Back to the Blue Lakes

Mt. Sneffels Wilderness

I've been trying all summer to get back to the Mt. Sneffels Wilderness. This weekend I finally made it.

Sneffels has taunted me a second time.

Getting There

I left Santa Fe on Friday afternoon. The summer monsoons made for a comfortable, if gloomy, drive all the way to Pagosa Springs, where the skies finally began to clear.

Daylight faded somewhere between Coal Bank Pass and the Idarado mine. As twilight turned to night mule deer appeared, grazing by the roadside. They were so numerous that I decided to stop for the night at the Idarado.

The weather forecast was about right, with overnight temperatures in the mid-40s F. It wasn't long before the inside of the car cooled to match. Shivering, I fumbled around for the sleeping bag and crawled inside it.

I got back on the road just before 5 am, still a couple of hours away from the trailhead. I wanted to hike from the Blue Lakes trailhead up to Blue Lakes Pass, and to get there early enough to have the option of attempting the Blue Lakes route up Sneffels. The online guides call it a technical scramble; I hadn't brought a helmet, but I'm pretty sure people try it solo.

When packing for the trip I'd loaded up the overnight pack, thinking I might want to stay overnight at the Blue Lakes campground. With all of the camera equipment the pack weighed in at 55 lbs.

On arriving at the trailhead I decided I didn't want to lug all of that weight upwards for more than 2000 ft. Instead I transferred a bunch of stuff into the day pack.

Moving gear around like this led to the usual disorganization. Among other things, I forgot the variable neutral density filter. Oh well, I wouldn't be shooting much video. No doubt my friends would be relieved ☺

On the Trail

I was finally hiking by 0730. The temperatures were still in the 40s, but it was sunny and calm. Within a few minutes the exertion had warmed my aching, cold legs.

Steller's jays were making their raucous morning rounds. I wasn't fast enough to get any of them focused and exposed through the backlit foliage, before they moved on to the next tree.

At the edge of a clearing a red squirrel stood sentry at the base of a conifer. It scolded me for a minute while I took its picture. When it finally departed I turned back to the trail, only to discover that mule deer had been watching the whole exchange.

Mule Deer
Mule deer leaving the lecture

Underwater Photography

I picked my way across the rocks to take picture from the middle of Dallas Creek. As I was finishing, a day-hiking couple arrived. They were just in time to see me slip and fall into the shallow stream. I landed on my right side with the camera completely under water. And then... I couldn't roll upright. My day pack was in the way. It probably took me ten seconds to regain my feet.

Why are there always witnesses? ☺

The Last Thing the Panny Saw
Dallas Creek at bath time

The camera is sitting in a bag of rice right now, drying out. I hope it isn't destroyed, but it may take a few more days of dessication to find out. [Update: it's on its way to the Panasonic service center. It would power on, but only slowly, and only if the LCD panel was closed.]

The mountain stream was cold and the air temp had climbed into the 50s. The morning was sunny, so instead of hypothermia I got a bracing half bath. No harm done.

I chatted with the couple for a bit. They were finishing a week in which they'd hiked about 26 miles, and they were planning to summit Sneffels. This gave me a little more desire to try it, especially since I had been making better time than they.

The log bridge at lower Blue Lakes had washed out. I eventually found a way across, carefully checking out the stones to make sure none of these had that special slippery film that I'd just learned about.

My self-made route missed the trail on the other side of Dallas Creek, but it did lead me up to a beautiful tributary waterfall.

Waterfall above lower Blue Lake

I took some pictures from atop a large fallen lodgepole pine, then scrambled up the mountainside to a rock pile where I knew the trail should be.

Starting up the switchbacks from the upper lake I met a guy who was running down from the pass. He had a "Mud Runners" hat on, with a Zia logo. Yet another New Mexican running down slippery trails that I need to take one tiny step at a time ☺ He modestly said that it would be a grind for him getting back to the top, but when he had seen the lake he just had to run down to it...

Near Blue Lakes Pass
The runner jogged down this trail. I shuffled down it carefully.

I made it to the pass in really good time, feeling pretty happy despite the dead camera. It was only about 1130, and so far the sky held only small, scattered cumulus. It'd be at least a couple of hours before they turned into anything real.

The start of the trail to Sneffels from Blue Lakes Pass is heavily traveled and easy to spot. It begins to the left of the rocky spines that approach the summit.

