Age of the everyday IoT entrepreneur is here and now ….

August 28, 2017

IoT is the new buzz word these days. Anyone who knows anything about Information technology is feeling the buzz. There have been a lot of products which are making all this happen for the everyday entrepreneur and also for the established companies. Access to electronics, access to code which makes it easy to interface with those, price of the components, easy access to amazing education through video tutorials, blog posts, meetup groups etc.

The feature of the everyday entrepreneur is here and now. If you can imagine it and even better put the ideas on paper to products on shelves then your time has come….

Bigger corporations have very few advantages over an everyday entrepreneur these days right from design, engineering, supply chain, distribution etc.

For anyone new to the space who has an idea we can help you get it to market by either partnering with you or consulting on the product…

The Hype of IoT and the areas of applications from an old Gartner article is clearly defined here:

Iot_

Source: Gartner (July 2014)

http://www.gartner.com/technology/reprints.do?id=1-27LJLAK&ct=150119&st=sb

 

Challenges:

The biggest challenges in IoT from a technology perspective are:

1)      Lightweight networking standards

2)      Securing the data

3)      Power Management in IoT devices

In the end I think if you are getting to the new space of IoT or have some great ideas it is time to put those into practice. Happy IoT’ing

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From the trenches – Arduino compilation and link errors and fixes to those

August 28, 2017

Error 1 – Loader error of undefined reference
Arduino: 1.6.5 (Windows 8.1), Board: “Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)”

myrobot.cpp.o: In function `__static_initialization_and_destruction_0′:
C:\Program Files (x86)\Arduino/myrobot.ino:57: undefined reference to `Michelino::Robot::Robot()’
myrobot.cpp.o: In function `loop’:
C:\Program Files (x86)\Arduino/myrobot.ino:272: undefined reference to `Michelino::Robot::run()’
collect2.exe: error: ld returned 1 exit status
Error compiling.

Solution
The problem is that the cpp file should not have the word class in it and only the header file.

Original code :

namespace test
{
class Ctest
{
public:
Ctest() {};
void a() {};
};
};

test.h
#ifndef rocketbot_remote_control_h
#define rocketbot_remote_control_h
namespace test
{
class Ctest
{
public:
// Ctest();
void a();
};
};
#endif

main

#include “test.h”

using namespace test;
test::Ctest r;
//Ctest r;

void setup() {
// put your setup code here, to run once:

}

void loop() {
// put your main code here, to run repeatedly:
r.a();
}

Fixed Code
Test.cpp
#include “test.h”
namespace test
{
//void Ctest::Ctest() {};
void Ctest::a() {};
};

Test.h
#ifndef rocketbot_remote_control_h
#define rocketbot_remote_control_h
namespace test
{
class Ctest
{
public:
// Ctest();
void a();
};
};
#endif

Main
#include “test.h”

using namespace test;
test::Ctest r;
//Ctest r;

void setup() {
// put your setup code here, to run once:

}

void loop() {
// put your main code here, to run repeatedly:
r.a();
}

Error 2 – Function not found

Arduino: 1.6.5 (Windows 8.1), Board: “Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)”

In file included from robot_vehicle_with_bth.h:61:0,
from myrobot.ino:55:
rocketbot_remote_control.h:11: error: no matching function for call to ‘SoftwareSerial::SoftwareSerial()’
SoftwareSerial BTSerial;
^
rocketbot_remote_control.h:11:16: note: candidates are:
In file included from robot_vehicle_with_bth.h:34:0,
from myrobot.ino:55:
C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries\SoftwareSerial/SoftwareSerial.h:90:3: note: SoftwareSerial::SoftwareSerial(uint8_t, uint8_t, bool)
SoftwareSerial(uint8_t receivePin, uint8_t transmitPin, bool inverse_logic = false);
^
C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries\SoftwareSerial/SoftwareSerial.h:90:3: note: candidate expects 3 arguments, 0 provided
C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries\SoftwareSerial/SoftwareSerial.h:47:7: note: SoftwareSerial::SoftwareSerial(const SoftwareSerial&)
class SoftwareSerial : public Stream
^
C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries\SoftwareSerial/SoftwareSerial.h:47:7: note: candidate expects 1 argument, 0 provided
no matching function for call to ‘SoftwareSerial::SoftwareSerial()’
Solution
Add extern keyword in header file
extern SoftwareSerial BTSerial;

