WorkAround: Console2 + Telnet.exe on Windows 7 Crashes ConHost.exe

December 14, 2010 Leave a comment

conshost-croak

Entering the Windows telnet.exe prompt mode causes the shell process underneath Console2 to crash on Windows 7. You can reproduce this by just invoking telnet with no arguments in a Console2 session. An alternate route to hit this is exiting a telnet session with CTRL+].

The symptom is Console2 freezing because it is no longer getting text from its slaved native console followed up with a crash dialog for conhost.exe and whetever your shell was.

Unhandled exception at 0xffdd1df9 in conhost.exe: 0xC0000005: Access violation reading location 0x0000000003385460.>    conhost.exe!SB_StreamWriteToScreenBuffer()  + 0x61 bytes   

A workaround is to launch telnet into a separate conhost.exe window.

#force telnet.exe to start in its own console window. 
function telnet { start $env:SystemRoot\System32\telnet.exe $args }

Or use putty –P port –telnet host as an alternative to telnet.exe. (I can’t get plink.exe to be interactive with telnet for me.)

Update

Unless you need something nifty that telnet.exe is doing, a more elegant solution is to Lee Holmes’ Connect-Computer.ps1 PowerShell script as a telnet replacement.

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FIX: VirtualBox Host-Only Network Adapter Creates a Virtual “Public Network” Connection That Causes Windows to Disable Services

September 18, 2010 12 Comments

vbox-host-only-net-net-n-sharing

vbox-host-only-net-connectletVirtualBox creates a “VirtualBox Host-Only Network” device which is essentially a loopback adapter for creating network connections between virtual machines and between the host and virutal machines. Unfortunately, it shows up to Windows as an unidentified public network. Connecting to a “public network” ratchets up your firewall and disables network discovery and SMB/CIFS network shares. This is kind of a big side effect of installing some VM software.Fortunately, Windows does have a way to mark a network device as virtual by creating a registry value.

The type of the device. The default value is zero, which indicates a standard networking device that connects to a network. Set *NdisDeviceType to NDIS_DEVICE_TYPE_ENDPOINT (1) if this device is an endpoint device and is not a true network interface that connects to a network. For example, you must specify NDIS_DEVICE_TYPE_ENDPOINT for devices such as smart phones that use a networking infrastructure to communicate to the local computer system but do not provide connectivity to an external network.

This powerhsell script will find the “VirtualBox Host-Only Ethernet Adapter device entry in the registry and adds the ‘*NdisDeviceType’ value of 1. After reboot, the “VirtualBox Host-Only Ethernet Adapter” will no longer be monitored by the Network and Sharing center. 

# tell windows that VirtualBox Host-Only Network Adapter
# is not a true network interface that connects to a network
# see http://msdn.microsoft.com/en-us/library/ff557037(VS.85).aspx
pushd
echo 'Marking VirtualBox Host-Only Network Adapter as a virtual device.'
cd 'HKLM:\system\CurrentControlSet\control\class\{4D36E972-E325-11CE-BFC1-08002BE10318}'
ls ???? | where { ($_ | get-itemproperty -name driverdesc).driverdesc `
-eq 'VirtualBox Host-Only Ethernet Adapter' } |`
new-itemproperty -name '*NdisDeviceType' -PropertyType dword -value 1
echo 'After you reboot the VirtualBox Host-Only Network unidentified public network should be gone.'
popd

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VirtualBox Trigger Windows 7 Bug Causing it to Believe the File System is Broken

September 13, 2010 1 Comment

Booting for 4 hours and another hour to go

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VirtualBox 3.2.8 (and possibly other versions) running on Windows 7 or Windows Server 2008 R2 as the host operating sytsem triggers a bug that causes Windows 7 or Windows Server 2008 R2 to believe that NTFS is corrupt. Chkdsk then runs on every boot. In fact chkdsk is chasing a ghost. There is no corruption but on my system chkdsk takes over 5 hours to run to completion.

I don’t believe that VirtualBox is doing anything hinky. It is just unlucky to trigger a regression in NTFS.

This is a known regression in Windows 7 in the NTFS file system.  It occurs when doing a superceding [sic] rename over a file that has an atomic oplock on it (atomic oplocks are a new feature in Windows 7).  The indexer uses atomic oplocks which is why it helped when you disabled the indexer.  Explorer also uses atomic oplocks which is why you are still seeing the issue.  When this occurs STATUS_FILE_CORRUPT is incorrectly returned and the volume is marked "dirty" which is a signal to the system that chkdsk needs to be run.  No actual corruption has occured [sic].

Neal Christiansen
NTFS Development Lead

Fortunately, a hotfix already exists. Applying KB982927 appears to fix the issue for me.

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Boot Camp: Dated Broadcom Driver Causes Audio Pops and Crackles

August 9, 2010 Leave a comment

broadcom-disable-802-11aI have had a problem with my MacBook Pro having intermittent crackles and pops in the audio in my late 2009 Macbook Pro Unibody. I previously suspected the Cirrus Audio driver.  Restarting “Windows Audio” (aka audiosrv) fixes the problem. The pattern is that everything is fine on boot. The crackles and pops start after resuming from sleep.

I just came across this post which indicates the problem is actually caused somehow by the the 802.11a feature of the Broadcom wireless network adapter. Somewhat incredulously, I gave this a try and it works so far.

It also seems that although, Apple has not seen fit to send out an update, Broadcom has published several newer versions of their 943XX driver. These are available from other OEMs using Broadcom chips (Acer, Dell and HP) that actually provide updates for Windows drivers on a regular basis. HP helpfully offers a version of the Broadcom Wireless driver that is almost a year newer than the one in Boot Camp 3.1. The revision history of here shows notes a series of performance enhancements over the Apple-distributed version 5.60.18.8.

Update

Some good folks have taken it upon themselves to scrape together Broadcom wireless driver downloads posted by various OEMs. Note that sometimes the stuff in the forums is newer than what is listed in the pinned initial post. At the time of this writing, the latest available is 5.100.249.2 from Acer.

Update 2

I’m still getting the intermittent pops and crackles. Perhaps I have unfairly maligned the Broadcom driver based on random info from the interwebs. I just realized that the speakers on my Cinematic Display are running at the same time as my nice speakers on the mini-jack. Maybe that has something to do with it. Still futzing.

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