UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Gemini 80-Bus System

TonyDuell · 14th Jun 2019, 4:55 pm

Oh, I know where most of my PDP11s are -- the large Unibus ones in rack cabinets, etc. This was just a little 2U high box with an LSI11 CPU board, RAM, and a couple of interfaces in it. Not actually the smallest PDP11 I own, but close.

From memory, my Gemini contains a CPU board, IVC board, and floppy/SASI board. The latter goes to some bridge board thing (I want to say Adaptec, but it may be Xebec or somebody else) and to an ST412-interfaced hard disk. One of the ports on the CPU board goes to that network interface I mentioned.

I also have (and have put with the machine!) the original keyboard and cable. Also what I believe was the video monitor used with it originally. Just a composite video monochrome thing of course.

Interestingly, I have a Torch-branded lightpen for the BBC micro. This consists of an inteface that plugs into the Beeb's analogue socket (DA15) and a light pen that plugs into the interface using a 5 pin DIN connector. That DIN connector is the right pinout to plug into the IVC lightpen socket.

14th Jun 2019, 4:55 pm	#90
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Gemini 80-Bus System Oh, I know where most of my PDP11s are -- the large Unibus ones in rack cabinets, etc. This was just a little 2U high box with an LSI11 CPU board, RAM, and a couple of interfaces in it. Not actually the smallest PDP11 I own, but close. From memory, my Gemini contains a CPU board, IVC board, and floppy/SASI board. The latter goes to some bridge board thing (I want to say Adaptec, but it may be Xebec or somebody else) and to an ST412-interfaced hard disk. One of the ports on the CPU board goes to that network interface I mentioned. I also have (and have put with the machine!) the original keyboard and cable. Also what I believe was the video monitor used with it originally. Just a composite video monochrome thing of course. Interestingly, I have a Torch-branded lightpen for the BBC micro. This consists of an inteface that plugs into the Beeb's analogue socket (DA15) and a light pen that plugs into the interface using a 5 pin DIN connector. That DIN connector is the right pinout to plug into the IVC lightpen socket.