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Tuesday, September 4, 2007

Studying

There’s a lot of information out on the internet about studying. I recently ran across an interesting article on zen habits about a holistic approach to studying, something I’ve felt strongly about for a while now.

Everything is connected. Why do yourself this disservice of learning it all separately? Memory works better when you make connections between the topics.

It seems that this is something a lot of educators and educational institutions could do better on. Some science courses will make the connection to other science courses or math courses (and vice-versa), but I’ve rarely seen them itemize even some of the connections to liberal arts type material.

posted by Zach at 4:22 pm  

Monday, September 3, 2007

Isses with peth error messages and ssh on production blades.

I ran into some issues with getting a steady stream of error messages about peth sent to tty0 on the production blades. This is yet another issue Cyrus already addressed (like the ssh issue on righteous). He even submitted a bug fix to xen for this one. It was just a matter of applying and configuring the bug fix and after everything was restarted, the error disappeared.

This did not fix the apparently unrelated issue of ssh on the blades “breaking”. The temporary fix for that is to log into the blade in the server room and restart networking. Still working on this one. Thanks to some help from Jeremy, we’ve determined that after a while, the server room network entry disappears from the resolve.conf file. This seems to coincide with ssh “breaking”

posted by Zach at 11:02 pm  

Monday, September 3, 2007

Automation of AoE

A few days ago, I took some steps to automate the ATA over Ethernet (AoE) startup process. I thought it’d be best to stick them in writing here:

  • Adding the necessary modules /etc/modules on the three machines currently running AoE (0010, 0011, and mirror)
  • Adding the necessary vblade exports to animal’s /etc/rc.local

What remains is to test the AoE environment to eliminate any bugs before moving the rest of the production images and machines over.

posted by Zach at 9:32 pm  

Monday, September 3, 2007

What happens when Animal boots up with the RAID units powered off.

Ever wonder what would happen if some moron were to try to boot Animal with the power supplies on the RAID units on “off”?

Well, it turns out that the raid card on animal flips out and makes the most annoying noise possible. In this case, what it took to make it stop was to: start the raid units, restart animal, go into the setup menu, confirm the settings with 4 LVMs (1 small one, 3 ~6 TB), and the change each hard drive from “failed” to “online” (except the hotswap ones), exit the config, reboot animal, and viola.

It sounds easy, but with the beeping noise that makes it seem like the world is going to end if you don’t hurry, it’s a bit more difficult.

posted by Zach at 8:40 pm  

Monday, September 3, 2007

Issues with SSH on Righteous

Righteous decided to stop accepting ssh. After a bit of poking around, we decided to run /root/scripts/iptables.sh, and it started working again. Yay for easy solutions.

posted by Zach at 8:25 pm  

Sunday, September 2, 2007

The OpenMPI Cluster “Server” Setup

The first step was to get another blade running xen. To do this, I took a backup of a production blade, unzipped it on blade 3, and changed the hostname information (in /etc/hostname, /etc/dhcp3/dhclient.conf, and /etc/init.d/sshd.conf), removed a pesky file causing some issues with the networking, set up aoe (add aoe and dm-multipath to /etc/modules), and was set for the dom0. At that point, I created a new xen image and config file (changing the drive locations, the name, and the mac addresses) on animal, exported them using vblade (vbladed 1 4 eth0 /mnt/raidB/xenlib/images/cluster.disk), and , on 0011, partitioned (using fdisk) and set it up with etch (using debootstrap). At that point, I mounted it, edited some config files (/etc/hostname, /etc/dhcp3/dhclient.conf, /etc/ssh/sshd_config, /etc/fstab, and /etc/networking/interfaces), and then started the image. I then ran into the error message “4gb seg fixup, process ___ (pid ___), cs:ip _______”, which popped up regularly for the majority of running processes. It was an easy fix; all I had to do was install libc6-xen, but it wasn’t very easy to find. I then worked with Ryan Lewis to set up the cluster account and key-based authentication to the lab machines. Ryan then configured the lab machines to allow ssh for only key-based authentication.

posted by Zach at 8:57 pm  

Sunday, September 2, 2007

The Importance of Information

Information is invaluable in any field, and it is especially so in one structured about information itself, such as web development. As Shane Diffily talks about in the A List Apart article Educate Your Stakeholders!, everyone in the entire website creation process needs to be sufficiently well educated about the process and the decisions involved in it. I’ve seen many cases where the process skips from a client requesting a website to the client being asked for a description of what they want. They don’t know what they want. It isn’t that they’re unintelligent, it’s just that they’re often uneducated or poorly educated at best about the process, the possibilities, and what they need to consider when making decisions. Somewhere along the line, the client needs to get the information necessary to make informed decisions.

posted by Zach at 4:02 pm  

Sunday, September 2, 2007

WCAG 2.0

There have been a variety of articles floating around (some for quite a while now) about WCAG 2.0 discussing a variety of issues with the guidelines. In reading those (and the draft guidelines), I’ve formulated some of my own opinions about the guidelines.

