8870 Adventures

© Joe Farr, 2011 – 2026

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Category: Documentation

  • NIROS – Nixdorf Interactive Real-time Operating System versions

    The picture on the left is a BA80 display showing the NIROS EX 3.3 log-on screen. The first version of NIROS that I can find any record of is 3.3 (not EX 3.3 just plain NIROS 3.3) and was the first version I used. Over the years, it went through many enhancements and updates. I’ve listed…

  • 8870 CPU instruction set

    ​If you open an 8870 system cabinet you will find circuit boards or plates, and if you open these plates you won’t find a CPU chip (actually that’s not completely correct as Nixdorf loved the Z80 CPU and you find them in all their peripherals), but the main system CPU was actually bit-slice technology; meaning it…

  • Communication interface personality boards

    There are many different ways to connect an 8870 to it’s VDUs, printers and the outside world in general. The 8870 supports PLC (Programmable Line Controller) devices that provide a lot of interface options and protocols but for general connectivity of VDUs and modems, the ALME (Asynchronous Line Multiplexer Extended) is the preferred and easiest…

  • 8251 Datasheet

    The 8251 is a Programmable Communication Interface controller and is found inside a DAP4 CPU board 1528-xx and form the interface between the CPU board electronics and the external personality interface board.