Screen Sharing from Ubuntu to OSX

OXS has a great feature where all the local (and remote macs if you use Back to My Mac) appear in the finder on the left side bar. If the Mac supports screen sharing, you can connect to it there, along with the normal file sharing options.

Well Mac screen sharing is just VNC will Bonjour. Ubuntu supports both VNC natively and Bonjour through Avahi.

So how do we get an Ubuntu system listed in OSX's sidebar and connect with screen sharing? Well its pretty easy, but not obvious.

1. As su edit the /etc/avahi/avahi-daemon.conf:

sudo vi/etc/avahi/avahi-daemon.conf

change the line:

#domain-name=local

to:

domain-name=local

OSX uses the domain local out of the box for mdns/bonjour/zeroconfig. Linux uses what ever domain you use when you set up your host. Changing the avahi-daemon file overides your domain, and puts you on the local domain with your Macs.

2. Enable VNC.

In Ubuntu goto System | Preferences | Remote Desktop

Check the box for "Allow other users to view your Desktop."

Uncheck (if you wish) "You must confirm each access to this machine."

Check "Require the user to enter this password."

Set the password.

Close the Window.

This is what it should look like:

3. Test!

On OSX open up a finder window. You should see under the shared heading on the lefthand side USERS's remote desktop on UBUNTUHOST, where USER is the name of your user account in ubuntu, and UBUNTUHOST is the name of your ubuntu system.

Here is what it looks like on my system:

Now hit the Share Screen button at the top right of Finder. You will get a log in prompt. Enter the password you used when you set up Remote Desktop in ubuntu:

You should then get a screen sharing window showing your ubuntu desktop:

4. Limitations.

Screen sharing on ubuntu is a tad different the OSX. In OSX the screen is shared by the OS before any user logs in, so you can connect to your OSX system and then log in as any user. OSX also uses User authentication for screen sharing. Your OSX username is your screen sharing username. The same is true for your password.

In ubuntu, the screen is shared by VNC after the user logs into the system. This means that a user must be logged into ubuntu before connecting with screen sharing. It also means that after you are connected the screen sharing, and you log out of your user account in ubuntu the screen sharing connection will be dropped. Also, authentication is handled by VNC, not ubuntu. There is no username, just the password you set in the Remote Desktop settings.h

Drobo Speed and the Mac Pro

I got a Drobo a little while back. Its a pretty cool device. I have however been a bit disappointed with the speed.

Searching through the internet I read that the FW800 interface on the Mac Pro ain't that hot, and that getting a PCI-E interface would prove faster. Well after hooping in newegg.com and $40.00 later, I tested it out.

Here are the results:

As you can see there is a pretty big difference. For example, sequential read with 256K blocks was about 38MB/s with the PCI-E card while the motherboard FW800 interface was about 22MB/s.

This benchmarking was done with XBench on OSX 10.6.1 with the Drobo having 4 Seagate 1.5TB SATA 300 drives.

Now the Drobo is faster, but still not as fast as I'd expect. Given that, Its still a pretty cool device, and speed is my only complaint.

Home Network Load Balancing

I'm been downloading some stuff with bit torrent via RSS feeds lately. With all the talk of throttling by ISPs, and to achieve domestic tranquility by having the MRS not bitch about slow internet at home, I've implemented load balancing with pfsense and my 2 broadband connections.

With bit torrent opening up an assload of independent connections to hosts all over the internet, you would figure its a prime candidate for load balancing. Well its not. I'm still trying to figure out why, but to achieve any sort of reasonable performance, I need to force it to a single interface with firewall rules.

Anyone with insight into why this is, please fill me in.

Netbook SSD Performance

I have a Dell Mini9. It has a 4GB STEC SSD drive. As SSD's are extremely different then HDDs in the way they operate, I was interested in its general performance under certain conditions.

My biggest interest is the difference between the stock Ubuntu 8.04 Hardy Heron and the New Ubuntu 9.04 Jaunty Jackalope. One of the primary differences between the two is that Jaunty supports EXT4 while Hardy supports EXT3. The kernel for Hardy is 2.6.24-SS LPIA, the kernel for Jaunty is 2.6.28-11 i386.

