Epson HX-20

EPSON HX-20 This is an interesting machine from the early 80s. It has a notebook form factor and a nice complete keyboard with real keys. At that time, large LCDs were not available, so it has a small LCD with 120x32 pixels. This gives 4 lines of text with 20 characters. It includes a built-in miniature printer and a miniature cassette drive for mass storage. This machine is extendable in many ways, with additional RAM and ROM modules, external monitor (then with more display space), and some other serial devices like barcode reader and what not.

Installing Ultrix 4.5 on MicroVAX 3100

Ultrix 4.5 on a MicroVAX 3100 I wanted to install Ultrix on my VAX, described here. Here is some log regarding installation. The installation was already documented by various people, so it is nothing new, and credits go to these people. Ultrix version used is from 1995, so 28 years old. The following screenshot shows, after installation, some DEC Windows tools, remote displayed on my Linux machine. You see 2xdtterm, dxpaint, dxpuzzle, dxnotepad and dxclock.


SCSI2SD SCSI2SD is an approach emulating SCSI hardware with software running in an PSoC microcontroller from Cypress. An ARM Cortex M3 controller is provided as part of the PSoC, and furthermore a bunch of programmable system parts, e.g. usable for interfaces etc. Focus is on mass storage, so SCSI2SD can emulate hard drives and other mass storage devices, all on a SD card. Main website is . Alternative PCB layout, specialized for Powerbook hardware, but can be used for general SCSI purposes too: https://www.

Digital DEC MicroVAX 3100

Digital DEC MicroVAX 3100 I bought this as a fully working machine. Series BA42A board and KA41A CPU. So this is a Microvax 3100-10. 16MB RAM. The machine contains two harddrives. One contains a VMS operating system, the other one a NetBSD installation. So it can run both VMS and UNIX. Contains a DHW-42-AA (also called: DSH32-B?) extension board. It offers 8 additional serial lines (for terminals) and 2 synchronous lines RS-423.

Digital DEC VT 330+ Terminal

DEC VT 330+ is a successor of VT330. My device has latest date codes from week 28 in 1990, so it is about 1990 or 1991. The electronics differs from the VT330, the digital logic part is build on a single PCB only. While older VT330 were built on two boards. This newer board has an Intel 8032 8-Bit CPU, 2x128 KByte EPROMS (27C010), 2xHM62256 2x32KByte RAM. The microcontroller has two companion chips SCC2692AC1N40, these are dual asynchronous receiver/transmitters.

IBM Microdrive

Microdrive, IBM DSCM-11000, with 1GB capacity. From year 2000. Connector type is “CF+ Type II”. Formfactor 1.8’’. Weight 16 gramms. These are real harddiscs, with super-small rotating discs inside, moving heads and all that fancy stuff. This was designed at a time, where it was not possible to create large semiconductor based non-volatile memory. At that time, it was easier to scale down the physics of a real harddrive and to create a tiny version of that.

PDP11 Assembler

PDP11 Assembler This text describes how to assemble PDP11 files on Linux. MACRO-11 assembler, linker, disassembler for Linux There are several ways to create object binaries for PDP11 on Linux. I have tested these tools that form a nice tool set for handling PDP11 assembler files on Linux: Macro-11 Assembler, see (written in C) Macro-11 Linker, see (Written in C++) PDP-11 Disassembler, see (Written in C) All tools did compile without any options by just executing make on them.

PDP11 bare metal coding

Coding for PDP11 machines without any target operating system (bare metal). Gnu GCC does the job. Github location There is useful code on Github, see here: Toolchain install # Download packages curl >binutils-2.34.tar.gz curl >gcc-9.3.0.tar.gz # Extract packages tar xvf gcc-9.3.0.tar.gz tar xvf binutils-2.34.tar.gz # Download/install prerequisites for compiler cd gcc-9.3.0/ ./contrib/download_prerequisites # Create build dirs cd .. mkdir binutils-build mkdir gcc-build # Build binutils cd binutils-build/ .

PDP11 Coding - with SIMH, and some Linux tools

If you want to write code for a PDP11 CPU or PDP11 machine, you need some environment to do so. I have only parts of a PDP11 machine and cannot simply use this to write code. So I tried several ways: Using SIMH emulator to emulate a PDP11 machine, boot up some PDP11 Operating System (RT11) and use the available tools from that OS Using native Linux executables that allow for assemble and link valid PDP11 executables Using Gnu GCC toolchain for bare metal programming The SIMH emulator way is described in this document further below.

Dual KA-61 Kompaktanlage

Für Freunde des guten Klangs, insbesondere bei Plattenspielern, ist Dual ein Begriff. Wie ich in Foren gelesen habe, sind die alten Dual Plattenspieler einem Neugerät normalerweise an Qualität überlegen, bis zu einer Neugerätmarke von rund 500 Euro. Erst dann bekommt man was Besseres. Ich persönlich würde daher immer einen Dual, oft für ein paar dutzend Euros, nehmen. Und tatsächlich sind diese circa 50 Jahre alten Geräte heute oft noch in sehr gutem Zustand, mechanisch robust, elektrisch dauerhaft hergestellt.