Search Results: "ckk"

13 March 2016

Vincent Sanders: I changed my mind, Erase and rewind

My recent rack design turned out to simply not be practical. It did not hold all the SBC I needed it to and most troubling accessing connectors was impractical. I was forced to remove the enclosure from the rack and go back to piles of SBC on a shelf.

View of the acrylic being laser cut through the heavily tinted window
This sent me back to the beginning of the design process. The requirement for easy access to connectors had been compromised on in my first solution because I wanted a compact 1U size. This time I returned to my initial toast rack layout but retaining the SBC inside their clip cases.

By facing the connectors downwards and providing basic cable management the design should be much more practical.

My design process is to use the QCAD package to create layered 2D outlines which are then converted from DXF into toolpaths with Lasercut CAM software. The toolpaths are then uploaded to the laser cutter directly from the PC running Lasercut.

Assembled sub rack enclosureDespite the laser cutters being professional grade systems the Lasercut software is a continuous cause of issues for many users, it is the only closed source piece of software in the production process and it has a pretty poor user interface. On this occasion my main issue with it was my design was quite large at 700mm by 400mm which caused the software to crash repeatedly. I broke the design down into two halves and this allowed me to continue.

Once I defeated the software the design was laser cut from 3mm clear extruded acrylic. The assembled is secured with 72 off M3 nuts and bolts. The resulting construction is very strong and probably contains much more material than necessary.

One interesting thing I discovered is that in going from a 1U enclosure holding 5 units to a 2U design holding 11 units I had increased the final weight from 320g to 980g and when all 11 SBC are installed that goes up to a whopping 2300g. Fortunately this is within the mechanical capabilities of the material but it is the heaviest thing I have ever constructed from 3mm acrylic.

bolted into the rack and operatingOnce installed in the rack with all SBC inserted and connected this finally actually works and provides a practical solution. The self is finally clear of SBC and has enough space for all the other systems I need to accommodate for various projects.

As usual the design files are all freely available though I really cannot see anyone else needing to replicate this.

01 September 2015

Bits from Debian: New Debian Developers and Maintainers (July and August 2015)

The following contributors got their Debian Developer accounts in the last two months: The following contributors were added as Debian Maintainers in the last two months: Congratulations!

31 August 2011

Axel Beckert: Useful but Unknown Unix Tools: How wdiff and colordiff help to choose the right Swiss Army Knife

In light of the fact that it seems possible to fit the plastic caps of a Debian branded Swiss Army Knife (Last orders today!) on an existing Swiss Army Knife (German written howto as PDF), I started to think about which Victorinox Cybertool would be the best fitting for me. And because the Victorinox comparison page doesn t really show diffs, just columns with floating text which are not very helpful for generating diffs in your head, I used command line tools for that purpose: wdiff Because the floating texts are not line- but just whitespace-based, the tool of choice is not diff but wdiff, a word-based diff. It encloses additions and removals in + + and [- -] blocks. (No, those aren t Japanese smileys although they look a lot like some. ^^). The easiest and clearest way is to copy and paste the texts from Victorinox comparison page into some text files and compare them with wdiff:
$ wdiff cybertool34.txt cybertool41.txt
+Schraubendreher 2.5mm,+ Pinzette, N hahle mit Nadel hr, +Holzs ge,+ Bit-Schl ssel( 5 mm Innensechskant f r die D-SUB Steckverbinder, 4 mm Innensechskant f r Bits, Bit Phillips 0, Bit Phillips 1, Bit-Schlitzschrauben 4 mm, Bit Phillips 2, Bit Hex 4 mm, Bit Torx 8, Bit Torx 10, Bit Torx 15 ), Kombizange( H lsenpresser, Drahtschneider ), Stech-Bohrahle, Kugelschreiber( auch zum DIP-Switch verstellen ), Mehrzweckhaken (Pakettr ger), +Metalls ge( Metallfeile, Nagelfeile, Nagelreiniger ),+ Dosen ffner( kleiner Schraubendreher ), Kleine Klinge, Grosse Klinge, Ring, inox, Mini-Schraubendreher, Kapselheber( Schraubendreher, Drahtabisolierer ), +Holzmeissel / Schaber,+ Bit-Halter, Stecknadel, inox, Schere, Korkenzieher, Zahnstocher
So this already extracted the information which are the seven tools which are in the Cybertool 41, but not in the Cybertool 34. Nevertheless the diff is still not easily recognizable on the first glance. There are several ways to help here. First wdiff has an option --no-common (the according short option is -3) which just shows added and removed words:
$ wdiff -3 cybertool34.txt cybertool41.txt
======================================================================
 +Schraubendreher 2.5mm,+ 
======================================================================
  +Holzs ge,+ 
======================================================================
  +Metalls ge( Metallfeile, Nagelfeile, Nagelreiniger ),+ 
======================================================================
  +Holzmeissel / Schaber,+ 
======================================================================
This is already way better to quickly recognize the actual differences. But if you still also want to see the common tools of the two knifes you need some visual help: One option is to use wdiff s --terminal (or short -t) option. Added words are then displayed inverse and removed words are shown underlined (background and foreground colors hardcoded as there is no invert colors style in CSS or HTML):

