Front panel switches - what did they do?

Jon Elson elson at
Tue May 24 11:50:35 CDT 2016

On 05/24/2016 11:32 AM, Swift Griggs wrote:
> On Tue, 24 May 2016, Jon Elson wrote:
>> The PDP-5 I did a fair bit of work on needed a bootstrap program loaded
>> in from switches, it had no internal ROM for that.
> How long did it usually take to do it?
We had contests, I think some people got under 15 seconds.  
All from memory, of course!
>> And, whenever a program crashed, it generally wiped the entire contents
>> of memory, so the boot had to be reloaded by hand.
> Uhh, ouch! That'll learn ya! You'd better be a careful coder, then I
> guess. Sheesh.
This could happen on any computer, but it seemed the PDP-5 
(and PDP-8, same instruction set) were most likely to do 
this.  Actually, the PDP-5 had the instruction counter as 
location zero of memory, so it may have been more prone to it.


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