Josef “Jeff” Sipek

Operating Systems: Three Easy Pieces

I just found out that Remzi and Andrea decided to write a textbook about operating systems. This is exciting for several reasons. Here are the top two.

First and foremost, the book is free. That’s right, a textbook that is free when every other computer science textbook is easily around $100. Why? I’ll let Remzi make the case. Long story short, publishing a textbook isn’t about making money. It is about sharing ideas. You can download it from the textbook’s website.

Second, the book is by Remzi and Andrea. This pair of professors from the University of Wisconsin is responsible for a ton of amazing storage related research. If you don’t believe me, check out their publication track record.

I suppose I should mention that I have read only very little of the book, but I did push it onto the top of my to-read stack and I’m slowly making my way through it. I’ll let you all know how it goes.

Imperial man shoots himself in the head while teaching firearm safety

Really, really stupid idea: drinking and teaching gun safety: Imperial man shoots himself in the head while teaching firearm safety.

Note: One of the big safety rules is to never point a gun at people/things you don’t intend to shoot.

AGM @ Trinity

This past week, Trinity Church (previous post) hosted the AGM.

As a result, the NY Times wrote an article about the event and change ringing.

Neat, I just found out that the ringers at Trinity have a new website.


The other night, just before midnight, STS-128 launched. I took a few screenshots of NASA TV. NASA described the launch as:

Liftoff from Launch Pad 39A was on time at 11:59 p.m. EDT. The first launch attempt on Aug. 24 was postponed due to unfavorable weather conditions. The second attempt on Aug. 25 also was postponed due to an issue with a valve in space shuttle Discovery’s main propulsion system.

The STS-128 mission is the 30th International Space Station assembly flight and the 128th space shuttle flight. The 13-day mission will deliver more than 7 tons of supplies, science racks and equipment, as well as additional environmental hardware to sustain six crew members on the International Space Station. The equipment includes a freezer to store research samples, a new sleeping compartment and the COLBERT treadmill.

Here’s the “beenie cap” with the moon in the background:
Beenie cap

A nice shot of the whole shuttle:

The engines:
Engine closeup

Beenie cap being retracted before launch
Beenie cap retracted

Later on, I found this image on NASA’s site. Wow.

STS-128 Launch
(original link)

Viewed from the Banana River Viewing Site at NASA’s Kennedy Space Center in Florida, space shuttle Discovery arcs through a cloud-brushed sky, lighted by the trail of fire after launch on the STS-128 mission.

Amazon Kindle SNAFU

This is why I don’t like DRM or any other scheme which allows someone else to grant/remove access to content which I should have access to - if I buy a (dead-tree) book, I should have access to it until I get rid of it (trash it, donate it, give it to a friend, etc., etc.).

The link talks about books, but the same ideas apply to DRMd music, movies, and whatever other content.


Tee hee…an amusing story from BBC News:

A man in the United States popped out to his local petrol station to buy a pack of cigarettes - only to find his card charged $23,148,855,308,184,500.


I was just watching the STS-127 launch. I couldn’t help but take a couple of screenshots of NASA TV…

Right after solid rocket booster separation:
SRB separation

The fuel tank, and separation:
External Fuel Tank
External Fuel Tank separation

And, it looks like NASA has a nice photo of the launch:
STS-127 launch

Formatting Error

Few years ago, I found a formating bug in PowerDNS’s web interface. It took a while for it to get fixed. Since it wasn’t a critical bug, I never tried to make the maintainer see the light — eventually he found it himself :) Now, I can say that PowerDNS is perfect :)

Last night, while roaming around BBC’s website, and I noticed this: formating error

I took a screenshot and earlier today I let them know about the problem. I don’t see today’s numbers displayed in engineering format, but today’s numbers are an order of magnitude larger than yesterday’s so I can’t tell if they already fixed it, or if it’s the larger numbers that are hiding the problem. We’ll see if I get a “thank you” note, or something :)

Sarychev Peak Volcano Eruption

Today, I came across a link to a photo with a long description. I’m going to include both below:


ISS020-E-009048 (12 June 2009) — Sarychev Peak Volcano eruption, Kuril Islands, is featured in this image photographed by an Expedition 20 crew member on the International Space Station. A fortuitous orbit of the International Space Station allowed the astronauts this striking view of Sarychev volcano (Russia’s Kuril Islands, northeast of Japan) in an early stage of eruption on June 12, 2009. Sarychev Peak is one of the most active volcanoes in the Kuril Island chain and is located on the northwestern end of Matua Island. Prior to June 12, the last explosive eruption had occurred in 1989 with eruptions in 1986, 1976, 1954, and 1946 also producing lava flows. Ash from the June 2009 eruption has been detected 2407 kilometers ESE and 926 kilometers WNW of the volcano, and commercial airline flights are being diverted away from the region to minimize the danger of engine failures from ash intake. This detailed photograph is exciting to volcanologists because it captures several phenomena that occur during the earliest stages of an explosive volcanic eruption. The main column is one of a series of plumes that rose above Matua Island (48.1 degrees north latitude and 153.2 degrees east longitude) on June 12. The plume appears to be a combination of brown ash and white steam. The vigorously rising plume gives the steam a bubble-like appearance; the surrounding atmosphere has been shoved up by the shock wave of the eruption. The smooth white cloud on top may be water condensation that resulted from rapid rising and cooling of the air mass above the ash column, and is probably a transient feature (the eruption plume is starting to punch through). The structure also indicates that little to no shearing winds were present at the time to disrupt the plume. Another series of images, acquired 2-3 days after the start of eruptive activity, illustrate the effect of shearing winds on extent of the ash plumes across the Pacific Ocean. By contrast, a cloud of denser, gray ash – most probably a pyroclastic flow – appears to be hugging the ground, descending from the volcano summit. The rising eruption plume casts a shadow to the northwest of the island (bottom center). Brown ash at a lower altitude of the atmosphere spreads out above the ground at upper right. Low-level stratus clouds approach Matua Island from the east, wrapping around the lower slopes of the volcano. Only about 1.5 kilometers of the coastline of Matua Island (upper center) can be seen beneath the clouds and ash.

RHEL 5.4: Now shipping XFS

Wow, it’s about time!

Sources tell me that RHEL 5.4 comes with XFS support. This is good news for all those folks wanting to use filesystems larger than 16TB and not trusting ext4 with their data (I couldn’t blame them). As far as I know, these unfortunate souls have been told to use GFS2 if they wanted a RH supported fs that did more than 16TB. (It’s worth mentioning that ext3 had a 8TB limit until about two years ago, when it got fixed up to support whopping 16TB.)

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