$ wdiff -t cybertool34.txt cybertool41.txt
Schraubendreher 2.5mm, Pinzette, N hahle mit Nadel hr, Holzs ge, Bit-Schl ssel( 5 mm Innensechskant f r die D-SUB Steckverbinder, 4 mm Innensechskant f r Bits, Bit Phillips 0, Bit Phillips 1, Bit-Schlitzschrauben 4 mm, Bit Phillips 2, Bit Hex 4 mm, Bit Torx 8, Bit Torx 10, Bit Torx 15 ), Kombizange( H lsenpresser, Drahtschneider ), Stech-Bohrahle, Kugelschreiber( auch zum DIP-Switch verstellen ), Mehrzweckhaken (Pakettr ger), Metalls ge( Metallfeile, Nagelfeile, Nagelreiniger ), Dosen ffner( kleiner Schraubendreher ), Kleine Klinge, Druckkugelschreiber, Grosse Klinge, Ring, inox, Mini-Schraubendreher, Kapselheber( Schraubendreher, Drahtabisolierer ), Holzmeissel / Schaber, Bit-Halter, Stecknadel, inox, Schere, Korkenzieher, Zahnstocher

But some still like to to use color instead of the contrast-rich inverse and the easily to oversee underlining. This is where colordiff comes into play: colordiff colordiff is like syntax highlighting for diffs on the command line. I works with classic and unified diffs as well as with wdiffs and debdiffs (the debdiff command is part of the devscripts package).
$ wdiff cybertool34.txt cybertool41.txt colordiff
+Schraubendreher 2.5mm,+ Pinzette, N hahle mit Nadel hr, +Holzs ge,+ Bit-Schl ssel( 5 mm Innensechskant f r die D-SUB Steckverbinder, 4 mm Innensechskant f r Bits, Bit Phillips 0, Bit Phillips 1, Bit-Schlitzschrauben 4 mm, Bit Phillips 2, Bit Hex 4 mm, Bit Torx 8, Bit Torx 10, Bit Torx 15 ), Kombizange( H lsenpresser, Drahtschneider ), Stech-Bohrahle, Kugelschreiber( auch zum DIP-Switch verstellen ), Mehrzweckhaken (Pakettr ger), +Metalls ge( Metallfeile, Nagelfeile, Nagelreiniger ),+ Dosen ffner( kleiner Schraubendreher ), Kleine Klinge, Grosse Klinge, Ring, inox, Mini-Schraubendreher, Kapselheber( Schraubendreher, Drahtabisolierer ), +Holzmeissel / Schaber,+ Bit-Halter, Stecknadel, inox, Schere, Korkenzieher, Zahnstocher
$ wdiff cybertool29.txt cybertool41.txt colordiff
+Schraubendreher 2.5mm,+ Pinzette, N hahle mit Nadel hr, +Holzs ge,+ Bit-Schl ssel( 5 mm Innensechskant f r die D-SUB Steckverbinder, 4 mm Innensechskant f r Bits, Bit Phillips 0, Bit Phillips 1, Bit-Schlitzschrauben 4 mm, Bit Phillips 2, Bit Hex 4 mm, Bit Torx 8, Bit Torx 10, Bit Torx 15 ), +Kombizange( H lsenpresser, Drahtschneider ),+ Stech-Bohrahle, +Kugelschreiber( auch zum DIP-Switch verstellen ), Mehrzweckhaken (Pakettr ger), Metalls ge( Metallfeile, Nagelfeile, Nagelreiniger ),+ Dosen ffner( kleiner Schraubendreher ), Kleine Klinge, [-Druckkugelschreiber,-] Grosse Klinge, Ring, inox, Mini-Schraubendreher, Kapselheber( Schraubendreher, Drahtabisolierer ), +Holzmeissel / Schaber,+ Bit-Halter, Stecknadel, inox, +Schere,+ Korkenzieher, Zahnstocher
(Coloured Screenshots done with ANSI HTML Adapter from the package aha.) Some, especially those who are used to git, are probably confused by the default choice of diff colors. This is easily fixable by writing the following into you ~/.colordiffrc:
newtext=green
oldtext=red
diffstuff=darkblue
cvsstuff=darkyellow
(See also /etc/colordiff for the defaults and hints.) colordiff has by the way two operating modes: So now let us compare the Cybertool 29 with Cybertool 34 in a normal diff (by using the texts from above and replacing all commata with newline characters) with git-like colors:
$ colordiff cybertool29-lines.txt cybertool34-lines.txt
12a13,14
> Kombizange( H lsenpresser
> Drahtschneider )
13a16,17
> Kugelschreiber( auch zum DIP-Switch verstellen )
> Mehrzweckhaken (Pakettr ger)
16d19
< Druckkugelschreiber
25a29
> Schere
Or as unifed diff with some context:
$ colordiff -u cybertool29-lines.txt cybertool34-lines.txt
--- cybertool29-lines.txt     2011-08-31 20:55:37.195546238 +0200
+++ cybertool34-lines.txt   2011-08-31 20:55:11.667710504 +0200
@@ -10,10 +10,13 @@
 Bit Torx 8
 Bit Torx 10
 Bit Torx 15 )
+Kombizange( H lsenpresser
+Drahtschneider )
 Stech-Bohrahle
+Kugelschreiber( auch zum DIP-Switch verstellen )
+Mehrzweckhaken (Pakettr ger)
 Dosen ffner( kleiner Schraubendreher )
 Kleine Klinge
-Druckkugelschreiber
 Grosse Klinge
 Ring
 inox
@@ -23,5 +26,6 @@
 Bit-Halter
 Stecknadel
 inox
+Schere
 Korkenzieher
 Zahnstocher
So if you want nicely colored diffs with Subversion like you re used to with git, you can use svn diff colordiff.

