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I had an odd situation over the weekend that resulted in the inability to view the passwords associated with keys in my Mac OS X user keychain. Every time I clicked on the “Show password” checkbox in a key’s detail window, I’d get an “Access to this item is restricted” dialog.

Needless to say, this was disconcerting. I happened to have a lot of data in that keychain — this is what I get for keeping the same one around since Mac OS X 10.0 or 10.1. While I could revert to a backup, the newest backup wasn’t as recent as I would like. Plus, I just wanted to know why the problem had cropped up.

So, I asked about my problem on the Apple-CDSA mailing list. If anyone would be able to help with the obscure corners of keychains, I figured the people there would.

Very promptly, I got a reply from Ken McLeod, which led me to check the validity of the code signature on the Keychain Access utility.

Clearly, the signature and the application didn’t match. Something was amiss.

I reinstalled Mac OS X 10.6.2 on the system, using the latest combo update installer package, and cleared up the problem signature mismatch.

In retrospect, although I wouldn’t have thought of this being a problem, this breakage between the signature and the app — and its affect on my ability to view stored passwords — gives me confidence that thought has been put into the code signing mechanism in Mac OS X. You wouldn’t want a compromised app displaying your unencrypted keychain items, after all.

I had interesting things happen when I ran out of disk space today.

The most notable one was that I saw “Process completed” — or some variant of that — every time I tried to open a Terminal window with a new shell session. I briefly staved it off by specifying Bash as my shell, but then it came right back after opening another tab or two in Terminal. Consulting Google led me to this “Terminal application quits” thread at Apple Discussions. On a lark, I tried deleting /usr/bin/login as one poster suggested. It worked!

…But only for a little while. The problem returned. In the meantime, I had freed up some disk space because I’d realized I couldn’t save files anywhere (“But ~/Pictures is writable!”). Clearly something else had become an issue, because disk space was available.

Then I found another thread, “Terminal’s ’Process Completed’ message and /usr/bin/login,” on Apple Discussions. The more permanent solution from that thread appears to be the removal of corrupted Apple System Log databases. Once I did that and restarted the ASL service, all was well and has stayed that way so far.

Filling up my disk must have corrupted the logs as they were being written or rotated, and led to this cascade failure. Like I said, interesting!

One of the posters in the second Apple Discussions thread indicated that the underlying database corruption issue is addressed in Snow Leopard. However, it seems that you could still see this on Leopard — my experience was with a recently-patched Mac OS X 10.5.8 system.

The new Apple Education Licensing Program replaces the Apple Maintenance Program (AMP) as the primary way to purchase ongoing software upgrade rights for a school, college, or university’s fleet of Macintosh computers. The Apple Education Licensing Program (AELP? or just ELP?) is a yearly, renewable license.

I think this is a big deal because it’s awfully close to what I’ve asked Apple for year after year — especially at venues like WWDC (at least when they have presented the opportunity for giving constructive feedback).

The ELP licensing for Mac OS X is actually a bundle — called the “Mac Software Collection” — of the operating system combined with the iLife and iWork suites. (It aligns with the same bundle of software in the standalone “Mac Box Set.”) I believe that the bundling of iLife is the biggest win, because it provides upgrade rights to software that is bundled with every new Mac but frequently updated. If you are managing a larger group of Macs over several years, the licensing and deployment issues involved with iLife could be complex — moreso because it’s the kind of software that people want on their computers. It also doesn’t hurt that Keynote is included — anecdotally, it appears to sell a lot of Macs in organizations all by itself.

The ability to keep the operating system and core applications from the Mac Software Collection up-to-date across a range of Macs with a single renewable license could be a tremendous savings in administrative overhead.

Organizations must cover 100 percent of their installed base of owned or leased Macs, at least for the Mac Software Collection. This may be a deal-breaker for a number of universities and perhaps other organizations that tend to be decentralized in their operations.

Apple’s other software can also be obtained through ELP, but can be purchased to cover 100 percent of computers at the departmental level. It is possible that the exact nature of the organizational unit is at the organization’s discretion.

ELP allows the flexibility to cover faculty/staff home use as well as students, should the organization elect to pay for that additional coverage.

Each ELP purchase appears to incur a one-time 10 percent enrollment fee. If an organization doesn’t renew for a year but then buys again later, it may be subject to the enrollment fee again. And, if you have a lot of departments seeking Apple’s Pro Apps or IT-related software, those 10 percent charges could add up to significant overhead. I’m not sure if there’s a clear way to allow two or three departments to get the software they want without requiring an entire educational institution’s Macs be covered.

