The If-Modified-Since header in HTTP requests is used as one way ofdoing 'conditional GET' requests, where the web server can give you anice bandwidth-saving '304' response if the URL hasn't changed sincethe version you already have. In theory the header has an arbitrarytimestamp and the server will 304 the request unless the page haschanged since that time.

In practice, the HTTP RFC strongly recommends that clients treat thevalue as a magic cookie, just

For reasons outlined in CPANProblem , I don't installPython packages using their setup tools; I build them into RPMs andinstall the RPMs. Python's distutils (the setup system used by mostPython packages) have a command to do this, called bdist_rpm , butit has some issues that have caused me to become quite familiar withits inner workings.

bdist_rpm works in the following steps:

1. use the distutils sdist command to create a source tarball.
2. write an RPM specfile.
3. create a local

I recently realized something: databases are APIs .

Just like library functions and classes with defined methods, thecolumns and tables and inter-table relationships in your databases areeffectively a collective API to the database. (As distinct fromthe APIs used to talk to the database program, ranging through ODBC toSQL.)

If you have what Martin Fowler calls an application database ,used only inside one application, you have an internal API, just likea module's interface or a class's methods. But if

(The following example is a simplified and modified version of anonline discussion I had recently. All errors are my fault.)

Here's an example large database problem; it's simplest to cast thisas a customer support system that you sell to big companies.

In your first version, the customer support application databasesystem includes a table of companies that are being supported.

Multiple groups write various programs against this database, and inpart against this table and other tables hooked to it (such as peoplewho

It's nice when everything works like it's supposed to; the mostexcitement we had today was swapping in a replacement drive in thisserver. (I like Mondays for this sort of thing, since I'll be in theoffice for the next four days in case problems come up.)

The old IDE disk needed replacement because it was starting to remindus that it was consumer electronics by flaking out on seeks underheavy IO load every so often (hopefully it was the drive and not thecabling