CSS Boxing Trick

February 4th, 2016 by ellery

Whenever I start trying to float things with CSS I run into trouble. I need to remember this:

How to sleep in a Windows .bat script

December 18th, 2015 by ellery

There is no sleep command for the Microsoft command line. Here is one way to add a fixed delay to a batch file script:

Use the ping command to ping an invalid address and set the timeout for the number of milliseconds you want to delay. So for example, the following command would delay for 5 seconds before proceeding:

     @ping -n 1 -w 5000 > nul

Suppressing the default namespace in ElementTree

July 7th, 2014 by ellery

xmlThis solution removes the default namespace from the input XML and makes typing ElementTree Xpath expressions a lot easier.  The trick is to remove the xmlns=”…” attribute from the input XML before parsing it.  Most other workarounds suggest traversing the tree of elements after parsing, and modifying the tag entries.


import ElementTree as ET

# Parse the contents of the XML file
tree = ET.parse(xmlFile)

# Get the root element
root = tree.getroot()

# Use fully qualified tag names in path expressions
extentX = root.find(".//{http://some/namespace}Coverage/{http://some/namespace}Extent/x")


import ElementTree as ET
import re # regular expression module

# Read the contents of the XML file into xmlstring
with open(xmlFile) as f:
    xmlstring = f.read()

# Remove the default namespace definition (xmlns="http://some/namespace")
xmlstring = re.sub('\\sxmlns="[^"]+"', '', xmlstring, count=1)

# Parse the XML string
root = ET.fromstring(xmlstring)

# Use much simpler path expressions
extentX = root.find(".//Coverage/Extent/x")

Thanks to this post on the always useful StackOverflow for suggesting the solution.

Vega Prime Viewer Hot Keys

September 26th, 2013 by ellery

bostonThumbnailI happened upon a list of the hot key functions for the Presagis Vega Prime standard viewer, which is used in the Lynx Prime Active Preview and is supported in the API by the vpApp class. Since I can never remember where to find them, I’m putting the list here.

vpApp responds to the following keyboard input:

        Esc : quit the application
          ~ : enable / disable the first stats page
          s : cycle forward through the stats for all channels
          S : cycle backward through the stats for all channels
  Backspace : reset the state vector for all observers
      Enter : capture the state vector for all observers
          c : put all observers at the center of the scene
          f : enable / disable fog for all channels
          l : enable / disable lighting for all channels
          p : print the absolute position for all observers
          t : enable / disable texture for all channels
          T : enable / disable transparency for all channels
          w : enable / disable wireframe for all channels
          a : enable / disable shaders for all channels
          x : enable / disable the position strategy for all observers
        Tab : enable / disable scene graph overlay drawing
     NumPad : pan position of the scene graph overlay
          q : scale the scene graph overlay up
          Q : scale the scene graph overlay down
         F8 : capture video stream
         F9 : capture still-image

Fix Broken Windows Boot After Installing Linux (grub)

October 8th, 2012 by ellery

When you install Linux or another OS alongside Windows in a dual-boot configuration, the installation often sets up a boot loader like grub to manage the booting alternatives. This can sometimes break the Windows boot loader, which can cause problems in certain situations.

One situation is where you have a Windows hard drive and a Linux hard drive. It works fine as long as both drives are installed, but say you remove the Linux hard drive: you would expect the Windows drive to boot up straight into Windows. But instead you might get a message like “BOOTMGR is missing”.

Another situation that I ran into was that I could not upgrade Windows 7 to SP1 in my dual-boot configuration.  Reasons why are discussed here.  I had to revert the boot loader back to booting directly into Windows before the Windows 7 SP1 update would stick.

There are also a few other situations that might cause your Windows boot loader to get corrupted, and you probably don’t want to resort to restoring your entire drive from a backup image or re-installing Windows from the ground up.  So here’s one relatively easy way to fix your boot.

Repairing the Windows boot loader

Here is one way to repair the Windows boot:  Find a Windows Full or Upgrade install disc. Boot from it. When it comes up, select your language, then at the next screen, select the Repair Windows option at the bottom of the screen. Select the Startup Repair. Indicate which version of Windows you would like to repair, if it finds more than one installation on your hard drive. It will do some checking, and should find that your BootMgr is in need of repair. Tell it to repair the problem. After that it should boot directly into Windows again.

This works with a Windows 7 Upgrade disc.  I’m not sure about Windows XP.

Setting up Cygwin

September 19th, 2012 by ellery

CygwinThis is my procedure for installing Cygwin on a Windows desktop. There are many ways to configure the Cygwin environment. This seems to work for me:

  1. Go to cygwin.com
  2. Download the Cygwin installer/updater to your desktop
    1. Choose setup_x86.exe (32-bit installation), or
    2. Choose setup_x86-64.exe (64-bit installation)
  3. Run it

Use the following settings to answer the setup questions:

Root dir:  c:\cygwin  (for 32-bit; or c:\cygwin64 for the 64-bit install)
Install for:  All users
Default file type:  DOS
Package dir:  c:\cygwin_install (recommended; can be deleted later)

Be sure to install the following packages:

Section  Package
------- -------
Net     inetutils
Net     ncftp
Net     openssh
Net     ping
Python  python
Python  python-imaging
Python  python-tkinter
Shells  chere
Shells  mintty
Shells  tcsh
Shells  xterm (for resize)
Utils   ncurses (for tset)
Web     wget

