Technical Musings

Windows Home Server 2011

I recently upgraded from Windows Home Server (WHS) to Windows Home Server 2011 (WHS2011). My old WHS machine was dying, and I was attracted to idea that WHS2011 was a 64 bit OS, and would hopefully perform better. I installed WHS2011 onto a 64 bit VMWare virtual machine with 4GB ram, a 200GB virtual for the OS, 3TB storage on an external USB HDD and a 100 GB virtual disk to backup the OS.

Incidentally, the OS only formatted up a 2GB partition on the 3GB drive, leaving a separate 1TB partition unused. I formatted this up later and added it to the pool.

I encountered several problems, but have overcome them all, and am very happy with the result.

1. WHS provided Drive Extender Technology, but WHS2011 does not.

A cool feature about the original WHS was that you could add extra storage to the box on the fly, and WHS would allocate it to one large storage pool. So rather than having a bunch of disparate disks of all different sizes, they’d all appear as one huge drive.

This feature was dropped from WHS2011.

That meant if one of my drives filled up, and I wanted to add more storage, it would appear in the system as a separate drive, and I’d have to alter my backup plans to use the new drive.

I got around this problem by installing DriveBender – a WHS2011 add-in which allows me to dynamically manage the size of my storage pools, provides redundancy, and makes managing a bunch of drives a lot easier. It only cost me $40, which (even for a tight-wad like me) was money well spent.

2. WHS2011 won’t backup a Windows 2008 Server

While the original WHS happily backed up all my servers, the WHS2011 connector would not install on my Windows 2008 server.

When I tried to install it, I got an error saying that the computer is running a version of the Windows Operating System that is not supported.

I got around this problem by loging into the WHS2011 server, and editing this file:

C:\Program Files\Windows Server\Bin\WebApps\Client\Package\supportedOS.xml

I added the following line to the XML:

EDIT (January 2013).

For a Windows Server 2008 (service pack 2) machine, I added this line:

You can figure out what numbers to use by running the WinVer utility that comes with windows. I.e. click on START / RUN and type WINVER [enter]

This will say something like:

Microsoft Windows Server:
Version a.b (build cccc: Service Pack d)

Use “a” as the “Major” parameter.
Use “b” as the “Minor” parameter.
Use “cccc” as the “Build” parameter.
Use “d” as the “SPMajor” parameter.

So my version of “Version 6.0 (Build: 6002: Service Pack 2)” translated to :
Major=”6″ Minor=”0″ Build=”6002″ SPMajor=”2″

After adding this line, and rebooting the server, I was able to install the WHS2011 connector on my server, although I received a warning telling me the OS was not on the list of compatible operating systems.

3. Disk Errors caused backups to fail

After a while, the USB drive started to fail. WHS 2011 reported that the Windows Server Client Computer Backup Service was not running. I tried to start it manually, but it failed. The event log gave the following error:
“ReadHeader File: D:\ServerFolders\Client Computer Backups\Commit.dat Error: Unable to complete the requested operation because of either a catastrophic media failure or a data structure corruption on the disk.”

To get around this problem, I used DriveBender to add a second (2TB) USB drive to the pool. I then used DriveBender to remove the faulty (3TB) UDB drive from the pool. Removing the faulty drive took about 36 hours. Basically DriveBender had to check the CRC of every file on the drive before copying it.

After removing the faulty drive, I stil received the same error, so I did a “repair” on the backup database, which fixed the problem.

I was then able to reformat and add the original drive back into the pool.

At the same time, I enabled data redundancy on the pool, so that every file added after that was duplicated on a second drive.

4. I could not connect to WHS2011 with Launchpad from one machine

This was the most annoying error of all and took me days to fix.

I had an old XP machine that refused to connect.

Whenever I tried to sign in I’d get the following error:
The server appears to be offline. Do you want to sign in to offline mode?

This happened, even though I could use Dashboard, and was able to access shares on the server from the old XP machine.

I scoured the web for solutions. Here’s a few I tried to no avail.

1. Uninstall and reinstall the WHS2011. As well as uninstalling the connector, I deleted all records of the old XP machine from the WHS2011 catalog. After reinstalling WHS2011 on the old XP machine Launchpad still would not connect to the server.

2. Uninstall and reinstall the .NET 4.0 framework. I restarted the machine after uninstalling, and even combined the process with uninstalling / reinstalling WHS2011. No joy. I still could not connect.

3. Disable my local firewall. Disable all inter-computer communication restrictions on my Endian firewall. Basically I was trying to make sure nothing was blocking communications between the old XP machine and the server. No success. I still could not connect.

