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2011 June 28-30
Tool of the day: R
I've finally gotten around to making real use of
R
and am glad to recommend it.
Ostensibly a statistics package, it is actually a sort of
combination of BASIC, SAS, and MATLAB, free of charge and
(like TeX) supported by a crowd of developers.
Not only statistics, but other advanced functions such as
singular value decomposition are built right in.
I don't recommend R as a language in which to develop software
(other than, of course, extensions of R).
It's a tool for exploratory programming, to decide what you want to compute.
Near-hiatus: Notebook entries are going to be quite scarce for the next
couple of weeks; I'm very busy. Please don't be alarmed!
Internet outage: We have had three substantial (multi-hour) AT&T DSL outages in the
past nine days. The latest, on June 26 from 8:30 a.m. to 4:55 p.m., looks awfully like
scheduled maintenance. I hope they've finished fixing it!
Money-saving tip: A caller to Adam Goldfein's radio show on WSB suggests that
if you have children, you should switch to commercial-free TV (such as Roku or
another Internet-based service, or Netflix disk rentals). Then your children won't be
indoctrinated to "want" one thing after another!
I note that Netflix is now the largest single TV provider in the country. Are we about
to see a remarkable shift in what it is like to be an American child? They're no
longer being trained to consume? And then they'll grow up and dominate the economy...
Zillow rewrites history again: Zillow has again
revised its estimate
of the value of my house.
They also revised the graph of past values — so they no longer say that
last week it was worth what they said it was worth at the time.
Clearly, every time they revise, they also update their estimates of past values.
Really bad idea of the day: For decades, perhaps a century, the power companies have held the
frequency of our AC power lines at 60.00 Hz,
even as the voltage varied, so that frequency-dependent motors would run
at a precisely controlled speed. That is why electric clocks stayed so accurate.
Now they're proposing to let the frequency vary.
Bad idea. There are still a lot of line-frequency-controlled clocks and timers (including some
digital clocks).
One of my very earliest memories is of a TV commercial similar to this one, with animated
pigs singing this song:
It was on TV in South Georgia around 1961. I think the commercial I actually remember is a different one,
with the three pigs dancing across a stage, vaudeville-style, facing the audience. Can anyone confirm that
that one existed?
Here is the computer that I built using Minerva's CPU and a motherboard and case from
Melody's parents. It, too, is named Minerva, and it's a quite serviceable Windows XP
and Linux system. But that's not all. It also boots DOS 5.0 (yes, DOS 5.0), under which
it can read all PC diskette formats, even my really old ones from DOS 1.1. All three
operating systems are in the GRUB menu.
DOS can't see the 300-GB hard disk. I had an older 80-GB disk and jumpered it (per
Western Digital's instructions) to make the BIOS see it as 32 GB, then booted DOS from
a diskette with the other hard disk disconnected (just in case).
FDISK saw 8 GB and made four 2-GB partitions, which, for DOS, is more wide open space
than anybody ever dreamed of. They work just fine, but Windows XP can't see them.
Linux, fortunately, can read and write the hard disk partitions of all three OSes.
Here is a picture of Minerva and some screen shots (all taken with a camera,
not by digital capture). Enjoy. Why do I build strange computers? Probably for
the same reason some people build ships in bottles.
DOS, booting:
(The message at the bottom, identifying the disk drive letters, is something
I put into AUTOEXEC.BAT.)
Our old friend Turbo Pascal:
Finally, my totally manual screen saver, klok (so named so that the command
would be easy to type with one finger):
I note with sadness the deaths, within just the past few days, of two
renowned electronics engineers who were also book authors,
Bob Pease
(with whom I have corresponded)
and
Jim Williams.
We were off the Internet for more than 36 hours, starting Saturday morning just
before noon. Our AT&T home DSL connection wouldn't reach the Internet, although the modem
showed a solid connection to something upstream from us. We spent much of Sunday
afternoon at Panera doing correspondence.
Recommended:KwicKwic, a fast and
versatile program for keyword-in-context (KWIC) analysis of written language.
KwicKwic was written by our own alumnus Dr. Clayton Darwin.
It has one quirk: it expects you to be working with a collection of texts,
which you must group together in a folder; you can't open just one file, unless
it's the only file in the folder. [Update: This is no longer the case;
now KwicKwic will also operate on individual files.]
"Hacking" is now mostly industrial espionage:
At least, that's the message of
this book
(Hacking: The Next Generation).