Error 3 — redefinition of ‘class Michelino::RemoteControl’
Arduino: 1.6.5 (Windows 8.1), Board: “Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)”

In file included from myrobot.ino:56:0:
rocketbot_remote_control.h:14: error: redefinition of ‘class Michelino::RemoteControl’
class RemoteControl : public RemoteControlDriver
^
In file included from robot_vehicle_with_bth.h:61:0,
from myrobot.ino:55:
rocketbot_remote_control.h:14: error: previous definition of ‘class Michelino::RemoteControl’
class RemoteControl : public RemoteControlDriver
^
redefinition of ‘class Michelino::RemoteControl’

Solution :
Fix to add the following since header file gets included multiple times
#ifndef rocketbot_remote_control_h
#define rocketbot_remote_control_h
….
#endif

Error 4
x.cpp file
robot_vehicle_with_bth.cpp:77: error: ‘Robot’ has not been declared
void Robot::Robot()

Solution
Solution is to include x.h file
#include “x.h”

Stay tuned more fun ones coming!

How to Kernel Debug Connected Standby/Modern Standby systems?

October 24, 2016

Premise:

Debugging a Modern Standby (Connected Standby earlier) scenario can be challenging as there are some smaller subtle things to keep in mind. Most modern standby/connected Standby systems are newer systems with USB 3.0 xHCI controllers so this blog post only focuses on systems which support USB 3.0 debugging.

What you need:

  1. USB 3 cable – http://www.datapro.net/products/usb-3-0-super-speed-a-a-debugging-cable.html
  2. USB Type C to type A adapter – Needed only if the device doesn’t have a USB Type A port
  3. Windbg Bits – Many sources including the Kits —  WDK or ADK

Methodology to setup Kernel Mode debugging

  1. Setup the machine for USB 3.0 debug  as mentioned here: https://msdn.microsoft.com/en-us/library/windows/hardware/hh439372(v=vs.85).aspx
  2. Make sure you Disable Secure Boot in the BIOS menu
  3. Hook up the cable as follows  setup
  4. Check the USB device hierarchy and turn  off all the components. You can do this from device manager, usb tools usb_hierarcy
  5. Disable Turning off  USB stack components – Hubs and controllers on target Disable Powersaving on USb controller For the uSB hub, Uncheck the box to allow the computer to turn off the debice to save power  usb_hub_power
  6. Disable Powersaving on USB HUB/s — For the uSB xHCXI controller, Uncheck the box to allow the computer to turn off the device to save power usb_hub_power
  7. If there are multiple controllers or Hubs make sure you pick the right one where you plan to debug . Also if there is another level of hub in between do the same for that as well.
  8. Debug away!!

 

Windows updates on Windows 8.1 almost made my system unbootable

March 15, 2016

I  have an older  (Haswell based) X1 carbon which is running Windows 8.1. I was installing updates on it and after that the system wouldn’t boot and would keep getting to recovery loop. The system is bit lockered. I couldn’t get the system into safe mode or enable debugging. System restore had restore points as I seldom log into my local admin accounts and use mostly my domain  joined account. I tried the startup repair diagnosis and that didn’t find much either. So the system was pretty much unrecoverable. I went and looked at the SRtlogs (attached) and they pointed to a corrupt cng.sys binary. Sure enough it was reduced to 4 kb in size. I tried to patch it with a binary from another 8.1 system but that didn’t help. In the end I ran the sfc tool and that’s when I started seeing issues. Error from the tool:

“Error :There is a system repair pending which requires a reboot to complete. Restart windows and run sfc again”.

I researched the Windows community board which actually led to the diagnosis that there was a pending update which was for whatever reason causing the behavior and found the dism command below. Ran this and rebooted the system came back online.

 

dism.exe /image:C:\  /cleanup-image /revertpendingactions

The drive above could be D: or another one.  Check your system for the drive which has the Windows, Program Files etc directory to be sure.