Blue Lakes to Sneffels
The start of the Blue Lakes route to Sneffels

Unfortunately, there are many variations, including some "trails" that are really just dirt left bare by natural erosion. I kept losing the path and having to pick my way back to it.

Once you get in among them the spires start to look like spikes sticking out of the earth, with passageways weaving maze-like among them. I kept scrambling up into the openings to see where I was, and to catch a glimpse of the crowds making their way up the Yankee Boy basin route.

Through a gap to Yankee Boy Basin
Looking through a gap towards the Yankee Boy Basin approach

Finally the dirt path faded away, and I began picking my way up a rocky chute. I wasn't sure I was anywhere near a route until I heard voices above me. About the same time I saw one cairn, then another. A head appeared, the first of a group of four or five. "Dude, there is nobody here." He said. Then he saw me, waved, and called back to his still hidden companions. I couldn't tell what he said, but it ended with "no monumental deal".

Rocky Chute
One of many rocky chutes

I reached the top of the chute and after a few moments picked out more cairns. They were set on shelves atop fairly vertical rock. I looked ahead, and all I could see was vertical rock. At the top, I saw someone standing. That must be the summit, and it was still a couple of hundred feet higher.

Cairn, stage left
See the cairn, middle left? Yeah.
There's another one in the distance, but I can't pick it out in this photo.

Everybody has their limits. One of mine was, "I'm by myself. I'm not climbing up anything that I wouldn't feel comfortable down-climbing." I went on to the 2nd cairn, hoping that, from it, I'd see some path less vertical.

No joy. SummitPost wasn't kidding when they called this a 3rd class technical scramble.

[Google Earth says I should have looked left rather than up, at the last cairn. That is, there appears to be a good trail on the northwest side of the saddle ]

The summit?
This is about as close as I got to the peak.
Looking down on Blue Lakes Pass
Summit or no, the views were spectacular. Blue Lakes Pass is bottom center, behind the rock in the foreground.

Who Ate the Bread Crumbs?

I turned around and started back up the chute I'd just descended.

Did I mention that the spires formed a sort of maze? It wasn't long before I took a wrong turn and got disoriented.

I should have stopped and looked back more often, on my way up. As it was, I "knew" only that the spires had almost always been on my right as I ascended, so they should be on my left going down.

Alas, what I knew was not true. After regaining the top of the chute I started down the other side. The spires were on the correct side, so I thought it was the one through which I'd passed the "no monumental deal" group.

But something didn't look right. I was sure I hadn't passed any snow on the way up. This chute had a bank of snow on its left side. I scrambled back up to the left, through a gap in the spires, hoping to find a match for my template: spires on the left, scree on the right.

Instead I saw the ridge leading off to Lavender Couloir to the east — the Yankee Boy route. I turned around and picked my way back to the top of the snowy chute. That had to be south or southwest facing, had to be the right direction.

In the distance I could see a small blue lake. I was so badly turned around that now I thought I must be looking out toward Blaine Basin (which would have been to the north or northwest and which, as far as I know, doesn't even have a lake).

Back to the Yankee Boy view. Back to the snow field.

There was dirty snow at the bottom of the snowy chute. It looked trampled, with pockets of brown that looked like a sequence of foot steps. Maybe this was just another variation up the Blue Lakes route. I decided to scramble down a bit and have a look.

"Scrambling" in this steep scree is difficult. It's too shallow for comfortable backward down climbing, but if you try to squat and step down, every move starts a small rock slide.

I got down to just above the snow. The chute was maybe six feet wide at its widest. It formed a "vee" about five or six feet deep, with dirty snow on the left extending all the way to the bottom, where the darker footprints started. On the right were big pieces of scree 3 to 5 feet long, cemented in place only by dried, dusty mud. The slope got steeper.

I still couldn't see well enough. Where did this chute come out? Where did the footprints turn, once they went out of view?

I was starting to get anxious now. It looked slightly easier to descend than to climb back out — everything I'd come down had slid the moment I put weight on it — but it wasn't clear that the chute didn't just drop away steeply. Still, maybe I could get down another couple of feet and get a better view.

And that's how I managed to reach a place where I really didn't want to be.

No Holds Barred

That rime-ice snow is the kind of stuff that, if you venture onto it while hiking in springtime, you immediately punch through. And those big pieces of scree? Only dusty dried mud held them in place, as I could now see much more clearly. And those footprints in the snow? They were just small bowls carved out by running snowmelt, which I could now see trickling out under the barely-anchored rocks.

