Run from SSD or Hard drive?

[James Zeun]

Is it possible it run the PiDP8 SD image from something other than an SD card? I had my PiDP8 set up as a Linux file server a few years ago. However after a year the SD card died, maxed out on read / writes.. I’d love to set it up again, but have it boot off the SD then run off a hard drive. 

Many thanks

[Heinz-Bernd Eggenstein]

Yes, you can with almost all models! The most recent Raspi 4 for example can boot straight from an USB device, without any SD card sitting in the slot, once you set some flags in the EEPROM that stores the bootloader configuration. 

The bootloader capabilities and configuration evolved quite a lot over the years of Raspberry Pi hardware development, and if you want technical infomation, this is the definitive guide:

https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#raspberry-pi-4-boot-eeprom

and

https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#usb-mass-storage-boot

and related chapters in the same document.

There are several HOWTOs on the internet, but again, the latest Raspi4 is different in this respect than earlier models so make sure to pick a tutorial that matches your board.

Cheers

HB

[James Zeun]

Many thanks for the response! I know its possible for the pi to boot from another drive other than SD, well more so in the later models. I THINK the model 2B+ can do it, but has to boot off SD first.

Anyway I’m getting off track, to be a little more specific I wonder if it was possible to boot the current PiDP8 SD image from something other than SD card. See I know the simh emulator does scan the USB ports for disk images and I wondered if that might cause issues.

Many thanks

[James Zeun]

Just skimming the first link you sent..If my understanding is right, I need a boot.bin file on the SD image. Then write the PiDP8 image to the hard drive of choice, instead of an SD card.

I’ll have to read further, but wow, that’s much simpler than I was anticipating 

[Steve Tockey]

"See I know the simh emulator does scan the USB ports for disk images and I wondered if that might cause issues."

You should be able to set it up in a way that won't cause any issues. First, the PiDP-8/I doesn't even scan the USB media unless you explicitly use the SingStep switch. Second, on scanning, it is only looking for a limited set of file extensions:

*.pt for paper tape images

*.dt for DecTape images

*.rx for RX01/RX02 floppy disk images

*.rk (or, *.rk05) for RK05 hard disk images

and maybe *.rl for RL01/RL02 images

Just don't have any files with these extensions in the top-level directory on your boot drive and you should be fine. The PiDP/8/I scans all mounted USB media, so putting your simulated images on a separate thumb drive will still make them findable.

-- steve

[James Zeun]

Steve, thanks! for the info! 

Ok then, I guess the only way to know is to try! I’ll report back later 

[James Zeun]

Just wanted to thank everyone who responded, was really appreciated.

I'm downloading the latest SD image from tangentsoft.com and going to try writing it to a spare SSD I have, I wasn't sure whether to use a mechanical drive. As I want to try and avoid another MAX read/write failure as before. But I guess the only way to find out, is to try. The PiDP-8 has been sitting on a shelf looking pretty for the past two years and I'd prefer to have it alive and doing something. Maybe I can finally get in to OS/8.