Apparently, a lot of corporate secrets leak out to people who pose as your fellow employees,
using information they got from the Web and from social media. Curiously, one point of vulnerability
is smoking areas, where everyone makes small talk and assumes that everyone else works for
the company.
Computers are now mainly tools for collecting unsecured information from the Internet.
Take-home lessons for everyone:
(1) The best way to keep a secret is not to talk about it very much. Even to the most trustworthy people,
one shouldn't chatter constantly about sensitive information. Some people are positively eager
to spill everything they know, the first chance they get. It makes them feel important.
(2) Anything you put on the Internet (even if only for "friends") will be seen and will be
put together. It is easy for a curious person to use Google to find and
assemble many separate pieces of a story.
(3) Corollary: Don't rely on "secret questions" that can be answered from your blog or Facebook.
Am I the only person who knows exactly where I got married, or what the name of our pet dog is?
Of course not!
More generally, don't assume that a small amount of trivial knowledge proves that a person
is an insider, or is who he says he is.
Geometry trivia: Etymologically, the word parallelepiped is
parallel-epi-ped ("parallel, upon the ground") and has nothing to do with pipe.
A parallelepiped is like a parallelogram in three dimensions. Here ped(ion) means
"the ground" (in Greek), not "foot" (in Latin). In Greek geometry, epipedion means "plane."
Retrocomputing continues: Minerva II now runs Windows XP, Linux, and DOS (yes, DOS), all of
which are on the Linux boot menu. Pictures tomorrow (probably).
We bid sad farewell to our old friend Bob Lucas of Altadena, California.
His wife Jeanie passed away in February. Both were well over 90 years old.
As newlyweds, Melody and I met them at church (First Baptist Church, Temple City, California);
the initial point of contact was Bob's interest in the TI-99 personal computer.
He worked for W. A. Whitney selling metal-punching tools and helped me with some electronic
projects.
Bob and Jeanie were an affectionate and godly couple and an inspiration to us.
I last saw them during my 2007 trip to Los Angeles and had received e-mail from Bob
quite recently.
There are said to be people who
believe that Bohemian Rhapsody
(a piece of 1975 rock music) is one of the high points of music history.
I am not one of them.
Now if I could just stop the tune from running around in my head...
June 16 was the centenary of IBM. In honor of this, I briefly turned on my 1983 IBM Personal Computer, which still works.
And IBM is starting to publish
technical papers
about Watson, the computer that played Jeopardy.
In the paper to which I linked,
the first item in the bibliography is (to my surprise and delight)
this book.
Maybe the world is starting to be ready for the research
I was doing 10 to 20 years ago.
Without entering the global warming debate, let me just point out that we may be
about to see a
slight
dip in the heat output of the sun
for perhaps the next fifty years.
It won't lead to an ice age, but it could lead to a period of
distinctly
cooler weather, counteracting recent global warming.
Most people don't realize how much the earth's climate has varied during just a few hundred
years. People in the central U.S. are often hit by unexpected floods simply because
nobody has lived in a particular place
long enough to know whether it can go a couple of centuries without flooding.
The East Coast has been settled longer (by people belonging to the current culture, not
just the Native Americans), but we still forget that, for example, the mid-1800s were chilly,
and in the Deep South, those high-ceilinged Victorian buildings were more comfortable in the summer in their own
time than they have been any time since the 1930s.
For an economic indicator, I frequently look at the estimated value of my house on Zillow.
I don't think Zillow estimates house prices very well, but their numbers certainly reflect something about the
local economy, and I'm trying to figure out what.
(Don't worry, I'm not selling or refinancing the house. Of course, if anybody wants to offer me a lot of money
for it, we'll talk... But I didn't buy it as an investment. I inherited it and bought out my sister's half-interest
in order to live in it.)
Anyhow, today Zillow showed a very large, sudden change in the value of the house. I presume either they changed
their algorithm, or they got some really important new data, or they made a mistake. I don't know which.
(I will update this entry if I get any more clues.)
[Note added June 18:] They have in fact
announced
that the algorithm and database underwent major changes on June 13.
From now on it updates 3 times a week and rounds to the nearest $200 instead of $500.
What is interesting is that their graph of past values of the same house also changed. It doesn't show the
values that they assigned to it in past years
— it shows what they now think it used to be worth.
At
two points that I can check, it agrees better with appraisals than before, although it's a little low.