4. Increase the ServicesPipeTimeout setting in the registry. The idea behind this was that perhaps it was taking a while for Launchpad to connect with the server. If I increased the timeout, perhaps it might have a better chance of successfully connecting. No joy. I still could not connect.

In desperation, I used the Wireshark packet tracer, as well as my Endian Firewalls log files to trace any packets from the old XP machine to the server. To my great surprise not a single packet was being transmitted. There were not even any unsuccessful transmissions. The workstation didn’t even appear to be trying to communicate. This led me to think that perhaps there was something wrong with the Winsock component on the client workstation. I.e. something on the local machine was stopping the communication before it even left the local machine.

So I tried listing all the LSP’s installed on the local machine using this command:

netsh winsock show catalog

This showed up something really interesting. I noticed that there was an old antivirus system (Comodo Antivirus) installed on the workstation. It wasn’t being used, but it had installed an LSP which was blocking communication between the old XP machine and the server.

I uninstalled Comodo Antivirus from the workstation, rebooted, and BINGO, Launchpad was able to connect.

I now have a fully functional WHS2011 backup solution. It has redundancy, scalable storage, and works like a charm. A couple of weeks ago, one of the local machines failed. I just rebooted that machine from a WHS2011 recovery CD, and it was up and running again in about 90 minutes.

If you’re having problems with WHS2011, I hope this post helps you sort them out.

ObSrv bug fixed (empty feeds)

Over the last few weeks ObSrv was often returning empty feeds.

I’ve fixed this bug.

If there are any further problems, please let me know.

Big Black Holes

Baby Black Hole by Nasa

This is an open question to anyone who might understand astrophysics better than me (which is probably most of the human race).

Assume there is a really big black hole. So large, in fact, that its event horizon is more than one light-year across. If you do the sums, the gravitational force near the event horizon of such a large black hole would roughly be about 1g – the same as what it is on earth.

Imagine coming close to this event horizon in a spaceship. It would be easy to accellerate away – after all, the gravitational force in the vicinity is only 1g. So any imaginary spaceship capable of escaping the gravity of earth – if it were near the event horizon of this super massive black hole, would be able to escape its gravity.

One of the horrors you normally hear about black holes is the tidal forces that would “tear you apart”. This is caused by the difference in gravitational forces as you move closer to center of gravity of the black hole. The same thing happens near neutron stars. Your head is being pulled with a lesser force than your feet. So you get “stretched”. But in our thought experiment, the centre of gravity of our supermassive black hole is over a light-year away. My head won’t feel any different amount of attraction than my feet would. There would be no noticeable tidal forces to speak of.

So imagine you’re sitting in your late-model spaceship, orbiting just outside the event horizon of this super-massive black hole. You don’t feel any tidal forces, and the black hole is exerting a similar gravitational attraction on your vessel as what you’d experience orbiting the earth.

Apart from the huge black sphere blocking half of the sky, and the strange lense-like effect of light bending as we look across the horizon of the black hole to the numerous stars in the distance, there’s nothing to be afraid of is there?

My point is it would only take a reasonable amount of thrust to move our vessel away from the black hole.

BUT… imagine as we sit near the event horizon, we move slowly towards it until we have moved INSIDE it. What would happen? What would we experience? My meagre understanding of physics leads me to think that the escape velocity just outside the event horizon would be slightly less than the escape velocity just inside the event horizon.

So the burning question then is why couldn’t you escape from this super-massive black hole, having visited the forbidden area just inside the event horizon? The gravitational attraction at this distance would be small enough for our ship to thrust away.

And this leads me to another question. If the gravitational force near this super-massive event horizon is about 1g, why couldn’t light escape from an object just inside the event horizon? And if light could escape, would there even be an event horizon? The “Black Hole” appearance of this thing is based on the assumption that no light can escape from it because the required escape velocity exceeds the velocity of light.

So please help me. I obviously know nothing about black holes. I must be making an incorrect assumption. I don’t mind asking stupid questions, and am hoping that a patient genius will take the time to reply and explain where I’m going wrong.

Thanks in advance

Update

Since I know so little about astrophysics I decided to pull together some formulas to demonstrate what I’m talking about.

First of all a few facts about black holes. For any black hole:

The escape velocity at its event horizon is “c” – the velocity of light in a vacuum – about 3 x 10 ^ 8 metres per second.
The radius of its event horizon (known as the “Schwartzchild Radius”) is directly proportional to the mass of the black hole.
The gravitational accelleration at any given distance from its centre is directly proportional to the mass of the black hole but inversely proportional to the square of the distance.

