Fiddling with Computers
For several years, I got my computer jollies as a parent volunteer
helping to administer the computers at the
local public school.
But that gig eventually ended
when my yougest kid graduated from high school.
I've continued to fiddle with computers at my home,
and have run across several issues that may be helpful to others:
- Networking Windows XP Home Edition
Despite having almost exactly the same name,
Windows XP Home Edition
and Windows XP Professional Edition
are very different to administer.
For example the things you would do as an administrator
to network Windows XP Professional Edition
are almost exactly what you should not do
in the process of networking Windows XP Home Edition.
If you find it necessary to work with Windows XP Home Edition,
here are some suggestions on how to network it.
- Troubleshooting: Guidelines and Techniques
Often administering computers is just dealing with one problem after another:
pin down the problem; fix it; rinse and repeat.
Isolating and fixing problems is often called "troubleshooting".
Think troubleshooting is a black art that a few people are good at
while most only stumble along?
It doesn't need to be.
Troubleshooting can be broken down into detailed and specific steps that can be learned.
In fact, here they are.
- Using alternative DNS services for different or better functionality, even despite apparent "intercepting"
At its core, DNS (Domain Name System)
—also called "name service"—
translates human-friendly textual computer names
into the numeric IPaddresses computers use internally.
Although DNS service
is usually provided by your ISP,
some alternative services are also available.
You may wish to use one of
these alternative DNS services,
either for improved performance or for access to different ancillary funtionality.
Unfortunately using an alternative DNS service
can be a bit tricky
because it often appears DNS packets are being "intercepted"
by the ISP.
By understanding what's really going on under the covers,
you can escape any possible "interception"
in virtually all cases.
- Single User Mode
A useful part of Unix-derived systems
is called "single user mode".
Special Unix runlevels can be useful for system self-maintenance,
for example repairing or replacing disk partitions.
In fact often more than one
thing is called "single user mode" ...which can be confusing.
Redhat/Fedora/CentOS distributions of Linux
try to reduce the confusion,
partly by introducing some new technology.
- Disk Surface Scan
It's unavoidable that almost all computer disks
(persistent memory for "files")
have microscopic flaws in the magnetic material that forms their surface.
Normally the disk itself compensates for these flaws.
But very occasionally there may be reason
to use Linux software tools instead
to compensate for these flaws.
- Dealing with a web indexing delay
Hopefully web indexing results are very current,
even for small non-commercial websites.
This isn't always the case though.
If all changes to your website seems to be subject to
a one or two week delay before appearing in a web index,
it's likely your website is being subjected to a poorly documented
(and maybe even supposedly non-existent)
You're probably not hallucinating (although many people will tell you you are),
and situation isn't hopeless.
It's usually possible to figure out
what the problem really is and fix it.
Sometimes when a webpage under development just won't behave,
it would help if the developer knew
exactly which events were being fired,
in what order, and how often.
These pages alert you to the typical firing
of several events.
One is page layout-related events; the other is user interface-related events.
(Having code figure out for itself
which events a particular version of a particular browser supports
is a harder problem which isn't addressed here.)
- Actual Reported Web Device Dimensions
Actual Reported Web Device Dimensions (Unconstrained)
Particular browser and device combinations
do not always report the dimensions one initially expects.
Problems with Media Queries often trace back
to assumptions about the dimensions reported by a device
not being true.
This is especially the case with devices that provide a
which should be controlled by a
in the HTML of the webpage,
but often isn't and often defaults to unexpected behaviors.
It's instructive to compare reported dimensions
a meta...viewport... statement.
- An Alternative to Media Queries
Supposedly a wonderful way to
provide different CSS to different devices
in order to implement different layouts
(sometimes called either
liquid layout or
is to use the CSS feature Media Queries.
But in many environments using the Media Query feature
turns out to be quite problematic.
An alternative approach that overcomes most of the practical problems
and works quite well in unpredictable heterogeneous environments
- Using Both Coordinate Systems of a Canvas
We're accustomed to HTML elements having only one coordinate system,
which we specify in CSS.
remain defined for a few HTML tags, we've learned not to use them.
But the new HTML/HTML5 canvas
A canvas has two different coordinate systems simultaneously.
The display coordinate system, defined in CSS,
controls how much space the canvas occupies on the screen.
The model coordinate system, defined in the HTML,
Fully using both coordinate systems
allows canvases of different sizes to all use the exact same
- Automatically Centering Text on a Canvas
Centering text drawn on an HTML/HTML5 canvas
either horizontally or vertically (or both) can be completely automatic.
There's no need to measure
the text and then use the text metrics to calculate the appropriate starting point.
Automatically centering text either horizontally or vertically
(specifying that text should be centered in both directions
- Intermittent Connectivity with NTP Time Service
The current implementation of the hoary NTP Time Service works quite well,
even with intermittent network connectivity, very accurate clock hardware,
and the current expectation of much faster syncing.
Be a better netizen
by using NTP to set up a shared local time reference
for all the computing devices in your house.
Sharing a local time reference minimizes the load
on both the network and upstream time reference servers.
While the suite of NTP programs has grown quite capable,
the lore of recommended usage and configuration tweaks
has remained firmly in the past and is now ridiculously outdated.
- Tweaking URIs (short version- the highlights) adapt new layout, be more friendly, improve SEO
Tweaking URIs (long version- the details) with Apache mod_rewrite via .htaccess file
Precedence of AND and OR in mod_rewrite RewriteCond combinations
you present to the world are in a sense your website's
Your file layout and names on the other hand
are essentially internal.
Oftentimes external and internal match.
But sometimes they don't.
When they don't match, the web server needs to perform
some sort of mapping from the
requested by the client to the right file or return code.
With the common Apache web server,
there are several different ways to do that mapping
(even on a shared webserver where the webmaster
can access only their own area,
not the global server configuration).
The most comprehensive mapping tool
is one of the many Apache plugin modules,
the one called mod_rewrite.
- Android Tasker offers a bewildering variety of string test alternatives
Tasker is a sort of programming tool
commonly used to automate and/or customize an Android smartphone.
Although not nearly as complex as a complete programming environment,
it's nevertheless somewhat like
a computer programming language.
Tasker offers several somewhat different overlapping
ways to test strings.
It can be a little unclear which method to use when.
Further, different methods provide different default options
(for example one method defaults to case-sensitive
and another to case-insensitive,
and the way to switch case sensitivity is not the same for the two methods.)
Although this is all thoroughly and completely covered
in the Tasker documentation,
you may find this description a little easier to follow.
My significant current interests include not only
this fiddling with computers, but also
exploring both old and new movies.