Critical Exponent

Here’s how to add or, better yet, create your own search engine in Firefox.

This has been getting some publicity lately, but I figure it’s always nice to have handy. Here’s Paul English’s cheat sheet to get around automated voicemail systems and speak to a live person.

While I’m at it, let me air a pet peeve: you dial some sort of service provider (bank, broker, it doesn’t matter), the voicemail system asks you to input your account number and other identifying information, puts you on hold, and finally transfers you to a live person… who then proceeds to ask you for exactly the same information you already typed in! Grrr….

After writing about virtual machines yesterday, I had a vision of the future of computing. Imagine this:

You go to your favorite computer stand, where there are public computers for you to use. Each of these has a virtual machine player installed. You sit down at one these machines, take your flash drive out of your pocket, plug it into the machine’s USB port, and run the virtual machine that’s stored on the drive. Your operating system comes up, just as you left it last, with your files. As long as you work inside your virtual machine, you cannot infect the physical computer you happen to be on, nor can it infect your virtual machine. When you’d done with what you need to do, you hibernate or shut down your virtual machine, take out the flash drive, and go about your day.

This isn’t at all far-fetched, and is eminently portable and pretty well secure (not absolutely, though: the host computer could be running a password sniffer, but even so, they cannot access the virtual machine files stored on the virtual file system on your flash drive).

There are two obvious drawbacks or hurdles with this model. First, public hardware must be ubiquitous (and must have been set up to have a virtual machine player, since that installation necessarily requires administrator privileges). While I can envision many computer booths in the city, remote areas and vehicles are unlikely to offer these facilities extensively. (Moreover, they must be financially self-sustaining, and perhaps people will grow tired of paying for every login even if it winds up being cheaper than buying a laptop.)

Second, a monoculture of the virtual machine players would have to be avoided. While monocultures are great for standardization, they also become attractive targets for security exploits, commonly lead to monopolistic complacency, and essentially require all users to trust a single entity to operate ethically.

Still, imagine if these problems were solved and you really could carry your operating system and your files in you shirt pocket….

Have you ever wondered whether the world around you is real or whether you are just a diesmbodied brain in a vat, your nerves artifically stimulated to create the illusion of your surroundings?

Well, now you too can create your own Matrix for your favorite (or least favorite) operating system. VMware offers a free VM Player for Windows and Linux and some virtual machines for download. Not Windows, of course, since it’s proprietary, although Hack-a-day tells how to take your favorite virtual machine and install an arbitrary OS on it without getting VMware’s vm-authoring products.

I spent a lot of my computer time this weekend migrating my personal finances to GnuCash 1.8, the open-source answer to Quicken and MS Money.

Thus far, I’m pretty excited about GnuCash and think it will be a more efficient way to keep track of money than the generic spreadsheet I’ve been using for several years. I’ve found a couple of minor issues:

• In the documentation, one first reads that the accounting equation is Assets - Liabilities = Equity + (Income - Expenses) which does not make sense to me as written, without any time indeces. This second equation, should, I believe, read as follows: Δ(Equity) ==Δ(Assets-Liabilities) == Income-Expenses, or Equity(i)==Assets(i)-Liabilities(i)=Equity(i-1)+Income(i-1)-Expenses(i-1) which is also consistent with the diagram on that page

• The standard Account Summary report has a mysterious “Total” line which appears formatted as though ti were the total for all the accounts in the report, but whose value is actually just Income - Expenses.

• When setting a semi-monthly automatic payment which will go into effect beginning with second transaction in the current month, that next transaction does not appear to be automatically scheduled.

Over a year ago, I got a second-hand Lexmark Z52 ink-jet printer. I set it up to work on my Linux box, using the driver that Lexmark provided for download. Unfortunately, I could not get the printer calibration program to work correctly; it would refuse to print its test files. I figured I had the printer working well enough and would get back to this later.

About a year ago, when I got the wireless router, I also tried to get the printer to work over Samba so that Knox could access it from his Windows laptop the same way that he can access shared directories on my Linux box. I never got that to work either.

This weekend, I finally resolved both issues– they had the same cause. See, my lpd server was set to examine files for printability (this appears to have been the default, despite the man page), so all the binary files from Windows or from the printer calibration program were failing unless I explicitly passed the -b flag to lpr to specify a binary file. This is easy to do in Samba (one just modifies the print command parameter in smb.conf) but not so easy to do in the Lexmark printer calibration program (since it is compiled code and has no configuration file).

The solution, then, turned out to be simple: I just added the line
check_for_nonprintable@no
to my /etc/lpd.conf file, and now it does not try to prohibit file formats it does not recognize. I no longer need to specify the -b flag to lpr, and the printer calibration program works 100%.

It took me a while to figure this out, as I was focusing on the printer-sharing issue and thought there was a Samba problem. It turns out Samba was working beautifully; it was just lpd being over-protective.

While I’m on the topic, kudos to Lexmark for providing Linux drivers and a Linux Developer Kit!

I’ve just released the first public version of ssh-tunnel, a very simple shell script that can be used to implement port forwarding with ssh. This is useful, for instance, when forwarding VNC connections over a series of secure links, but is also applicable to any application that requires ports to be forwarded securely. I was inspired to write this by the hassle required to forward my VNC ports over all the connection hops required to securely get through my corporate firewall to my office machine. Now, a single alias does it all for me! Could working at home get any easier?

Part of my motivation, too, was to get experience contributing open-source software to the world at large. The GNU website explains how to do it. Eric Raymond’s The Art of Unix Programming also discusses various types of licenses.