Here are a few formulas:

Schwartzchild Radius, r_s = 2Gm / c², where G is the Gravitational Constant, m is the mass of the black hole, and c is the velocity of light in a vacuum.
Gravitational Acceleration, a = Gm/r²

This means we can work out how big the event horizon of a black hole will be if we know its mass. And we can work out what the gravitational acceleration will be at any given distance from a black hole if we know its mass.

This allows us to ask the question, is there any mass of a black hole at which the gravitational acceleration at the event horizon will be similar to what we experience on earth (10 m/s²)?

I think there is.

Lets assume there’s a galaxy about 50% larger than our Milky Way galaxy. It would have a mass very roughly equal to about 1.5 x 10¹² solar masses.

If we squashed this galaxy down into a small enough pile, so that it became a black hole, its Schwartzchild Radius, r_s, would be about 4.5 x 10¹⁵ metres, or about 1/100th of a light year.

If we stand 1/100th of a light year from this object, what would its gravitational acceleration be? Using the above formula for a,we arrive at 10 m/s².

The bottom line of all this rambling is that hypothetically I think you can have a black hole where the gravitational acceleration at the event horizon is similar to the acceleration that an object would experience at sea level here on earth. That black hole would have a mass of 1.5 x 10¹² times that of our sun. And that means the question I raised at the start of the article is a valid one.

ObSrv – Appropriate Images Please

I’ve added a mandatory “Safe Search” filter to all images served up by ObSrv.

To most users, you won’t notice any difference, but the problem was that some people were using ObSrv to generate adult images, which got me in trouble with Google Adsense.

This is a business decision, not a moral one. Using ObSrv to generate adult images would get my Adsense account cancelled. No Adsense income = No ObSrv. Everyone would lose. So the simplest solution I could find was to block anything that didn’t pass the Google “Strict Safe Search” test.

If you find your image feeds aren’t generating images any more, please consider using less adult-related search terms.

Low-res Brain

Thought experiment.

Close your eyes and imagine a clock face with hands and numbers.

Imagine the clock face as a whole. Try not to think of just parts of it.

In your minds eye can you see the individual numbers on the clock face all at once?

I can’t.

I have to “zoom” in to each part of the clock to see all the numbers. I can’t see them all at once.

If the brain can’t do this while we’re awake, then it’s no wonder we don’t have vivid details of items when we’re asleep and dreaming.

If our brains imagery has such low resolution, why do we seem to have such hi-resolution memories?

Maybe it’s different for you. But that’s how it is when I try it.

This whole experience helps me understand how my brain visualizes things. It’s not like the “Pictures” folder on my computer. I don’t store high-resolution pictures in my head. I think it’s more like a short-hand way of reconstructing a picture. Without realizing it my brain says “A clock is a circle. And it’s got numbers around it from 1 to 12. And it has hands. And it ticks”.

Perhaps it’s like that for someone’s face as well? Do you know every freckle, mole or scar on your partners face? When you think about it, how much detail of someone’s face do you actually remember? I think perhaps we actually store a low res “caricature” of a persons face in our brain, and when we see that person, we match what we see of their face with the low res memory of it, and somehow our brain can recognize that the two things represent the same person.

I think our physical perception of reality is a lot less detailed than we realize. When we look at a page in a book, there’s only a small circle of our vision that can actually see fine detail – about the width of our thumb held at arms length. If you hold your thumb in front of a book held at arms length, and focus on your thumb, you’ll find it almost impossible to read the book. That’s because the Fovea (the bit that sees detail) in your eye only occupies a small part of your Retina (the bit that actually sees things). But our brain manipulates us to think that we can see everything in detail, because our eyes dart around, and our brain puts all the jigsaw pieces together.

So next time you’re certain you saw something, remember that what you saw, what you thought you saw, and what you remember seeing are all totally different!

Isn’t the brain an amazing thing?

Problems Activating and Updating Windows 7 behind an Endian Firewall

I have had problems Activating and Updating Windows 7.

I have an Endian firewall appliance.

The main error I was getting was 0x80072EFD – unable to connect.

For me, the solution (after hours of heartache) was simple:

Go into Control Panel / Network and Internet / Internet Options / Connections tab / LAN Settings,

UNTICK “Automatically detect settings” and press OK.

Activation then works.

Updates then work perfectly.

Sorry – I’m not sure why this happens. I suspect it’s a bug in Endian version 2.2 which is fixed in later a version, probably relating to the internal Endian Proxy server which in my case is disabled anyway.

I hope this helps someone.

Many thanks to my son, Lachlan, who also had this problem, and figured out how to fix it after several days of heartache.

