The piece no longer fits properly, and the spray arm fails to spin and rinse the dishes in the upper shelf.

Disassembling the arm was very easy. The problem was getting the replacement part from Frigidaire. We tried several times, got the wrong part once, and ended up with an utter failure. I’m sure a repairman would have been more successful, but given how simple this repair is, why should I have to pay for that? This is where the MakerBot at CrashSpace comes in to the story.

CrashSpace has a MakerBot. This was a good excuse for me to learn how to use it to create a replacement part. The MarkerBot is a 3D extrusion printer. Above the red platform you see in the picture on the left is the extruder. It heats a thin strand of ABS plastic and extrudes it on to the red platform. The platform moves left to right and back to front until the plastic creates the first layer of the piece you’re trying to make. The extruder then moves up a small amount and the process is repeated until the entire piece is created.

ABS plastic is extremely strong and comes in a variety of colors. We have black, white, and red material at CrashSpace. LEGOs are made out of ABS plastic so you know how strong they are. The MakerBot  had no problem making a replacement part for my DishWasher.

These are the $7 digital calipers that I bought from Harbor Freight. They allowed me to measure the part so that I could model it. They can be set to millimeters or inches. Millimeters worked very well for several reasons. First, the calipers show one decimal point, so that means I could get down to 1/10th of a millimeter. Second, the rest of the tool chain used for the MakerBot is referenced in millimeters, so there’s no additional scaling required. Finally, 1mm seems to be minimal feature size that is reasonably handled by the MakerBot. It can move in smaller increments, but it’s very tricky to do anything smaller.

The dishwasher piece is pretty simple. It is really three cylinders with a cylindrical core cut out of the middle. There’s also two little “antennae”  at the top. I looked at how the piece fit in the dishwasher and it seemed that I could leave the antennae off. I made my drawing solid all the way up, and thought that I could always cut away the extra material to make the antennae if they were necessary. I also noticed that on the original part the largest cylinder was really thin. That’s why it wore out so easily, but given the way it fit in the other pieces it could be as large as I wanted. I made it 2mm thick, which should make it hold up much better.

This is my final model in Blender. Blender has a rather steep learning curve, so I won’t go in to much detail here. I’m putting together a Blender for MakerBot class that I’ll give at CrashSpace in the near future. The short description is that I created 3 mesh cylinders with the required sizes. I used the transform tool to enter the precise location of each piece. Next I joined them together in to a single object. Then I created a fourth cylinder that match the hole in the middle of the cylinder and used a technique called constructive solid geometry to subtract the cylinder from the piece. That leaves the picture to the left. That file is saved for Blender and as an STL file which we’ll feed in to the MakerBot software.

This is an image from the ReplicatorG software. On the left hand side you see the model. It has generated the g-code, which are the instructions that control the motions of the MakerBot. On the right hand side you see the path that the print head will take as it creates the part.

Once I created the part and made sure it looked like what I expected, it was time to head over to CrashSpace and connect my laptop up to the MakerBot. It takes a few minutes to connect everything up, let the extruder warm up, and position the head to the starting point. Once I pressed the build button the printing itself took about 5 minutes. I printed a couple just in case.

This is the final part. I forgot to include something for scale in the picture, but it’s about the size of a quarter. You can see the ridges from the bead of plastic. The plastic can easily be sanded if needed.

Another thing to note is that the original part has quite thin walls, but my piece is solid. That should make it stiffer and hold up much better with use.

These are the three pieces that make up the entire assembly. The new piece is placed inside the cog shaped piece at the top. The thinest cylinder fits through the hole and the widest cylinder fills the inside area, preventing the piece from dropping through the hole. Finally the arm is press fit on to the thing protruding thin cylinder.

When the dishwasher is turned on water will flow in to the center region of the cog, through the center of the piece, and finally out the arm. The arm has holes in the ends that push the water out the side as well, which causes the arm to turn.

The thin cylinder needed to be the right size so that the arm would press fit on to it, and still rotate smoothly. I measure carefully, but I also suspect the ridges on the side of the part helped make it fit nicely.

This image shows the pieces fully assembled. The black piece is hidden away in the middle where you can’t see it. The arm swings smoothly. The cog piece screws in to a fitting in the top of the dishwasher.

We made a few test runs and it seems to be working great. I think my version will hold up much longer than the original one.

I’d like to leave you with a few final comments on the process as a whole. It would have been cheaper (if you include my time) and easier to call a repairman. The hardest part was dealing with Blender to make the model. Blender has a rather steep learning curve, and it took me quite a while to get a hang of it.

With all that, I learned a lot in the process. I learned how my dishwasher works, how to use Blender, how to use the MakerBot, and even something about how modern equipment is created. So while this piece cost me more in time and effort, I think I can do my next project substantially faster. If you just want to print objects that already exist in Thingiverse, then you’d skip most of the hard parts.

