drallison

Single pointer lists using the XOR trick were used, I believe, to implement the XDS Sigma 7 operating system block free list back in the day when memory was not free and core dumps were the primary debug tool. I remember writing a column on the algorithm for Dr. Dobbs Journal back in the 1980s. There are lots of bit twiddling techniques that use XOR. Henry Warren's Hackers Delight is a good reference there. And, of course, Don Knuth's AOCP has lots of information. Volume 4A, available as a fascicle, has a number of XOR algorithms.

Leap seconds adjust clocks which are run at an atomic standardized rate to meet the astronomical reality and keep UTC in sync. So far there have be 18 seconds of correction. Leap seconds are a bad idea. They confuse geophysical data. The interval of time between two measurements is not the difference between the clock values when the measurements were made.

I don't know if Peter G. Neumann remains "the most influential voice on computer security" at this point in time (January 2021) but he is still an important in the field, still a mentor, still doing RISKS, and still a voice of reason.

Josiah Zayner's and his company, The Odin, has classes, tutorials, kits, materials and lab tools to get yourself started. http://the-odin.com. The biohacking community is a good place to start; the vibe is exciting, rather like the beginning of the PC movement. Hands on experience is way more informative than book learning.

The Recognitions (William Gaddis)was one of the assigned readings in my honors English 1A class at UCLA in 1957; another was Generation of Vipers (Philip Wyle). We read three or four other books but I only remember Gaddis and Wyle. The class, taught by an enthusiastic graduate student, was lively, intellectually stimulating, and formative.

Much of the discussion here centers upon "race" and its use in the headline and in the medical literature. A better term might be "genetic variation" as it has less baggage than "race".

What is significant is genetic variation tends to be geographically distributed. https://www-nature-com.stanford.idm.oclc.org/articles/ng1435. Making a universally effective vaccine needs to start off with a geographically diverse sample of both the virus and the population to be vaccinated.

Everyone should read this collection of some of Ted Nelson's insightful comments. Read slowly and considered carefully. Ted is a non-linear thinker whose insight is frequently extraordinary and sometimes embarrassing. You will be the better for your efforts.

Everything is 0-indexed in C. It is convenient for each day in a month to correspond to it's ordinal position.For example, the Ides of March would be entry 15 in the structure containing data for the month of March. There is no 0-th day in a month so there are extra, unused entries but this is better than continually changing day values at each reference. The months are just a list and so are 0-indexed and dense.

Dear Santa Claus, I want one of Nvidia's latest desktop workstation for Christmas. Please. I promise I have been good. I'll leave out some chocolate chip cookies for you and a carrot for Rudolph. Denny

Paul Krugman has a point: If we cannot stomach impact of the COVID-19 pandemic, how will we ever be able to stomach the hard choices which will accompany the impacts of climate change and global warming? Extinction will be instantaneous at a geological time scale and has already begun.

I used Bourbaki as a second text in an advanced math course I took when I was at UC Berkeley in the early 1960's. I remember with delight the spare clarity of the presentation of the material and organic, intuitive organization of the topic. French has always seemed to me to be the language of mathematics, reason, logic (and love).

Disambiguation: Herb Gross was a mathematician of note and a teacher.

Herb Gross should not be confused with Herb Grosch. Herb Grosch was an irascible curmudgeon, a founder of ACM, and at one time one of the computer field's most visible characters, notables, and pioneers. Herb Grosch passed in January 2010.

Ever the curmudgeon, Herb proudly claimed to have been fired twice, personally, by IBM's Thomas J. Watson Senior.

A true geo-hacker would have written "If the World Were Created by a Programmer [Comic]". The subjunctive (see https://en.wikipedia.org/wiki/Subjunctive_mood) is an important semantic tool and should not be abandoned.

Kinda depends whether by "correctness" you mean "proof". I always found Social Processes and Proofs of Theorems and Programs by Richard A. De Millo, Richard J. Lipton, and Alan J. Perlis inspirational.

I do not know of any collection of proof techniques that would be uniformly useful for greedy algorithms. If you discover such a collection, please share it with me.