 

If you get stuck in a loop with the message Windows couldn’t update the system… Try F8 to use restore point or try and reeboot before you reach the We cant install the update screen and this will cause recovery to be invoked. Happy fixing…

 I cant imagine non technical savvy user doing this…

 

Hope this helps!!

 

Windows 10 Power management

July 13, 2015

Win 10 scenarios covered

  • Battery Saver — For Better reporting accuracy, OEMs may need to run E3 micro benchmarks
  • Modern standby — Cheaper alternative to connected standby
  • Power scheme settings — Hibernate for CS systems
  • Project Centennial — Converting Win 32 apps to UWP apps

Battery Saver

  • New Windows 10 Shell option which shows battery consumers on the system at runtime
  • This uses a general model of the platform to indicate battery use
  • The accuracy of data is higher if OEM runs micro benchmarks on their platform or use the Maxim chip at an additional cost to the BOM

 

batteryuse_settings

 

batery_use_set2

Modern Standby

Why does it matter?

  • CS hardware requirements do have a BOM adder(Storage and Network)
  • Modern standby allows for instant on
    •     S3 systems from telemetry may have twice as large S3 resume

times

MS_1 Ms2

  • Background activities (non network related) can still happen
    • Store apps activities
    • Reminders
    • Bth sync
                           Battery drain Hibernate timer OEM setting
Exceptional 9 days or longer battery life Use of Hibernate timer is optional
Ontrack 6 days or longer battery life Use of hibernate timer after 24 hrs is recommended

Modern Standby Implementation

Ms_implememtation

Power management – Hibernate times

  • New Win10 Hibernate Settings for end user
    • Default is same as Win 8/8.1
    • Not to hibernate the system
    • Changing the setting allows the system to Hibernate while in CS
    • Criteria to set the Hibernate values

hibernate_1

Lowering power consumption with UWP apps

Build 2015 – OpenSource, Partners, visual Studio, Cloud, IoT… Need I say more?

May 27, 2015

Build 2015 was full of treasures. Partnerships, open Source integration, Visual Studio, Azure, IoT were the big areas. New face of microsoft with a focus on open source and 3rd party support like github was a huge part of the Visual Studio suite.

There was so much of new stuff disclosed at the Conference. The Key notes(keynote1 and keynote2) gave an idea:
http://channel9.msdn.com/Events/Build/2015/KEY01
http://channel9.msdn.com/Events/Build/2015/KEY02

The big themes of the conference was developing apps for the Cloud and developing UAP apps with Visual Studio 2015 platform. You could download the preview version of the community one here.
http://visualstudio.com/products/free-developer-offers-vs
It was clear that Microsoft had been listening to the developers and was beginning to integrate with open source tools. Azure was a big focus area where developers from a lot of SMB varying from insurance /accounting to gaming were looking at Azure as a potential platform. In the space of Big data Azure Data factory was an interesting talk about reuse patterns for Big Data with machine learning analysis built in step as part of the workflow.
Visual studio tools for converting iOS and Android apps to Windows apps was well received. It is surprising how many developing on iOS using Objective C and were delighted to hear cross platform support for Objective C. The new Visual Studio Code IDE has an intelisense rich environment to build Android apps was a welcomed by everyone. This should be a welcome change from the Android IDE’s such as h Eclipse or Android Development studio. Check the newest member of the Visual Studio family which is pretty lightweight and takes less than 60 Mb of space.
http://code.visualstudio.com/editor vs Ide
Image below shows the power of the Visual Studio platform

universalwindows platform

Halo lens created a lot of buzz with developers being able to play with it. Lot of verticals such as education and Architecture. Gaming maybe next …
Buzz
Big buzz events of the event were Halolens and support for Objective C and Java.
Visual Studio support of Open source software such as Alljoyn and Github and 3rd party software especially in the Big data space and its integration with Visual Studio was very well received.

Key takeaways from Builds

App. Gap between Windows Phone and IoS /Android will be bridged by project Astoria and Islandwood. This allows developers to port their existing IoS apps and Android Apps to Windows apps. There maybe restrictions on phone hardware needed to run such apps. This is great news for Windows Phone OEM’s.

