulation) RT-11, RSTS V4, BSD 2.9 and V6. I have not debugged the split I & D but it's there. If you send me a RK05 image with TSX on it I'll try and boot it in sim. The last FPGA version I did had no MMU but it did boot RT-11. It had some disk problems which I have since corrected. I believe I could synthesize and run the "no mmu" version pretty quickly. The mmu version need still needs some work do make 50mhz timing. something like a PDP-11/93? Well, as I said, the no-mmu version runs at 50MHz. I could improve that. The mmu version probably won't run faster, mostly due to the 20ns rams on my fpga board. back in the day I spent a lot of time on TSS/8. I wanted to run it again :-) And, I want to work on cpu's when I grow up. I also spent a lot of time on RSTS and TSX, hence the pdp-11. I know the s/w sims are better, but I like hardware and love running h/w simulations. -brad Brad Parker Heeltoe Consulting 781-483-3101 http://www.heeltoe.com