Instead of changing the variable and recompiling, you can do the following. Declare your desired variable(s) as

extern const uint8_t myVar;

After compiling the main image, take a look at your symbol table by typing

 tos-set-symbols --read /path/to/main.exe

This will show a table like following:

AMQueueImplP__0__current             :  01  [.]  (1)
AMQueueImplP__1__current             :  01  [.]  (1)
ActiveMessageAddressC__addr          :  01 00  [..]  (1)
ArbiterP__0__resId                   :  01  [.]  (1)
CC1000RssiP__currentOp               :  04  [.]  (4)
CC1000SendReceiveP__BIT_CORRECTION   :  1b 1c 1e 20 22 24 26 28  [... "$&(]
CC1000SendReceiveP__rxBufPtr         :  5c 02  [\.]  (604)
CC1000SquelchP__clearThreshold       :  20 01  [ .]  (288)
MyModule__myVar              :  00 00  [..]  (500)
SerialDispatcherP__0__messagePtrs    :  fb 02 2a 03  [..*.]  (53084923)
SerialDispatcherP__0__receiveBuffer  :  fb 02  [..]  (763)
SerialDispatcherP__0__recvType       :  ff  [.]  (255)
TOS_NODE_ID                          :  01 00  [..]  (1)
atm128_stdout                        :  00 00 00 02 00 00 00 00 fb
00 00 00 00  [..............]

tos-set-symbol /path/to/main.exe MyModule__myVar=1234

This allows you to directly set the value of your desired variable. Just be careful, as any programmer should be, about variable types.
tos-set-symbols is part of the avr-gcc environment, and uses avr-objdump.

Initially we used this method to generate new images with different node IDs (TOS_NODE_ID variable) from the same base image. Now our testbed’s web based interface allows the user to draw a topology visually and assign such variable values to each of the nodes. It can also automatically map your desired topology to available nodes in the testbed.

Nice view Thank goodness I don’t have exams anymore.

In order to promote their main socail network, Google Plus, they eliminiated Reader’s features with no provision of seemless migration. I can see this as an engineer’s assumption that new “toys” automatically attract new people. Marketing people might disagree, pointing to brand loyalty.

The engineering versus marketing approach Google took towards Reader reminds me of their Android operating system. In October Michael DeGusta of The Understatement summarized his observations about Android updates for devices shipped between 2008 and 2010 as a chart. His visualization shows a clear message: Google does not intend to support their older devices.

My own experience supports this horrifying observation. While I am not sure about internals of Android’s framework and drivers, the ending result for users like me has been shaky reliance on courtesy of application developers to include my device in their small list of supported devices.

My experience with iPhone and Windows Mobile/Phone have been clearly different. The fact that I still receive updates for my 4 years old device says a lot. But the problem with iOS is it only has one active line of devices. You can get a newer version of iPhone but that is your only choice. However, Windows Phone has been more welcoming. My observation was WP7 suffered a poor release process, including poor support of developers in the early days and taking months before releasing copy & paste capability in an update. I hope they don’t make the same mistake again, and I can safely return to Windows Mobile family!

Update: I ran into another article discussing how internal instant messaging products of Google are not “synchronized” with each other. In my opinion it shows lack of a unified standard layer between users and Google products. As a friend pointed out, Google has been more concerned about shipping new products faster rather than keeping them synchronized.

But after a one semester trial, I am completely disappointed. Apparently Outlook is not intended for use with an IMAP server. Each time it would take almost minutes to load messages. For Thunderbird, it was merely seconds on the same server.

Apparently Microsoft developers are aware of this problem, but it is not fixed yet. There are hacks and suggestion to improve it, such as this one. Unfortunately these “solutions” don’t fit my needs and I am back to using good old Mozilla Thunderbird.

This announcement comes few days after AT&T made public they are considering cutting back amount of data users can transfer on their iPhones. AT&T has been criticized for network problems due to higher data usage, and now seems to be projecting the problem to their customers. You might be wondering how much data on average an iPhone user transfers per month? This article puts that number close to 100MB in 2008, although the source did not mention if that amount is per month or per day. Even if we assume it is per day, a very unlikely assumption, the total would be close to 3GB per month. Again, very unlikely, but let us assume that is the case.

The question that popped up in my mind after reading about the 4G mobile finally coming to the market, was how will the providers handle this new rates? If AT&T cannot handle current small number of iPhone owners, estimated to be around 6.4 million by Nielsen, how will they be able to persuade users to upgrade to 4G cell phones once they are available? The technology of the cell phone devices and the BTSs will make transfers quicker, but still the back bone that is required to carry this amount of data needs to be upgraded. And if they are more interested in “managing” how their customers use their cell phones rather than making that upgrade right now, there is no guarantee they will be willing to do perform those upgrades once customers start using the faster 4G devices.