There were several things I found interesting about the Merry Go Round. First is that it’s $2.00 to ride and you can get a jumbo beef dog and a large drink for $3.75. That’s pretty great value for your family entertainment dollar!

When we first showed up they had the speed cranked up pretty fast. Later when there were more small children it was slower. I suspect the operator can control the speed.

It’s clear that restoration is in progress. There’s a mix of worn and newly painted pieces. Both of beautiful in their own way.

Some of the senes depicted seemed sort of odd. Some sort of elves chasing fairies and tigers killing deer for example.

You can see the pictures we took in the album.

We also hiked up the hill and down again to end up at the old zoo. The old zoo was built and 1913 and closed in 1965 to be later replaced by the current Zoo. They’ve since turned several of the exhibits in to cook out areas. You can also make your way around back and see some of the sections behind the scenes. Much of it has been vandalized, but it was interesting to see. We didn’t get many good pictures, but I found another site that did.

Overall a really nice day trip out on the motorcycle.

Let’s look at how AMS structures these deals. You’re signed up a one year contract. You pay a fixed fee per month ($38 in my case) for the warranty. Then if you have a problem with an appliance you contact them and they send out someone to do the service. Each service call costs you an additional fee ($55 in my case). Then in theory they fix or replace the appliance.

If you take a look at their pricing and plans page you’ll see the appliances they cover and the average replacement cost. Gee this looks reasonable. They could save me a lot of money. Not so fast, not the fine print that says Please read your contract for specific coverages, exclusions, and limitations. You’ll also notice that they don’t show you the contract on the web page. You have to read the fine print on the printed version to see that. That’s where the biggest gotcha lies. Most people don’t read it, don’t pay enough attention to it, or even if they do they put it away and forget about it. That’s particuarly bad when it’s thrown in with your house purchase, because it was a free and you’ve got way to much other paperwork to deal with.

Here’s three of those pieces of fine print that bit me during my time with AHS.

1. AHS doesn’t cover parts that are considered wear items. So when my garage door had a problem, they sent the guy out to fix it, but he said we needed new springs. Those aren’t covered. So my cost for this home warranty repair was about $150 for the springs and another $55 for the service. Over $200.
2. AHS only covers the repair itself not the ancillary repairs that might be necessary afterward. When they fixed a leak in my bathtub they had to cut a whole in the wall next to the tub to fix it. They don’t send someone to fix it and paint. We ended up taking a small cash payment and fixing it ourselves.
3. The contractor gets to decide whether to repair or replace the unit. Believe me they are going to repair anything they possibly can. It doesn’t matter whether it is a lasting fix, as long as you sign off and the contractor gets out of the house, he’s happy. When the water stopped working in the door of our fridge, we called AHS. The appliance guy determined that water had frozen in the hose. He used a hot air gun to defrost the tube, and turned up the temperature in the fridge. Of course, it refroze within a couple weeks.
4. Finally, if you don’t use their service guys, they can provide a cash payment, but you don’t have any say in the matter. That cash payment is limited in their contract. This one is the big one that finally pushed me over the edge to write this post. Let me explain.

Our water heater broke. We called AHS. They sent out a local repair shop to fix it. Here’s where the problem began. The local repair shop wanted an additional $1000 to fix the water heater. Why? They claimed our water heater was not to code, and needed additional plumbling and drainage. I didn’t believe that. Our water heater is in the garage and had been inspected prior to my purchasing the house. At this point I contacted a local licensed home inspector who looked at the water heater and said that the additional work was not necessary. I called back AHS and explained the problem, and asked them to send out another plumber. AHS refused and said that I had to deal with the one they sent. Since their plumber refused to do the work and I had no hot water I called another licensed plumber to do the work. He bought a new hot water heater and installed it. Total cost was about $500. Then I called AHS to submit the work and was told they’d pay use $200! Let’s look at this more carefully:

First, the plumber AHS sent out was clearly committing fraud. He said we were required to do extensive work that two other licensed contractors said wasn’t necessary. He wouldn’t do the work without that.

Second, I called AHS and explained the situation including citing other licensed contractors and they refused to send out a second plumber. I’m stuck with no hot water and AHS has left me a choice of paying $1000 or hiring my own plumber. AHS supported the original plumbers fraud.

Third, if you look at the AHS website they say water heater replacement costs between $456 and $520 according to a Marshall and Swift. Our repair was right in that range. AHS tells me their cost is $200 and that’s all they’ll pay.

How’s that work? I’m out $555 and it still ends up costing me about $350 for the repair.

