Author Archives: gmcdavid

Unknown's avatar

About gmcdavid

Retired IT professional with a wide range of interests. Married. Three sons, two with autistic-spectrum disorders and the third being transgender with Ehlers-Danlos syndrome. From Chicago but now living in the Twin Cities metro, Minnesota. Episcopalian. Carleton College (BA 1972, physics) and Stanford University (MS 1974, Applied Physics; MS 1976 Statistics).

Made a knife

Years ago I started making a knife from a file. I put the project aside, but when Mia and I started watching Forged in Fire earlier this year I was inspired to pick it up again.


knife as ground

Knife as of Dec. 1 2021. File initially ground into knife. Started from an 18″ file. Prior to December 2021 I had ground it into this shape.
Continue reading

Rang Gaeilge, 15ú lá Mí na Bealtaine 2022

Duinnín agus Imleacán Kali (tuilleadh)

Dineen and the navel of Kali (continued)
  • Lig Brady osna as, ach thug sé an treoir chuí do phóilín a bhí ar dualgas.

    Brady sighed,but he gave the appropriate direction to a police officer on duty.

    treoir Guidance, direction f
    cuí Fitting, proper
    dualgas Natural right, due; customary fee or reward
    ar dualgas on duty
  • Léigh tuilleadh

Free42 on Ubuntu

I noted in Slackware Diary that I had installed Free42 under Slackware. As I wrote in 2006 I fell in love with HP calculators and their RPN notation back in the 1970s, and still find the conventional algebraic notation rather awkward. I no longer carry a physical calulator, but I have Free42 installed on my phone and my tablet, and on my Windows systems. Now I also have it on Slackware. So I circled back to see if I could install in on Ubuntu.

Continue reading

Electrons and Positrons

I have known about Electron–positron annihilation for at least 52 years, from my course in Atomic and Nuclear Physics at Carleton College in the spring of 1970 if not before. The reaction is

e + e+ → γ + γ

I had always assumed that the inverse reaction

γ + γ → e + e+

was also possible because of time reversal symmetry. Apparently so had everyone else, but it has only recently been observed: Matter arises from light? We finally know the answer to this question!. Even now there is a caveat about “virtual” as opposed to “real” photons.

Slackware Diary – 2

Continuing from Slackware Diary – 1

Fixed the prompt by copying .bashrc and .profile (renamed as .bash_profile) from my primary Ubuntu system. This works and I have nice color prompts in Slackware. Need to see if I have scripts from my previous Slackware days to add environment variables, aliases, etc. Life in Slackware means a lot of time on the command line.

The next task on my list was to install Flatpak so I could use apps from Flathub

“Failure is always an option.”-Adam Savage

Rang Gaeilge, 20ú lá mí Aibreáin 2022

Duinnín agus Imleacán Kali (tuilleadh)

Dineen and the navel of Kali (continued)
  • ‘Rugadh agus tógadh Marie i Sr. Cuffe agus is ansin atá cónaí ormsa. Baisteadh Marie i Sráid na mBráithre Bána. Dhein sí a céad chomaoineach ann. Tá ag éirí go maith le Mr. McCausland sa bhanc agus thóg se an teach seo ar cíos anuraidh. Ar ndóigh, ní bheinnse ag seadú anseo ach go bhfuil gá ag Marie le cúnamh agus Mr. McCausland san … ospidéal.’

    ‘Marie was born and raised in Cuffe Street and that is where I live. Marie was baptized in Whitefriars Street. She made her first communion there. Mr. McCausland is doing well in the bank and he rented this house last year. Of course, I wouldn’t be here except that Marie needs help and Mr. McCausland is in the … hospital.’

    comaoineach Communion f
    cíos rent m
    seadú Settlement; stay, wait m
    cúnamh help m

    Léigh tuilleadh