I was now standing on dried mud on a slope that probably exceeded 45 degrees — and that felt like 60 — facing out. I hyperventilated a little.

I don't know how long it took, but I slowly and very carefully got turned around. This was a small improvement: I could no longer see the slippery chute that, when the first hold gave way, would send me arcing down the mountainside in a big smear of red.

On my right there was now a big piece of rock, cemented by mud, that joined the top of the snow. There were two holes in the dry mud beneath it, just big enough for a hand jam. Everything else was either sloping, or sitting loose.

The inner dialog began. "This sucks. I can either weight something that gives way and squirts me out, or... doesn't. All I really know is that I can't stay here."

Screw the inner dialog. I started talking out loud. "If I jam my hand in there, will it hold when I weight it?" Deep breath. Jam. Pull, just a little. It holds. "If I jam my foot in the other hole, will it hold?" Yes.

After what must have been 15 minutes of tediously debated moves, each accompanied by a sense of impending doom, I was back at the top of the chute.

Did you know? Even agnostics can be grateful, even when they're not sure to what they owe gratitude, for having been spared a painful experience.

Back among the spines, I was well satisfied that the snow chute was not the correct way down ☺ I decided to have another look through that gap, the one with the view toward the Yankee Boy route, with its spiny ridge across the saddle and the spires on the right. Maybe I'd be able to see a cairn or a dirty path if I looked again.

Heh. Yes, there was a big spire immediately to the right, on the "wrong" side of me. But that spiny saddle leading off into the distance? That was for Blue Lakes Pass, not Yankee Boy Basin.

I picked my way down, taunted once more by Sneffels but happy to have been not (quite) killed by my own stupidity.

Smoke If You Got 'Em

The rest of the day was less dramatic and very satisfying.

Coming down the switchbacks I saw thin weathered tree stumps appear, well above tree line: they were marmots, popping up straight to keep tabs on the late afternoon hikers.

I paused to filter water where the stream cuts through the big glacial slump "levee" at the edge of the upper Blue Lake.

The cut in the levee
The uppermost blue lake drains through a cut in a slump of scree and dirt from the surrounding mountains. The lake itself may rest within a slump.
Glacial Slump
I think these mounds of scree and dirt are called glacial slumps. This one is on the south side of the uppermost blue lake.
Lowest of the Blue Lakes
I think this lake is fed only by the streams in the center of the image.

A bird was hopping around the grasses on either side of the stream, catching bugs and leaving tiny white droppings on the rock. Its size and movement reminded me of a dipper, but this was an above-water bird, and it filled a complementary niche: dippers catch larvae under the water, and this little thing was snatching adult insects above the stream.


Woodland Creatures

Following the trail instead of bushwhacking as I had on the way up, I came across the one pika that wasn't making noise. It stopped to watch me for a bit, clenching a long leafy stem in its mouth.

I passed several groups of humans on the way down through the forest. One family had a bell on their dog, to help alert bears. Another family was spread out, with a boy about seven and his younger sister ambling several hundred feet ahead of their parents.

Nearing the home stretch at about 1800, I came through a small opening in the pines. Here the trail was straight and almost level.

All of a sudden, bounding straight up the trail towards me is... a puppy? It has fluffy fur and a face like a Pomeranian. But the movement isn't quite right. It undulates.

It draws closer. Its fur is the same yellow gray as a grizzly. This can't be some kind of mutant bear cub, can it? Am I about to get mauled by its mother, whatever it is? But it's acting like a puppy happy to see its owner, round black eyes and all.

It's funny to recall each ill-fitting branch of the decision tree as my mind played a fast game of 20 Questions, trying to decode the scene. I was throwing relays and getting progressively nuttier answers. At the same time I was torn between delight at such a friendly approach and an uneasy feeling that I should be more cautious.

Earlier I had called out softly to the marmots and pikas, once they had seen me. I did the same now while reaching for my phone. That furry little thing was so close even the phone camera would yield a good picture.

"Hi there," I murmured. "What the heck are you?"

I wish I had kept my mouth shut. It was a weasel, a big one, and somehow it had not seen me until I spoke. It stopped, cocked its head for a moment while I fumbled for the phone, and then bounded off the trail, resuming the same pace. It was not at all worried, just bouncy and happy — and no doubt on its way to hunt down a meal.