I don’t believe AHS is responsible for the fraud, but I do believe they’re responsible for supporting it. They made sure there was no way I could get my water heater replaced for free, even though that’s the intent of the warranty.

I’ve done a bit of reading since this incident occurred and I’m not the first one to have these sorts of problems. One of the articles I read explained how AHS works with their contractors. I can’t vouch for the validity of this article, but it seems plausible. The article says contractors sign up with AHS to get referrals and drum up extra business. The fee the home owner pays for a service call goes to the contractor. AHS also covers the cost of the parts for the contractor. The contractor isn’t paid for the hours involved. So if the service call takes several hours the contractor still only gets the basic fee, in my case $55. Therefore the contractor has an incentive to add on additional uncovered expenses to the bill to pad his rates.

I’ve never actually had AHS replace a piece of equipment, but you are supposed to get the equivalent equipment. For the water heater I replaced we bought an equivalent 50 gal water heater at home depot. That cost over $400. My plumber got a fee for his work as well. If AHS is saying their cost for a water heater is $200, I don’t think I would have gotten an equivalent water heater.

Don’t forget in all these repairs I’ve been paying $38/month for the AHS warranty on top of the costs to the contractors. That’s an additional $456/year. If you use their service twice a year (add another $110) you could have spent $566 with your contractors for the same amount of money. Chances are your expenses are even lower.

One other interesting tactic from AHS. As I mentioned earlier the home warranty is actually a contract. They bill your credit card every month. At the end of the year they automatically renew the contract for you. That makes cancelling their service sort of tricky. You have to pay out the remainder of the year. If you decide you want to stop the service, you’ll typically want to wait until the end of your contract, but if you forget at that point you’re stuck for another year.

I got my AHS home warranty “free” when I bought my house. I didn’t use it at all during the first year. After that I had a few occasions to use it and generally was only slightly unhappy with how the calls were handled. Eventually I slipped in to a bit of a gamblers attitude where I hoped something major would break so I could get my money’s worth. That never happened. I was really unhappy with a few of the repairs, but I was busy and missed my chance to cancel the service at the end of the year. Finally, the water heater incident dragged on all year, and I’ve finally cancelled the service.

Bottom line is that AHS home warranty is a lousy deal. They seem to treat their contractors and customers badly. If you’re buying a house, my suggestion is to ask for $500 in cash instead of the AHS home warranty. I hope this post helps other people avoid making the same mistakes I did allowing my AHS home warranty to continue.

Tivo has been adding internet based capabilities to their products recently. They’ve got the swivel search, pictures from picassa, video rentals, and even ordering domino’s pizza. Tieing your accounts together between the Tivo and the other service is the first hurdle. Some of the services, such as picassa, require you to repeatedly type your login and password using the Tivo remote control to get in to the service. Doing that once is down right aggravating, doing it multiple times makes the service almost unusable. Netflix/Tivo solved this in a nice manner. When you activate the service is gives you a short code and tells you to connect to Netflix.com/activate. Then you use your normal login to the website and enter the code, and the service is activated. Once that’s done there’s no need to do it again. That was very nicely done.

Netflix has an interesting collection of videos available for instant viewing. The Starz collection has a lot of somewhat older movies. There were a number of old favorites that I’m looking forward to sharing with my significant other. They also have a good collection of recent and older TV shows. Once you find programs you’re interested in you can add them to view instantly queue.  The movies/TV in that queue then become available on to watch instantly on your Tivo.

The Tivo displays the watch instantly queue in order. So you’re top movie in the queue shows up first on the Tivo. The Tivo displays the same summary information and picture that Netflix shows on their website and has menu choices to start playing. If you stop a movie and come back to it later menu choices to resume playing and start from the beginning are available, which is a nice feature. You also have an option to remove the movie from your watch instantly queue. For content which is actually multiple shows (like a TV show disc) the Tivo displays a folder with the shows in it.

Once you decide to start a movie it spends a brief period downloading. This is only a few seconds. During this time it also shows you the quality of the program being downloaded. The quality is changed to match the download speed of your internet connection. Since I have fibre networking to the house, I expect I should always be getting the best quality available. It appears that Netflix has HD and non HD content. That’s indicated by an HD logo when the show first starts downloading. There is also a bar graph that shows 1 to 10 bars for quality.

Fast forward and rewind work similar to the Tivo. There are three different speeds you get by repeatedly pressing the buttons. Playing the image during fast forward and rewind is rather tricky in a streaming application. Netflix/Tivo have decided to show you a smaller inset image that updates about once a second during fast forward or rewind. It gives you a rough idea where you are in the movie. You also have a time bar similar that shows you how long the movie is and where you are in the content.

