At work with the University of Oslo, we have several hundred computers +in our computing center. This give us a challenge in tracking the +location and cabling of the computers, when they are added, moved and +removed. Some times the location register is not updated when a +computer is inserted or moved and we then have to search the room for +the "missing" computer.
+ +In the last issue of Linux Journal, I came across a project +libdmtx to write and read bar +code blocks as defined in the +The Data Matrix +Standard. This is bar codes that can be read with a normal +digital camera, for example that on a cell phone, and several such bar +codes can be read by libdmtx from one picture. The bar code standard +allow up to 2 KiB to be written in the tag. There is another project +with a bar code +writer written in postscript capable of creating such bar codes, +but this was the first time I found a tool to read these bar +codes.
+ +It occurred to me that this could be used to tag and track the +machines in our computing center. If both racks and computers are +tagged this way, we can use a picture of the rack and all its +computers to detect the rack location of any computer in that rack. +If we do this regularly for the entire room, we will find all +locations, and can detect movements and removals.
+ +I decided to test if this would work in practice, and picked a +random rack and tagged all the machines with their names. Next, I +took pictures with my digital camera, and gave the dmtxread program +these JPEG pictures to see how many tags it could read. This worked +fairly well. If the pictures was well focused and not taken from the +side, all tags in the image could be read. Because of limited space +between the racks, I was unable to get a good picture of the entire +rack, but could without problem read all tags from a picture covering +about half the rack. I had to limit the search time used by dmtxread +to 60000 ms to make sure it terminated in a reasonable time frame.
+ +My conclusion is that this could work, and we should probably look +at adjusting our computer tagging procedures to use bar codes for +easier automatic tracking of computers.
+ +