TD Systems TDL-11 QBUS (SCSI?) card

[Jon Elson]

On 05/04/2015 12:54 PM, Noel Chiappa wrote:
>      > From: Seth Morabito
>
>      > Well now I have egg on my face...
>
> Don't worry, you're not the only one... :-)
>
>      > No, actually it DOES work.
>
> Wow. Live and learn.
>
> Or maybe actually DMA indeed _doesn't_ work with the CPU stopped
Yes, some models of the PDP-11 do not handle DMA requests 
when halted.  I'm pretty sure the 11/45 does.
And, I'm pretty sure the 11/05 does NOT, as I recall not 
being able to perform disk requests directly from the console,
but had to write a short program that went into an infinite 
loop after commanding the controller card to perform a transfer.

Jon