In between those known points, it has changed substantially — for instance, a strange peak in 2009 has
been scaled down.
I think what has happened is that the "range" of values, at any given time, is the same, but now they are saying
the most probable value is well below the middle of that range; it used to be well above the middle.
Anyhow, the take-away point is that Zillow's graph of past values is not a graph of past Zillow estimates.
It's something else.
If you're using Internet Explorer 9 and vertical movement is very slow and halting,
particularly when you scroll with the mouse,
turn off smooth scrolling. I'm not kidding.
You may also benefit from turning off GPU rendering (accelerated graphics).
Right-click on the round gear and choose Internet Options, Advanced.
Highly recommended math book with misleading title
I highly recommend
Data
Analysis with Open Source Tools, by Philipp K. Janert, with the proviso that the book
tells you comparatively little about open-source software. (It tells you enough to help you
pick good software tools, but it's not a how-to-use-it manual.)
What it is, mostly, is a book of mathematical common sense, following the principle
that the three rules of clear writing are
get to the point,get to the point,
and
get to the point
(which are also rules that I live by).
Because the explanations are shorter, they are clearer that you can get in most
other books, and a very wide range of useful concepts are covered.
Click through and read the samples.
A crimping tool for all three sizes of modular plugs
Further to my disquisition about crimping tools the other day,
the one I ended up with is very satisfactory:
a
Platinum Tools
All-In One Modular Plug Crimp Tool,
which crimps all three sizes of modular plugs, as well as cutting
and stripping round and flat cable.
It even ratchets to ensure that you squeeze it far enough.
Highly recommended.
If your Brother labeler does this, it's not broken
I should have RTFM...
For years, the Brother labelmaker on my desk printed all its labels off-center
and preceded by little tick-marks, like this. I thought either the labelmaker
or the tape cartridge was defective. I tried resetting it by removing the batteries
for about five minutes, and that didn't help.
Eventually I got a new labeler, with an instruction sheet, and experimented with
the "margin" button. Presto — same problem!
It turns out this is normal behavior when you ask for less than the full amount
of blank space on the ends of the labels. The labeler can't shorten the part that
precedes the message, so it prints tick-marks to tell you where to cut. The part after
the message is shortened per your request.
On older labelers, this setting is Code, Tape and you should choose "####" on the menu
for full-width margins. The minimum, "-", is for printing labels as close together as
possible, for cutting apart later. The other values, "#", "##", and "###", give you
effects like that shown in the picture.
In 1981-82, until I married her and took her away from all that, Melody was the art
director of the Marietta Daily Journal ("MDJ") in suburban Atlanta.
Somewhat to her annoyance, some of her co-workers called her "Mel."
As a going-away present, they gave her, among other things, a big glass mug
with "Mel" engraved on it.
Yesterday (June 10), after almost 30 years of faithful service, the Mel mug broke
spectacularly coming out of the dishwasher. Farewell to this memento of the MDJ.
The "modular" plugs used with telephones, network cables, and other equipment
come in three main sizes.
The largest, 8 conductors wide, are used on network cables;
they are called 8P8C (8 positions, 8 conductors, RJ-45).
Intermediate is a common telephone connector that is wide enough for
six wires (6P6C) but may only have four or two (6P4C, 6P2C, RJ-11).
And the smallest is used on telephone handsets (4P4C, RJ-22).
I needed to replace a 4P4C plug and didn't have a crimp tool that would
accommodate it. So I bought
this one.
And I had to return it, because although it was supplied with three sizes of
plugs (8P8C, 6P4C, 4P4C), it wouldn't actually
crimp the smallest of these, lacking both a correct-sized hole and
a correct-sized "anvil" (that's what they call it) to press the conductors into place.
Somebody in marketing, quite high up the supply chain, made a mistake.
Fortunately I found something suitable on Amazon. See the June 13 entry.
There's a 14th-magnitude supernova in M51, the Pinwheel Galaxy.
I have photographed it, but not well.
This is a stack of three 5-minute exposures through my 8-inch telescope in my backyard
under rather murky skies. The supernova should last for weeks and I hope to get a
better picture.
Here
(with more links) is some timely information for the summer.
People drown in swimming pools, even while other people are watching and
don't realize what's going on.
Key points:
Drowning people don't yell. They can barely breathe — they can't yell.
Drowning people don't wave their arms. They are using their arms to try to stay afloat.
