Recent content by cbscpe

Seems similar to my Seems to match my goals that led to my PDP-11/Hack computer. FPJ11 is not really necessary as it only increases the speed of floating point instructions, but the DCJ11 already supports them in its microcode. Have a look at my home page. Feel free to ask questions.

Nice, I was not aware of ZuluSCSI and RaSCSI. I was only using SCSI2SD in various versions. One question though. One of my SCSI2SD is setup to emulate a SASI Drive, replacing a MFM Drive with a Xebec S1410 controller board connected to a Plessey Disk Controller that emulates an RVL12. This...

It all depends what you want to put into those Bootroms. If the goal is to just Boot or Autoboot a device, e.g. DL, DU, DD, etc. then this should be straightforward. I have here a Plessey Bootrom that occupies the two 256words (aka 512bytes) windows and provides a prompt and allows you to...

Send me a PM then I can send you the current source code.

As far as I can see from the Semiconductor Handbook Volume 1 the input and output levels of the T-11 are compatible with TTL and so are the levels of the AT150X CPLDs. So there should be no issue to mix and match T-11, TTL, EPROM, SRAM and CPLD.

All I have from Plessey is linked to the description of my own Plessey System https://www.5volts.ch/posts/plessey/

I have two of those as well and happen to have some information about them, look here https://www.5volts.ch/downloads/Plessey-6200-SV-128.pdf those are Q22 cards and I used to run them in my Plessey PDP-11/23 system.

Thanks a lot for the insight information and the link to the documents. Very interesting story. I was not aware that CIS was one of the key features. Honestly, although I worked quite a lot with PDP-11s I've only read about but never seen a PDP-11 with the CIS option installed. As all systems I...

How much is known about the PDP-11/74 and what is actually available. E.g. pictures, documentation, programmers that have worked with it? As far as I know this machine has never been made available to the public. However there is still so much said and there are many notes even in DEC documents...

Be aware the 74LS640 are open collector on both busses. So you need to add pull-ups on the internal bus. But I think using a tri-state buffer is ok. You also often see the AM2908 to drive BDAL0..15, they are expensive but still available.

Hi Lee, I completely understand the anachronism stuff. The main reason my card is SMD and rather small is that prices for PCB in full Dual Width Q-Bus Format are very expensive, at least here. Although the 2N3904 seems an elegant solution I recommend to use a 74F38 (yes the F Version, they...

The address latches do not need to be cleared at all. Just latch the address using SYNC (inverted BSYNC as you do). See also my version of a Q-Bus Memory Card . This one is mostly SMD mainly because the only 1Mx16bit SRAM for 5V I could has an SMD package. There is also a 2Mx16bit SRAM but only...

When you boot DU0: you most likely need to configure the other DUx: devices, what does a "show dev:du" display when you are in RT-11?

Yes to be able to use two MSCP controllers you need to do a sysgen, the default for DU$POR is 1. After that you can assign the DU drives to either port.

Thanks for the links. I don't know what I did but never was able to find those. So I immediately ordered a few. They just arrived today, as you mentioned they are not as shallow and allow for a wider tongue, but that's no issue here. The contact is the same and for the tongue I plan to make the...