Started 18April2016 – updated 22Nov2021 This page is in group Technology. Technical debt exists as a term. It doesn’t seem like technical deposit is a corresponding term. I try to do something with this here. (Observe that «depth» (with p and th) is how deep something is, it has nothing to do with «debt» that’s […]

Excerpt: Can time be part of a contract? Is it a contract when time is included? «Shall we meet at half past eight at the Pub for a beer?» Let’s steer past that one. Timing requirements are important, they are extensively used in hard real-time systems. In some protocols a client does not need to send any «end of request» signal as the server times out after a period of inactivity to close the connection (like HTTP persistent connections). This blog note tries to discuss when timeouts are fine to use, and when they do turn the components’ interactions into a quiz.

There is a nice series of development boards by ST called STM32 MCU Nucleo (here [1]), based on an ARM. One of these appeared on a table near me. They guy who had it said that «they also tell about a free operating system». It happened to be FreeRTOS™ (here [2]) by Real Time Engineers Ltd on freertos.org [3]. I eagerly looked it up and was fast pointed to WITTENSTEIN HighIntegritySystems (by The WITTENSTEIN Group) here [4]. They do SafeRTOS, so I downloaded its manual here [5]. This is a IEC 61508 (here [6]) approved RTOS. Since I work with safety critical systems (and have some blog notes here covering some aspects of 61508, like in note 065 [7]) I started to read. It spurred some questions.

Started 1May2015. Updated 12Jul2024 (FNIRSI). See my standard disclaimer. Intro For a small private project I have tried the best of the scrapped scopes I brought home from work, but the 1997 model Fluke PM3380A didn’t pass its own diagnose procedure. The amplitude of channel 1 changed when I pushed the curve up. And the old Philips […]

This page is in group Technology. Started work on this 1Feb2014, probably finished now (updated 7Jul2020 (table)) Intro In this note I will describe two articles about software components. The article «Component Models for Reasoning» (Seceleanu, Crnkovic) [01] and «Tool support for the rapid composition, analysis and implementation of reactive services» (Kraemer, Slåtten, Herrmann) [02]. […]

New: 10Nov2013, updated 22Feb2024 (Some moved to 254:[] typos, plus added some). This page is in group Technology. This note on the Internet Archive‘s Wayback Machine: A reactive manifest Disclaimer Whether this note manifests itself as a manifest, remains to be manifested. Background I will in this blog try to critically analyse The Reactive Manifesto [1]. The […]

21okt2013, oppdatert 10april2014 (13nov2023). Notatet er i gruppa Technology. In Norwegian, Google translate here. This note (in Norwegian) is about an early teen age friend, the book «Learn electronics by building» (or «The radio building book»); which I googled – but finally found at a local library. I have scanned some of the pages and written […]

25 April 2013 (last edit 21June2013) This page is in group Technology. Background Concurrency on Wikipedia or [3]. This note is a branch from 065. 035, 023 are perhaps also relevant. My XCHAN paper is a contribution to making concurrency easier, trying to merge the how SDL and CSP may view communication (Also discussed in 056). If you checked the references […]

Published 3Jan2013, updated 20Nov2018 This page is in group Technology. In this blog I will jot down some experience with installation and use of the FDR2 tool [1] which analyses CSP (Communicating Sequential Processes) specifications [5]. My experience is that I try to avoid Unix, OSX, Terminal and bash scripting. But here is my last journey into it. Important notice about […]

This page is in group Technology. History 3jan2013 initial, without comments 14Mar2013: Comments #1. Rolv Bræk 2July2013: [1.B] and [12] are new 20Jan2014, inserted [13] 28Sept2016, inserted Notes on SDL runtimes 11Oct2023, Telox mentioned Intro I hope that somebody from the SDL (Specification and Description Language) community [1],[3] will find these points interesting to reflect […]