I hope the major cell phone providers understand that when a customer pays higher price in terms of mandatory data plan and a longer contract, they expect to use the device they received as an incentive. And I hope while researchers and developers in hardware manufacturing companies are working on the technical aspects of the 4G devices, the business people in carrier companies are also working on understanding customer data usage trends and plan to upgrade their networks accordingly.

UPDATE, three months later: March 12 2010, AT&T CEO unsure if LTE will trigger pricing changes but “reiterated his position that such a move would happen.”

calling AMSend.setSource( *amsg,  addr) may change the source address locally, but when you are sending the packet it will be reset to ActiveMessageAddressC$addr.

After almost two days of wondering why I couldn’t forge messages on a base station, a friend more familiar with TinyOS gave me this warning. I couldn’t find it on the web, so .. here it is!

One other note: if you are using a bash script to do the TOS_NODE_ID assignment for you, you should call tos-set-symbol with ActiveMessageAddressC__addr. Using $ would -obviously- cause bash to consider it a variable and replace it with empty string.

In the recent years more and more wireless providers have started to provide femtocells to their customers. The customer can deploy the femtocell in any location that the coverage of normal towers are weak or absent.  Consider a product like Samsung’s Ubicell. The user can plug this femtocell in their home internet switch, and use their regular cell phone to connect to the final service provider, e.g. Sprint.

E-UTRAN architecture from 3GPP document 36.300-880

As of December 2008, 3GPP documentation for Long Term Evolution networks has started to mention Home eNB as part of the Evolved UTRAN. This move can be a significant advantage for the final users, only if service providers fully recognize the extent of service this final addition can offer. This recognition might require a careful study of 802.11a/b/g Access Points, considering the similarities of the two products. Both these products are the front end of a network to final customers. While these final points are accessible to the customers, the actual network is not controlled by them.

Most APs initially were merely wireless transmitters, but they soon started evolving into more sophisticated equipments. The need to provide more functionality for the end user to adjust settings, e.g. channel or user access rules, resulted in simple interfaces to configure the AP. Currently wireless APs are commonly acting as firewalls, switches, DSL modems.  But the true revolution for the APs happened when vendors such as Linksys started to provide open source firmware for their products. Because of the delay in this revolution, many golden opportunities are gone and we do not see as many diverse applications.

Given how larger organization such as universities might consider deploying a number of Home eNBs throughout their campus, there is a high level of interaction that would be only limited to these eNBs. As an example, in a university campus many calls and data interactions would be between students on the same area. Or consider an event like SXSW. While this year AT&T added enough resources to guarantee good coverage, smaller scale events do not motivate service provider to make such adjustments. Instead the organizing institute is well aware of the scale and the available resources and would be able to allocate more eNBs to the event area. One other aspect is access control: if I am paying for a Home eNB, I may not want my neighbor to user it for free unless it is an emergency call.

By providing good configuration options to the deploying organization, all sides of such scenario would benefit: the organization would enjoy faster service on their campus, the service provider would not have to worry about resource management and the manufacturer would ensure better sale of its products.

There are many challenges in providing such control to the final user. However, I believe the designers of 3GPP LTE have started taking initial steps and now the manufacturers need to move forward.

Related:

• Sprint Airave
• T-Mobile @Home
• Verizon Wireless Network Extender
• AT&T: 3G Microcell?
  
• Femtocells for Everyone
  

I will try to briefly explain the steps that I took, and how they were useful. As usual, it is just my experience. Verify everything and decide for your own. Here is a summary of links if you are in a hurry:

• Edmunds Paid Price and Buying Experience Forum
  
• Annual Percentage Rate Calculation Program
• Yahoo! Finance Resources
• Edmunds Price Estimator
  
• Excel Sheet Auto Loan Calculator
• Edmunds Long-Term Road Test Blog
• Confessions of a Car Salesman

Read more about my experience using these links below…

• Find out the price range

You need to decide: (a) how much down payment you can afford (b) how much you can pay each month, if you are looking for auto loan. Please note that buying a new car will change amount of monthly insurance and gas payment from what you spend now.

Once these two are decided for, you can estimate the final price of the car you are looking for. Some companies have reverse calculators. You enter monthly payment and down payment and they tell you what car and what total price you can buy. Honda has a simple tool here.

Later in the process I used software like Annual Percentage Rate Calculation Program. Better than that was a Excel sheet auto loan calculator. I used it to calculate some different prices that I guessed. I had these prints with me, and was able to catch an unannounced change in price in one dealership. Saved me $1000!

This step helped me narrow my search to a smaller number of models.

• What make and models are close to my price range? Which of them have good reviews?

