Losing Wi-Fi connection after sleep

Problem:

I use a HP Probook Laptop at home running Windows 8.1 pro. I usually close the laptop whenever I take a short break so that I can resume my work where I left after the break. But, I find that upon opening the Laptop, the wifi does not connect and that too randomly. That means, it works fine on certain occasions and it doesn't on certain occasions. Some times, a restart helps connecting but not always. What could be the problem and how to get this resolved.

By: Lalith Venkateswaran

Solution:

This could be due to a combination of multiple issues relating to the configurations in your laptop and as well as on your router.

Upon closing the lid, the laptop goes to sleep mode and powers down the built in wifi device. Which might cause orphaned IPs at your router end and as you reconnect again and again, you might exhaust the DHCP range that your router is configured with. Check if this issue happens when you are on battery. If yes, then you may configure your power options so that your device does not get powered down, every time you close your laptop. You find this setting in the Power management tab of the wifi-adapter configuration. You may also review the advanced power settings for the wifi adaptor under the power options.

When your wifi connection fails upon wake up, you may check if you are able to connect to a different wifi network. If you don't have a different wifi network, you simply use the hotspot feature on your smartphone and try if your laptop can connect to it. If yes, then it is not just the wifi device on your laptop, it could be due to issues with your wifi router as well. Some routers may have issues in accepting connections from the same devices with the same mac id, as the previous connection might still be there. Try the following steps, which might solve your problem:

• Try setting a shorter DHCP lease time, so that the orphaned connections get released sooner, so that your router has no problem in accepting a fresh connection.
• Use the DHCP reservation, so that every time the laptop tries to establish a connection, the router assigns the same IP and thus no need for lease expiry / renewal.

Post a comment if this does not solve your problem.

TWAIN vs WIA

Question:

I have taken up an academic project to work with the imaging devices, like video and still image capture. I have read about TWAIN and WIA as the popular toolkits or APIs available for the purpose. I need help in deciding as to which API is good to go with and guidance on any other tools or SDKs would also be of help.

By: Matt Charles

Answer:

You are right that TWAIN and WIA are the widely used APIs for applications around image acquisition. The choice of the toolkit can be made by looking at the following criteria:

• OS Support: Microsoft's Windows Image Acquisition apparently works only on Windows platform. But TWAIN works on Windows, Linux and Mac. If your project requires cross platform solutions, then look at TWAIN or else WIA is preferred for its other advantages. While TWAIN is an offering of TWAIN Working Group having leading device vendors as its members, WIA is Microsoft's offering which builds on top of low-level hardware abstraction STI and is available with Windows Me or later.
• Programming Support: Working with TWAIN API require C/C++ skills. There are commercial high level libraries which expose various programming language specific APIs for ease of use. WIA, though primarily designed for C/C++ development, it offers ease of use with .NET programming languages as well.
• Device Support: Most of the windows compatible imaging devices including digital cameras, webcams, video cameras and scanners are WIA compatible. But not all devices come with TWAIN support. The list of devices supported by the TWAIN specification 2.3.0 can be found here. 

TWAIN though originally developed in 1992, it is a sophisticated API and its portability across various platforms. TWAIN also offers a 'native' (Device Independent Bitmap) transfer mode in addition to the modes 'memory' and 'file' offered by WIA. WIA provides a TWAIN compatibility layer that allows TWAIN-aware applications to communicate with WIA devices, though such applications will not have full access to WIA functionality.

Here are some cool references or code samples for image acquisition using WIA

ADF Scanner Library
OpenNETCF WIA Library

Some of the commercial APIs that make building TWAIN aware applications a lot easier are:

EZTwain Pro 4.0
csXImage - ActiveX Image edit and Twain control

You may also want to explore JS-Feat a javascript library.

Assuming that your project is of academic nature and that you would be looking at a windows specific solution, I would recommend you to explore WIA.

Chrome on Windows 8 Freezes often

Question:

I have been experiencing issues while using Chrome on Windows 8. Randomly the system PC become unresponsive to keyboard and mouse. While some times the freeze is for a few seconds, most of the times it never comes back. The PC then had to be hard rebooted. Though I have been experiencing more with Chrome on rare circumstances, the system did froze even when I was not using Chrome at all, For your information, I have applied all windows updates and the device drivers seem to be upto date. Any help in resolving this is highly appreciated.

By: Mohan Ramalingam


Answer:

There is no straight fix for this problem, as the cause for this issue could be many fold. For example, I have come across issues around solid state disks with inappropriate hardware and driver configurations. Generally, try these fixes and one of that could work for you.

