firewing1's blog

Vista + Loose SATA cable = Bad news

So... Here's what I have been doing during the past 5 hours:

I was noticing some odd behavior from my PC, which runs Fedora Linux as its primary OS but it also has Windows Vista installed for gaming. The machine would boot without any indication of trouble, but once it had been up & running for about 5 minutes, the system would hang and the hard disk activity light on the case would stay permanently on. A soft reboot wouldn't fix the problem either - a complete shutdown was required. At first I thought it was an OS problem, so I rebooted into Vista but found it was affected too. I immediately thought, "hardware". I tried leaving the computer alone for an hour to see if it it would eventually come out of the freeze, but it clearly wasn't doing anything with the disk because the system remained frozen and I could not hear the disk heads moving (and on a 10K RPM drive, those are pretty loud). I ran memtest86+ and did a 3 minute S.M.A.R.T self-test on /dev/sda in Fedora, but oddly enough both came up clean.

Since my hardware seemed OK, I powered down the PC, opened the case and made sure there were no loose cables. Sure enough, the problem was the SATA cable which connected my motherboard to my hard disk. After disconnecting it, blowing off some excess dust and reconnecting it, everything was fine. But that's not where the story ends.

By the time I had reproduced the problem, tested the RAM & hard disk and reconnected the SATA cable, I had done about 15 power cycles. Linux handled the whole situation pretty gracefully - it logged the specific SATA errors (Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK,SUGGEST_OK) and put the root filesystem into read-only mode. After reconnecting the cable, Fedora was up and running as if nothing had happened (it did do an automatic fsck upon booting, but the check came up clean). Vista, on the other hand, didn't take it so well - it informed me that I need to run CHKDISK upon starting up, so I let it repair C:\ and it orphans thousands and thousands of files... After CHKDISK completed I was (surprisingly) able to boot up, but many programs - including explorer.exe - were crashing. Judging by the amount of orphaned files, I'm guessing that quite a few system files were missing or corrupted.

So, long story short, if you have any SATA problems and Vista starts orphaning a tons of files during CHKDISK, save yourself some time by canceling the CHKDISK and make sure you have your Vista installation DVD handy.

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Coming soon...

Well, it's exam time so it's been a while since I last posted. Only 4 days left though! I'll be back with more stuff to post soon...

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The infamous PNG gamma/color correction problem

PNG images are great for Web work, but there's one problem that was really getting on my nerves: the color correction problem. PNG images, like many other formats, support embedded ICC profiles for color management. For websites this feature can become a big hassle since some Internet browsers (namely, Safari 3.x and up) will adjust the gamma and colors of images according to their embedded profiles, but the colors defined in CSS stylesheets are viewed with the native color profile. So if an image with an embedded ICC profile is used in combination with "background: " rules defined in a CSS stylesheet, the image will not match the background color of the page!

Fortunately, GIMP is capable of converting an image's embedded profile into the sRGB profile which was designed for use on the Internet.

First, GIMP requires a bit of setup:

  1. Select the color profile for your display by selecting Edit > Preferences from the menu and clicking on the Color Management section
  2. Set Mode of Operation to Color managed display
  3. From the Monitor Profile drop-down box, choose Select color profile from disk... and select the ICC profile which is you are currently using (tip: On OS X, ICC profiles are stored in /Library/ColorSync)

Once GIMP has been informed about which ICC profile your display is using, it can convert embedded profiles to the sRGB workspace:

  1. Open the image you want to convert
  2. Select Image > Mode > Assign from the menu and ensure that the sRGB profile is currently assigned
  3. Select Image > Mode > Convert from the menu and select the ICC profile that your display is using (the same one you chose in the setup sets)
  4. Save the image and if applicable, pass it through pngcrush to make it smaller
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Conficker

I have to admit, I'm pretty curious about what the giant botnet of Conficker-infected computers is going to start doing tomorrow. A large-scale denial of service attack is my first guess, but my instinct tells me there's something bigger in store... Either way, my clock currently reads 11:53PM so we're about to find out!

Edit: Did some quick research and it looks like the media hype got me. The only thing that's changing is the method which one variant (and not even the most popular one) receives new instructions.

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File Fragmentation

The 500GB SATA drive in an external enclosure that I use for backups (eSATA/USB 2.0 connectivity) is currently NTFS-formatted for compatibility reasons. I would much prefer to use ext3 or HFS+, but it's pretty hard to get those two working correctly on all operating systems. Thanks to NTFS-3G and (Mac)Fuse, I can reliably access NTFS partitions on Linux, OS X and Windows (of course) so it's become my FS of choice when it comes to compatibility.

Unfortunately, that means that the drive becomes horribly fragmented (and pretty quickly, too). I decided to do a defrag today and found that the NTFS partition was 38% fragmented with 78% file fragmentation... Yuck. I'm going to be really happy when there's a filesystem that I can use on all operating systems that doesn't fragment or choke all the time. Ext2/3 was looking like a pretty good for the "doesn't fragment" part, but the ext2fsx project for OS X seems to have died out and ext2fsd, the only driver I've found for Windows that supports ext3 filesystems with inode sizes > 128, tends to bluescreen a lot. Back to waiting, I guess...

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