Archive for the ‘Operating systems’ Category

VMWare shared serial ports with Windows XP

Tuesday, March 17th, 2009

Recently the serial communications ports on a VMWare machine I had setup for embedded development stopped working. I believe what triggered the problem was booting the VM while another VM had the same physical serial ports locked and it appeared to get the XP device stack into an odd state. I found that by deleting the serial ports under hardware manager and performing a reboot it cleared the problem.

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Windows domain slow login

Friday, March 6th, 2009

Today I was creating a new VMWare virtual machine to install some embedded development tools I need for an upcoming project but don’t use often enough to have cluterring my main machine. The first login after adding the machine to the Windows domain took approximately 20 minutes. It reminded me I’d had the same problem a few years ago and the problem can occur when the machine is set to use an Internet DNS server rather than the DNS server for the local domain. Adding the local domain DNS server as the first priority DNS server for the network adapter corrected the problem.

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Vista network changes for older devices

Sunday, March 1st, 2009

Recently I installed Vista x64 and had some hassles with some older gear caused by changes to the default behaviour of the TCP stack. An HP Colour LaserJet 4550N would occasionally print a page of junk, I had a few problems with a Cisco 827 ADSL router corrupting some packets and also had file corruption problems using wireless networking to an XP Toshiba laptop running over a WLAN.

The following were the things I did to turn off the new features which solved my problems. I started by turning off SMB2 by inserting the following registry entry:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters]
“SMB2″=dword:00000000

Under device manager I disabled the following features for my network adapter:

IPv4 checksum offload
TCP Checksum Offload (IPv4)
UDP Checksum Offload (IPv4)

From an elevated command prompt ran the following to turn off TCP auto-tuning features:

netsh interface tcp set global autotuninglevel=disabled
netsh interface tcp set global rss=disabled

Then I typed ‘OptionalFeatures’ in the Windows start search box and turned off ‘Remote Differential Compression’

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