Why blinkenlights ?

[Dave McGuire]

On Mar 20, 2007, at 4:18 PM, Jos Dreesen wrote:
> I am currenly contemplating what kind of IO to put on my coming  
> i8008 system : what is it that makes blinkenlights (i.e. leds and  
> switches ) seem so attractive ?
>
> It must be about the worst possible way to interact with a computer...

   Uhh...they're *easy*.

> So why is it then  that almost all early micros had them ?

   Debugging.  I've debugged a WHOLE LOT of code on my Imsai's front  
panel in the mid-1980s.  Nothing is simpler (IMO) as debugging via a  
front panel

> a 7segment display with keyboard ( as in a H8) is clearly more  
> usable, and would have cost nothing more. Or were early eproms (for  
> the monitor program) that expensive ?

   Well, there were no such things as EPROMs (or chips at all, for  
that matter) on the earliest lights-and-switches machines.  I think  
single-stepping and debugging of very low-level stuff is much easier  
with a lights-and-switches front panel.  Numeric displays are nice,  
but I find many keypad interfaces to be very cumbersome.  The H-8  
keypad is probably one of the nicest I've seen (it seems to make the  
most sense anyway) but even it isn't as clear and unambiguous as "set  
the switches to the address you want, and press 'load address'".

   For today, though...blinking lights are Just Plain Cool.

           -Dave

-- 
Dave McGuire
Port Charlotte, FL