That right there was worth the price of admission.

Signing Out

I got back to the trailhead at 1830. The register said the hiker couple, whom I'd last seen arriving at Blue Lakes Pass some 15 minutes after I had started into the spires, had returned at 1630. It wasn't their first time up, so maybe they actually summitted. Maybe I should have hung back and followed them!

The show wasn't quite over. The Stellers jays had been noisy at dawn, and they were at it again, calling out from all directions. It was growing dark, and the mule deer were emerging, cautiously grazing around the edge of the dirt parking area.

I put my pack in the car and idled off to find a camping spot. Mishaps notwithstanding, the day had gone really well: I'd climbed much quicker than five years ago and had made it back without a completely seized-up shoulder. My knees even felt better than the last time, though my right vastus lateralis (had to look that up), where it joined the knee, was so tight it was sore to the touch. And I had met my first wild weasel.

Sneffels from the road
Goodbye Sneffels, until we meet again
and you taunt me a third time.
I wouldn't mind just driving back to this spot, when the aspen have turned.
Trailhead: 9350 MSL
Blue Lakes Pass: 13015 MSL
Sneffels Summit: 14105 MSL
I think I made it to about 13700 MSL.
Total distance about 14 miles according to my phone, 
or about 11 according to Google Earth.

After: Wild and Dead

I can't end this post without paying respect to some unfortunate wild animals who had crossed paths with us and our machines.

Between Silverton and Durango I found a porcupine on the inside pullout of a sharp curve. I'd never seen one before, and was unlikely ever to get so close to one again. I took photos, trying to capture some of its extraordinary features.

As I put away the phone I noticed a few footprints leading to where the carcass lay. It hadn't been killed outright, but had crawled a short distance before expiring.

North American Porcupine — about two feet long
Pads and Claws of the left hind foot
Pads and claws of the left hind foot
Ancestors of the porcupine rafted to the Americas from Africa, more than 30 million years ago.

Hours later, just south of the turn for the NM Wildlife Center in Española, Sunday evening traffic slowed down. Soon I saw why: in a section of highway enclosed by concrete barriers a large German Shepherd had been hit. Its head lay near the white road edge line, its large body extending toward the barrier.

But it was much too big for a shepherd, and its hind legs were much too thick.

It was a black bear. It left me wondering how, in this unusually wet, presumably food- and water-rich August, this poor creature had gotten trapped in this tunnel.

Recreating a Fusion Drive

Not the Apple Car

I recently decided to trade in my iMac. To prepare for trade, I needed to erase the fusion drive and re-install OS X. This proved harder than expected.

One apparent reason for the difficulty was that I had turned on FileVault for the whole volume. This may have been one reason why the El Cap Installer app would not let me install onto the fusion drive. (But I'm not sure: the new Disk Utility GUI sure is reluctant to inform users about why controls are disabled, and about the specifics of any errors it detects.)

A more significant problem was that I couldn't boot from the recovery partition. About a year ago I had replaced the old iMac's internal hard drive with a 2.5TB fusion drive. I'd used OWC's instructions to create the fusion drive's CoreStorage volume. Those instructions – at the time of the upgrade, at least – made the recovery partition a part of the Core Storage multi-disk volume that constitutes the fusion drive.

A recovery partition needs to be separate, not part of a logical volume family. Otherwise you can't boot from it.

(Apologies if I'm getting the terminology wrong. I don't understand CoreStorage very well at all.)

The upshot of all of this – a recovery partition buried within a logical volume family, and a password-protected logical volume [family] – was that, shortly after I started the erase/install process, I found myself with an unbootable logical volume.

Bootable External Drive FTW

To recover, I installed OS X on an external SSD and connected it via Firewire 800. I needed to run full-up OS X because it provided command-line access to diskutil. The bootable El Cap installer thumb drive with which I'd started did not include Terminal app, and the aforementioned Disk Utility GUI was not up to the task of recreating a fusion drive; it appeared unable even to split the fusion drive into separate SSD and hard drive volumes.

I recreated the fusion drive with the help of these websites:

Even with all of this help, I couldn't figure out how to create a recovery partition, which has a filesystem type of Apple_Boot. Fortunately, the examples in the diskutil man page provided the necessary incantation.