23 August 2010

Patrick Schoenfeld: Why do I use facebook and co?

Recently I blogged a serious complain about Facebook marketing practices.
I must note, that, while writing this, this is still a standing fact.
And it somehow leads me to the question why I use facebook (and similar portals like Xing or Meinvz at all) at all.

I would say that I'm a person, who values security. Probably I need to, because my job involves security aspects, even if its only to protect data.
Additionally I value privacy. I would never go onto a toilet in a glass case, where everybody could watch me doing my business.
The idea to keep the door to my flat open all the time would trigger all alarm bells inside of me.
But on the other hand I have a blog on which I write about technical topics, and personal topics. Like the death of my grandma or how my neighbours disturb me. And I use Facebook. And MeinVZ.

I'm well aware of how this makes it easier to trace me. How this could be used against me, if I happen to search for a job. Aware of the everlasting memorization of the internet who will keep this.. eventually forever.
And I have friends who have a serious antipathy against this and probably would never use such a portal at all.
So why do I use it?

That I started using that portals were some kind of peer pressure. I'm a person who likes beeing "thereby" and I like beeing present. Many of my friends were already using those portals and so I followed an invitation to use it, too. But I did think about several points:

I came to the conclusion that there are pros and cons for and against using these services. And I found that I can live with the cons due to the convenience they bring to me. And that I could always stop using them.

However: That does not mean that I have to "Eat or die" what they serve.

Oh and on a side note: I found "Facebook, Br ste und die Currywurst" to be an interesting article about the topic. Its a recommended reading, although only for the people who understand German.

21 February 2007

Ingo Juergensmann: Wireless Bridge Linksys WET54G

Ok, for some time now, I've been using my old Samsung Vm8100KXDT Laptop to connect my wired network to my Linksys WRT54GS router, which resides on another floor.

Well, if you read my old Drupal blog, you may have noticed, that I complained several times about my Netgear WG311T PCI card, being not able to be run in my PowerPCs. That's the reason why my Laptop was acting as a wired/wireless bridge (or more exactly a router between both worlds).

Today I bought a Linksys WET54G wireless bridge to replace my Laptop for that purpose. My Laptop was just too noisy and too power consuming and - even worse - the harddisk began to die. It was giving loud klackklack noises from time to time, resulting in a loss of DMA and therefore needed a power cycle afterwards.

Anyway, the WET54G is a nice small box with one antenna and one ethernet port. It is advertised as being a operating system independent device - which is clearly not true. You'll need a Windows PC to configure the device and it's quite awful to configure.

Instead of accessing the WET54G bei http, the CD-Rom contains a small program that scans the ethernet for that device. Next problem will arise when you want to configure your WLAN/WiFi settings. It is pre-configured to use channel 6 and infrastructure mode. Unfortunately, you'll need to first configure infrastructure or ad-hoc mode before you proceed to configure your ESSID, channel and b/g/mixed mode settings. Even worse because you can't change the channel or the mode when you have chosen infrastructure mode.

So in order to change your channel, you'll need to configure it in ad-hoc mode first, then change your channel and mode first, safe your settings, let the device reboot and continue with configuring infrastructure mode again.
Really badly tested piece of software, Linksys!

But beside of this huge annoyance the WET54G works quite nice once setup properly. Alas, I can't recommend it to buy for the above reasons.

Update:
After configuring it the first time, there actually is a webinterface, where you can configure the device with your favorite free OS. However, it was not accessible the first time to me, although I configured a Laptop to use the described default network in the manual. The above mentioned problems of not being able to configure the channel in infrastructure mode still exists in the webinterface.