On a more technical level, there was a clear difference between the quality of the HD and non-HD content. I added Pirates of the Caribbean: At Worlds End to my watch instantly queue. When I started it, that showed up as an SD program and 9 out of 10 quality bars. I also wanted to compare that with some HD content, so I found the HD section on the Netflix website and added Heroes: Season 3. That shows as HD content with all 10 quality bars. From looking at a collection of movies and TV I added to my queue, it appears that 10 bars means HD, and that many of the movies aren’t encoded at that quality so I get 9 out of 10 bars instead. I examined the quality of several other movies as well. There is a blog post by Neil Hunt of Netflix describing their encoding.

The quality difference between 9 and 10 bars is substantial. 9 bars seems below modern DVD quality, and the compression artefacts are fairly obvious if you look for them. With that said, opinions vary, so a little perspective might help. I work in the film business in Hollywood and my company makes a product that is used to do quality control on uncompressed digital studio masters. I’m used to looking at the highest quality content available. Therefore I think I’m among the more picky viewers. The HD content looked very good. Although I could pick out the compression artefacts, the general viewer would be hard pressed to find them. According to Neil’s post the HD content is 720p. It’s encoded in SMPTE VC1 Advanced Profile at up to 3.7Mb/s. The SD content is the same encoding at up to 1.5Mb/s.

Overall I think this is a great implementation of video on demand. I’ve already added a number of programs to my instant watch queue. It’s great to be able to watch something right away without sending back a disc, and waiting a couple days. Of course, I’ve got a few suggestions for improvement. My first request is, of course, to get more content encoded for HD. The quality difference is dramatic. My second, is that it would be great to have a browsing capability for the entire library of instantly available content. The instant watch queue is great and I wouldn’t do away with it, but it would be nice to not have to go to a web browser to add shows to the queue. Finally, a much smaller nit, but I’d like to see the fast forward and rewind images update more than once a second. If you fast forward at any speed, that’s not often enough to get a decent sense of where you are in the content.

First let me say that there is a lot of hype around 3D right now. Hollywood embraces 3D every twenty years or so, but I believe the technology has finally gotten to the point where doing 3D really is feasible for the theater market. I define three key aspects to making 3D feasible:

1. The technology has to allow consumers to comfortably watch a full length film
2. The technology is priced reasonably enough that it can be deployed and used
3. There is a benefit to the film beyond the fact that is in stereoscopic 3D

Several technologies are involved in meeting these goals this time around that weren’t available last time. The first piece of technology is digital cinema. The film industry has been rolling out digital cinema as was to improve the quality of film prints and to reduce the cost of distributing film. The high end projectors that are being installed for digital cinema are also capable of display stereoscopic 3D movies if the theater owners add some additional equipment. Starting with the Disney release of Chicken Little in 3D in 2005, theater owners found that they could charge a premium for watching a film in 3D. Increasing revenue and increasing reasons for audiences to go to the theater are business incentives for studios to make 3D pictures.

In previous incarnations of 3D you would wear a pair of paper glasses with red and cyan filters. That allows only red light to enter one eye and anything but red to enter the other eye. The left and right stereo images are then processed so that one has only its red values, and the other has the green and blue values. Your brain then reassembles the images in to 3D. This process is called anaglyph 3D. The big advantage of anaglyph 3D is that you can display the images using standard film/print technologies. The downside is that it is a really awful 3D image. Creating the image requires throwing away have the information available, and because it isn’t the way your brain is used to seeing 3D it can lead to eye strain and headaches.

The digital cinema systems use a different technology (most commonly based on polarization) to produce stereoscopic 3D. In this case two separate images are displayed at a rate six times the normal film rate. Three of those images are images for the left eye, and three of those images are images for the right eye. That’s called tripple flashing and helps produce better quality images with less flashing. Polarizing filters are attached to a wheel that is synchronized with the projector. Each time a left eye image is display, the wheel applies one polarizing filter, and each time the right eye image is displayed the wheel applies the opposite polarizing filter. The glasses you wear match those filters and make sure the correct image enters the correct eye. Unlike anaglyph 3D these images are full color and have a high refresh rate which makes them much more comfortable for the viewer to watch. The downside is additional cost because more hardware and a silver screen are required by the theater owners.

I said the most common solution is polarization. That is the technology used by RealD who has deployed the most theater systems. Dolby has a different technology based on color bands, but the end result is basically the same for the consumer.

I mentioned that the roll out of digital cinema is being driven by studios wanting to lower the cost of distributing prints. I also mentioned that theater owners are finding that they can charge a premium for presenting 3D. That helps cover the cost of the stereoscopic 3D display system. Finally, the studios need a way to make 3D movies in a cost effective manner. In the past every 3D movie created their own 3D equipment which is expensive and time consuming. New technologies (including systems my company builds) are making that process easier. Digital acquision, on set previewing, and commercially available solutions are lowering the barriers to entry. When you place all these factors together you get a reasonable economic model for 3D feature film production.

