Wrestling with Apache’s mod_rewrite
mod_rewrite is a great (read: extremely useful) module. For those who may be unfamiliar with its amazing abilities, unlike mod_alias, mod_rewrite actually re-writes a given url, so that
http://www.mydomain.com/some%20ridiculous%20url%20with%20spaces%20in%20it.html
turns into
http://www.mydomain.com/this
and other such wonderful things, completely replacing what would otherwise be visible to the browser's url bar and to search engines. Thus, this becomes a staple of the "Search Engine Friendly" url contingent for CMS-driven sites (such as those hosted under Joomla! and WordPress, for example).
Updating Firefox on Linux: the Dreaded “Couldn’t load XPCOM”
I bumped into this annoyance while updating my openSUSE 11.4 workstation tonight.
There are numerous mentions of this issue on the net, and numerous suggestions for addressing it. However, none of them (which I saw) really hits on the underlying problem, which is that somewhere, somehow, XPCOM can't start.
To understand what's going on, it's important to have a basic understanding of what XPCOM is, and how it is involved with Mozilla apps. XPCOM is an acronym for "Cross Platform Component Object Model," which is Mozilla's equivalent technology to CORBA or Microsoft's COM. Like any other "object model," XPCOM's function is to provide a modular framework vs a monolithic one. This modularization allows XPCOM to be (mostly) platform-neutral, making it possible to run the Gecko rendering engine on a variety of platforms. So, as the Gecko engine is composed of XPCOM components, if XPCOM cannot start, Gecko cannot start. If Gecko cannot start, then there is no rendering engine for the application, essentially stopping whichever Mozilla-based app one might wish to run, before it even gets started.
The strangest laptop repair I’ve ever done
Those of you unfortunate enough to have purchased notebooks (and video cards) with so-called "high performance" video in recent years with some Nvidia (and other manufacturers', I would guess) chips have my deepest sympathy. We spend (spent) a good deal of money for the "upgraded" video, only to find that truly, the light that burns twice as bright burns half as long, and typically, just outside of the 3-year warranty (in the case of the ThinkPad T-series), we get not only a BSOD, but garbled output on an external display, as well.
Nvidia's problem has been quite well documented on the net (for examples, see here and here and here).
Well, my wife's T61 was no exception, and about a month out of warranty, sure enough, after some fanfare (intermittent BSOD, hangs, etc.), it finally went black (well, mostly). Connecting to an external display proved that the system was indeed running, but that the video was unreadable.
I considered attempting to purchase warranty service after the fact, as recommended by the Lenovo rep quoted in the third link, above, but after reading more in that particular thread, I decided to try reflowing the solder myself.
It took me about an hour to strip down the machine to pull the system board (hint: if you do this, be sure that you take your time, and prepare for the reassembly of the machine, particularly insofar as keeping your removed hardware in order and obtaining a supply of thermal grease for the reinstallation of the heatsink & fan assembly). I noted that the board fit perfectly in our Black & Decker toaster oven, so I pre-heated the oven to ~385℉, fashioned three support "balls" of aluminum foil (each approximately 1" in diameter), and placed the board face up on the supports. When the oven was at temp, I put the board in for about 7 minutes.
Remember that the burning point of paper is 451℉ (like Ray Bradbury's book!), so the labels didn't even singe. I did not remove any of the plastics on the board (the insulation sheets), nor did I remove the VGA connector (which has a plastic insert).
Contrary to all of the warnings by the aforementioned Lenovo employee (Mark) in the forum, I had no trouble with this procedure (hey, the warranty was up, anyway; a new system board for this model runs about $600 from IBM/Lenovo - yes, some have reported factory repair quotations of less than this; I suspect that those repairs only include properly reflowing the solder for the GPU, and not a complete board replacement). The board shows no sign of being subjected to any heat beyond the normal range one would expect after 3 years of continuous use. I did not shield any parts of the board with aluminum foil, as some youtube videos seem to indicate is necessary when using a heat gun for the procedure (I figured it would be better to evenly heat the board in an oven, than to blow hot air on it "in a circular motion," subject to the ambient temperature).
After an hour to cool down, I began reassembling the machine. This procedure took me about two hours; I cleaned as I went. After that, I had to scare up a power supply (I had a replacement unit in stock which didn't seem to be working; however, upon re-seating the battery, I found that the adapter did actually apply power to the notebook). I pressed the power button, and almost fell out of my chair (up to this point, I pretty much gave the whole thing about a 50/50 chance of success). The screen was bright & beautiful, with no sign of its previous trouble.
How long will it last? Who knows! Could I offer this as a service to my clients? Absolutely not. The risk of failure, I suspect, is not worth the time and effort to try (I don't mind wasting 3 hours on my own junk, but spending 3 hours on someone else's, with no result, either yields an unhappy customer or an unhappy me).
Anyway, if you're seeing similar issues with your ThinkPad T4x-series or T6x-series machine, and you're out of warranty with a few hours to kill on a Sunday afternoon, at least you know that it worked for me. 😉