Now I know this is not a scientific test, as there are a bunch of variables that I have not controlled for, I.E.; kernel, kernel architecture, fs, and so on. I did use the noatime option on both ext3 and ext4.

All tests were performed with iometer. They were performed on /dev/sda1 as I didn't want to write directly to /dev/sda directly, as this would blow away the underlying OS. I may do that in the future.

The first set of tests is read performance, both random and sequential. I did this with 2 different transaction sizes, 4KB and 2MB. As the SSD block size is 4KB this is the smallest effective transaction possible. The 2MB size I thought was big enough to give an idea of larger transactions.

Both IO/s and MB/s are ascertained. The IO/s tells us how quickly a transaction can be accomplished. If you have multiple processes accessing different data simultaneously, the more IO/s you have the better. The MB/s is obviously how much data through-put that transaction provides.

Here are the results:

As you can see, Jaunty and EXT4 excel at every test.

Below are the write tests. To do the write test, the drive was aged. If you dont know why aging a SSD drive is important check out this article by anandtech.

Again, Jaunty and EXT4 excels. You can also see that the write through-put is very low. .03 MB/s. This is a result of the aging of the SSD. I will look at a fresh SSD's write performance soon.

Nine Inch Nails Live

So last week I got to see the NIN concert in Philly. This was the tour for both Year Zero and The Slip. There was no show in DC so I drove up. Any one who has seen NIN live knows that the shows are a big deal.. lots of lights and crazy effects and stuff.

This show by far was the best I've been too, and I've been more then I can count. The technology they used for the light presentation was mind blowing. It appeared to be a massive grid or RGB LEDS that was probably 30'x50' that would lower infront of behind the performers. When it was dark, it could be seen through. The grid was able to obviously show video, but was was even more amazing is that it appeared to have light detecting nodes though out. With that they did all sorts of crazy things:

They put the screen infront of the band, and put the band in the dark behind it. Then they would do 2 spots across the stage infront of the band, behind the screen. Video would be shown on the screen, but as band members moved into the light, the video would black out in that area and that band member could be seen through the screen.

The next thing was nuts.. They put up a very minimal grid of squares on the screen. The drummer then walked out with a tiny flashlight and lit up some of the squares... it turns out the screen was a giant drum machine. He programmed it through out the song with flash light.

They also did lots of light feedback and effects by projecting other lights on the screen with the music.

For an engineering geek like me, it was truly an amazing thing to watch. The thought and creative energy that went into that show was just off the chart. If you ever get a chance to see NIN live, or pick up a concert video, I would not balk at the chance.

Pictures via Kelly

Plan!t Now

I'm volunteering for Plan!t Now. It is an organization dedicated to grass roots disaster response planning.
As made evident by hurricane Katrina, some disasters can overload Federal and State disaster planning. By planning at the personal and community level, the damage can be mitigated and return people to thier normal lives quicker.

Plan!tNow

944 no more

So my mostly finished 944 was totaled last month by an asshole. Oddly enough, the asshole wasn't me.

Here is why he is an asshole.
1. The accident was on Rt 66 in VA. In the middle of a 4 mile back up, this asshole figures out how to get up to about 40MPH, with out regard for a car that is stopped in front of him.
2. The asshole couldn't manage to find his brakes during his experiment with momentum. Or perhaps he was texting, and didn't even know he about to hit a car in a traffic jam that had been stopped in front of him for over a minute.
3. Emergency break down lane? Thats only for emergencies.. and its only an emergency after an accident right? Isn't there a law about pulling into that lane? I must be better to hit some one instead.
4. Who needs a drivers license really? I know I'm 17, have no experience behind he wheel, its dark, its raining, there is an assload of traffic and I'm by myself with my learners permit, what could go wrong?

Soon to come, why we should burn all the insurance companies to the ground, but not after my claim is settled by the nice, but amazingly incompetent people at nationwide.