Once the fusion drive's volume and the separate recovery partition had been created, I needed to copy the El Cap installer app to the SSD drive and run it from there, from within a full OS X environment. Every time I tried to install OS X by booting from the thumb drive, I had to enter my iTunes Store credentials; then, after downloading the entire OS from iTunes, the installer would fail with a generic error message.

By contrast, when I launched the installer from the booted SSD, it immediately began installing with no iTunes login and no download. A few minutes later the system rebooted to the "Set Up Your Mac" (sic) UI. Ready to pack and ship...


Here are the commands I used to recreate the fusion volume. Note that the sequence of disk names is a little odd:

  • disk0 was the internal SSD.
  • disk1 was the bootable installer on a thumb drive, which I hadn't yet copied to the external SSD.
  • disk2 was the external SSD drive.
  • disk3 was the internal spinning disk.

First, see what constitutes the existing CoreStorage logical volume groups.

$ diskutil cs list
CoreStorage logical volume groups (1 found)
+-- Logical Volume Group ABCDEF01-2345-6789-ABCD-EF0123456789
    Name:         FusionDrive
    Status:       Online
    Size:         2479299067904 B (2.5 TB)
    Free Space:   2471479828480 B (2.5 TB)
    +-< Physical Volume 01234567-89AB-CDEF-0123-456789ABCDEF
    |   ----------------------------------------------------
    |   Index:    0
    |   Disk:     disk0s2
    |   Status:   Online
    |   Size:     479760007168 B (479.8 GB)
    +-< Physical Volume 89ABCDEF-0123-4567-89AB-CDEF01234567
        Index:    1
        Disk:     disk3s2
        Status:   Online
        Size:     1999539060736 B (2.0 TB)

Break the FusionDrive logical volume group back into its physical volumes.

$ sudo diskutil cs delete FusionDrive
The Core Storage Logical Volume Group UUID is ABCDEF01-2345-6789-ABCD-EF0123456789
Started CoreStorage operation
Destroying Logical Volume Group
Erasing disk0s2
Initialized /dev/rdisk0s2 as a 447 GB case-insensitive HFS Plus volume with a 40960k journal
Mounting disk
Erasing disk3s2
Initialized /dev/rdisk3s2 as a 2 TB case-insensitive HFS Plus volume with a 155648k journal
Mounting disk
Finished CoreStorage operation

Carve out the recovery partition, with filesystem type 'Apple_Boot', from the 2TB drive.

$ sudo diskutil splitPartition disk3s2 JHFS+ DataPart R %Apple_Boot% %noformat% %recovery%
Started partitioning on disk3s2 Internal2TB
Unmounting disk
Waiting for the disks to reappear
Formatting disk3s2 as Mac OS Extended (Journaled) with name DataPart
Initialized /dev/rdisk3s2 as a 2 TB case-insensitive HFS Plus volume with a 155648k journal
Mounting disk
Finished partitioning on disk3s2 Internal2TB
/dev/disk3 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk3
   1:                        EFI EFI                     209.7 MB   disk3s1
   2:                  Apple_HFS DataPart                2.0 TB     disk3s2
   3:                 Apple_Boot                         650.0 MB   disk3s3

Create the CoreStorage logical volume group, giving it the name "Fusion".

$ sudo diskutil cs create Fusion disk0 disk3s2
Started CoreStorage operation
Unmounting disk0
Repartitioning disk0
Unmounting disk
Creating the partition map
Rediscovering disk0
Adding disk0s2 to Logical Volume Group
Unmounting disk3s2
Touching partition type on disk3s2
Adding disk3s2 to Logical Volume Group
Creating Core Storage Logical Volume Group
Switching disk0s2 to Core Storage
Switching disk3s2 to Core Storage
Waiting for Logical Volume Group to appear
Discovered new Logical Volume Group "FD2E200A-F7B4-4E10-BC9A-E3666F9653DF"
Core Storage LVG UUID: FD2E200A-F7B4-4E10-BC9A-E3666F9653DF
Finished CoreStorage operation

Finally, in the words of the diskutil man page, "Export a new logical volume family, with a new logical volume under it, out of a CoreStorage logical volume group." Make it a journaled HFS+ volume (jhfs+).

