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

• Oct 26, 2022 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.

• Oct 23, 2022 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.

• Oct 22, 2022 retro-computing pal-1

  Long Road Back to the Tandy TRS-80 Model 100

  

• Oct 19, 2022 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.

• Jul 9, 2022 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!

• Jun 29, 2022 electronics theory videos

  Ohm's Law Power Wheel Made Simple and Rational
• Jun 9, 2022 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.

• Jun 9, 2022 electronics theory

  Nyquist what?! Gobsmacked by Sampling Frequency

  A note to capture what I learned the hard way about sampling frequencies.

• Jun 8, 2022 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.

• Jun 8, 2022 retro-computing pal-1

  PAL-1 Entering a Program via Serial Port

  Note describing a minimalist example of how to input via serial and run a program on the PAL-1.