We’ve covered the first and second criteria that the films are comfortable to watch and that there is economic model for the technologies deployment. That leaves the final criteria that there is some additional value beyond just being a 3D movie for doing it. That’s the one that I don’t believe is handling very well yet, but there’s an economic reason for that, and the situation is improving.

Almost every major theatically released stereoscopic film released to date has focused on the 3D as a feature of the film. These films where spears poke in your face, and things jump out of the screen at you, are designed to be more like theme park rides than traditional movies. The viewer goes to these films primarily to have the 3D expereince and the story is primarily a path to lead you between the 3D events. That can be fun, and there is a place for that, but that’s not focusing on the story which is the value of good movies.

This is somewhat driven by the encomics of 3D films today. There are only about 1000 3D capable theaters in the US. Those theaters get to charge a premium for showing 3D films, but they need to have a lot more of their seats filled to make the same revenue as a 2D film showing in many more theaters. Therefore they really need to have an “in your face” 3D experience so that the 3D viewers get their monies worth. Unfortunately, every time something pops in your face, it takes you out of the story. The object is no longer in the scene but instead in the theater. Instead of just watching the story the viewer is waving their arms trying to touch the object.  It’s a fun theme park ride, but not a narrative film.

That situation is going to change. By the end of next year there should be between 3500 and 5000 3D theaters (depending on who you ask and how well the roll out goes). That is going to allow 3D films to reach a wider audience, fewer of whom will be there only for the 3D theme park ride. The novelty will wear off and more 3D films will have rely on story to effectively fill the theaters.

This is very much akin to the early days of special effects. Every effects film made effects the central focus of the film, and the story guided you between the explosions, car chases, and aliens. Although those sorts of films still show up every summer, almost every film today has some special effects and you barely notice. They are just another tool used to tell the story and the same thing will eventually happen with 3D films.

When stereoscopic 3D is designed to keep the 3D effect near the screen plane and not in your face, the 3D experience changes from being a theme park ride to being  immersive. You feel like you’re in the movie watching it as a spectator. It adds to the enjoyment of the story just as surround audio does. U2-3D and the Hanna Montana concert both showed that. Viewers felt like they were in the audience of the concert.

Because the technology is so new, cinematographers are learning what works and what doesn’t in 3D films. They are learning to be carefully about the transitions between shots where drastic convergence changes can cause eye strain. They are learning how to effectively use the new technology. They are learning a new language for stereoscopic film making. It’s another transition in the industry, just as adding sound, adding color, or adding surround sound took additional education, so will making good stereoscopic 3D. Eventually stereoscopic 3D should become a standard tool available for making any film.

The bottom line, and getting back to 3-D TVs, is that Hollywood is making a big investment in stereoscopic 3D and that is going to drive better content. As more of that content is produced more people will want to watch it at home. Manufacturers will finally have content to show on their 3D televisions, and a reason to produce them more widely.

That was a long setup to why 3D TV is coming. Now let’s address the specific items that Stacey references in her article.

The Entertainment Technology Center has always been an interoperability center for studios and content creators. They are most well known for managing the Digital Cinema Initiative (DCI), which standardized how content players and projectors work to display content in a digital cinema. It brought together studios and system vendors and allowed them to agree on what they needed. That effort was a sucess in the US and that’s part of what has allowed digital cinema to be rolled out to theaters today. It’s no surprise that they are continuing that roll in defining a stereoscopic 3D system. The ETC has never been involved with consumer devices.

There are several ad-hoc efforts to provide 3-D television for the home. Texas Intstructments, the makers of the DLP chips, added stereoscopic 3-D as part of their features last year. Every rear projection DLP set made in 2007 or later is 3-D capable. There’s also a company called dynamic digital depth that has been working with consumer electronics vendors to incorporate their 3-D technology in consumer devices. They also sell a set of 3D glasses for use with various 3D capable televisions. Samsung has mad a major effort to create 3-D capable displays, both using TI DLPs in their rear projection TVs and by adding 3-D support to some of their plasma televisions. These efforts allow you to buy a 3D capable and make it work, but without a standard it is a difficult process.

These sets are 3D capable, but what does that really mean? 3D capable means that the set can display stereoscopic 3D images. In most cases that means you connect some additional hardware, you wear active shutter 3D glasses, and if you feed your display properly formatted 3D content, it can display stereoscopic 3D. That’s all well and good, but here’s the steps a consumer has to do to watch 3D:

1. Buy a 3D capable TV
2. Buy a set of 3D glasses and their controller
3. Connect a PC to the TV
4. Buy and load 3D software to run on the PC
5. Buy properly formatted 3D content to run on the PC
6. Put on the glasses
7. Run the software
8. Enjoy the content

Yeah, right. There’s no way the typical consumer is going to handle that. To make matters worse, there are several different ways that content can be encoded to work with the set. Right now that means you need some specialized software or hardware to format the content for the display. Not only that, this only works for things like DVDs, it doesn’t help it all for broadcast content.

