booting os/8

Bill Gunshannon bill.gunshannon at
Wed Mar 22 18:25:30 CDT 2017

From: cctalk [cctalk-bounces at] on behalf of Don North via cctalk [cctalk at]
Sent: Wednesday, March 22, 2017 5:30 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: booting os/8

On 3/22/2017 10:47 AM, Bill Gunshannon via cctalk wrote:
> ________________________________________
> From: cctalk [cctalk-bounces at] on behalf of W2HX via cctalk [cctalk at]
> Sent: Tuesday, March 21, 2017 11:49 PM
> To: General Discussion: On-Topic and Off-Topic Posts (cctalk at
> Subject: booting os/8
> Hi folks,
> I have a PDP-8/e that I've been working on. I have completed construction of AK6DN's RX01/02 emulator. I got to the step tonight where I was trying to boot an OS/8 disk image and nothing was happening. I realized that I do not have the bootstrap diode board in my 8/e so begin the bootstrap triggered by the "SW" switch.
> Does anyone have the program I can toggle in for the bootloader? What I found is somewhat confusing. Here is a discussion on this topic.
> It seems one fellow was attempting to edit/improve the bootloader of another fellow. I was wondering if anyone has distilled this into something simple. At the moment, I care only about booting from RX01-Disk0.
> Any pointers greatly appreciated. Thanks
> Eugene W2HX
> ___________________________________________
> Well, I am sure glad someone posted this.  I had never heard of the work done by AK6DN and have considered
> looking into such a project in the past.
> So, has anyone looked at someting sililar for RL drives?
> bill

Look here:   for info on my Arduino based RX02 emulator using a microSD card.
Works on RX11/RXV11/RX8E as RX01, RX211/RXV21/RX28 as RX02. Passes DEC hardware diagnostics.

Reinhard has done an FPGA based RL01/2 drive emulator, see:

aka AK6DN

I saw that.  I ordered a set of boards from OSHPark today.  Once they come I will see about ordering the
parts and building at least one.  I may wish I had more controillers. :-)

I will take a look at the FPGA solution.  But I still have to ask, is there any reason why it could not be done
with an Arduimo like the RX emulator?  I haven't researched it deeply, but I never thought the RL drive
itnerface was all that complex.


More information about the cctalk mailing list