As part of the introduction of ELP, educational institutions are being encouraged to move to the new licensing program before December 13, 2009, through a waiver of the enrollment fee. It appears possible to crossgrade from AMP to ELP, at least if you talk to your Apple account team.

I am not aware whether Apple has rolled out something similar to organizations outside education.

The default installation of Python on Mac OS X Snow Leopard is version 2.6.1. According to the man page for Python on Snow Leopard, Python 2.6 executes as a 64-bit application by default.

If, for some reason, you need to run it as a 32-bit application, this can be changed at the command line:

The preference can be set in either the User or Local filesystem domain in Mac OS X, following the normal precedence rules. To unset it, presumably you would change the boolean to “no” — or perhaps even delete the “Prefer-32-Bit” key.

There is also an environment variable that can override this preference.

I see a lot of complaints about Belkin SOHO-series KVM (keyboard, video, and mouse) switches. I think many of these complaints are warranted; I’ve used two of these KVMs for a long time and have some familiarity with them.

However, one complaint that does have a workaround covers the mapping of the Mac’s Command and Option keys. For the hybrid PS/2-USB KVMs I have used, you must use a PS/2 keyboard and mouse.

That PS/2 terminal requirement assures that your keyboard is going to be labeled for PC/Windows use. If you connect any Macs, you’ll be frustrated by the key layout of Command and Option. Initially, the Alt key will act like Option, and the Windows key will behave as if it’s Command. This is the opposite of what you’d expect from an Apple keyboard — or another keyboard designed primarily for Mac use.

The good news is that this behavior can be changed, and it applies individually to each KVM port. If you have a Mac on Port 1 and a Windows computer on Port 2, they can each have the settings you’d expect. To do so, switch to the port connecting to a Mac and press Esc-A. This puts that port in the “Mac function” mode. In this mode, PS/2 Alt is Command and PS/2 Windows is Option.

Other keys also change, according to a table from an addendum to the Belkin manual. Given that it was a separate sheet in the box, I’m not surprised that many people have apparently missed it.

To reverse the setting back to the previous function mode, press Esc-Y to disable the remapping. Again, you have to do this on a port-by-port basis.

If you ever switch the computers connected to the ports, you will need to disable this change for each affected port; it by no means updates itself dynamically. That’s why there’s a problem in the first place.

I owe Greg Madore for this tip, as he's the one who originally found it for me.

Unfortunately, this does not fix another failing of the Belkin SOHO KVMs for my kind of work — namely, the inability to change startup behavior on Macs. (I have not yet seen a KVM with keyboard emulation that consistently allows the use of modifier keys — such as C, T, Option, H, etc. — to change the startup behavior of a Mac. That capability would be extremely handy for KVMs used in technical support scenarios.)

It should come as no surprise that Apple Installer installation packages can contain scripts. These scripts are supposed to conduct important operations during the course of the software installation.

However, when you are the system administrator of more than one Mac, you find that developers sometimes miss a good balance between what you think should be in the installer payload versus what should be in its scripts. The payload of a installer, by definition, are the files and links that should be installed, along with information on where they should be installed as well as how (i.e. ownership, permissions).

Therefore, developers should not need to run scripts that create or delete files — they should be created from the payload itself, and if a file must be deleted during the install then consider that perhaps you’re doing it wrong. Likewise, there should be little need move or copy files, because as many copies as desired can be installed from the paylod. Similarly, the need to change ownership or modify permissions should be taken care of in the payload.

Perhaps I’m being a purist here. I’m certainly accused of that, from time to time. However, this just makes sense to me and I happen to think that many developers are similarly logical people. They just aren’t the kind of logical people who happen to spend effort on software installation, especially the kind that results in a deployment-friendly installer package.

So how do we as administrators verify the quality of the scripts in installers? Is there a way we can quickly peer into them to decide if any of the scripts’ steps will be superfluous or even (gasp!) harmful?

Well, I have a quick suggestion for scanning packaged installers. The following one-liner shell command will search an installer package or metapackage for scripts that have the kinds of steps outlined above.

Note that this will only work for the traditional installer packages; it will not work with Leopard-style flat packages (which are documented so badly by Apple that the best description comes from reverse engineering by Iceberg's author). The one-liner will currently only find the defined install operations scripts: preflight, preinstall, preupgrade, postinstall, postupgrade, and postflight. (Any other scripts are likely to be called by one of those six.) It assumes those scripts will be shell scripts, currently, even though any of them could be written in other scripting languages installed with Mac OS X, like Python, Perl, or Ruby. It will also not work on the JavaScript-based system and volume requirements portions of the installation.

