RX02 Bootstrap

From: Ben Franchuk <bfranchuk_at_jetnet.ab.ca>
Date: Thu Feb 28 16:10:22 2002

Andreas Freiherr wrote:
>
> Ben,
>
> let me continue to be picky, as I often learn new things by trying to
> really and thoroughly understand how something works. ;-)

This example was made as a general example not a real machine.

> Will work for some, but not all, media. RL01/RL02, for example, can be
> done this way. I have seen a four-word bootstrap that indeed only
> consists of putting the required command into the CSR and then WAITing.
> Operating instructions: "let the program run for a few seconds, then
> HALT and restart at address zero."

The front panel is your friend.:)

>
> Will the IRQ really clear the halt F/F, causing the processor to resume
> running? - I need to get my machines running soon, memory is fading...

While this was not a real example, often a bootstrap I suspect could use
of
tricks with the hardware after reset.
 
> Other disk types, such as the RXs, require loading of more than one
> sector, and not many controllers are like the RK11 in that they
> automatically increment sector counters.

But did not the big disc controllers have front panel as well?
I always used paper tape on a PDP-8 with a front panel.
 
> What I wanted to point out is that you need to have some kind of
> "handler" for the reset button if you want your PDP-11 to have a life
> after that. I might call this "handler" a "bootstrap" :-) - And I
> intended to have a PDP-11 processor execute the instructions, not a
> human! ;-)

One other factor with device drivers like on the PDP-8 they had to be
small and support swapping all of core to and from disk.

> --
> Andreas Freiherr
> Vishay Semiconductor GmbH, Heilbronn, Germany
> http://www.vishay.com


-- 
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html
Received on Thu Feb 28 2002 - 16:10:22 GMT

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