What we’d really like is for there to be a standard for the distribution of 3D content. Then I could put a 3D disc in my blue ray player and have 3D content on the screen. I’d like to turn on my cable/satellite/over the air tuner and pick a 3D channel and watch that as well.

Defining that standard is the work of SMPTE. In fact, they put a recent press release that they have created a task force to standardize stereoscopic 3-D Mastering for Home Display. The results of that task force should be standardization needed to make 3D successful in the home. SMPTE does take a while to create standards. Once that’s ready the blue ray players, televisions, and cable receivers will need to support it. My guess is that changes required will be minimal, and that the formats will mostly match what is happening ad-hoc today. For those of us with a 3D capable set that probably means buying a 3D converter box to connect to our television.

With the work of SMPTE and the ramp up in Hollywood I look forward to consumer 3D in the home to be feasible in the next 18 months. I’d say the hype is appropriate. The results will be amazing. It will just take some time for the content creators, the distribution systems, and the consumer electronics manufacturers to all get on the same page. Tim Sassoon, an expert in stereoscopic 3D in Hollywood, was recently asked “What films would be better without 3D?”, his response was “Anything that would better in real life with one eye closed.” Stereocopic 3D is a more natural and immersive way to view a scene and will be used to create more compelling content in the theaters and the home in the not to distant future.

In the film industry we do have many problems that parallelize very well. Physical simulations is one example that people are often familiar with using parallel processing. Rendering is an extremely good example because we can often get parallelism not only within a single image, but because a film is made up of many images, we get additional parallelization by processing multiple images at the same time. My company, Digital Ordnance, builds a high performance image capture and play back system. We take advantage of both CPU and GPU parallelism quite heavily in our systems.

But, the thing that struck me about the post, is that concept that large numbers of cores are applicable to a wide audience. I’m really not convinced that’s true.

My biggest complaint is that for the typical home or business users computers are faster than they need to be. Most users are surfing the web, reading email, running some office applications, and maybe playing some light games. They’re basically doing one task that’s limited in performance by human input. For them pretty much any modern computer has more than enough power. They’d be better suited by having reliable disk storage (RAID), better screens, or cheaper systems, than they would be having faster CPUs. I’m sure there will be some killer app in the future that will set a different baseline for computers (maybe good speach recognition for example), but until that happens they don’t need faster computers.

I think that handles the majority of the computer users out there. But let’s move on to the other case of users who really do need powerful machines.

First, we need to recognize that adding more cores often comes at the cost of slower clock rates. The total number of cycles per a second if you combine all the cores is greater, but the speed of each individual core is slower. That means that to take advantage of all those cores, you have to have a problem that parallelizes across multiple cores. If your software only runs on one CPU you get slower not faster.

Second, we reflect on Ahmdal’s Law. Ahmdal’s law basically says that the speed up you get by parallelizing a problem is limited by the amount of time that must be done serially. For example, if you have a problem where 90% of the computation can be done in parallel, and 10% of the computation is spent managing the CPUs, distributing data, and collating results. As you add more cores the time spent on the parallel part of the computation goes down, but the serial computation remains fixed (or sometimes gets worse, but we’ll talk about that later). As you approach an infinite number of cores, the parallel processing time goes to 0. But that 10% of the time remains constant. That means that if 90% of your compute time can be parallelized, no matter how many cores you throw at it, it will never run more than 10x faster than one core. If your code is 99% parallizable, then you can not get better than 100x faster. That’s the best case, but the situation is actually worse than that.

We already mentioned one of the issues that limits that performance. As you increase the number of cores, the speed of the cores typically decreases. I realize that Ghz isn’t really a good metric, but for this exaxmple, I’m going to use it. I can buy a 3.2Ghz single core processor or I can buy a 2.0 Ghz quad core processor. That quad core gives me 8 Ghz. that should be much faster than 3.2Ghz, right? Well, let’s look at my 90/10 problem above. Let’s say it takes 10 seconds on the one processor. If we ran that on one of our 2.0 GHz cores, it should take 3.2 Ghz/ 2.0 Ghz times longer which is 16 seconds. Now we know that 10% of the time 1.6 seconds is contant, the other 14.4 seconds we’ll assume parallelizes perfectly across the 4 cores for a time of 3.6 seconds. Our total time is therefore 1.6 + 3.6 = 5.2 seconds. We had 2.5 times the computing power but we only got a 1.9 decrease in compute time. Ahmdal’s law and slower cores used up the rest of that performance.