However, it’s a start. The output displays the offending file and line number, so you can conduct more careful examination of the matches it finds.

I haven’t run this on an exhaustive list of installation packages, but I have already seen at least one installer that produces worrisome output.

Update: I’ve changed the regex for the pre/postflight script so that it is more general that what I originally posted. I’m also having some problems with the snippet working with a certain installer whose scripts I know have cp and chmod commands. So, I may be back to the drawing board with this; comments are welcome.

John C. Welch’s article, On Installers, is linked from Daring Fireball today. He links to me — thank you very much John, for that and for the kind words about my signal-to-noise ratio (whatever my front page says on that score right now) — placing me one jump away from Daring Fireball.

I was a little worried about that until I checked my Web analytics account. Luckily, my link is third to last and at the end of a long article, or my Web host might be having words with me about traffic.

It was very good to be mentioned, and even be situated in auspicious company between Greg and Nigel. All of us are current or former Radmind admins, and as a group I think Radmind admins tend to know a bit about the foibles of vendors’ installers. Along its famous learning curve, Radmind teaches you a lot about the filesystem and about what’s going into it.

Anyway, for anyone completely new here, you can follow the Mac OS X system administration topic on its own — and skip others, like random Python, Mercurial, Western New York sports, Drupal, and personal chatter.

In this MacEnterprise list thread about printing authentication, Greg Neagle mentions that:

Under Leopard, all local users are members of lpadmin, but I think network users are not. So this method won't grant network users CUPS rights.

To confirm Greg's suspicions, I ran the following shell snippet.

This loops through the fictional accounts, "mobile_account_user," "network_account_user," and "local_account_user." These accounts are, as you might expect, as a locally-cached mobile account from a network directory, a wholly network directory-based account, and a simple local admin account. While the accounts presented here are fictional, the results were confirmed on a live system bound to a directory service.

The rest of the snippet determines if the accounts are members of any of the specified computational groups that debuted in Leopard. The last group checked is the "lpadmin" group. By looking at these group memberships, we can determine whether Leopard thinks that the account being tested is a local or network account.

Running the snippet above, with the right accounts available, produces the following output:

So, it appears mobile and local users get added to the lpadmin group automatically in Leopard, but network accounts do not.

Note that I didn’t check whether membership in the “admin” group made a difference or not. I also didn’t isolate for that factor.

I found it interesting that the mobile account is a member of “netaccounts” but not “localaccounts.” (By group membership alone, I’m not sure you could identify whether an account was a mobile account or not. Yet, that kind of test is part of the point of having these computational groups in the first place.)

I’m keenly interested in the CalDigit RAID card for the Mac Pro. It looks like a much better solution than the Apple RAID card to the storage problem — a First World problem if ever there was one — facing certain Mac Pro owners.

I’ve asked myself, “Now that you have this beast, how do you fill up its drive bays?”

The answer is somewhat difficult. You can put four drives in the bays, but in order to get a single volume, you’d minimally need software RAID. For example, you could configure a RAID 1+0 volume with Disk Utility. You could get the expensive Apple RAID card. You might populate a Drobo and connect it via FireWire. Or, you could get a CalDigit RAID card — which is the only bootable, fully-internal RAID controller I’m aware of that competes with Apple’s card.

One advantage of a solution that fits completely inside the Mac Pro case is that you have one less power cord to deal with. In this sense, the CalDigit RAID Card seems preferable to a Drobo. The CalDigit card interfaces directly with the Mac Pro’s own SATA ports, so you can use the existing internal drive bays and slide drives into the normal SATA/power connectors.

I just need to find one on sale …

From the “I didn’t post this when it was current” files is an article from Stories of Apple, titled Ten years ago: here comes Mac OS X Server. On January 5, 1999, Apple announced Mac OS X Server.

I had access to a Macintosh Server G4 running Mac OS X Server 1.2. I recall being pretty baffled by it at the time, especially when the setup assistant wanted to configure an entire network routed by the server. The OS looked like a darker version of classic Mac OS, but was very different in every other respect from that OS I'd become so comfortable with. The filesystem layout was foreign. The administration tools were Web-based, and relatively poor (to my thinking) compared to AppleShare IP 6’s. However, there was the sense that this new system was the future, and that Mac OS X Server 1.0 and 1.2 were the gateways to it. I wanted to know more.

And my, how far we’ve all come in a decade.

[Via Eric Z.]