$ sudo diskutil cs createVolume FD2E200A-F7B4-4E10-BC9A-E3666F9653DF jhfs+ "fusion drive" 100%
Started CoreStorage operation
Waiting for Logical Volume to appear
Formatting file system for Logical Volume
Initialized /dev/rdisk4 as a 2 TB case-insensitive HFS Plus volume with a 196608k journal
Mounting disk
Core Storage LV UUID: 138E437B-867C-4DAF-A007-E0E8240652D8
Core Storage disk: disk4
Finished CoreStorage operation

Use the Desktop, Luke

The last steps, once I bumbled onto them, were to boot to OS X on the external SSD, copy the El Cap installer app to the desktop, and run it from there.

Not Just Clogged Pipes

Coronary Artery Disease as Clogged Pipes


Although the image of coronary arteries as kitchen pipes clogged with fat is simple, familiar, and evocative, it is also wrong.

most cardiac events occur at lesions that appeared mild on previous angiography

These plaques contain a lipid-rich core covered by a thin fibromatous cap. Inflammatory cells (eg, macrophages and mast cells) within the plaque may become activated by microbes, autoantigens, or inflammatory molecules (activated plaque model). The activated cells secrete cytokines and proteases that weaken the fibrous cap, causing it to erode or rupture.

Before rupture, these plaques often do not limit flow and may be invisible to angiography and stress tests.

Anecdote: My dad had ​a stress test and angiography in early 2003. It showed him to have low risk for heart attack. Less than 8 months later Dad had a heart attack, with a subsequent quintuple bypass and a stent.

in the setting of myocardial infarction, the model of an obstructed pipe is accurate, and interventions aimed at eliminating the thrombus, either thrombolytics or angioplasty, can be lifesaving. But for patients with stable disease, local interventions can only relieve symptoms; they cannot prevent future myocardial infarctions.

Although atheromatous plaques contain lipids, they are not composed of fat directly from the diet. Low-density lipoprotein is produced primarily in the liver...

growth within the vessel walls is accommodated by outward enlargement of the vessel. In that case, large plaques may not encroach on the lumen and are therefore hidden from angiography.

High-density lipoprotein removes low-density lipoprotein from peripheral tissues through reverse cholesterol transport to the liver and may have antiinflammatory properties

Although saturated fat increases low-density lipoprotein cholesterol, it also increases high-density lipoprotein, so the net effect on cardiac risk is neutral.

More recent observational studies do not support the use of low-fat diets. ​ low-fat diets had adverse effects on high-density lipoprotein cholesterol. But for patients with elevated low-density lipoprotein, they have tightened restrictions on saturated fats and now recommend that consumption not exceed 7% of total calories.

in many products, fat is simply replaced by sugar. More recently, the AHA recommended that people limit their intake of sugar, which now appears to contribute to obesity, hypertension, and subsequently coronary heart disease.

Useful Python Modules

My top 5 ‘new’ Python modules of 2015 « Robin's Blog


This module is so simple but so useful – it makes it stupidly easy to display progress bars for loops in your code.


[...] to use it within the Jupyter Notebook just make sure that the map object (map_1 in the example above) is by itself on the final line in a cell, and the notebook will work its magic and display it inline…perfect!

​ Many thanks to Robin Wilson for the summaries. It will be fun to try folium, especially.

iosnoop no longer works on OS X 10.11 El Capitan

[Note: This all started because some process – I'm still not sure which – is chewing on my hard drive for minutes at a time. This behavior started when I updated to OS X 10.11.1. Given the duration, it seems unlikely to be a simple re-indexing by mdsworkers.]

I recently tried using iosnoop to find out which processes were chewing on my Fusion drive with enough vigor to make the hard drive audible. Instead of a running log of events, I got this:

That's not right.

I filed a radar with Apple. (TODO: Create a corresponding Open Radar entry.) The response was unsatisfying, as it effectively means iosnoop is no longer usable:

This issue behaves as intended based on the following: Some significant portions of dtrace are not compatible with System Integrity Protection. Unfortunately, the iosnoop script contains probes that are not compatible, and thus cannot run.

The iosnoop(1m) man page says nothing about this. At the least this is a documentation failure on Apple's part.


Twitter turned up a workaround/solution:

@sevanjaniyan To reenable dtrace reboot to recovery, open terminal. csrutil disable; csrutil enable --without dtrace

Unfortunately this isn't working on my late 2009 iMac. As I understand it the problem is that, when I installed an SSD and configured a Fusion Drive last year, I didn't put the recovery HD outside the fusion drive. So I have some storage reconfiguration to do.


