Even more PDP-8/A weirdness (was: Re: PDP-8 diagnostics SR settings?)
rick at rickmurphy.net
Sat Sep 12 18:27:56 CDT 2015
At 12:31 PM 9/12/2015, Charles wrote:
>Update: The first thing I tried was removing and reseating the boot
>ROMs (465A2/469A2), since they did not use good machine-tooled sockets.
>Now the boot loader performs normally, no incorrect locations, and
>OS/8 boots from Drive 0 whether using the boot key or manual start at
>So of course, ANOTHER new problem shows up... OS/8 boots and runs,
>will run PFOCAL, BASIC, give directory listings...
>But when I hit a Ctrl-C (for example, during a directory listing),
>Drive 0 Ready goes out, the Fault lamp lights and OS/8 halts. The last
>instruction showing on the display is 07605, 6213 (CDF CIF 1).
>I can hit the boot key and as soon as the drive becomes ready again,
>presumably relocating track 0, the system boots back to the "." prompt.
A halt at 7605 means that OS/8 was unable to write the keyboard monitor
onto the system device scratch blocks.
The fact that the drive is dropping "Ready" seems to be what's causing
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