l i k a . b e

How to implement a hierarchical permission tree in the project-management tool Trac.

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Unrouting a complete PCB in Eagle means that all routed tracks on the board are reverted back into so-called ‘airwires’. Airwires are lines that show that there is a connection between 2 points on the board, but that no actual connection is routed yet.

Unrouting signals on a board is called ‘ripup’ in Eagle slang.

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Excel easily allows to extract a list of unique items and count them. Handy when you have to extract an order list from a BOM of a PCB for example

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Comparing the wave traces of 2 different simulations in Modelsim is quite easy.

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To enable tab completion in a command terminal on Windows, perform the following steps:

• Open regedit (Start->Run->’regedit’)
• Go to HKEY_LOCAL_MACHINE\Software\Microsoft\Command Processor
• Set the value for the key CompletionCharacter to 9

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When plugging in an external USB drive on Mac OS X, it gets nicely mounted under /Volumes and appears on your desktop.

However, since I use my MAC mini as Slimserver machine for my squeezebox, I want this automount also to happen after boot, before a user is logged in.

This seems not to be so trivial. I’ve tried several mechanisms to obtain the automount feature, from scripts executed at boot time to modifiying the fstab. None provided an acceptable solution.

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Searching for a certain text in mulitple files? Just run:

grep -lir "word" *

And you’re all set. It will return you the name of the files containing “word” in the current folders and subfolders.
E.g.:

~/projects/xap $ grep -lir "header" *

If you then need the lines that contain the search term, just omit the ‘l’:

~/projects/xap $ grep -ir "header" *

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OK, so you have that nice and shiny server up and running with a RAID array, and all of a sudden you start getting ‘Degraded Array’ messages…

Assuming the error is not hardware-related (i.e. one drive of the array that is failing) you can easily recover from this message.

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To log a specific signal in a ModelSim simulation, make  a script like this:

view list
add list -hex /tb_name/dut/signalname
configure list -usestrobe 1
configure list -strobestart {<time> ns} -strobeperiod {<period> ns}
configure list -usesignaltrigger 0
configure list -delta none
configure list -usegating 1
configure list -gateexpr { /tb_name/dut/rst_n=='1' }
write list -window .list <output_filename .log>

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OK, it’s time to reinstall my Linksys NSLU2 NAS device (petnamed ‘slug’) to finally put it into ‘production’. This is a list of steps that I have taken, together with some notes that might come in handy if I ever need to do this again.
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