• Run the following command bcdedit /set disabledynamictick yes using the command prompt as an administrator and then reboot the system. Dynamic ticks, which exists in Linux for over a decade, is implemented in Windows 8 for the first time. This does not significantly benefit desktops, but mobile devices such as laptops, smartphones and tablets, are expected to be benefited in the form of extended battery life. Unfortunately, Microsoft’s implementation of dynamic ticks in the Windows 8 kernel does not go well, may be due to its dependency on some hardware devices and/or related drivers and thus causing the issue that you have described above. Disabling this on a desktop is unlikely to have any significant adverse impact.
• It is widely reported that using a solid state disk with older SATA controllers, which are not designed to manage the higher speeds of SSDs could also cause similar issues. It is recommended to use SATA II controller based mother boards. Just in case if you are using an SSD, you may want to check the underlying hardware specifications and fix them if needed.
• Other possible solutions include:
• If the issue is specific to chrome, try disabling the chrome extensions on a trial and error basis and some users how found success in resolving the issue by disabling some of the fixes.
• Ensure that all your hardware devices have latest drivers supported by Windows 8.
• Run System File Checker tool to see if there are corrupt system files. For this, you may run the command sfc /scannow in a command prompt with administrator privileges. This will report if there are issues with system files and if so, you may want to reinstall or reset the Windows 8 operating system.
• Defrag your hard drives
• Clear history and temporary files

You may write a response to this post in the form of comments, if any of the above has helped resolve your issue.

Update:

If your experience of freeze is not specific to Chrome or any one application, then you have reason to suspect the hardware. Overheating CPU has been found to be one of the most common cause of such freezes. Ensure that the fan mounted on the Processor and other fans attached to the chassis are working fine. Use the hardware monitoring tools supplied by the manufacturer to keep a watch on the CPU temperature.

The next possible cause would be incompatible drivers. Ensure that you have all the hardware drivers updated. Usually, when you have upgraded your Windows 7 to Windows 8, it might be possible that the old drivers continue to be in use and Windows OS might not find updates. But driver updates could in fact be available from the device manufacturers. Better search for the appropriate updated drivers and apply them.

How to take Screen Shot in Android Phone?

Question:

I have seen my friends taking and sharing screen images using their iPhone. While I think that this should be possible in Android Phones as well, I could not figure out how to take screen shots in my HTC One M7 running Android Jelly Bean.

By: Niranjan Babu

Answer:

Yes, Android natively supports taking screen shots in Ice Cream Sandwitch and Jelly Bean versions. It is not an explicit menu or a built in app though. The trick is that while you are at a screen that need to be framed, press and hold the Power button and the Volume Down button simultaneously. You may have to hold press and hold these buttons for about two seconds or little more, until you hear the camera click sound and visually see the screen being framed and saved into the Pictures/ScreenShots folder. Some specific vendor tweaked versions may have explicit touch buttons within certain applications.

For those who are using older Android versions like Gingerbread or earlier, then you are left with the option of using an application. You may search through the app store and find as many applications that facilitate taking screen shots. Beware that some of such apps may require you to root your OS, which is not recommended as certain manufacturer specific features may stop working once you root your phone.

Unknown device on DELL XPS 13

Question:

I use a DELL XPS 13 Ultrabook. Though Windows 7 was the bundled operating system, I have upgraded to Windows 8. Though it all work fine, I see a device in device manager marked as unknown. The properties dialog lists the hardware IDs as ACPI\VEN_INT&DEV_33A0, ACPI\INT33A0 and *INT33A0. My attempts to search DELL driver download have failed as I could not find the appropriate driver. Can you help me find and fix this?

By: Rakesh Sharma

Response:

INT33A0 should be the port for Intel Smart Connect Technology (iSCT). Given that Windows 8 is designed as the OS for PCs and as well as smart devices, there is a need to use the communication components even when the device is in sleep mode. Intel's iSCT enables this feature and this feature is controlled by the System BIOS. Not all hardware may have support for this feature, but those that have the support would have a setting in BIOS to enable this capability. Just make sure, you may check out your BIOS and try disabling this feature and you may notice the 'Unknown device' disappear in the device manager.

The driver for this feature can be downloaded here on the Intel website. Try installing this component and see if your problem gets resolved. You may have to run the installer using 'Run As Administrator', even though the user account with which you have logged in has Administrator privileges.