For quite some time now I have been designing a computer that looks like a
mainframe from the early 70s -- Many toggle switches and lamps, and a large
cabinet. It's CPU will be a Z80, but the CPU control panel will be
controlled with a PIC. Basically, the system will be built out of about 5 8"
high x 19" rack panels, 1 each for the Power-supply, RAM, ROM, I/O and CPU.
I know this isn't directly PIC related, but, shucks, there are a bunch of
smart people here :)

My questions:

1) The system bus will need to be around 32 inches long. The CPU/bus will be
running at 10 MHz. Will I have any problems? I am planning to use a 50 wire
ribbon cable with 50 pin IDC connectors stopping off at each module (rack
panel).

2) Where could I get toggle switches with wide, long, flat actuators, like
those used on the PDP/8? I am looking for switches that will line up nicley
in a horizontal row. I would need to have switches that support ON/OFF,
MOMENTARY/OFF and MOMENTARY/OFF/MOMENTARY positons. I would prefer switches
with a contact for the OFF position too, so that I can use a flip-flop for
debouncing, rather than loading down the PIC with debounce timing.

3) Does anyone have a paper-tape reader for sale for a reasonable price? I
wish I could use punchcards, but finding a punchcard reader that I would not
feel guilty about butchering would be hard, and finding a punch card
supplier would probably also prove problematic. (I can cut my own paper
tape)

I have been designing this thing for some time, and finally am accumulating
enough money to build it. I want it to have incandescant lamp indicators,
just because they will look more 'magestic' when the computer is running.
The inside of the cabinet will be quite bare, as I am using semi-conductors,
not vaccum tubes :) I am mostly building the cabinet for effect -- To have a
5' tall cabinet (I am going to have a dead 20" area on the bottom of the
cabinet, available for future expansion) full of toggle switches and
flashing lamps will be quite impressive :)

The PIC in this system will control the programming interface on the CPU
panel - It will take over the bus using the Z80's DMA facilities, where data
can be manually entered into RAM using the toggle switches. The PIC will
also control the system clock when it is allowed, so that code can be slowly
stepped through for debugging. I think that a PIC will also control the
paper-tape reader if I can find one.

- Keelan Lightfoot