I thought I’d revisit that theme, but now with an updated class composite photo, using images taken during a recent 50th birthday event hosted by Jono Goldstein at his place in Cape Cod.

Updated details to follow, when I get some time…

Some people might remember the original Mac OS equivalent, which was January 1st, 1904. From what I remember back in the day, Jerome Coonen picked that date (instead of 1900) because it simplified the leap year calculations. And using an unsigned 32 bit value for seconds meant that Macs could handle dates up to 2023 or some point way in the future.

Then yesterday I came across the MUMPS/Caché “$h” date format, which is described as:

This format returns the date as the number of days since 1st January 1841, and the time as the number of seconds since midnight.

I was speculating with my friend as to why they picked 1841, and guessed that this was some convenient date (similar to the Mac 1904 choice) that was before the birthdate of the oldest person they could imagine being in the system, back in the 1960s.

After turning to the Source of Truth (Wikipedia’s article on MUMPS), it seems like our guess was correct. James Poitras explains why he picked this odd date:

I remembered reading of the oldest (one of the oldest?) U.S. citizen, a Civil War veteran, who was 121 years old at the time. Since I wanted to be able to represent dates in a Julian-type form so that age could be easily calculated and to be able to represent any birth date in the numeric range selected, I decided that a starting date in the early 1840s would be ‘safe.’ Since my algorithm worked most logically when every fourth year was a leap year, the first year was taken as 1841. The zero point was then December 31, 1840

Pretty sweet – it does a good job of tracking, even in the foothills of the Sierras, where GPS signals come and go.

I wish I could directly embed the map of the hike, but that requires an , which isn’t allowed by wordpress.com – oh well. You can still click here to view it on the garmin.com site.

Erika Kosina has done a great job of setting this up, and I’m looking forward to meeting more of the local tech community.

Some of the things I’ll be touching on are:

• Why big data is the cool new kid on the block, or why I wished I really knew statistics.
• Crunching big data to filter, cluster, classify and recommend.
• How big data + machine learning == more effective advertising, for better or worse.
• The basics of Hadoop, an open source data processing system.

Hope to see you there!

Unfortunately most of the relevant content I’ve got is for Java programmers interested in using Hadoop. Things I could talk about, based on personal experience:

• A 600M page web crawl using Bixo.
• Using LibSVM to predict medications from problems.
• Using Mahout’s kmeans clustering algorithm on pages referenced from tweets (the unfinished Fokii service).

I’m looking for relevant talks that I can borrow from, but I haven’t found much that’s targeted at the technically minded-but-not-a-programmer crowd.

Comments with pointers to useful talks/presentations would be great!

So I ran into the Apple store in San Francisco and grabbed a new 60 watt adapter – the one with the “L” style MagSafe connector, versus the older “T” style connectors I’ve got on my other three adapters.

Raced back to the client. Plugged it in – and it didn’t work. Spent 20 minutes cleaning my connector, trying different outlets, etc. No luck.

Headed back to the Apple store, and verified the following:

• My new adapter works with three different MacBooks on display.
• None of the 60 watt power adapters with “L” style connectors being used for display Macs worked with my MacBook, but all of the 60 watt adapters with older “T” style connectors did work.
• The 85 watt power adapter at the Genius Bar did work with my MacBook.
• The new 85 watt power adapter that Mitch @ the Bar set me up with didn’t work with my MacBook.
• The older 60 watt power adapter Mitch extracted from the store’s repair supply stock did work.

After all of the above, I got in touch with a friend who works as a Genius at the Manhattan store. Turns out she’d just had to deal with a similar issue, and the root of the problem is that the System Management Controller (SMC) needs to be reset for some older MacBooks to work properly with new power adapters.

Apple has information about how to reset the SMC, and on that page it lists one of the reasons why you need to do this as “The battery does not appear to be charging properly”.

I’m hoping Apple updates the info found on both this page and their Troubleshooting MagSafe adapters page, to make it easier to find in the future for other users. Before Apple Stores run out of these older “T” style power adapters.

Previously I’d had a Sierra Wireless AirCard (595U) with Sprint, and it worked great, but I couldn’t justify $60/month for the occasionally trip to the Bay area.

But Virgin Mobile with its pay-as-you-go plan seems perfect. I can spend $10 for a 10-day plan with enough data (100MB) for my email and light web surfing needs. So I bought the modem, and went to sign up. Which brought me to this page on their web site:

This is the error screen you get when you don’t fill in the address fields. Which aren’t marked as being required.

But after using their Broadband2Go app, I can see that having a polished UI experience isn’t high on their priority list. I’m just hoping the Sprint-provided service works as well as with my old WiMax setup.

Previously I’d had a directory in my user directory called “SVN”, and this is where I’d checked out all of my SVN-hosted projects. At some point in the past I changed the name of this directory to be “svn”.

In the terminal, it shows the directory as having the lower-case name, as expected.

But in Java, if I call File.getCanonicalPath() on a file in this directory, the directory name comes back as the old “SVN”. And that in turn caused some tests to make assumptions about the nature of the filesystem, which triggered a cascade of failures.

To fix it, I created a new temp directory, moved everything from inside “svn” over, deleted “svn”, then created a new “svn” and moved everything back. Really strange…

Just pull first, fix any merge problems, and then push.

But this morning I still got the error after doing a pull, then a push to the Bixo project on GitHub.
It turns out I need to read the git output more closely. The error message said:

! [rejected]        master -> master (non-fast forward)
error: failed to push some refs to 'git@github.com:bixo/bixo.git'

But I’m working in a branch (called ‘fetch-flow’). And the “git push” command will try to push all of the branches. But “git pull” only pulls the current branch.

So I had to “git checkout master” to switch to the master branch, then “git pull” to bring that up to date, then “git checkout fetch-flow” to switch back to my branch.

And now my git push works fine. Note that the push did work, in that my ‘fetch-flow’ branch was pushed – it’s just that the auto-push to master failed, and that made me think my entire push had failed.

There seems to be some new information required, where they want the secret question/answer pair that now seems to be part of every company’s registration system. But after my login I got this interesting message:

Looks like a case of the right hand and the left hand not being in sync.