From 2 March 2015:

Exclusive: Obama sharply criticizes China's plans for new technology rules | Reuters:

In an interview with Reuters, Obama said he was concerned about Beijing's plans for a far-reaching counterterrorism law that would require technology firms to hand over encryption keys, the passcodes that help protect data, and install security "backdoors" in their systems to give Chinese authorities surveillance access.

Obama said the rules could also backfire on China.

"Those kinds of restrictive practices I think would ironically hurt the Chinese economy over the long term because I don’t think there is any U.S. or European firm, any international firm, that could credibly get away with that wholesale turning over of data, personal data, over to a government," he said.

From 24 February 2015, an exchange between Yahoo's Chief Information Security Officer and NSA Director Mike Rogers:

Yahoo's security boss faces down NSA director over crypto ban - Boing Boing:

AS: [...] So, if we’re going to build defects/backdoors or golden master keys for the US government, do you believe we should do so — we have about 1.3 billion users around the world — should we do for the Chinese government, the Russian government, the Saudi Arabian government, the Israeli government, the French government? Which of those countries should we give backdoors to?


MR: I think we can work our way through this.

AS: I’m sure the Chinese and Russians are going to have the same opinion.

MR: I said I think we can work through this.

AS: Okay, nice to meet you. Thanks.

Connecting to a headless Raspberry Pi w. VNC

Rather than dedicate a keyboard, mouse and display to my Raspberry Pi I'd prefer to access it over the network. ssh access is usually good enough, but sometimes I'd also like to use its graphical desktop, via VNC.

This post at My Raspberry Pi Experience provides all the required info in one place. Many thanks!

To recap the article: with the Pi connected to my network, and with its IP address reserved on the router, log in via ssh. Then install tightvncserver:

$ sudo apt-get install tightvncserver

Create a script, somewhere on the path, to start the VNC server manually:

# start_vnc_server
# Starts a VNC server listening on port 1, with a 16-bit pixel depth.
vncserver :1 -geometry 1024x768 -depth 16

Run the script (natch).

When you're done, either unplug the Pi or shut down the server. If you're as forgetful as I am, you'll need a script for that, too:

# stop_vnc_server
vncserver -kill :1

I use Jolly's Fast VNC as my vnc client. The Pi's server doesn't seem to advertise its presence via ZeroConf/Bonjour, but it's pretty easy to configure:

Pasted Image 3 8 14 12 23 PM 5

And there it is:

Pasted Image 3 8 14 12 42 PM 2

Coincidentally, it's curious that all of my iOS devices show up in the server list. Someday when time is free I should investigate how to view them via VNC...

Mavericks, OS X Server, and CalDAV

Well, that's inconvenient. I didn't set up an email address for my local sync user.

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Happily, changing account type to Manual allows one to specify a username and a server address.

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Now to follow Jay's advice from Setting up your own sync server: Export existing iCloud-synced calendars one by one, then import them into the new local server.

Mavericks, OS X Server, and local sync accounts

I've installed OS X Server under OS X 10.9. Among other uses, I wanted to use it for local sync of contacts and calendars, in place of iCloud.

For the most part I've followed the beautifully clear instructions posted at (Setting up your own sync server). Everything has worked as documented, right up to the point in Configuring OS X to connect and sync with the server where Jay writes

[...]select ‘All on My Mac’ (this is where all the originals should be), select all of your contacts and drag them to ‘All OS X Server’.

Whenever I would drag to 'All OS X Server', the green "+" badge would not appear on the drag icon. I could not drop my local contacts onto the "All OS X Server" group.

Eventually it occurred to me to try to set up a CardDav account – the approach described in the section on configuring an iOS client. So, instead of adding a new OS X Server account, I'm doing as follows:

In System Preferences > Internet Accounts, select "Add Other Account...". Then instead of selecting "Add an OS X Server account", select "Add a CardDAV account".

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In the resulting sheet, enter the account information much as you would have done when adding an OS X Server account.

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Go ahead and create the account. You may get a warning about being unable to verify the identity of the server, if you're using a self-signed certificate like I am. If this happens you can click "Show Certificate" and, opening the Trust section, explicitly trust the certificate.

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Click Continue to add the account.

With the new account in place, quit System Preferences. Launch Contacts. You should see a new group with the local name of your server. Better yet, you should be able to drag contacts from "All on my Mac" and drop them onto your new server account.

I haven't gotten around to trying a similar workaround for the OS X Server Calendar service. Here's hoping it works just as well.