But first, some background. In the late ’90s, the W3C created a new working group, the WCAG WG, as part of the WAI. The WCAG WG was tasked with the creation of the WCAG, a set of tiered guidelines for web developers to use to ensure the accessibility of their content. The first version of these guidelines, know as the WCAG 1.0, were completed in mid 1999. A year and a half later, in early 2001, development began on what would come to be the WCAG 2.0. Work on these guidelines continued through early 2007, when a “final working draft” (basically what is intended as the final version before submission for approval) of the guidelines was released. It was met, to put it mildly, with wide criticism and, to put it more realistically, outrage. That brings us right up to around now. Amazing how history works.

And now, my opinion on the matter. In order for the WCAG to be of any use, they (the guidelines) need to do four things (some of these things they do, others they don’t):

  • Be guidelines
  • Address accessibility in a clear way (be accessible themselves)
  • Be useful
  • Be broad, but not too broad

Be guidelines

Guidelines are not rules. They do not need to be enforceable. They should serve as suggestions for ways to improve the accessibility of web content. (What a crazy idea; the Web Content Accessibility Guidelines should be guidelines about the accessibility of web content!)

Address accessibility in a clear way

Accessibility is what Accessibility Guidelines should be about. That should be the main criterion for inclusion of a checkpoint (or whatever term is deemed most appropriate) not whether it shifts the balance of the document to specific disabilities or whether it can’t be easily tested.

The guidelines also need to be kept to a reasonable length. 10% of the current size (~50 pages) would be more reasonable than the the current size (~500 pages), which few people will ever read (I’m trying to wade my way through them, although it may take a while).

Be useful

There needs to be a big push made to educate those in fields dealing with the creation of web content about the existence about the WCAG and the WCAG needs to be in a format that is useful to them (see the discussion of length above). The idea of companion documents is a noble one, but it has created far too much (and sometimes contradictory) material.

Be broad but not too broad

They need to be technology independent. They really do, but they can’t be so broad as to cover absolutely every detail of everything (see the discussion of length in “Address accessibility in a clear way” above). Accessibility isn’t something that varies from one web medium to another, so why should the guidelines? One of the most popular arguments against technology independence is that more useful guidelines can be created in a technology specific document. Maybe we do need technology specific clarifications, but that isn’t the purpose of the WCAG. It’s purpose should simply be to address the accessibility of all web content in a clear, concise way.

Some of the “variety of articles” I mentioned:

posted by Zach at 1:10 pm  

Sunday, September 2, 2007

Undo as a Standard Feature

Why isn’t undo a standard feature in every user interface? I can’t speak for the rest of the human race, but I know I’ve made my fair share of mistakes selecting “Okay” on those annoying pop ups. It’s entirely automatic; you see a pop up, you skim it and hit okay, only pausing to think about what it said after it’s too late. As Aza Raskin says in the A List Apart article Never Use a Warning When you Mean Undo, people form habits of simply clicking okay without pausing to think about the consequences, and there’s no good way to force them to stop and think. Because of that, providing the ability to undo a possibly dangerous action is just as important (if not more so) than warning users of the danger in the first place. Why not take them time to add the undo and make the application a little more user friendly?

posted by Zach at 2:30 am  

Sunday, September 2, 2007

The Necessity of Content in a Website

In reading a recent article about “Reviving Anorexic Web Writing” on A List Apart, I was struck by both the Amber Simmon’s approach to ensuring adequate site content: not beginning the design process without it in hand, and her differentiation between content and copy: that copy is just the marketing fluff while content is what the site is about. She makes the point that while reduction of copy on websites is a good and necessary practice, reduction of a site’s content is in many cases ill-advised. The archaic practice of “eliminate, eliminate, eliminate” is sometimes applied to content without thought to the fact that without content, there is no reason for a site to exist. She continues on to point out that alt text is more important than often thought (if it’s just a picture and the visually impaired wont be missing anything by missing it, why do you need it in the first place?) and that footers are often under-utilized (why can’t you put something other than copyrights and links, such as actual content, down there?).

It seems to me that people in web related fields (web design, development, writing, etc.) often forget the importance of website content, even though it seems like an impossible thing to forget, because without the content, the entire site is pointless. Logically speaking, content should serve as the foundation for the website, with everything else serving to enhance it. Why isn’t the content-first method of web development the most popular one? I can’t think of a good reason not to use it.

posted by Zach at 2:30 am  
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