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paulfdunn

4 karma · joined February 19, 2026

Electrical engineer by training; broad practical experience. I created the first computerized method for calculating dosimetry for iodine-125 radiation seeds (used to treat brain tumors), running on a PDP-11, in 1985. (I participated in brain surgery during its first use. Note this was during a summer job while in college.) I went on to design HW/FW to control HDD servo systems, then read channels. Later, I designed production equipment to qualify tape media used in tape drives (Quantum DLT/SDTL/LTO). That got me on a path that transitioned me to SW where I: wrote test SW for large-scale storage devices, wrote WDC's OpenFlex management interface, and worked in data engineering for a large SaaS provider (Zendesk).

I've always had a strong interest in business, finance, and economics. I started retirement planning when only a few years out of school. I started programmatic trading in 1996.

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paulfdunn··on Show HN: Portfolio simulator using trend-following indicators and rebalance API
I've written several comments that all got flagged a GenAI - so here is a quick off-the-cuff version hoping it gets through.

I made this tool because I have long used trend following to protect against market downturns. (Important for those at or near retirement.) There are places like Yahoo Finance where you can use basic trend-folling, but there are no backtests and you need to check the results daily.

This tool has all the backtest results available and I have a Make.com blueprint you can use to alert you to changes.

Enjoy - I hope this actually survives the AI checks....

paulfdunn··on Microsoft's new 10k-year data storage medium: glass
These demos are technically interesting, but often lacking practical rigour.

In 1994 I was hired to design the servo (motor controls) for a holographic storage solution. During the interview I asked a lot of questions, but rarely got more details than "we've got 30+ PHDs, top of their field, trust us it works." They were certain they had it all worked out, and they would be bought or go public relatively soon. I took a chance and joined, which required selling my house and moving from Colorado to Texas. I was the first person to join from the storage industry.

A few weeks in: Me: What are the position holding requirements? PHDs: +/-30um Me: Wow, ummm, how long does that need held? PHDs: milliseconds, maybe hundreds of milliseconds until we get better media. Me: That's impossible

After a few weeks of tolerance analysis on the mechanics of the problem, I proved that the design could never actually work in a product. One off demos on a 6x10ft air table, yes, but integrating that into a full height 5 1/4 form factor could not be done.

They were bankrupt months later. Bell Labs was working on a similar design, similarly confident. They tried to hire me but I declined. They spun out of Bell Labs as In Phase Technologies. Over a period of about 6 years there were press releases, an investment by Steve Jobs, then bankruptcy.

TL;DR Data storage is hard. Getting a consumer level product developed adds much more difficulty than researchers generally understand.Fingerprints, dust, temperature variation, air flow, all create challenges; and removable media creates an even broader set of challenges.