Win32 apps to to UAP apps. with project continuum
This I think is one of the best messages not just for developers but also for OEMs to move their first and third party apps to UAP apps from Win32.
This was ISV’s can convert their Win 32 apps to UAP apps by using Project Centennial. The apps. can then be purchased using the Store. This helps the apps. to be more secure, less resource intensive and battery freidnly.

Edge the new browser – Better web experience
Key reason for using the browser is primarily around because it will work well with optimized sites, supports Cortana and many other gems such as Web extensions, pointer lock for shooter games and reading lists . IE due to compatibility reasons may not support but with forked code. This allows for edge supportability forked with IE compatibility. The best part is that Edge can launch IE for sites which are not compatible for example which need VB script.
Other things are distraction-free offline reading and built-in note-taking & sharing. Below is a comparison of Alaska airlines website on a mobile device.

browser_comparison

http://channel9.msdn.com/events/Build/2015/2-656

Design for Win 10 by the user for the user
Please ask folks from outsider to join the insider program to get an early feel for Windows and provide feedback as the feedback is taken seriously including for UX. The builds with new features are flighted directly to the system.

One  Store

For those of you have written Windows apps for phone and desktop OS like me on Win 8.1. The experience can be nerve wrecking as you need to create 2 accounts one for Windows Phone and one for desktop. Duplicate everything from monetizing, geographies of release, price, screenshots and descriptions. I just saw a note from Microsoft for my store application called “SecureData”

Phone: http://www.windowsphone.com/en-us/store/app/securedata-windowsphone/22280807-99c0-4c10-aaef-ec18662e7815

Desktop : http://apps.microsoft.com/windows/app/securedata/d9355748-f172-4f26-8a33-d69ca28e5a81

There will be now one store, one submission and one process for everything. One does have the option to create multiple packages for OS or platform…

myapp

Win10 app migration

There will be now one store, one submission and one process for everything. One does have the option to create multiple packages for OS or platform…

 

Project Continuum

What is Continuum?

  • Two apps run simultaneously on two screens
  • Windows Apps transition seamlessly and look beautiful on any screen
  • Keyboard and mouse support

To make the application adaptive to any screen size understanding effective pixel is key. Effective pixel is independent of screen. Some terminology. More on that here:

display terminology

Think about how your app. Scales to the big screen. Scaling which depends on pixel density and viewing distance. There is no rule of thumb that a desktop has higher scale than a mobile phone. It is primarily dependent on pixel density and viewing density.

scale_x

Some other cool features include using the other screen not just to mirror but to take advantage of the 2 screens simultaneously with multi screen API …

2screns

Some technologies to watch out for

Nano Server – Nano server doesn’t just remove features but is a self contained engine. Microsoft defines its Nano Server as a “headless, 64-bit only deployment option for Windows Server.” It’s like Server Core, except that it’s 20 times smaller. The compressed size or reduced server “footprint” brings a number of benefits, including fewer security vulnerabilities to address, reduced patch and reboot times, and scalability improvements.

nanoserver

  • 3d printing
  • IoT Maker movements – Raspberry Pi and Arduino

Lots of great talks on IoT. Some of the interesting ones given below.

IF you are considering buying parts for maker projects here is an interesting site. http://www.bizoner.com/

Confidence invoking statements

Windows itself is evolving with feedback from Insider program. Instead of fixed set of design the design is evolving which appears to be by design and is sometimes misconstrued as instability.

The other comforting thing for developers is that the new browser edge which is a UAP was designed using the same tools as a developer would use for their own apps.

Summary of the key areas

 

Area Features
Universal App. Platform(UAP) platform Universal App. Platform offers the capability to write your app. Once and run it on all Windows Platforms starting with the Windows Embedded (Athens) to Mobile to Desktop to new Surface HubApps are coded to Universal App. Platform and not to the hardware platform or Operating Systems using Windows.Foundation.Metadata.Apiinformation. What that means is that applications shouldn’t be designed for Win 10 Mobile or Win 10 desktop etc This alleviates the need to code to least common denominator hardware they would be supporting
Visual Studio Visual Studio teams had a busy year with a lot of new features.. To name a few:·         Web Apps(JS etc),·         Android (Java)·         iOS(objective C),·         Open source integration(Git hub, Alljoin, Big data programming ),

·         Cloud apps,

·         Unit testing, perf.