Now I’ll add another problem to the mix. As Ahmdal said, your performance increase is limited by the time spent in the parallel part of the process. As you add more cores, the time spent managing them goes up. Consider that your problem has to be devided among all the CPUs and the results need to be put back together. The more cores you have the more data you need to move around. Sometimes a data structure needs to be updated by one core at a time to avoid each core writing on top of each other. The more cores you have the more time each of them spends waiting for their turn to write the data structure. These problems are hard to describe in detail, but they do contribute to the time spent doing serial processing. So in an ideal world 10% of your compute time would be spent on serial data regardless of how many cores are involved by in reality the percentage of time goes up as the number of cores goes up.

Finally, I’ll describe the lockstep or partitioning problem. In our example 90/10 example I assumed that the 14.4 seconds would be split perfectly among the 4 cores. It turns out that in many cases splitting a problem up perfectly is very difficult. Let’s take a familiar parallel processing problem like rendering an image. If we had four cores we might just split the screen in to quarters and have each core handle one quarter of the screen. In most cases that would work fairly well. But let’s say my image is blank in one corner and has a bunch of mirrors in another corner. In that case, the core handling the blank section will get done quickly. Where the corner with the mirrors takes more work to calculate and takes longer. Since you can’t display the image until all the cores are finished, that means you end up waiting for the slowest core. You might argue that you could break the image in to more pieces, to make the partitioning more fair, and you’d be right, that does help. You might also devise a clever way that when one core finishes early it takes some of the work from a core that is running more slowly. Again, a great idea that will help. But neither of these solutions solves the problem. These extra steps add overhead which slows down the general case, and in the end you still have some cores finishing before others. The time spent with idle cores lowers our overall performace improvement.

One other problem, that’s tangentially related to these discussion, is that how you parallelize your code is often dependent on the target system. If I know my code is going to run on a machine that has 1000 cores, then I’m going to break my problem down in to very small pieces. In doing so, I add a lot of overhead. If I use that same technique on a system with only four cores, then that extra overhead is much more expensive. Applications do their best to partition their problem in to the right size for the number of cores they have, but that isn’t easy and isn’t always perfect. Parallelizing your application for one platform is hard enough, and parallizing it for a wide range of platforms is much more difficult.

Even with all the nay saying there are some applications or portions of applications will be able to use more cores effectively. There are exciting projects that we’re undertaking where we use as many cores as we can get. But there are also bottlenecks where you want one core to run as fast as possible. It would be interesting to work with an architecture where you had a few really fast cores and many slower cores. The exact balance would vary by application, but it would provide a unique way to handle the serial and parallel programming aspects. That’s a problem for the hardware architects to chew on.

I also believe that specialized cores (such as GPUs) are interesting solutions. They work very well for our application, because we’re doing a lot of image processing, but perhaps specialized cores that performed matrix operations quickly might be useful to other clients. The downside to these non-standard cores is that programming them to take advantage of their power is often difficult. The tools need to be put in place that make it just as easy to use these special cores as it is to use a standard core.

Finally, compilers need to get a lot smarter. They need to determine when there is parallelism to exploit and to automatically generate the code to do it. To do that, you need to be able to characterize these cores well enough that a compiler can decide whether the performance improvement would be more than the overhead. Again if we consider that the you might write the application for a wide variety of platforms, that would require that this sort of optimization be done at run-time. How much just in time compiling would need to be done?

All these cores in a variety of designs is making for a very interesting computing landscape for the years to come. I hope we continue to make the most of it.

Worse than that, I generally don’t want to share all my social activities with everyone I’ve ever met, even on one social network. Maybe that makes me weird, but I don’t tink clients I do business with, need to see pictures from a party I’ve thrown.Maybe only my family should see pictures of my father in the hospital. No social network I’ve joined (and has enough of my connections to be useful) let’s me control what type of contact the person is and easily give them different access rights.

The reality is that I have a real collection of contacts on Linked-In. I’ve found it useful for keeping track of where people I know are currently working and it gives me their current email address so I can reach them. I don’t tend to long on to Linked-In very regularly. Basically I go there when I’m looking up a contact, when someone I know sends me an invitation, and every once in a while to look for new contacts I might have missed. Of course, it’s easier to let them come to me, than it is to chase them down.

All the interest in Facebook got me to join that as well. Now I get a duplicate set of friend requests. Then I also get a ton of requests to be a vampire, ninja, warewolf, race car, etc. Those are big time wasters. All the fun boards etc seem to show is silly content.  My front page has gotten so huge with everyone’s updates that it isn’t really managable. I read today that Facebook is coming up with a new interface, but I think that misses the point. I’m not sure organizing the junk is really worth it.