Point taken but it is too late to correct. :-(

The Five Eyes + 1 nations are positively Orwellian. They say

   "We, the undersigned, support strong encryption, which plays a crucial role in protecting personal data, privacy, intellectual property, trade secrets and cyber security,” the Statement commences, adding: “Encryption is an existential anchor of trust in the digital world and we do not support counter-productive and dangerous approaches that would materially weaken or limit security systems.”

Which is to say, they support encryption but then they want to have a backdoor that would materially weaken or limit security systems. Orwell would have been proud that double speak has emerged again in the wild.

Yes. I use a line editor but an advanced one. I'd prefer emacs but tend to us vim because it works better over poor Internet connectivity. I can (and have) used ed, nano, pico, and the like, but find that a little context helps.

The mental model needed for line editing and the one needed for visual editing is different. The former requires a mental model of the document being edited where the latter just requires that you can read. There is a world of difference.

Jaron's point-of-view is, as always, fresh and on-point. Recommended.

I think caryd is wrong. People seem to be having problems with evidence based reasoning. People seem to distrust scientific experiments and data. Part of that may be in reaction to the commercial noise about products, usually in health care, which are "scientifically proven" to do impossible things.

While I have not yet tried Zope 5, it looks like Zope has been revived as an option for the web. We used Zope for a large education platform and found it to be efficient, quick, and powerful. It's nice to have an updated version back in the toolkit.

It usually helps to have a systematic mathematical model for the problem you are trying to solve, and systematic mathematical models for the sub-problems into which the full problem is decomposed. It is frequently better to conceive of each step in the program as ensuring some property is invariant rather than conceiving each step as performing some action.

It is probably better not to think of yourself as a coder or a programmer; consider yourself a problem solver with mathematical skills and move on to there.

Always convince yourself that the problem you are trying to solve has a solution.

I think yes. There are numerous Anthropocene existential threats which are likely to lead extinction. <Edited to deleted enumeration of threats and snarky comments about nothing being done about it.> Decisions we make now will have a major impact on whether humans survive or not.

This 2001 paper describes a system which allows journal articles to survive on the Internet even though copies are removed and the hosting journal disappears.

LOCKSS: A Permanent Web Publishing and Access System by Vicky Reich and David S. H. Rosenthal describes a practical system which guarantees survival of published articles even when the hosting journal disappears.

See http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.68....

The DG Nova in its day was a workhorse mini-computer. I worked with Bob McClure (Unidot) and built an "optimizing" C compiler that had surprisingly good performance. We ended up re-organizing the code generated so we could take advantage of the short offset and indirect addressing of the machine without adding extra instructions. Likewise, we used an unusual approach to managing stack frame addressing which was well suited to the DG Nova addressing.

The DG Nova hadware was simple largely because it was built in TTL and the ALU was a 74181. In the mid-1960's the final project in the logic design course was to design a DG Nova machine using TTL.

DCC and DG clashed over the cloning of the DG machine. See https://en.wikipedia.org/wiki/Data_General_Corp._v._Digital_....

The dark orange sky, reminiscent of descriptions of what nuclear winter would be like, the smell of smoke, the rain of small hunks of grey ash raining down, the warnings about going out of the house into small particle contaminated hell have become the new normal. There are said to be 20,000 firemen on the lines. Many friends (and others) have lost their houses and possessions. But worst of all, the fires are inserting more CO2 into the atmosphere and acerbating the global warming and climate change which has made the fires worse. Why have we not treated this as an critical emergency and used every possible resource to put out the fires and change our forest management policies to minimize greenhouse gas release which contribute to global warming.

What I see is a total failure of our society to meet the challenge of near-term existential events. Our leaders barely acknowledge the problem and most people ignore it.

Cory Doctorow has created a kickstarter for his latest book, the third in the Little Brother series. It's an experiment in self-publishing ebooks and audio books outside of the Amazon/Audible ecosystem and without draconian protections.

dvd as an abbreviation for Dasvidaniya, which in Russian means goodbye. Dasvidaniya is actually two words, not one: до (until) and свида́ния (meeting / date). So literally it means “until the next meeting“. Dasvidaniya is a formal way to say goodbye and should be used with people you don't know and those older than you.(Cribbed with Google's help from learnrussianwords.com.)

dvd removed files in Unix Version 6 and earlier. If memory serves, it operated directly on the file system data structures and was useful for recovering when the file system got "stuck".

They missed a few, or example, "dvd".