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Comment: Entrepreneurship vs. mental illness: distinct? (Score 3, Informative) 257

by dsgrntlxmply (#46655927) Attached to: Start-Up Founders On Dealing With Depression

One model claims that manic depressive tendency is under-recognized and over-represented among entrepreneurs. This sounds intriguing, but I must admit not being aware of any data that directly support the claim.

Another factor is post-mission depression. Here, we have something in common with military people, aid workers, and religious missionaries returning from deployment. One's life was for a time directed by a highly directed sense of purpose and mission, held in common with one's principal cohort. This often was within an organizational structure that made high demands, but diverted attention toward the mission and away from unknowns and uncontrollables. When the mission ends, the coherence and structure end with it.

Startup culture can reward what in other contexts would be seen as manic and obsessive/compulsive behaviors. In a bubble market with an IPO pending or recently made, it can be difficult to distinguish reality from illusion from delusion. For a while, one's life can evolve toward an obsessive focus upon one number: a stock price.

Spoken from experience.

Comment: Re:Not the first (Score 1) 356

by dsgrntlxmply (#41330245) Attached to: WD Builds High-Capacity, Helium-Filled HDDs

It took only microseconds for head switching, but rotational latency was the usual 8.33ms average. The impact of rotational latency could be reduced, depending upon the application and controller hardware, by ordering operations according to the upcoming sector boundary.

We used these in realtime bank transaction processing (for ATMs and POS terminals) circa 1977, to look up card numbers and a very limited amount of associated information (much like the credit card deny-list book that merchants used to keep at the cash register).

Comment: Not the first (Score 5, Informative) 356

by dsgrntlxmply (#41328705) Attached to: WD Builds High-Capacity, Helium-Filled HDDs
These drives are not the first. Circa 1969, Digital Development Corporation of San Diego sold a line of head-per-track disks that used a helium atmosphere. A typical unit took around 24 inches vertical height in a 19-inch rack. Given the difficulties of sealing anything against helium leakage, these drives required a small helium cylinder and pressure regulator to maintain a small positive pressure within the enclosure, and had a pop-off valve to vent excess pressure. The electronics consisted of about a dozen circuit cards built with discrete transistors. The capacities of these units were amusingly small by modern standards: the first one that I had direct experience with, held something like 128K bytes.

Comment: Re:Buy vintage BMWs! (Score 1) 291

by dsgrntlxmply (#41327095) Attached to: BMW Cars Vulnerable To Blank Key Attack

My '73 2002 was great fun (on good days at least), but by 1988 it had become difficult to obtain certain parts (like the original air cleaner) needed to pass California emissions visual inspection, much less functional tests.

Finally, it developed mysterious electrical problems that made it stop running at inopportune moments. Despite the fact that the car was dead simple by comparison with anything modern, I never was able to diagnose the problem, and ended up giving that car up in favor of a Honda.

That 1988 Honda now has mysterious electrical problems that make it stop running at inopportune moments. Some of these clearly are due to deterioration of wiring insulation and electrical connectors on the maze of emissions and fuel injection components. Connectors for e.g. thermal sensors onto the wiring harness, are arcane proprietary things that eventually fail and are not available as separate replacement parts. This necessitates improvised reconstruction.

Comment: Not really about tape, about interfaces (Score 1) 97

Interfacial effects in electronic materials are interesting.

Alves et al reported [Nature Materials 7, 574 (2008)] high conductivity (metallic-like, not superconductive) at a junction obtained by simply placing the faces of thin crystals of two very poor organic conductors (TTF and TCNQ) into contact and allowing the crystals to self-laminate.

Interesting questions arise, including whether the conductivity is nearly 2-dimensional rather than fully 3-dimensional.

I tried to investigate this in an undergrad project, but a number of technical difficulties could not be surmounted within the available time and resources.

Comment: Re:Come on (Score 2) 584

by dsgrntlxmply (#41197303) Attached to: What's your usual coffee-making method?

Actually it's PSVT: paroxysmal supraventricular tachycardia. Paroxysmal: sudden. Supraventricular: originates in some part of the heart above the ventricles. Tachycardia: rapid heart rate.