Set the HOME environment variable in Windows (Computer->Properties->Advanced->Environment Variables) (put your username instead of username):

Win XP:
HOME  c:\Documents and Settings\username
Win Vista/7/8:
HOME  c:\Users\username

Optional environment variables:

$OSG_HOME (OpenSceneGraph)

Set the PATH environment variable. Cygwin will inherit the Windows PATH, but you need to add the directories containing the Cygwin executables. This is a very minimal .cshrc file. You will probably want to add a more sophisticated one. I have a small set of “dot” files that I copy into a user’s HOME directory when setting up Cygwin. To create the minimal .cshrc file, type the following lines at a shell prompt, ending with the <Ctrl-D> (Cygwin EOF) character:

/usr/bin/cat > $HOME/.cshrc
set path=(/usr/local/bin /usr/bin /bin $path)
setenv CYGWIN nodosfilewarning

Run the following commands (put your username instead of username):

Win XP:
/usr/bin/mkdir /home
cd /home
/usr/bin/ln -s /cygdrive/c/Documents\ and\ Settings/username/My\ Documents username
Win Vista/7:
/usr/bin/mkdir /home
cd /home
/usr/bin/ln -s /cygdrive/c/Users/username username


mintty shortcut:

C:\cygwin\bin\mintty.exe -i /Cygwin-Terminal.ico /bin/tcsh

Create ~/.Xdefaults containing the following:

rxvt.scrollBar_right: True
rxvt.visualBell: True
rxvt.cursorColor: red
rxvt.saveLines: 5000
rxvt.geometry: 80x40
rxvt.font: courier
rxvt.foreground: black
rxvt.background: white
xterm.scrollBar_right: True
xterm.visualBell: True
xterm.cursorColor: red
xterm.saveLines: 5000
xterm.geometry: 80x40
xterm.font: Consolas
xterm.foreground: black
xterm.background: white

Put mintty in the Windows Explorer folder right-mouse menu:

Run the following command to create a Windows Explorer context menu entry:

/usr/bin/chere -if -t mintty -s tcsh -e "Cygwin Terminal Here" -o "-i /Cygwin-Terminal.ico"

If you get an error like this:

Error (5): Access is denied.
/usr/bin/chere Error: Hive not writable
/usr/bin/chere: Aborting.

it is a UAC (permissions) problem.  Launch the shell as Administrator and try it again.

Modify /etc/csh.login as follows, to let the shell run by chere start in the proper directory:
Replace the last line:



if ( ! ${?CHERE_INVOKING} ) then

KeeFox on Ubuntu

May 8th, 2012 by ellery

KeeFox is a plugin for Firefox that communicates with the KeePass2 password manager. I like KeePass2 because I can maintain a local secure password database without involving a server. It works great under Windows, and runs with Mono on Linux. However, KeeFox was complaining that the KeePassRPC.plgx plugin (in ~/.keepass/plugins) was incompatible. To fix it, I had to install the mono-complete package.

CMake Debug and Release Builds (in Eclipse)

May 1st, 2012 by ellery

While coding recently in C++ on a project that uses CMake, I needed to build my code with Debug settings in Eclipse.  It’s Eclipse, so there are probably many ways to do it.  I followed this approach.

I ran into one small problem.  I was modifying a project that I had already been working with.  So when I tried running the cmake commands to generate the Release and Debug makefiles

mkdir Release Debug
cmake -E chdir Debug/ cmake -G "Unix Makefiles" ../ -DCMAKE_BUILD_TYPE:STRING=Debug
cmake -E chdir Release/ cmake -G "Unix Makefiles" ../ -DCMAKE_BUILD_TYPE:STRING=Release

nothing was written to the Release or Debug folder.  To fix this, I had to first delete the CMakeCache.txt file from my project folder.

rm CMakeCache.txt

AppleSyncNotifier.exe – Entry Point Not Found

April 30th, 2012 by ellery

This error occurs on Windows (Win7 64-bit in my case) after an iTunes update.  I have had to fix this two or three times now.  I do the install, but on the next reboot I get a popup titled AppleSyncNotifier.exe – Entry Point Not Found.  The message in the popup is:

The procedure entry point sqlite3_clear_bindings
could not be located in the dynamic link
library SQLite3.dll.

To fix it, copy SQLite3.dll from

C:\Program Files\Common Files\Apple\Apple Application Support


C:\Program Files\Common Files\Apple\Mobile Device Support

It looks like other people might get slightly different errors, so you may need to copy other DLLs also.

My guess as to what is happening here is that putting a copy of the DLLs with the Apple software causes the Apple software to use that copy.  Otherwise it gets whichever  version of the DLL comes up first in the system search path.  Since many tools use some of these support libraries, it’s a bit of a crap shoot.

The last time I had to fix this problem, The How-To Geek blog article here helped me remember what to do.

Caffiene for Toshiba Drives

April 18th, 2012 by ellery

I'm sleepy.  Where's my cover?We have some Toshiba USB drives whose power-saving feature puts them to sleep at inconvenient times. The spinning down and spinning up can make some long-running jobs take a lot longer. Fortunately, Toshiba has a utility that will turn off the sleep function. You can download it here.