Archives for: December 2005

12/31/05

Permalink 08:49:20 pm, by fumanchu Email , 258 words   English (US)
Categories: IT

Win98 to the rescue

My, that was fun. Four hours of restoring a corrupted SAM on my mother's XP laptop—she has 46k dialup. :/ Here's the error message on boot:

lsass.exe - System Error "Security Accounts Manager initialization failed because of the following error: The handle is invalid. Error Status: 0xc0000008. Please click OK to shutdown the system and reboot into Safe Mode, check the event log for more detailed information."

The final resolution process:

  • On another computer, obtain NTFS4DOS, install it on a floppy, then burn the floppy contents onto a CD.
  • Boot the laptop from a Win98 CD. When prompted, choose "Run the computer with CD-ROM support."
  • Stay on the command line, pull out the Win98 CD, and insert the NTFS4DOS CD. Run NTFS4DOS.EXE.
  • NTFS4DOS loads, then waits for you to type "Yes" or "No" to the question, "Are you using this on a private computer?" Boring nagware, but a useful moment for us to swap CD's again—put the Win98 CD back in, so COMMAND.COM can be found on it.
  • Answer "Yes" to the nagware prompt.
  • Follow the instructions from Microsoft (method 2, step 3) to replace your corrupt or missing SAM with the one from windows\repair:

    copy c:\windows\system32\config\sam c:\windows\tmp\sam.bak
    delete c:\windows\system32\config\sam
    copy c:\windows\repair\sam c:\windows\system32\config\sam

Of course I considered Knoppix, but have you ever tried to download a 750MB ISO over dialup?

12/27/05

Permalink 11:34:47 am, by fumanchu Email , 106 words   English (US)
Categories: IT

Open source needs more pop quizzes

Glyph recently wrote:

I have also made no attempt to be fair, and I don't want to do this again any time soon, so if your favorite operating system got trashed here, don't bother to tell me that I'm not being fair. Think of it as a pop quiz!

Open source projects need more pop quizzes. There's a reason why you don't let developers run usability tests—it's far too easy to jump in with justification for why your product didn't work "just this once".

I'm just writing this to remember the "pop quiz" meme. Made me smirk. :)

12/26/05

Permalink 11:37:08 pm, by fumanchu Email , 226 words   English (US)
Categories: Dejavu

Dejavu 1.4 now in beta

After more than a year since 1.3 was released, I'm just about ready to officially release Dejavu 1.4! In addition to bugfixes, there are some major new features:

  • Sandbox.recall now returns a list (use xrecall to get an iterator).
  • Associations are now aware of whether they are to-one or to-many.
  • logic.Expressions can now take multiple positional arguments (so you can test multiple Units at once).
  • Improved multirecall, including full support for INNER and OUTER JOINs for all Storage Managers. Since the signatures for recall and multirecall now align, the "multirecall" name has been dropped; just call Sandbox.recall(classes, expr) whether you're querying a single class or multiple ones.
  • Units may now have arbitrary identifiers (primary keys).
  • Unit Properties have a new "default" attribute.
  • Simple inheritance is now supported; recalling one class will also recall its subclasses.
  • New Sandbox "magic recaller" methods, like inv = box.Invoice(13).
  • New Sandbox.view method, to retrieve persisted data without creating full Units.
  • A new Schema class to help manage changes to your model, and helper methods to sync database schemas.
  • New logging support.
  • A new test runner.
  • Python 2.4 fixes for codewalk, the test suite, and fixedpoint.

As you can see, a year's worth of work. ;) Feel free to kick the tires on all the new stuff. I should bless a release candidate in early January.

12/21/05

Permalink 02:08:17 pm, by fumanchu Email , 338 words   English (US)
Categories: Dejavu

Dejavu is adding schema versioning

I just dumped a first crack at a Schema class on the trunk. Test code is here (search for 'schema'), docs are here. I haven't written anything like this before, so if anyone has recommendations or warnings about the direction it's heading, now is the time to speak up (before 1.4 is officially released ;) )!

Basic design: there's a dejavu.Schema class which your app can subclass. Whenever you need to change the underlying database (or other persistence mechanism) schema of your app, you write a new upgrade_to_X method, where X is an incrementing version number. Each such method contains the commands which will upgrade an installation from (X - 1) to X.

At runtime, you call MySchema.upgrade(), and each deployment will run any upgrade_to_X methods that it hasn't yet run, in order. The "currently deployed version" number is stored in a magic DeployedVersion Unit.

The upgrade_to_X methods can choose to stay database-neutral and just use the (new) arena.add_property, drop_property, and rename_property methods. But because each Schema is application-specific, you can also write optimized instructions for your known StorageManagers. For example, say you need to change an int property to a string. The "database-neutral" way would be to have additional Arena methods for such tasks. Some of those methods may be added in the future, but nothing's stopping you now from writing non-portable SQL statements if you know your app is only deployed on, say, Postgres (but you should probably assert that before you execute the SQL statements).

Anyway, I'd be interested to hear from anyone else who has written database-versioning tools. Save me from a pitfall if you can. :) Have fun with the new Schema class and let's see if there are a couple of other common methods (like add_column) that should go into the Arena and the StorageManagers.

12/19/05

Permalink 04:34:13 pm, by fumanchu Email , 99 words   English (US)
Categories: General

Which super hero am I?

Do you need to ask?

You scored as Batman, the Dark Knight. As the Dark Knight of Gotham, Batman is a vigilante who deals out his own brand of justice to the criminals and corrupt of the city. He follows his own code and is often misunderstood. He has few friends or allies, but finds comfort in his cause.

Batman, the Dark Knight

75%

Lara Croft

63%

El Zorro

63%

The Amazing Spider-Man

54%

Neo, the "One"

50%

Captain Jack Sparrow

46%

James Bond, Agent 007

42%

Maximus

42%

Indiana Jones

38%

The Terminator

29%

William Wallace

25%

Which Action Hero Would You Be? v. 2.0
created with QuizFarm.com

12/05/05

Permalink 11:23:32 am, by fumanchu Email , 103 words   English (US)
Categories: WSGI

WSGI gateway for mod_python status fix

After much woe, I think I finally tracked down the status problems I was having with modpython_gateway.py (which is now available on my "misc" Trac site). It should now correctly handle redirects, 404's, and .css and .js content. I think it also fixed my earlier "delayed content" problem.

I hereby nominate mod_python's status API for the "One Obvious Way To Do It" booby prize. Having req.status, a return value/status, and the option to raise a status makes far too many combinations.

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