<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div><font class="Apple-style-span" color="#000000">Circa </font>Wed, 3 Jun 2009 22:46:54 +0200, SPC <<a href="mailto:spedraja@gmail.com">spedraja@gmail.com</a>> asks<br><br></div><blockquote type="cite"><div>Is SIMH capable to load and execute ROMS which could execute later a<br>bootstrap and so ?<br>Would be possible to create one general device named ROM...<br></div></blockquote></div><div><br></div>Depending on exactly what you are up to...<br><div><br></div><div>The KA630 CPU Technical Manual has a description of what the Q-bus PROM footprint looks like.</div><div><br></div><div>See page 3-17ff at: <a href="http://bitsavers.org/pdf/dec/vax/630/EK-KA630-UG-001_Feb86.pdf">http://bitsavers.org/pdf/dec/vax/630/EK-KA630-UG-001_Feb86.pdf</a></div><div><br></div><div>With OpenVMS VAX (or MicroVMS), it is VMB that looks for this signature and not simh, and VMB that calls into it.</div><div><br></div><div>The old-time hack was an MRV11, but other gizmos have deliberately left that signature in Q-bus memory space, too.</div><div><br></div><div>With the PDP11 pieces, I don't know. But a quick search of the simh source pool might show a detail or two. The PDP-11 boxes I've dealt with either executed code off of a device boot ROM (halt, set the toggles for the CSR address, load and go), or you ended up toggling the whole bootstrap in from the switches. </div></body></html>