Rather than just bitching, what do I want? Well I think linked-in basically works. It stays out of my way. It has useful information I can reference. It isn’t too hard to deal with the updates. I think we need a good single sign on system so I don’t have to register with every service out there. Instead I use my single sign on, and your service sets up my account automatically the first time I try to use it. Single sign on also lets me create one friend network. Now when I connect to a new service it knows who my friends are and connects them up autoatically according to a user preference. With those changes, everything gets simpler and more useful for the user. Then my final request would be for services to do a small number of things really well, instead of trying to be the wrapper around everything. Then I can decide what features I want to use, and all my friends can see my content without having to join. Personally, I’d probably stick to a few things like a blog and photo/video sharing, but that’s my choice. if you want to play all the Facebook games, then you can join that too.

I think that would make the world of social networking much easier to deal with, and more flexible. It does go against the money flow. Getting everyone locked in to one service that all your friends are on, is really about extracting the dollars. My suggestion would spread the cash around, so developers won’t like that as much.

In large companies there’s a lot of bureaucracy. There are more people who have to be involved in any project and it gets more difficult to synchronize their schedules. There are more people who have to approve a project, so it takes time to process everything.

So it should be better with a small company, right? Not really. Now the problem is that lack of resources, sometimes that’s money, most often that’s time. In a small company everyone is working so hard that there’s not enough slack to add an additional project.

Either way things take longer than you’d expect.  Maybe there is some ideal middle ground, but I don’t think I’ve ever seen it.

This is the trailer for a reality program called Tiger Team which is going to be airing on CourtTV (which, by the way, will be renaming themselves TruTV in January).

It’s a reality show where they follow a company that does security penetration testing. You contract with them to break in to your facility. They give you a 30 day window in which they are going to attempt the break in, but they don’t tell you when and the don’t want you to warn anyone. During the break in they take/create some proof that they performed the task, and afterward they report back on what they did and how you could improve your security.

Having done some penetration testing in the past, security is still a hobby of mine. I found the show quite interesting. The first episode dealt with breaking in to a high end car dealership and the second episode dealt with breaking in to a high end jeweler. The approaches they took in the two episodes were very reasonable. In fact, they handled them pretty exactly as I would have, but they are much more practiced and have at least one trick I didn’t know about. The level of detail on the show was actually very good. You could follow along with that they were doing. They also didn’t sensationalize it to much.

How real is it? We’ll never know how much was set up by the producers, but my opinion is that it was mostly unscripted. In fact, they described the difficulty of getting the camera man to follow in their path without triggering the the motion detector, and that they had passed on some less safe alternatives for entry.

Someone on another blog mentioned that they were surprised they didn’t include a “kids don’t try this at home” message. I’ll say that here. Kids don’t try this at home. These guys are professionals. If these guys get caught by the police I’m sure they can pull out a letter from the owner saying that it was authorized. If you try this on your own, you’ll like get thrown in jail, hurt, or killed.

My final thoughts from the show:

• Security is only as good as the weakest link. So pay attention to ways people can go around your security.
• Security is inconvenient, more security is more inconvenient. The more security you add the better protected you are, but if you go too hard it becomes so inconvenient you can’t get your job down. (And people will work around that defeating your security.
• There is no such thing as totally secure. (follow on to the previous item)
• It’s a good thing criminals are generally dumb. The techniques used in this show really aren’t that hard. Hopefully criminals won’t get better at doing them by watching it.

We got our groove on Saturday night at Harvelle’s in Redondo Beach with grammy award winning blue artist John Lee Hooker Jr. This was the end of the promotional tour for his latest albumn, Cold as Ice. He puts on a great high energy show. He did a mix a classic blues, some boogaloo, and some funk. He had a couple tribute pieces to his father, but he really stands on his own.

This was my first time to Harvelle’s in Redondo. I’d been to the one in Santa Monica several times. Harvelles Redondo has got to be four times bigger than Santa Monica, but it still has an intimate feel. There are plenty of booths and tables where you can sit down, plus a good sized dance floor. You enter on the ground floor at the pier and then decend a staircase to enter Harvelles.

I was surprised that the place was so empty. Of course, it was the weekend before Christmas, so maybe that explains it. There couldn’t have been 50 people there. So it was just like a private show. Our friend Chris took the photo I linked above. Linda and I got out on the dance floor a couple times. She also got to dance with Chris and a couple other people there.
I had a great time. If you get the chance to see John Lee Hooker Jr, you should take it. It was well worth it. I’m going to keep an eye out for more events at Harvelles at Redondo. It’s got the right vibe.