I looked at Consumer Reports annual special issue for new cars. They have classified cars based on price, quality, consumer satisfaction and other factors. I don’t know much about cars and their reviews were consistent with what my know-about-cars friend told me. I also asked a couple of friends who had recently bought cars. This narrowed my search to base model of Honda Fit and Nissan Versa 1.8S.

One important thing is to check which cars are going to be redesigned. If a car is redesigned next year, your new car will look “old” from the moment the new design comes out.

• What options these model have that are useful for me?

Again, I consulted friends who had driven the same car before as well as online resources and Consumer Reports. Specially I liked the Edmunds’ Long-Term Road Tests Blog. Also, Edmunds has a step by step price estimator, during which you can select options and see the prices. In this step I decided I liked to have ABS and cruise control options in the Versa. Honda Fit did not have any option for the base model.

Also note that some options are always installed on cars. For instance most Nissan Versas that I saw have splash guard installed by default. I realized this when I checked inventories of Nissan dealerships in my area. You can either check their inventories from Nissan’s main website or local inventories. Also you can search third party sites like AutoTrader.com or Cars.com. My experience was the inventory of Nissan’s main website was not up-to-date. Also, the third party websites did not have all the details of options installed on the cars sometimes.

• Talking with dealers and finding good deals

I tried getting online quotes from dealers through Nissan’s main website. The result was not so interesting. Then I tried using the third party websites and Edmunds.com. The ones I contacted using Edmunds.com were the ones I got good price quotes from.

After the initial quote, I had around 10 emails passed back and forth, negotiating the price. They made “mistakes” sometimes and quoted me the MSRP. I would remind them the fact that I have a better quote, and then they would correct their quote. Ahmad just reminded me that there is no need to mention you are getting financing from them before going to their dealership. In fact what I did was I would let them convince me that I needed the financing from them. This makes negotiating easier, as you still have the “upper hand” somehow.

I noticed, with Ahmad’s help, that Nissan had an incentive choice of either $1000 cash back or a %1.9 APR. Most dealers would give a price quote with the $1000 reduced. So when I mentioned I am getting the APR in the dealership, they would jump $1000 up. When getting quotes, ask them for quotes “before reducing any incentives applied”.

One good website to see the price quotes others get is the Edmunds forums. I usually searched Versa+paid+price in Google to reach the forum. The first result is usually the answer: http://townhall-talk.edmunds.com/WebX/.ef17997/ You can check the prices and see what is the good prices people get. This should be way lower than the MSRP unless the car is in high demand. In my case the MSRP was $1350 higher than the final price I paid. Worth the time, isn’t it?

• Test drive, negotiate and buy

Test Drive: During the test drive I only tested how was the visibility and how I liked the shape of the car. Also I asked a friend to come with me, and before the test drive when the dealer was driving I would seat in the back seat and see how was the back of the car. After the drive I would write down the VIN number of the car.

Price: I usually would almost finalize a price over email with the dealer. Telephone price quotes are hard to prove and the dealer may claim there was a “mistake”. I would ask every detail, i.e. the VIN and the options and price before incentives, to be sent to me with email. Then I would take prints of the emails from all dealers when going to see a dealer. The prints are very useful for negotiating. I got a lower price from a dealer to “match the price” of another dealer, just by showing their printed quote. Also if you are trying to get an incentive that the main company provides, print that page and have it with you.

Buying: During the final buying step, I just made sure nothing other than what was agreed was there in the price break down, of course by mistake. Also, the accompanying friend told me that the “finance” person that I was supposed to talk after the dealer was in fact a sales person for the extended warranty stuff.  “Just say no!”., he recommended. Go through the documents that you sign, take your time and check this is what you want. I also wrote the VIN number on the check for down payment, just in case.

This is my experience and I hope to update here in near future if I remember something more. Hope it helps you get a better price. Again, verify everything. I don’t share your car with you, and I don’t share the trouble either Good luck with your new car!

Unfortunately some of the people who actually design ATM machines have not passed this course it seems. Last Wednesday I withdrew some cash from an ordinary ATM, and the machine failed to return my cash. But my account balance was reduced! The machine actually was able to tell me that it had failed and the operation was canceled, but it seems it forgot to tell its friends back in the Wells Fargo network to cancel the operation. I had to call the customer service a couple of times to get my money back.

There is no conclusion from this post. It just surprised me that a simple basic idea we are taught in classes is not actually implemented in real life.

UPDATE: My old friend Pooya asked in the comments if the ATM in question was a Diebold ATM. Diebold is the company that also makes voting machines in US. Next time I was in Student Union I checked the ATM, and guess what: it is a Diebold ATM! I now have some serious questions in my mind!

I should mention that Wells Fargo checking people were very nice and quick and solved my issue by a couple of phone calls.