Wednesday, September 21, 2011

The Dyson DC41 Review (Flawed)

This is a great product and is probably the best vacuum out there. But that hasn't stopped me from noticing a few defects. There are really 2 major ones that nearly made me return this product.

The first issue is that they got rid of the foot lever that typical vacuums have to engage the beater bar. Instead you just force it down and start vacuuming and when you are done you just put it back up and it latches and stays upright. This is pretty neat but when you are putting it upright there are 2 distinct things that happen, it engages the wand hose and then it engages the lock that holds it up. The switch for the hose is much louder and happens first so this leads you to believe the vacuum is upright and to let go when it is not latched properly causing it to fall over if you are not quick enough to catch it. This makes me respond by putting it upright much more forcefully then I want to do to something I’ve bought for nearly $600.

The second main issue is the path the air flows to the motor. There are 3 zones in the canister. The air goes from the outer to the inner getting cleaner as it progresses. The outer one is for big debris and dust, and then air flows through those tiny cyclones on the top and deposits its finer dust in the middle zone. Finally after leaving those cyclones the air goes through the filter (accessible though the top of the canister) and down the inner zone to the motor then finally out through the filter in the ball. The problem with this is that when you empty the canister the dust can and will cross contaminate from the other zones and into the post filter, inner zone. This means next time the vacuum is started it will suck in that dust into the motor and the ball filter.

So here is the story of how I found out about this defect: to test out the DC41 I took it to a house that was very dirty (some parts had not been vacuumed for a year) and vacuumed nearly the whole house. I had to empty the canister 3 times. After the 3rd time the vacuum got clogged (A peppermint in the narrow hose tool) and it activated the thermal cutoff. After learning about the thermal cutoff and what it meant, I took apart the vacuum and cleaned out all the access ports. Also looked at the post motor filter and saw that it was absolutely filthy but the filter in the canister was still white. So the dust was bypassing the canister filter somehow. So I figured it was when I dumped the canister the dust plume went everywhere including back up into the part of canister that is meant to be dust free. That amount of dust can’t be good for the motor.

Here are a few more nit picks:

It feels a little harder to navigate then the DC25

I wish it had a light and something to automatically rewind the cord.

Sometimes it feels like it’s about to break in my hands.

It does not have a spot for all the tools.

The hose wand sometimes doesn’t extend all the way out of the hose and sometimes causes the airway to be blocked when used. I think the DC25’s wand was better.

The reason I decided to keep this vacuum is the active base plate, I have a lot of wood flooring in my house and I want to get as much dust up before I use the Swiffer. Using this vacuum I now only have to use one pad each time I clean with the Swiffer instead of several.

And the DC41 will not be facing that dirty house again so it will never be that full of dust again.

Here are few good things about it:

It has great suction.

It survived that dirty house.

Its cord is long enough that I can plug it in anywhere and vacuum the entire floor.

Ultimately I think this is a great vacuum but for $600 I expect the best with no flaws and this has 2 too many flaws for that price. Unfortunately I can’t find a better vacuum so I’m stuck with this one.

Tuesday, October 19, 2010

Review of Starship Troopers by Robert A. Heinlein

I just read starship troopers by Robert A. Heinlein. It was definitely not what I was expecting, but I enjoyed it. It’s completely different from the movie. He spends like 60% of it in boot camp the other 30% in officer training and 10% in combat. During most of the time while in boot camp, he has flashbacks to his social and political class. And during his officer training they talk mostly about social and political stuff. So this is political and social essay hidden as a science fiction book. Considering this was written in 1959 it seamed like he was talking about today’s society. He was spot on with a lot of subjects. I would recommend this book.

Thursday, October 14, 2010

Review of The Circle by Ted Dekker.

I just read the first three books of the circle series by Ted Dekker. I was quite disappointed. The first book had a good hook with the main character living in two worlds. When he falls asleep in one he awakes in the other. This was very interesting. One of the worlds was loosely based on the Bible where in one generation they go from the Garden of Eden to the equivalent of crucifixion of Christ. The other is modern day where some baddy is trying to take over the world with a virus. The mechanics of jumping between worlds and seeing his version of the bible was the only thing that kept me reading. Other then that the characters are just too simple, and the plot is rather weak. He kills off and brings back characters so often that you expect everyone who dies to come back. The events in the modern earth are so unlikely and insulting to my intelligence that in the last book I just scanned though them so I can skip ahead to the bible world, which itself was very predictable. So my conclusion is that I would not recommend these books to a friend.

