Fitts' Law and edge-flipping in window managers
Simplified and summarized a lot, Fitts' Law says that the four ofthe five easiest locations to reach with the mouse are the fourcorners of the screen, because they require very little precision.(There's a lot more to it than just that, of course; see AskTog .)
A number of window managers, fvwm2 included, have virtual screensand a feature called 'edge flipping': if you move your cursor toa screen edge where there's another virtual screen beyond it andkeep
Randomly engaging NumLock considered irritating
Dear Fedora Core 6 X server: please stop randomly turning my NumLock on.It's getting really old by now, especially since I use a BTC-5100C minikeyboard and so turning NumLock on sprinkles numbers around my typinginstead of the letters that I expected.
(It also makes various fvwm2 operations not fire, since I'm not hittingshift+alt+mouse button, I'm 'hitting' shift+alt+numlock+mouse button.I'd tell fvwm
How comment spammers behave
One of the things that watching your logs while trying out variouscomment spam precautions is good foris seeing how comment spammers seem to behave, or at least how thecomment spammers that drop by WanderingThoughts behave. (Your mileagemay vary, since there are a lot of comment spammers out there and theycan't all be using the same tools.)
As before, I'm only really interested in defeating the automated commentspammers; a dedicated person is always going to be able to leave commentshere. (
Weekly spam summary on March 24th, 2007
This week, we:
- got 12,733 messages from 249 different IP addresses.
- handled 21,567 sessions from 1,259 different IP addresses.
- received 197,829 connections from at least 58,846 different IPaddresses.
- hit a highwater of 8 connections being checked at once.
This is up from last week , althoughthe messages received count remains down from the usual levels.
| Day | Connections | different IPs |
| Sunday | 29,9 |
Counterintuitive RAID read performance
While doing performance tests on an iSCSI RAID controller, we recentlyturned up some unexpected results: the controller could writesignificantly faster than it could read, to both RAID 5 and RAID 0targets. In one case, a six-disk RAID 0 target could do streaming writes20 megabytes/second faster than it could do streaming reads (75 MB/swrite versus 55 MB/s read).This surprised me a lot, because I usually expect reads to run fasterthan writes. (It
Making user home directories on a stock Solaris machine
I was charmed to recently discover that Solaris 10 still hasn't fixedthat useradd issue I saw with Solaris 9 .For my future reference, since I am likely to wind up doing this a lot,here is how I add users on Solaris 10; this may or may not be theofficially approved way to work around the useradd issue.
useradd -c Whatevermkdir /export/home/chown/export/home/ (This may
An irony of conditional GET for dynamic websites
Ironically, dynamic websites are the least served by HTTP conditionalGET , because by the time they've worked outwhether or not a page's content is the same as what you've already got,they may well have generated the entire content. As a result, the onlything conditional GET really gets many dynamic websites is bandwidthsavings, which may go some way to explaining why many dynamic frameworksdon't have very good support for it.
(The same is true for HTTP
HEADrequests, generally
Users are almost always right
One of the rules of system design ought to be this:
When the users keep doing it wrong, the users are right and yoursystem is wrong.
I don't mean this in the sense that accommodating users is the rightthing to do; I mean this in a very pragmatic sense. If the users keepmaking some error, changing their behavior is going to be very difficultand therefor costly. (In a fight between user inertia and anything else,bet on user inertia.)
This means that changing
On educating users
In a context that's not important, someone on our local sysadminmailing list recently wrote:
I think the bottom line is end-user education.
I disagree. It is my opinion that any time end-user education appearsto be the answer, we have already lost. People do not change theirbehavior just because we want them to, and they rarely really changetheir behavior because we threaten them. (Although they are very good atfaking it until we are just enough out of sight.)
The
The three strata of virtualization
It struck me recently that you can view the general virtualizationworld as having three strata:
- at the first level, people are just interested in virtualizing andisolating user-level programs. This is the world of FreeBSD jailsand Solaris zones.
- at the second level, people are interested in virtualizing theentire operating system. This is the world of server consolidation,hypervisors, paravirtualization and so on.
- at the third level, people actively want to virtualize even thehardware itself. This is often the world of testers and so
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