A drowning person bobs up and down with the mouth intermittently out of the water.
Drowning people are usually upright, not in a normal swimming position.
Here's the reason, as best I understand it. Human beings have a swimming instinct, which kicks in automatically
when a person is on the verge of drowning. Drowning people often
seem to be climbing an invisible ladder and don't use their legs effectively to swim (just their arms).
That's why they drag rescuers underwater. But these behaviors would have good survival value in ponds
with sloping sides and in any place with debris underwater, such as dead trees (where the ladder-climbing
behavior would be crucial). The vertical sides of
a swimming pool make it especially dangerous because survival instincts won't get a person out of it.
Further to yesterday's entry, I should explain that I have no pressing need
to read my old DOS 1.1 diskettes (from 1983). But they are an interesting test
of functionality.
On the retrocomputer, when I boot DOS from a diskette, I can read them just fine, but
DOS can't see any part of the 500-GB hard disk; the sector numbering is beyond its
comprehension.
I experimented with installing FreeDOS, an impressive,
Linux-like replacement for DOS. It installs the way Linux does, auto-detecting
your equipment, and supports large disk drives, CD-ROMs, networks, and even USB devices.
The procedure was as follows:
(1) From Linux, use gparted to create a small (30-MB, not GB but MB) disk partition
with the LBA flag set, formatted as FAT16.
(2) Create a file in this partition (I created one called "usethis.txt") so you can positively
recognize the partition later.
(3) Boot from the FreeDOS CD. Confirm that FreeDOS sees only one disk partition — the one
you just created — and that it contains the file you put there. To FreeDOS, it will
be drive C.
(4) Install FreeDOS there.
(5) Reboot, and in Linux, do a sudo update-grub to put FreeDOS on the boot menu.
All went very smoothly. But the disappointing thing was that although FreeDOS claims to know
how to format all those old diskette formats, I couldn't get it to read one.
So I ended my brief experiment with FreeDOS.
Minerva rides again too
(And a note from the strange forgotten world of diskettes)
From the best parts of my recently-decommissioned computer Minerva and a computer
recently taken out of service by Melody's parents, I've built a retrocomputer —
a computer specifically for backward compatibility with old software and media.
It has working 3.5-inch and 5.25-inch diskette drives, as well as a 2.4-GHz Pentium 4,
a 300-GB hard disk, a CD-DVD burner, and USB and Ethernet connectivity.
At first I was going to install a whole zoo of operating systems on it, but sanity took hold
and I settled on Windows XP and Ubuntu Linux 10.04 LTS. It will also boot DOS from a diskette.
I couldn't install Windows 98 or anything earlier — the hard disk is
way too big. (Even making a small partition wouldn't get away from the fact that the
cylinder and sector numbers are too big.)
And Windows XP
won't read all the diskette formats PCs have ever used.
The old DOS 1.1 8-sector (160K and 320K) and DOS 2.0 single-sided (180K) formats are unsupported.
But if I boot DOS from a diskette, I can read these. I can only copy them to another diskette,
of course, because DOS can't see any of the hard disk partitions.
I call them "diskettes," not "floppy disks," because since 1987 they have been in hard
shells, not floppy.
We were astonished this morning to learn that it hasn't been salvaged — it's still
on the back lot of the place where we used to have it repaired — and one of the
mechanics wants to get it running.
He'll do fine, with his own labor to invest in it, and our trusty old minivan won't die.
Today's news story out of Atlanta belongs in Ripley's Believe it or Not.
By way of background, you'll remember that a while back, the University of Georgia
furloughed faculty members for a few days because of budget problems.
Fortunately, UGA thought about it before they did it, and various safeguards
were in place.
I think it's a tacky move, and a costly one. Do they realize that from now on, it's going to
be harder (that is, costlier) for them to hire teachers? They've marked themselves as an
untrustworthy employer.
Note in the news story that although the judge lifted the restraining order, he
invited the teachers to sue for breach of contract. Sparks are going to fly.
And note that the Clayton County School System is not the brightest jewel in our crown;
it actually
lost its accreditation
for a while starting in 2008.
Clayton County is the site of most of the Atlanta Airport.
Part of the airport is in Fulton County.
I wonder what measures our state constitution provides for dealing with a rogue county, one that
persistently fails to perform its legal duties. Can the Legislature de-charter a county, or put it under
some kind of conservatorship?
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