Archive for December, 2006

Today I can go no farther (part 6)

This is part of the hard disk recovery documentation.

Part 6.

Today I can go no farther (so I stopped)

The last days of this project are spent on two tiring tasks that do not gain me very much, but must be done to carry this project to its logical conclusion. One of these is to decrypt a few very small, but important NTFS-encrypted files. The other is to wring the last readable bits out of the broken Seagate drive by splitting all the error regions to isolate the unreadable regions as much as possible. These can proceed in parallel.
(Read the article)

The story begins (part 0)

My laptop hard drive died a painful death last week. Thanks to a friend (PGD) who agreed to be my ghostwriter for the initial draft, the process of my shuffling through the ruins is documented. This documentation is long, so it will be split into parts. The parts are assigned to the correct dates when the things described happened. Therefore, the sort order of the parts and the sort order of the dates do not necessarily match.

Part 0.

The story begins:

A 40GB laptop hard drive using NTFS became corrupted. The laptop could not boot off its normal disk, so was booted by CD into a Linux environment to recover the data. The idea was to quickly save a raw image of the NTFS drive onto another disk, and to use recovery tools on the image… It turned out this was much easier said than done.

On to Part 1.

The tide turns (part 5)

This is part of the hard disk recovery documentation.

Part 5.

The tide turns (rather quickly)

After the exceedingly annoying but ultimately inconsequential ext2 interlude, I’m back on track with the original problem of recovering data from the broken Seagate drive.
(Read the article)

I rammed my head against the wall, and all was clear (part 4)

This is part of the hard disk recovery documentation.

Part 4.

I rammed my head against the wall (of absurdity that is ext2), and all was clear

The obvious need to fork off another hard disk recovery project from a hard disk recovery project was just too pathetic to think about so I kicked this aside for a day. Today I started back from the beginning, this time researching the ext2 filesystem. The documentation (that is within reach of Google) for this file system is just poor. Whoever is responsible for documenting this part of Linux should be flogged, or at least made to go home and do it over. Yeah, I can go look at the source code (which I did), but I’m sorry, that does not constitute proper documentation.

(Read the article)

Today I became suspicious of everything (part 3)

This is part of the hard disk recovery documentation.

Part 3.

Today I became suspicious of (the ext2ifs driver, the mkfs command, the USB enclosure, and basically) everything

On Christmas morning Santa Claus had not granted my wish: ddrescue was still running, but the image file had not been timestamped any more recently than when I left it, and the damaged drive had spun down by itself. dmesg revealed a syslog message “too many IO errors” or something like that, which had caused Linux to give up on reading from the damaged drive. I was very frustrated because, well let’s see, I had expected the disk imaging to make good progress, but instead… I must suffer a reboot and the induced indefinite re-churning of the drive, with even more data loss! What.
(Read the article)

I tried a whole bunch of things, and all that (part 2)

This is part of the hard disk recovery documentation.

Part 2.

I tried a whole bunch of things (most that didn’t work), and all that.

What is there to do? Data recovery services that run into the thousands of dollars can probably get most of the data back — they have a track record of that. My data isn’t worth nearly that much, sad to say. But I don’t feel like abandoning perfectly good data, either. Yes, there is probably McNorton ViralGhostSpy or whatever this bloatware is called these days; I don’t know… I prefer more flexibility so I’ll take the trouble to proceed with free or freely available tools.
(Read the article)

Today I became suspicious of Seagate products (part 1)

This is part of the hard disk recovery documentation.

Part 1.

Today I became suspicious of Seagate products (and my fortune in general)

Windows XP was running, and programs were being used. The disk was probably being accessed for memory cache. I noticed the drive making repetitive noises, spinning down and then spinning up, and the machine became unusable. I power-cycled the machine, and it was “NTOSKRNL.EXE is missing or corrupt.” Bad news.
(Read the article)

ebay arbitrage

There is a surprising amount price variation on the auction closing price for the same piece of good on ebay. Certainly most of the time this includes consideration for the reputation of the sellers and other such miscellany, but even when the same seller sells, over time, multiple pieces of the same good, at the same time of the day every day, the price fluctuates by a least a few dollars each way around the mean, and occasionally by five dollars or more.

I am surprised that this happens. The distribution of closing prices should be sharply cut off at the lower end, because any good selling at substantially below the mean is subject to arbitrage on the price distribution. This works best for abstract goods like gift certificates, where there is no shipping cost to complicate matters. For example, a gift certificate sells for $100 on average, so you bid on all auctions for it at $95. If there is enough price fluctuation, you will get a few at that price. Now you relist them. There are more sophisticated options but let’s say you just relist them as auctions. Then on average, you will get $100. So you make $5 for each one sold.

If everybody thinks this can be done, they will all go do this and there will be no auctions that close below $95.

This shows closing prices of equally valued amazon gift certificates sold on ebay within the last two days. There are a lot of “buy it now” transactions listed, and those tend to be at the higher end. It seems like an excellent arbitrage opportunity right here to bid on auctions selling at below $80 and relist as “buy it now” for, say, $88. Ebay and paypal fees will eat about $6, so there is still a profit of at least $2 each time this happens.

mail interception, postal abuse, stamp value

Boy, this one may need a table of contents…

Let’s see, it all started with somebody wondering if you can get a letter back from the postal service once it has been mailed, but before it has been delivered. Maybe you changed your mind about sending the letter, for example. I still don’t know the answer, but I’m guessing if there is no return address on it, forget it. If there is a return address, however, it ought to be possible, right? The sender will get the letter back normally in the case that it is undeliverable, so the sender is essentially a secondary recipient. What does the postal service do with undeliverable mail that has no return address anyway? Shred it? Anyway, this doens’t seem like a satisfactory conclusion in any case, that the return address should play an unrelated role in the mail interception problem.

Which brings me to the second topic. (Read the article)

What’s up with AT&T?

Old news but news to me.

Cingular, which just a year or two ago acquired AT&T Wireless and changed everything to the orange color scheme, will change everything back to AT&T again.


The newly reborn AT&T, fresh off of digesting BellSouth, plans to turn off the lights on their Cingular Wireless brand by next year and name it AT&T Wireless.


Cingular originally was unconnected to AT&T; it was a joint venture between SBC and BellSouth.

Subsequently, AT&T sold its wireless assets to Cingular; AT&T proper remained a separate company, and “AT&T Wireless” ceased to exist.

Last year, SBC acquired what was left of AT&T, but they adopted the AT&T corporate name (due to its much stronger brand recognition). This made Cingular a joint venture of AT&T and BellSouth.

Now AT&T intends to acquire BellSouth. Once again, the AT&T brand will survive the takeover, meaning that AT&T will own 100% of Cingular.

Thirty-odd years after the break-up of AT&T, it is piecing itself back together… hoho, the regulators of the 70s must be rolling in their graves… or wheelchairs, whatever.