Steve Jobs

While the web is filled with memorials, testimonials, quotes, etc about Steve’s passing, I figured it only appropriate that I say something… since while I am a System Administrator by profession, I am a Mac user by lifestyle. From the computers I’ve used at home since I was 5, to the servers I work with today, I work with Apple hardware. I’ve always loved Apple hardware, even when they made rather uninspiring devices during period between Steve Jobs’ leaving, then returning to Apple. I wouldn’t call myself a cultist, but I would call myself a skeptical believer. Apple has made some missteps in my mind (killing the Xserve, the rather drastic changes in 10.7 server, etc), but I do believe that what they do they do because they truly believe “this is how it should be”. It’s not just a “this will make us money” or anything like that. Steve, and Apple, both thought they were taking something that was imperfect, and bringing it closer to perfection. And he realized that perfection was out there, somewhere just beyond reach, so you had Apple products that evolved from generation to generation.

What hit me yesterday was that Steve basically bookended his career with the birth, and the (arguably) death of the personal computer. The Apple I/II, and the Macintosh were largely the birth of the real personal computer, and with the release of iOS 5, you have an iPhone, iPad that can be used PC free, which some argue has brought about the end of the PC era. I’m not sure if I agree with that, but it certainly is a step toward the lifestyle where we may have an actual computer at home, or work, but day to day, our lives will largely be played out on phones, tablets, etc. This is already the case for most of us, and will only become more so for others as time passes.

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Mail.app and 32-bit signed integers

Mail.app does not like it when a mail server reports the NEXTUID to be greater than 2^31 (which is the limit for signed 32-bit integers). I could end this post here, but it’s worth explaining how I got here, and how I fixed it… just incase.

A few weeks back, a faculty member hit quota for his email. This isn’t unheard of, but for some reason, this faculty member hit quota in such a way as to cause Dovecot (the central mail server’s mail service) to rapidly increase the UIDs for his email. I’m guessing something like the following happened.

  1. User is near quota, and receives message
  2. Dovecot writes out message to Inbox, but lazily updates dovecot-uidlist
  3. Delivery of message causes quota full
  4. Dovecot goes to update uidlist, but can’t since the quota is full. Which causes a race condition where it tries repeatedly to write it out, and in the process, increasing the base UID each time
  5. After this repeats a few thousand times, the user gets below quota again, and we end up with a NEXTUID of 3829200751 (yes, 3.8 Billion).

Now, there are two things you can think about this. One, is “this is a dovecot problem”. Well, yes, but… they’ve warned users not to store the uidlist files on quota enforced volumes:

Dovecot can’t currently handle not being able to write the control files, so it will cause problems with filesystem quota. To avoid problems with this, you should place control files into a partition where quota isn’t checked.1

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  1. http://wiki2.dovecot.org/MailLocation/Maildir []

“Server” is a concept, not hardware or software

Today Apple “announced” Mac OS X 10.7 “Lion” Server, and that it will seemingly be an add-on to 10.7 client. It’s basically always been this way, Apple is just finishing the job (for the last server OS X releases, you could effectively upgrade 10.x client to 10.x server by running the server essentials install).

Before we get into the post too much, let me start with an analogy that will lay a bit of the groundwork further on. Go to a restaurant and tell me the difference between your waiter, and the hostess (can’t think of a gender neutral word for this position). The hostess doesn’t bring you your food, they just seat you and maybe bring you water. But, is there really much difference between the two? Could the hostess just as easily wait tables? Or the waiter become the hostess? Sure! Or, they could even be a patron (client) and eat the food given to them by other waiters.

Since the “announcement” (I say it in quotes because basically, all that happened was marketing finally put up a page on the Apple site that acknowledges 10.7 Server will exist, in some form) the two big Apple Server mailing lists (the official one [email protected], and the Mac Enterprise list [email protected]) have been all aflutter with people going apeshit over what is and isn’t listed, the fact that it’s not a separate DVD, etc. Some of this is no doubt left over rage about Apple killing the Xserve, but really, IT people are largely FUD (Fear Uncertainty and Doubt) mongers. You think stock brokers/traders are skittish… if half the people on these lists owned any reasonable amount of Apple stock, the price would be in the news more than Linsey Lohan.

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