yet another pdp-8 in a fpga, but this time running tss/8

Congratulations are in order! This is certainly a different approach approach taken by SIMH. Many times, using two different methods will highlight problems that each one has since the results should be identical. By this time, SIMH is likely to be getting almost everything right, but there always seems to be isolated cases. As most of the classiccmp list knows, my addiction is the software on the PDP-11, mostly running RT-11, but of late making the same program also run under RSTS/E, TSX-Plus and RTEM. From that point of view, can you possibly answer two questions? (a) Without being very accurate, and based on your experience with the PDP-8, how long do you think that it would take you to implement a PDP-11? Just a rough estimate in months or years! (b) About how fast might the FPGA solution be compared to something like a PDP-11/93? Again, just a rough estimate like 10 or 20 times as fast. One advantage of SIMH and Ersatz-11 is that when a faster X86 CPU arrives, the emulation is automatically faster. Plus there is no additional FPGA hardware required for each additional user, just a standard PC which are usually generally available for other purposes such as e-mail. Note, however, that terminal emulation such as a VT100 may not be automatic, especially under Ersatz-11 for 132 character mode text lines in full screen mode. I had to test a number of video cards before I found one that managed to support 132 character text lines using the full screen mode. As for how fast the emulation can be, my preliminary tests on a 2.66 GHz Intel 8200 core 2 duo CPU is about 100 times the speed of a PDP-11/93 for just the CPU speed and about 200 times the hard disk speeds of most Qbus EDSI or SCSI hard drives using SATA II 300 GB drives. And talk about crazy, how much am I addicted to RT-11 when a Y3K bug fix is actively being researched as to what the technical problems will be? Or fixing bugs that no one else even knows about, let alone cares about? Any idea why you did an FPGA implementation of the PDP-8? Jerome Fine