osiweb.org

I don't mind paying for the scanning cost as long as people are wanting to buy duplicate boards :) I'm also fine with putting the Gerbers up for free -- I'll probably put them on GitHub so they're not dependent on me, and try to get people to mirror them as well. I will probably do like I did with t...

Has anyone cloned the Ohio Scientific 560Z board? This is the CPU Expander that supports the Intersil IM-6100 PDP-8 on a chip. There's one in a lot of boards I'm looking at. I'd be willing to clone it and have more boards produced using Mile High Test to scan the board, as I did with the OSI 495 pro...

Good work so far! You might look into breaking up the schematic into several sheets -- I see you've used global nets which means you can break up the schematic and the nets will stay connected. Makes it easier to digest when you have it separated into a number of sheets by related function. This is ...

And, here's the writeup: http://www.glitchwrks.com/2016/05/17/64k-ram-for-osi I'm probably going to turn this into a proper PC board/kit. Obviously the RAM circuit won't take up the whole board -- I was thinking of doing the rest as a buffered prototype space, with control lines for using the onboar...

I *finally* got time to put the second 32K bank on my prototype RAM board tonight! Required 3 more ICs including the Static RAM, and only very slight modification to the existing circuitry. I will do a full writeup with schematic changes and pictures probably tomorrow, provided my day job isn't swam...

A box containing 114 74LS30 8-input NAND gates arrived over the weekend, so I should be able to finish building the top 32K segment once I get some down time from billable work!

BillO's board is probably the more appropriate solution for C1P systems with the 40 pin DIP expansion, unless you want a 40 pin ribbon cable going to a separate daughterboard. From the looks of it, you could reprogram the GAL to give you another 32K and just stack the board on top of the lower bank ...

It would include 0x8000 - 0xBFFF as well as 0xD000 - 0xEFFF for CP/M systems using the 510 CPU board, all switchable so you could disable it if you didn't want it. You could also plug in a 27256 EPROM in the second socket and put 8K BASIC in a single ROM if you don't have it on the CPU board. Using ...

As promised, I've designed, built, and written up a project for putting a modern static RAM on the OSI bus: http://www.glitchwrks.com/2016/04/23/32k-ram-for-osi Complete with schematics, explanations of the various blocks of the circuit, and assembly tips! This was of course built on one of the clon...

Posted a writeup on the creation: http://www.glitchwrks.com/2016/04/22/cloning-the-495

I've started working on a RAM board using one of the 495 boards, so a writeup with directions + schematic should be coming soon!