2 Apr
2002
2 Apr
'02
8:55 a.m.
Ethan Dicks wrote:
I don't have one, and PC emulating a terminal
is no fun.
--- Ben Franchuk <bfranchuk(a)jetnet.ab.ca> wrote:
But could you hand wrap 100 boards. In some ways the old PC's like the
PDP-8 were more dence than today's computers, comparing the size of the
active parts with the overall pc size.The wire wrapping of Flip/Chips
made for some dense computers.
Ethan Dicks wrote:
Here in a city of 10E+06 people, about all we have left is Rat Shack,
too. When I was a kid, there were lots of surplus places and new
parts places to shop at (c. 1978). They've all gone mail-order and
shut up their sales floors for cost reasons.
I do most of my component shopping online these days (BG Micro, Mouser,
Digikey, Allied...)
While I can recommend a real PCB if the setup
costs and the per-sq-in
costs are not killing you (price an Omnibus or Unibus-sized 4-layer
board, complete with gold fingers!)...
Out here the only parts store is Radio Shack or wait 6 months to get to
a larger city. Thus mail order and internet shopping works for me. With wire wrap I would spend too much time
hunting for bad
wires/connections or paying $$$ for parts. A PCB is a simple upload of
my gerber and drill files.
Simple upload, yes, but for larger designs, it starts to get pricey
again until you make things in quanity. I did several runs of a two-
layer Zorro-II board (GG2 Bus+) - q. 100, they cost around $15-$20 each,
including spreading out the setup charges. That's with a lot of gold
(100-finger Zorro edge, plus a full 16-bit ISA edge), and a foot-long
PCB. If only I hadn't ordered that last run of boards... :-( At q. 25,
they were significantly more expensive. At q. 5, ISTR they were over
$50 each. I think you missed my point... yes, the demoware
packages let you lay
out a 3"x4" board for free.
What is the point? I don't use the demo stuff. The ONE free PCB package
for dos works well for me.
If you increase the
size of the board and keep things under 8MHz, 2 layers (and a sensible
layout) will probably be fine. A 1MHz 6502 design will probably not
require multi-layer unless you want it the size of a pack of playing
cards.
If I remember the APPLE II/g? was the first computer to use really fine
tracks for a PCB layout. It is the EDGE speed of your logic not the
clock speed that determines your noise factor. Also a BIG board is easy
for people who are all thumbs.
That would have been fun.
Well I can sell the
plans cheap... No I can't , they are free.
Well I
don't but remember with out the proper I/O a pdp-8 is NO FUN.
True. I already know how to make a front panel pulse the lights.
Driving a TTY is a lot more fun. Yep. Been a happy customer for years. Thinking of
placing an order
this week.
But some parts you still need to get elsewhere. A 20 pin PLCC socket and
IDC headers come to mind from my last project.
--
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html