Seagate hard drive for PDP-11/23+

[retrobits]

(also posted on CCTECH)

Howdy,

I love the dual RL02 drives on my PDP-11/23+. It's great fun to hear them spin up, and they are a neat conversation piece. However, I fear that ongoing operation will eventually lead to their demise (as with all things). I'd like to move to a (slightly) newer technology.

My goal is to:

1. Purchase a Seagate ST-225 or ST-251 hard drive in working condition.
2. Build a cable and interface assembly as described at http://home.windstream.net/engdahl/rqdx3.htm, and put the drive in an external case/PSU.
3. Properly insert my RQDX3 (in my stock, but not in the machine) into the PDP, and connect to the drive.
4. Use the ZRQCH0 utility in XXDP (perhaps loaded from a TU58 emulator) to format the drive as a RD31 or RD32 (depending on the Seagate model).
5. Determine how to boot from RT-11, and perhaps TSX-Plus.

Is this doable? Will the KDF11-BA built-in bootstrapper ROM boot from a RQDX3? Also, my RQDX3 card is assumed working, but untested. Is there any way to test the controller board functionality without having a drive attached?

Thanks for any thoughts!

- Earl

 

[Lou - N2MIY]

Yes, all that works. I did all that almost exactly, see here: http://www.vintage-computer.com/vcforum/album.php?albumid=54&attachmentid=2444 . However, I wire-wrapped something a bit more sophisticated that Jonathan's breakout cable. In order to also connect floppy drives, I wire wrapped most of an M9058: http://www.dunnington.u-net.com/public/RQDX/M9058_schematic.pdf . On rare occasion, an M9058 or BA23 signal distribution board shows up on ebay, which make life easy.

To know if your 11/23+ has the MSCP bootstrap, you have to tell us the rom numbers. The roms are in the upper right corner when the fingers are down and components are facing you. The earliest 11/23+ processor did not have the MSCP bootstrap. I had one once and upgraded it: http://www.vintage-computer.com/vcforum/album.php?albumid=49&attachmentid=2719

However, I believe that the RL02 is a high performance, fast, and reliable drive. It is very nice to be able to switch packs depending on what you want to play with. Originally all I had were Micro pdp-11s with RQDX1 and RQDX3, but now I prefer the flexibility of the RL drives.

Lou