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Mon Nov 13 09:26:42 EST 2017
Slept from eleven to seven. Woke briefly around four.
High of forty-one and cloudy today.
Work:
- Work on MECS
Done.
In a systemd service file, what's the difference between "WANTS" and "AFTER"?
https://www.freedesktop.org/software/systemd/man/systemd.unit.html
> Before=, After= These two settings expect a space-separated list of unit names. They configure ordering dependencies between units. If a unit foo.service contains a setting Before=bar.service and both units are being started, bar.service's start-up is delayed until foo.service has finished starting up. Note that this setting is independent of and orthogonal to the requirement dependencies as configured by Requires=, Wants= or BindsTo=. It is a common pattern to include a unit name in both the After= and Requires= options, in which case the unit listed will be started before the unit that is configured with these options.
Basically, WANTS asks that the named services be marked "active" but without AFTER doesn't guarantee that those services have actually started yet.
So, no, WANTS and AFTER are not redundant.
Relatively few interruptions today, so I got a lot of work done on MECS.
Twenty-five-minute walk at lunch.
Overcast, and some residual puddles.
Suddenly, the trees are mostly bare.
Home:
- Work on blogs
Done.
http://www.paulgraham.com/hp.html
> In fact, of all the different types of people I've known, hackers and painters are among the most alike. What hackers and painters have in common is that they're both makers. Along with composers, architects, and writers, what hackers and painters are trying to do is make good things. They're not doing research per se, though if in the course of trying to make good things they discover some new technique, so much the better. [...] And then at the other extreme you have the hackers, who are trying to write interesting software, and for whom computers are just a medium of expression, as concrete is for architects or paint for painters.
> The mathematicians don't seem bothered by this. They happily set to work proving theorems like the other mathematicians over in the math department, and probably soon stop noticing that the building they work in says ``computer science'' on the outside. But for the hackers this label is a problem. If what they're doing is called science, it makes them feel they ought to be acting scientific. So instead of doing what they really want to do, which is to design beautiful software, hackers in universities and research labs feel they ought to be writing research papers.
> The way to create something beautiful is often to make subtle tweaks to something that already exists, or to combine existing ideas in a slightly new way. This kind of work is hard to convey in a research paper.
> All the time I was in graduate school I had an uncomfortable feeling in the back of my mind that I ought to know more theory, and that it was very remiss of me to have forgotten all that stuff within three weeks of the final exam.
> Now I realize I was mistaken. Hackers need to understand the theory of computation about as much as painters need to understand paint chemistry. You need to know how to calculate time and space complexity and about Turing completeness. You might also want to remember at least the concept of a state machine, in case you have to write a parser or a regular expression library. Painters in fact have to remember a good deal more about paint chemistry than that.
> For example, I was taught in college that one ought to figure out a program completely on paper before even going near a computer. I found that I did not program this way. I found that I liked to program sitting in front of a computer, not a piece of paper. Worse still, instead of patiently writing out a complete program and assuring myself it was correct, I tended to just spew out code that was hopelessly broken, and gradually beat it into shape. Debugging, I was taught, was a kind of final pass where you caught typos and oversights. The way I worked, it seemed like programming consisted of debugging.
> For a long time I felt bad about this, just as I once felt bad that I didn't hold my pencil the way they taught me to in elementary school. If I had only looked over at the other makers, the painters or the architects, I would have realized that there was a name for what I was doing: sketching. As far as I can tell, the way they taught me to program in college was all wrong. You should figure out programs as you're writing them, just as writers and painters and architects do.
> The other way makers learn is from examples. For a painter, a museum is a reference library of techniques. For hundreds of years it has been part of the traditional education of painters to copy the works of the great masters, because copying forces you to look closely at the way a painting is made.
> Writers do this too. Benjamin Franklin learned to write by summarizing the points in the essays of Addison and Steele and then trying to reproduce them. Raymond Chandler did the same thing with detective stories.
Oh, wow. My di.fm subscription give me access to other services too:
- https://www.jazzradio.com/ (Bebop, Hard Bop, Blues, Paris Cafe, Cool Jazz, Timeless Classics, Gypsy Jazz, etc.)
- https://www.classicalradio.com/
- https://www.radiotunes.com/ (Just an aggregation of the other sites?)
- https://www.rockradio.com/ (80s Alternative, Blue Rock, Metal, etc.)
https://markstretton.blogspot.co.uk/2016/02/did-crescent-arrow-heat-cut-rope-ship.html
Answer: yes.
Watched a documentary about da Vinci while I moved old blog posts from Quickly, Quietly, Carefully to devilghost.com.
Lunch: coffee, gyro
Dinner: Italian sub, fries
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