One cause can be small lesions that disrupt the normal organization and smooth evolution of electrical flow through the heart cycle. The effect can be like a not-quite-stable oscillator suddenly beginning to run at a harmonic rather than the intended fundamental frequency.

It's not usually especially dangerous but it can be very frightening. I feel that the anxiety around episodes can make them longer and worse.

Comment: As mentioned previously: domain specific (Score 1) 1086

by dsgrntlxmply (#40941787) Attached to: Ask Slashdot: How Many of You Actually Use Math?

I have lived on both sides of the fence, having written code for 35 years having failed second quarter calculus and thus the entire university program. After 35 years, I took a break from work, went back to school, passed 4 semesters of calculus and many other courses, and came out with a BS in Physics at an amusingly advanced age.

In the course of my first-segment career, there was were a couple of projects where I had to rely upon someone with greater math background and an expensive MATLAB DSP application package.

The first project was a low-jitter timing subsystem, where a device needed to synchronize to timing derived from a signal from a master device. I coded it, then used a combination of fragmentary digital filter experience that I'd picked up on a couple of silly personal projects over the years, and partially informed intuition, to run the filter algorithm at two different rates: a high (but CPU-expensive) rate for acquisition (where the abstract design failed), and a lower rate, exactly according to the abstract design, for tracking.

The background that I received from 4 semesters of calculus (that included a skeletal introduction to differential equations) might have helped here, but it would not have been sufficient.

The second project was a digital payload processor / modulator. I initiated and functionally specified much of the project (which mostly was an implementation of certain published standards), but it required contributions from 3 PhD researchers with evolving expertise in CIC filter design, to make the implementation feasible in a modern FPGA with integrated multiplier/accumulator blocks.

My contribution consisted mostly of generic software, but there was one area where I had to quickly try to teach myself some mathematics, and it was mathematics that would not be taught in undergrad physics, and most likely is not universally taught in other than cursory treatment, in undergrad comp. sci. programs: finite field arithmetic (error control coding). The objective here was to examine whether a legacy implementation whose design rationale had not been adequately documented, was truly equivalent to a published standard (it was, but I discovered a subtle gotcha), and to validate a proposed implementation against the standard.

What arguably has been most valuable after emerging from even a late and rudimentary education in a scientific discipline, back into software work, is having been exposed and held to a scientific standard of rigor. This stands in devising a sufficient and feasible scheme of measurement, in collecting sufficient data, in formulating claims that are supported by data rather than mere belief, and in making clear when the line between data and belief must be drawn and crossed. At times it turns me into an organizationally inconvenient holy terror. It also allows me to deeply examine and locate defects that are potential product and reputation killers, to endure hypothesis-destroying experiments, and to emerge with a clear understanding of the nature of the defect, and how to cure it.

I do wish that I'd had time and energy for more math: a practical course in statistics and design of experiments, preferably one designed to teach students who are well along in some field of study, rather than as an early weed-out for weak students in oversubscribed majors. The introductory statistics course at my university, which mercifully is not required in the physics major, is of the latter type and is generally reviled, even by the capable.

Comment: Re:Try -68 F Room Temperature (Score 1) 122

by dsgrntlxmply (#40900979) Attached to: Managing Servers In the Frigid Cold
Circuits must be specifically designed and qualified for low temperature operation. Common low-cost ceramic capacitor dielectrics (Z5U) are rated only to +15C and are useless by 0C. Y5P/Y5V are rated to -30C. X5R / X7R will get you to -55C. Aluminum electrolytics are useless at low temperature; tantalum is required.

Comment: Re:So Apple (Score 2) 142

by dsgrntlxmply (#40374411) Attached to: Apple Patents Polluting Facebook, Google Profiles

Nope. Claim 1 is the sole independent claim, and begins with "A device-implemented method..."; no alternative embodiments are claimed there. All of the other claims are dependent upon claim 1. Infringement can only be asserted against what is delineated in the claims.

Humans are not (yet) devices, so direct human acts cannot infringe.

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