Welcome to decuser's blog
Topics on this blog include computing, retro-computing, operating systems, math, and whatever other technical subjects I happen to be exploring that I find interesting enough to take and share notes about.
Posts
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unix research-unix v7
Installing and Using Research Unix Version 7 in the OpenSIMH PDP-11/45 and 11/70 Emulators 3.0
This note covers building a working v7 instance from tape files that will run in the OpenSImH emulator. First, the reader is led through the restoration of a pristine v7 instance from tape to disk. Next, the reader is led through adding a regular user and making the system multi-user capable. Then, the reader is shown how to make the system multi-session cable to allow multiple simultaneous sessions. Finally, the system is put to use with hello world, DMR style, and the learn system is enabled.
The note explains each step of the process in detail.
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retro-computing m100 basic
Notoriously S.L.O.W BASIC
This week, I spent some time writing code for my m100. On my list of things to do with the little machine, was to write a disassembler. In order to disassemble memory, it helps to know what's there, so I decided to write a memory dump utility first.
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retro-computing m100
model-100-bibliography
A list of known Tandy TRS-80 Model 100 books and articles, with links. My faves are in bold.
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retro-computing pal-1
Long Road Back to the Tandy TRS-80 Model 100
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unix research-unix v6
Installing and Using Unix V6 in the Open SIMH PDP-11 Emulator
This note details the process of building a working v6 instance from a copy of the original tape distribution. The v6 instance runs in a virtual PDP-11/40 provided by OpenSIMH, a masterwork emulator.
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retro-computing pal-1 videos
Programming the PAL-1 Using the Keypad
A video walking the user through the process of programming the PAL-1 using the keypad. It begins with a short overview of the PAL-1, then covers prelims like where the START program resides in ROM, how to set up the IRQ and NMI vectors, how to view the Accumulator contents, how to enter a program, where it should go, and how to run it normally and single step.
Enjoy!
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electronics theory videos
Ohm's Law Power Wheel Made Simple and Rational
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electronics analysis
Using an el-cheapo logic analyser to detect address bus activity
This note documents my exploration of using a $9.99 logic analyzer to watch my PAL-1 go through some address bus gyrations.
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electronics theory
Nyquist what?! Gobsmacked by Sampling Frequency
A note to capture what I learned the hard way about sampling frequencies.
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retro-computing pal-1
PAL-1 Loading MOS Paper Tape to RAM
This post describes how to get your Mac talking to your PAL-1 in order to send MOS papertape format ascii files via minicom to your PAL-1 and run them. Future installments will go into more detail, from the ground up.