·         New VS Code part editor part IDE

One $tore for all Windows Platforms One can now link apps meant for Windows Phone to Dekstop.1 submission for all, 1 certification but and 1 pricing. Typically the greatest common denominator if one has apps on both mobile and Desktop is chosen. The base price from is chosen from Windows (desktop), screen shots are chosen from both to give user flexibility, category is chosen from windows(desktop) etc…There is the option of having multiple packages for old OS 1 package. The dashboard is on dev.windows.com is redesigned.

Some folks asked me about the sessions I attended and Below are the some sessions I found useful. These are not in any particular order and cover ranging topics from Azure, IoT, UX, Programming:

Sessions I found useful

Topic Link
Nano sever : A Cloud Optimized Windows Server for DevelopersMicrosoft defines its Nano Server as a “headless, 64-bit only deployment option for Windows Server.” It’s like Server Core, except that it’s 20 times smaller. The compressed size or reduced server “footprint” brings a number of benefits, including fewer security vulnerabilities to address, reduced patch and reboot times, and scalability improvements.To address the cloud, the GUI built into the server had to go. Instead, Nano Server gets managed using a remote GUI through a browser-based application. For instance, the presentation showed off a browser-based dev-ops program called Visual Studio Release Management. It doesn’t use Remote Desktop Protocol to remote into a server. Instead, it uses Core PowerShell scripts for management, along with Desired State Configuration, which is PowerShell’s push-pull configuration technology. http://channel9.msdn.com/Events/Build/2015/2-755
Porting Android apps using Astoria There are some hardware restrictions on the memory and disk space for such apps. http://channel9.msdn.com/Events/Build/2015/2-702
Project Centennial”: Converting your Classic Windows App (Win32, .Net, COM) to a Universal Windows App for Distribution in the Windows Store This allows Win32 apps to run in a container security. The app becomes a UWP app and hence can run on Xbox, Halo lens, Surface Hub etc.To help support Win32 apps which need Winsock, CreateThread() API’s these API’s will be available to UWP apps also. WMI, DAM, COM works just like Win32. Access to click once API’s lost after the first launch.Some features like active X deployment wont work etc. http://channel9.msdn.com/Events/Build/2015/2-692
Project Spartan”: Introducing the New Browser and Web App Platform for Windows 10 Key reason for using the browser is primarily around because it will work well with optimized sites, supports Cortana and many other gems such as Web extensions, pointer lock for shooter games and reading lists . IE due to compatibility reasons may not support but with forked code. This allows for edge supportability forked with IE compatibility. The best part is that Edge can launch IE for sites which are not compatible for example which need VB script.Other things are distraction-free offline reading and built-in note-taking & sharing. Below is a comparison of Alaska airlines website on a mobile device. http://channel9.msdn.com/events/Build/2015/2-656
Windows Design for Developers: An Executive Panel Windows Insider program feedback has been taken into account for UX design for Win 10.One of the better talks I attended. This talk gave me a perspective on how much of Win 10 UX design is incorporating feedback from Windows Insiders Only slideshttp://channel9.msdn.com/Events/Build/2015/2-778
Optimizing Windows Apps for ContinuumEffort involved in letting applications working across multiple screens is very little especially for mobile. You can resize your application on desktop to test the look and feel on mobile.Some key concepts are effective pixel, pixel density and viewing distance etc. More here: http://channel9.msdn.com/Events/Build/2015/2-703
Building Rich, Contextually Aware Universal Windows Apps Using Sensors There is support for batching sensor request to save on power. Applications can use background triggers to detect things like user activity (like walking etc). There is also availability of sensor history data.Custom sensor can be easily added and apps. can use GUID to detect the device. Sensor simulators are available from Github to build and test applications. http://channel9.msdn.com/Events/Build/2015/2-735
Store: Deep Dive on Publishing Universal Windows Apps From now on there will be :·         one store for everything,·         one submission for all,·         one certification

Optional support for multiple packages for OS and platform are available.

