Fazal Majid's low-intensity blog

Update (2011-05-12): the answer is no, it’s a Navteq 3D mapping car with a LIDAR array. Thanks to Darrell Kresge for the clarification.

As I was walking to lunch today, I caught sight of this weird contraption, and had just enough presence of mind to grab a few snaps of it.

One strange feature is a spinning white cylinder inside the arm canted at a 45 degree angle.

It doesn’t look like any of the Google Street View vehicles captured before, nor does it have the Google markings. The Michigan license plate is a bit odd as well. A prototype, perhaps? Or is some other company is getting into this racket, perhaps Microsoft?

This may be of use to people experiencing the dreaded “You do not have sufficient permissions to access this page.” message when trying to reach WordPress’ admin page, even when logging in as a proper administrator. WordPress embeds the table prefix in 4 different locations:

• The wp-config.php file
• The name of the tables
• The name of user metadata keys
• The name of blog options

Thus if you want to change the prefix, you have to:

1. Edit wp-config.php to change the prefix
2. Rename your tables
3. Rename your user metadata
4. Rename your site options

Missing steps 1 or 2 will cause WordPress to not find the tables, and it will go through the initial install process again.

Missing step 3 will cause the account to lose its roles, and thus not be authorized to do much besides read public posts.

Missing step 4 is more insidious, as it destroys the option wp_user_roles, the link between roles and capabilities, and thus even if your account is an administrator, it is no longer authorized for anything.

It feels quite clunky to embed the database prefix in column values, not just tables, just like WordPress’ insistence on converting relative links to absolute links. The former makes moving tables around (e.g. when consolidating multiple blogs on a single MySQL database) harder than necessary. The latter makes moving a blog around in a site’s URL hierarchy break internal links. I suppose there are security reasons underlying Automattic’s design choice, but security by obscurity of the WordPress table prefix is hardly a foolproof measure.

If you are renaming the tables, say, from the default prefix wp_ to foo_, the MySQL commands necessary for steps 2–4 would be the following:

UPDATE wp_usermeta SET meta_key=REPLACE(meta_key, 'wp_', 'foo_')
WHERE meta_key LIKE 'wp_%';
UPDATE wp_options SET option_name=REPLACE(option_name, 'wp_', 'foo_')
WHERE option_name LIKE 'wp_%';
ALTER TABLE wp_commentmeta RENAME TO foo_commentmeta;
ALTER TABLE wp_comments RENAME TO foo_comments;
ALTER TABLE wp_links RENAME TO foo_links;
ALTER TABLE wp_options RENAME TO foo_options;
ALTER TABLE wp_postmeta RENAME TO foo_postmeta;
ALTER TABLE wp_posts RENAME TO foo_posts;
ALTER TABLE wp_redirection_groups RENAME TO foo_redirection_groups;
ALTER TABLE wp_redirection_items RENAME TO foo_redirection_items;
ALTER TABLE wp_redirection_logs RENAME TO foo_redirection_logs;
ALTER TABLE wp_redirection_modules RENAME TO foo_redirection_modules;
ALTER TABLE wp_term_relationships RENAME TO foo_term_relationships;
ALTER TABLE wp_term_taxonomy RENAME TO foo_term_taxonomy;
ALTER TABLE wp_terms RENAME TO foo_terms;
ALTER TABLE wp_usermeta RENAME TO foo_usermeta;
ALTER TABLE wp_users RENAME TO foo_users;

Not only do Webpass give me fast 45Mbps symmetrical access for $45/month, with no capricious restrictions or anticompetitive shenanigans, but they are also real mensches.

When you visit the Dell website, the first thing they force you to decide is whether you are a Home, Small Business or “Enterprise” business customer. At one point, the thin and light laptops were only available in the Enterprise section—perhaps plebs and small businesses are judged unworthy of appreciating the finer things in life, unlike the kleptocrats who run large corporations. We hoi polloi presumably should be content with our fate and make do with last year’s (decade’s?) technology.

When you search for products on Amazon, you have to select a “Department” to enable sorting by price. What do I care whether a microfiber cloth was filed under “Automotive” or “Electronics”? Taxonomies are inherently subjective, a fact librarians know well, but is surprisingly poorly understood outside the field.

Both cases illustrate what happens when a self-centered organization puts its internal structure and implementation details ahead of its customers.

Since you keep hitting me with these spammy popups no matter how many times I click on “Do not show again”, you leave me no choice but to switch to VirtualBox (much better software in any case, and less Windows integration means less chances a virus breaking out of the virtualized Windows ghetto.

Oh, and installing MacFuse without asking permission (unlike VMware Fusion): not cool.

Don’t let the door hit you on the way out.