But here are books I would recommend:
The Wheel of Time series by Robert Jorden and Brandon Sanderson,
The Mistborn series by Brandon Sanderson,
The Honor Harrington series by David Weber,
The Banned and the Banished series by James Clemens,
The Gaunt’s Ghosts series by Dan Abnett,
The Malazan Book of the Fallen series by Steven Erikson,
The Zombie Survival Guide and World War Z by Max Brooks,

Thursday, August 12, 2010

Smudge proof Touch Screen password screen.

The current problem with touch screen password screens is that smudges can give away what your password is if you don’t clean them right after you log in. The smudges reveal where you put your finger to press the numeric touchpad or the pattern you put in.

The simple solution is to randomly change the location of the buttons each time the screen is presented. This only works for numeric touchpad’s though and has the issue of people expecting numbers to be in order. So I recommend using colors instead.
Here are examples of what it would look like:

This would eliminate the issue of smudges giving away passwords making a much more secure way of protecting cell phones.

Wednesday, January 14, 2009

The project file ‘ ‘ has been renamed or is no longer in the solution. In Silverlight.

Recently one of my projects at work was moved to a different SCM. After the move a message box that said “The project file ‘ ‘ has been renamed or is no longer in the solution.” would appear every time we tried to compile the solution. After a while I figured out how to fix this. The solution has a silverlight project; somehow the web app that hosted it got corrupted. The fix was simple right click on the project and click “Properties” and under “Silverlight Applications” tab remove the blank silverlight project and add the intended silverlight project. The code now compiles.

Monday, December 1, 2008

Fast Persistent Data Storage Idea

There are several types of data storage technologies out there. The hard drive is cheap but slow seek speeds kills it when random access occurs, and a physical impact can literally kill it. Flash memory is faster then a hard drive and can withstand physical impacts but it has a limited lifetime do to the number of writes it can take. Random access memory like ddr3 is even faster then the flash memory and does not have lifetime issues, but is volatile meaning it looses its data when it loses power.

A while ago I thought of an idea on how to have the speed of ram but have it persist like flash. Its rather simple really, just combine on a single chip or board a equal amount of ram and flash and a capacitor to power the ram long enough to write the rams contents to the flash.

So this is how it would work:

When powering up the device (ram, flash, capacitor, and controller) would copy the contents of the flash over to the ram and charge the capacitors.

Until the capacitors are fully charged access to the drive would be denied.

When the device is accessed all reading and writing is done to the ram.

When the device looses power it copies the Rams data over to the flash. (Could add logic to only copy what has changed.)

This increases costs quite a bit but it gets rid of all the weaknesses of known storage technologies. It will be shock resistant, fast, long lasting, and its data persistent.

Porting Mono's SslStream to SilverLight

I have recently run into another problem with Microsoft’s stripping of the silverlight runtime. This time I was looking into using Sockets, because of the crippled WCF implementation. But sockets have been badly stripped. The only thing in the System.Net.Sockets namespace is the Socket class. No TcpClient no UdpClient and no NetworkStream. The System.Net.Security namespace is also gone. Meaning no SslStream.

With no SslStream and a sorely lacking implementation of WCF, silverlight is pretty insecure. Not in the fashion of a computer virus but in how FTP transmits passwords in clear text.

I’m not sure what kind of applications Microsoft expects people to write without being able send files larger then a few megabytes with WCF or to secure their Socket’s data with an SslStream. I’m starting to think Microsoft made a very bad mistake with trying to shrink the runtime so much. I bet people will either write insecure applications and blame silverlight or avoid it all together. Deep market penetration caused by a small download will mean nothing if developers don’t write programs for silverlight.

Anyways that’s enough complaining about the free framework that Microsoft spent a lot of money to write.

A rather simple yet time consuming solution to this issue is to port Mono’s implementation of .Net APIs that are needed. I’m not sure how much effort will be needed, but it should be rather simple to do. Write access to Mono’s repository would be required keep it synced with Mono so that’s not something I can do. Basically you would just sprinkle some compiler directives to exclude classes and methods that are not possible. Also add extension methods to extend silverlight classes that don’t have needed methods. Then write build scripts that compile those for silverlight. For limited subset of classes like the NetworkStream it should be relatively easy to port them to silverlight. Classes like the SslStream will require more effort because of its reliance on Certificate stores.