http://channel9.msdn.com/Events/Build/2015/3-710
Developing 3D Printing Apps and Services in Windows 10The 3d print space has many individual,  challenges with nonstart drivers, low print success rate, limitations on information exchange,  limitations in existing formats , formats not designed for 3d format.The 3mf consortium tries to solve some of these with open source, compact human readable. This will allow for repair capabilities API, plug and play, enable cloud printing. There will 3d builder inbox which will allow for visualizations and validation and repair. This removes the single highest barrier to entry removed.3d content is open for partners to develop. More details here: www.thingverse.com/Emmett http://channel9.msdn.com/Events/Build/2015/2-718
API Contracts (or How I Learned to Stop Checking OS Versions and Love Feature Detection)Least Common Denominator API’s really suck,. Instead have adaptive apps which run on multiple platforms. Use the Windows.Foundation.Metadata.Apiinformation classes and methods to find out what features your app. Targets. http://channel9.msdn.com/Events/Build/2015/3-733

Some things I found useful to try

  1. Join and give feedback on Windows Insider – This feedback contributes to many things including UX design etc.
  1. Try Cortana – Scenarios such as weather, how much RAM do I Have?
  2. Try Project Spartan/Edge browser on your Nokia Phones and Desktop’s
  1. The build app. Was great to get the summary of all sessions in case you are curious on any developer topic. The app. Works on Windows, Android and iPhone platforms.
  2. INSTALL Visual Studio 2015 and VS Code

VS 2015-  https://www.visualstudio.com/en-us/downloads/visual-studio-2015-downloads-vs.aspx

VS Code – http://code.visualstudio.com/

Etc etc

Comparison of Developer conferences

In this competitive world it is difficult to not compare. I looked at the 3 of the more important key notes of developer conferences.

Build in my opinion had one of the best key notes. The Google key note was dull and lacked appeal, IoS on the other hand was not bad but Apple ecosystem is very limited compared to what Microsoft covers. Build had powerful demos and tremendous wow factor with Halolens especially. We will see more in a couple of weeks when Apple and Google 2015 conferences are held.

Conclusion

Overall I think Win 10 is going to be a great platform for at least a billion devices. So if you are a developer this present s great opportunity on writing all sort of apps. for so many different platforms…

Part 2 of this coming soon looking at more cool windows features …

Read the rest of this entry »

bulk copy data

May 5, 2015

the main goal of this blog is to focus on tools available for doing a bulk copy to a SQL server on windows.

Inserting sequentially –
Sqlcmd – it is a freat tol if you have the data on the machine hosting the SQL server. You can use it if you have the data on a network share but you run into issues with credentials.

BCP- It is a great tool but you need to understand the format files and the syntax of the command. Bcp is like a scripting language where the sepecial characters like “,”, “;” etc. are to be carefully monitored. Also, it is very fical when it comes to validity of source data. For eg: Data time format fields with hours or minutes or seconds not in the HH:MM:SS format will give you a lot of trouble. Missing leading 0’s can be cause of many an issue.

Debugging – Insert a field manually and get it using bcp out.

Hibernate and Hiberfile sizes

June 13, 2014

Windows reserves typically 75% of the Memory for Hiberfil.sys . This is normally enough after compression but maybe less especially if you use memory tools. The way to change hiberfile size is as follows :

powercfg /h /size

To turn off Hibernate use the following command:
powercfg /h off

Turning off hibernate in Windows8+ is:
1) No fast startup so impact on boot time
2) No way to save data if the battery reaches critical levels.
3) No way to save data on Thermal conditions

Decrypting wdf01000.sys interrupts with WPA

June 13, 2014

If you are trying to figure out which WDF driver is the source of all interrupts there is a way out. Since wdf01000.sys fields all interrupts and then calls the actual driver, it is difficult to figure out which driver caused the interrupts. Fortunately, there is a way out: You need to use the trace flags in the kernel – WDF_INTERRUPT and WDF_DPC. You can find all Kernel trace flags by the following command: “xperf -providers KF” .

