On Tue, 20 Jul 2004 06:43:51 -0700 "Robert Armstrong" <bob(a)jfcl.com> wrote: I would 'vote' for the above. What I am looking at building is something to toggle in machine code. I haven't bootstrapped a PDP-8 since the early 80's and the level of system I would prefer to make is a row-of LEDs type system to run very simple code on. Maybe I should get a real PDP-8 sometime, but it would take up a lot of space. I have aprox. 100 6100 chips in original tubes, and have had the idea of designing some sort of a partial 'kit' for sale. The SBC6120 is definitely the 'practical' direction for a kit project to go in, a row-of-LED and switch bank project would be more of a novelty flashy-desk-toy kind of thing. The SBC6120 fills this role admirably. The idea of running FOCAL code has some appeal to me. I probably have a homework assignment or two from 1979 filed away somewhere that is FOCAL code (yes, the Intro Computer Programming Course I took in undergraduate college in 1979 used FORTRAN and FOCAL as the target languages). With only a 4K memory map, 'Mass storage' would amount to battery backed up CMOS memory, sort of psuedo-core I suppose. The 6100 processor is one of the simplest chips out there to casually 'breadboard' together into a primative computer. It has probably the most relaxed clocking requirement of any microprocessor ever (certainly the most relaxed of anything realistically available today). The 12 bit data path is the most 'difficult' factor involved, since all the garden-variety micros that common peripheral chips and memory are built around have an 8 bit path.

Here's my 2 cents: I think quite a substantial effort has been in replicating/reproducing the mystical "blinkenlights" effects of a real PDP8..culminating in the FP6120, a brilliant effort I must say (although price is a bit steep for me personally). Perhaps it's time to veer away from the "lights and switches" track. Perhaps I can suggest this: Use the 6100 to build a minimal system. Memory to the max; i.e. 32kW (battery backed to emulate core). A standard console. No lights no switches to save costs. No IDE/ATA, again to save cost. With the money saved in the IDE interface we can plunk in more core (err..SRAM) to emulate storage, I dunno, say a dual TU56 worth of storage? 512kW. So now we have PDP8/E with a maxed out core and a dual TU56. Now, I'm just thinking as I type.. Just thought of cool idea. Why don't we add an Omnibus slot into our little 6100-based PDP8? That'll be cool to the neo-hardware hackers!! Or maybe we increase that to 4 Omnibus slots, so that we can test existing boards...RK8E, etc. Heh. How about a 10/100Mbps Omnibus board? :-) Or a Omnibus sound card? Wow! The list is endless... Wonder if you could squeeze a rudimentary TCP/IP stack below 32kW? You know what I'm getting at.. :-) Run www.pdp8.org with a real PDP8!! I think I've rambled enough... Robert Armstrong wrote: -- /wai-sun