ObSrv Performance Improvements

I’ve improved the load speed of the ObSrv home page. Sometimes it would take a long time to load.

I’ve also improved the speed of the image feeds. It still can be sluggish at times – that’s because it’s heavily used, but to counteract this, the Image Feed will ignore requests from the same computer if they come more frequently than about once every 3 or 4 seconds.

For most people this won’t be a problem, and the only time you really notice delays on the Image Feed is if you try and display it in your browser.

If site performance is still an issue for you, please let me know.

Around Pine Rivers

Here’s a brief description of each of the photos in the “Around Pine Rivers” theme for iGoogle.

If you’ve got any suggestions, corrections or improvements, please let me know.

Click on the images for a larger view.

Bell’s Scrub is the only remaing parcel of virgin lowland vine rainforest in the Pine Rivers district.
See http://blog.neilennis.com/index.php/bells-scrub-lawnton/

Some of the stunning late afternoon views in my street.
see: http://blog.neilennis.com/index.php/everyday-beauty/

Fleeting glimpses of childhood on the North Pine River.
See http://blog.neilennis.com/index.php/fleeting-glimpses-of-childhood/

Christmas Beetle.
See: http://www.flickr.com/photos/magictyger/sets/72157603351606109/
Wikipedia Article: http://en.wikipedia.org/wiki/Anoplognathus_pallidicollis

Lightning in the Gum Trees.
See: http://blog.neilennis.com/index.php/lightning-in-the-gum-trees/

Ebert Family Vineyard.
See: http://blog.neilennis.com/index.php/echoes-in-the-vineyard/

Stephen Lawn Park.
See: http://blog.neilennis.com/index.php/nuts-about-history/

Lake Samsonvale.
See: http://blog.neilennis.com/index.php/lake-samsonvale-2/
Wikipedia article: http://en.wikipedia.org/wiki/Lake_Samsonvale

South Pine River near the site of the old Normanby Rum Distillery.
See http://blog.neilennis.com/index.php/bikes-rivers-old-rum/

Yebri Creek.
See http://blog.neilennis.com/index.php/exploring-on-sunday/

Sunset on the North Pine River.
See: http://blog.neilennis.com/index.php/sunset-on-the-north-pine-river/

Lake Kurwongbah.
See http://blog.neilennis.com/index.php/cycling-by-the-lake/
Here’s a wikipedia article: http://en.wikipedia.org/wiki/Lake_kurwongbah

Why only 21 images at a time?

Aaron asked a good question they other day.

Why does ObSrv only ever return 21 images at one time?

I thought it was a bug in my code, but it’s not. ObSrv pulls images from Google Image Search, and Google only ever returns 21 images in one go.

But this is not a problem. The images are embedded into a MediaRSS feed. That feed is cached for a maximum of one hour. After this time if you request the same feed, ObSrv will search again, but it will add in up to 21 extra images that weren’t shown last time. So on subsequent calls you’ll get more than 21 images in the feed. In the unlikely event that it runs out of images, it starts searching from the beginning again.

So although there’s nothing I can do about the 21 images at a time issue, it’s not a major problem because you will get more images after the feed refreshes – but remember, to save server resources (and to stop Google from banning me) it waits an hour between doing searches on the same terms.

On Yer Bike!

View Larger Map

I took Steve and Harrison on a bike ride this morning, along the North Pine River, up to Lake Samsonvale, and then back along the North Pine Rover.

It was a hoot! A little bit slower than normal, because Harrison is only 9 and his bike is a bit worse for wear. But it was fun all the same.

And I got to try out a new program for my Nokia N95 mobile phone. Nokia Sports Tracker Uses the inbuilt GPS on the phone to record speed and height info. While you’re cycling, your N95 acts like a speedo, and odometer, showing you all the vital stats. But when you get home, you click the button, and upload the data to sports tracker.

The really cool thing is that if you take any photos with the phone on your journey, it will upload and geotag them.

So the map on the left here is where we went. You can drag and zoom it if you want more detail.

But the fun part is that the data is also uploaded to the Sportstracker community. Here’s a link to the data for our ride today. If you tick the “altitude” box, you can see every hill, and how fast we were going.

The thing I like most about this technology is that it adds to the fun of getting out and exercising. At times I’ve found it hard to overcome my inertia to regularly exercise. In regards to exercise, if it makes me think “Oh yeah! I want to do that again!” then I think it’s a great thing.

Oh – and you can use Sports Tracker for running, walking, skiing, rowing – whatever floats your boat.

P.S. I’ve ordered a mounting bracket to attach my phone to my handlebars. Till that arrives, I’m using some of Lilly’s hair ties