You can trace as follows: ”

xperf -on diageasy+WDF_DPC+WDF_INTERRUPT+0x48000000+PROC_THREAD+LOADER+INTERRUPT+DPC+CSWITCH+TIMER+CLOCKINT -stackwalk TimerSetPeriodic+TimerSetOneShot+CSwitch+readythread+profile -clocktype perfcounter -buffersize 1024 -minbuffers 1024

xperf -d test.etl

Tidbits on technical interviewing

November 14, 2011

I have interviewed a lot of candidates for various roles within Microsoft. They range from college graduates to automation testers.
I broadly qualify them under 2 categories:
1) college hires for driver development
2) Automation using powershell
College Hires of Kernel/driver development
For college hires my interview style was to make sure I give them questions which ar not easily available off the internet. For that purpose I always used questions or challenging problems which I was working on at that time. Also, I tried to keep my questions consistent to compare candidates and since I knew the approaches and solutions pretty well.

One question I asked which was typical of what that candidate would be expected to do was to give the candidate a help guide for a particular kernel API and then showed a snippet of code and asked him to figure out what was that doing. For eg: Given the help page for “InterlockedCompareExchange” ass the candidate to figure out what some piece of code was doing. It normally is a good test of understanding of code and kernel concepts.

Some other areas which I would quiz on for kernel/driver development positions:
1) IRQL’s
2) Synchronisation primitives
3) C coding
4) Virtual memory

If the candidate got through my coding question I would give some logic puzzles to keep it interesting. More coding questions sometimes just makes the interview dull.

Categorie 2 – Automation code developemnt
Recently we had a need to hire someone who could help automate some tools. I have realised over time that on of the best skills for automation is not C# but powershell. With the cmdlets support working with powershell makes for really fast development time. It has the caveat of no type safety but is great for smaller projects which need to be developed quickly. The typical thingsin our probelm space were parsing input in .txt, .csv files etc reporting as html output etc
For eg: I saw that for a problem of finding all 3rd party exes under “program Files” folder it takes a person around 2-3 hrs to solve in C# given a developer with 5 yrs of experience. However consistently most candidates solved under 1 hr using powershell.

There are several such examples I came across.

My goals were to wait for the right candidates with a good mix of technical skills (powershell experience of more than 6 months) and good soft skills (self starter, sincere and detail oriented etc). I let the recruiters know to do their own filtering thus reducing the onus on me as the sheer number of candidate resumes I was getting was enormous.
One way i decided to save time was to have a phone screen prior to meeting the candidate face to face. This saved me immense amount of time. My phone screen was to give the candidate an introduction to the position followed by giving him a real world problem to solve using powershell. All problems were the ones that I encountered while trying to automate and i would give the candidate an hour to solve. Some examples:
1) Parsing and reporting question(phone screen):
Given a .txt file parse it and then generate an HTML report with some tables.
2) Simple question – good to give the hiring agency
Given a root path create folders with iteration numbers every time the script runs. For eg:
If the root is c:\test. The first time a script is invoked create C:\test\1\
If the script is invoked a second time, it should recognise that c:\test\1\ exists and create c:\test\2\ and so on.

Things to watch out for:
The code shouldn’t take more than 20 lines of powershell in the worst case
Easily tested by powershell .\.ps1

3) ) In person interview
Find all 3rd part exes (this is not literal but just omitting Windows or Microsoft in the folder or exe name was enouh) under program files etc.
Things to watch out for:
Program files under 64 bit system has 2 folders for program files. Try running the powershell script on your own machine and see if it works and shows the correct output.

I gave the candidates normally an hour and kept the time consistent to compare candidates. Also, the goal was to not only look at their problem solving capabilities but also ability to ask for clarifying questions. If the solution was not well formed I would give feedback and see if the candidate had the inclination to send me an improved solution. This also showered some light on the candidates sincerity to improve and take feedback besides communication.

In the face to face interview I would more whiteboarding and sometimes focus on other soft skills lile being detail oriented and creative . I also woudl ask at least one more member of the team to interview in case the candidate had to work with him and also to get another picture.

Hope this helps as it has helped me tremendously to hire some great candidates. They are worth it as the extra amount of time spent in picking the right candidates pays very rich dividends when it comes to explaing problems and finding solutions.