Lojic Technologies

Archive for January 2008

Arc has been released

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This has been a long time in coming. Paul Graham and Robert Morris have released an initial version of the Arc programming language.

Language Web Site

They recommend using version 352 of MzScheme because the latest version apparently breaks Arc. I already had 360 installed and was in a hurry, so I tried it, and most of the tutorial seemed to work fine except for the web server which failed. I’ll try later with 352 and see how it goes.

The language is still quite volatile, so I’m not sure if anyone is too interested in investing a lot of time creating libraries yet, but when the language settles down, I’m very curious about the acceptance level of Arc.

It seems to have quite a bit of Lispy goodness, and I’ve agreed with Paul’s language philosophy from what I’ve read about what he wants Arc to become. Hopefully it will live up to those ideas. On the one hand, I can see benefits in having a standard such as the one for Common Lisp, but on the other hand, Ruby & Python have done extremely well with the BDFL model with Matz & Guido, and I think Paul Graham could pull off that role if he wants to.

A problem with a “standards” approach is the proliferation of implementations dividing the community; whereas, the single implementation languages seem to have a more unified community.

If Arc can retain the best of Lisp, add some niceties from other languages and attract an active developer community, I think it may become very interesting.


Probably one of the best things I’ve gotten out of the Arc release so far was a tip from a guy on the forum on how to add readline support to the Arc REPL using rlwrap. I’d never heard of rlwrap before, and it’s awesome! I can now get readline support for logo and arc without needing to rebuild them with native support.

sudo apt-get install rlwrap
rlwrap logo

What a great idea 🙂

Written by Brian Adkins

January 29, 2008 at 9:14 pm

Posted in programming

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Automatically Delete Unwanted Cookies in Firefox

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I prefer to not have cookies stored in my browser, but it’s impractical to not store any cookies since this would require repeatedly logging in to authenticated sites that I frequently use. A simple solution in Firefox is the following:

From the Edit menu, choose Preferences and then click the Privacy tab. You should see a dialog similar to the following one:


Check the “Accept cookies from sites” checkbox. For the “Keep until” setting, select “I close Firefox”. The latter is the key – it will erase all cookies from Firefox whenever you close the program. Of course, we don’t want to erase all the cookies, so click the “Exceptions…” button on the right and you’ll see a dialog similar to the following:


Just type the name of the web site you want to allow in the text box and click the “Allow” button, and Firefox will add it to the exception list so it won’t be deleted when you close Firefox. You can add a full URL such as http://www.MySite.com, or just the domain name MySite.com to allow cookies for any host in that domain. You an also add sites you want to disallow any cookies from by clicking the “Block” button.

I have about 30 sites that I allow Firefox to store cookies for, but this technique has helped me avoid accumulating tons of unwanted cookies in Firefox. I hope it’s helpful for you.

Written by Brian Adkins

January 26, 2008 at 1:06 pm

Posted in internet

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Dolphin Bubble Rings

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My uncle passed on a link he received from my cousin to an amazing video showing dolphins cleverly making sophisticated bubble rings and manipulating them in interesting ways:

Written by Brian Adkins

January 22, 2008 at 9:25 am

Posted in science, video

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Beware of LEGO Mindstorms NXT on Mac OSX

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I recently installed the software that came with a LEGO Mindstorms NXT kit onto a Mac Mini running OSX 10.4. I was somewhat concerned when the install program prompted me for an admin password, so I attempted to install the software into a directory in my home directory instead of the main Applications directory, but it still prompted for an admin password. Since LEGO is a large reputable company, I gave them the benefit of the doubt and figured the admin password may have been necessary to install Bluetooth drivers or some other feature. I should’ve learned a lesson from the Sony root kit debacle with respect to blindly trusting large corporations. In the Sony case, maliciousness was involved, in the LEGO Mindstorms case, I think only incompetence is to blame.

After installing the LEGO Mindstorms NXT software, I noticed that the OSX Activity Monitor failed to start which was puzzling. I also noticed that my Missing Sync program (used to synchronize data on my Treo 650 with the Mac) was failing as well – probably related to Bluetooth misconfiguration. I discovered later that, independently of the software issue, the LEGO Mindstorms NXT kit was malfunctioning (some attachments worked, but the motors couldn’t be activated), so we sent it back for an exchange.

I thought that uninstalling the LEGO Mindstorms NXT software might return my Mac OSX system to normal, so I found the uninstall shell script in the Applications directory. With many OSX applications, it’s sufficient to simply delete the directory associated with the particular application from the Applications directory, but since Bluetooth drivers (and possibly other stuff) was installed, I figured the uninstall script would remove anything that was installed. I viewed the contents of the script briefly, but I was in a particular hurry at the time, so I double-clicked the icon for the uninstall script before I thoroughly reviewed it. It took longer to execute than I expected, and to my great dismay I shortly discovered why.

The LEGO Mindstorms NXT uninstall script removed the entire Applications directory from my Mac OSX system!

I’ve contacted technical support at LEGO Mindstorms mainly to try and determine how this happened. One of the reps did admit that this has happened before. I’m not sure what they could do to resolve this to my satisfaction other than pay me for the time I’ve lost in trying to get the Mac back to normal. I’ve been able to get the bundled applications reinstalled with some effort, but I still have a fair amount of work to do to reinstall many open source apps.

If LEGO Mindstorms comes up with a creative solution to resolve this to my satisfaction, I’ll be elated to post an update, but I expect that to be unlikely to say the least. Hopefully this blog post can save at least one person from losing an entire day to a similar problem.

When the replacement LEGO Mindstorms NXT kit arrives I’m either going to install the software on an old Windows PC, or create a new virtual machine for that purpose, but I don’t think I can trust LEGO Mindstorms enough to install it on an important computer at this point. Regardless, I’m going to be much more careful (paranoid?) when installing software that requires root access in the future.

Update 1/18/2008: It’s been ten days since I originally called LEGO Mindstorms NXT technical support, and I haven’t received a call from a supervisor or level 2 person as was promised. I just called them again and talked to the same person who opened the ticket originally. He still refuses to allow me to talk with his supervisor (actually, he states he doesn’t have a supervisor, and that level 2 is his “supervisor”) and simply repeats the same mantra about how my issue has “been escalated several levels”. I can’t recall a tech support experience that has been quite this bad.

Update 1/18/2008 13:00: I just received the following email response a few minutes ago (probably because I communicated the situation to LEGO corporate headquarters).


Your issue has been escalated to the developers in Denmark.
They will get back to you, but we have no control over when that will happen.

In the meantime the only solutions we can offer to you are to repair user permissions and to do an archive reinstall of your Operating System.

Update 1/24/2008 14:10: Just spoke with David C. from LEGO Mindstorms NXT QA (he was referred to me by a LEGO consumer specialist I had spoken to a couple days ago), and he explained the situation to me. This was a known issue (deleting all your apps on Mac OSX) that has apparently been fixed in the current release of the software. He apologized and will send me a free LEGO Mindstorms NXT kit. It doesn’t match the monetary loss in time, but it’s a nice gesture and I appreciate it. I expect it’s more than many companies would do to remedy the situation.

As to the communication issues with the first line technical support, out of respect for David I won’t go into detail, but suffice it to say that they are aware of issues with their front line support and are endeavoring to correct them.

Written by Brian Adkins

January 8, 2008 at 6:19 pm

Posted in programming, technology

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