When doing integration testing or fixing a bug in a piece of Java code that uses Oracle as a database, being able to do quick exports and imports of your schema can be a big help. Sometimes just calling Oracle’s imp/exp commandline tools from your code can be of help, but I was looking for something a bit more portable and less demanding on my local development machine. I found that Oracle’s datapump functionality can be called from stored procedures, which in turn can be called from a normal JDBC statement.
Author: rolfje
Arduino and the QVGA 2.2″ TFT SPI screen
I went through all the struggles everybody else seems to be going through to get this screen connected to my Arduino Nano. I had the 5V to 3.3V voltage conversion problem, and the “only works with software interrupts” problem which makes the display run slow. The solutions are not complicated but not very wel documented. Until now.
IARU Region 1 Bandplan up to 500MHz
For some reason I have trouble finding a document which lists the complete IARU Region 1 Band Plans. To end my “can I transmit here” quests, I’ve combined the information from several resources into a usable graphical representation of all Amateur Radio bands and modes up to 500MHz. I’ve not listed bands above 500MHz, please post links to those in the comments if you have them.
Exact use of a frequency may differ in your local region, so always listen first.
Hand me a napkin
It’s not until you or someone very close to you becomes dependant on a wheelchair until you notice that the world is not as wheelchair friendly as you might think. Hotel rooms are wheelchair accessable, but the lobby can only be reached by stairs. People with kids can take strollers all the way up to the airplane seat, but people in wheelchairs need to magically heal themselves and leave the wheelchair at the gate.
But this is not a rant about inconsiderate travel company employees. This is about helping people with “a challenge”, as our funny American neighbours tend to call it. And no, this is also not a rant about helping in a big way, raising a million for a cause, getting all the local supermarkets to give away groceries to people in wheelchairs, or TV shows selling tear-jerking advertisement minutes while building a house for a familiy who really needs it.
No, this is about the little things. Things that make you and me different. Things that require only a little twitch of a muscle for healthy people. Quirky things like aligning the napkin to the edge of the table, or petting a cat, or getting a different color straw because it doesn’t match the color of your shirt.
Imagine you had to ask somebody to align your napkin to the edge of the table. That person would find you demanding, and because he doesn’t see what’s solved by doing that, it’s very likely that the napkin will never move. Soon, you will stop asking people to do the little things that used to make you who you were.
It’s a tough choice. Loose friends because they think you’re too much of a demanding prinsess, or loose friends because you stop being you.
When you see or know somebody in a wheelchair, remember that their mind still wants to do those quirky things that make them who they are. It’s okay to say no, but please consider this little blogpost when somebody asks you to straighten their bracelet or clean their glasses.
The world does not need one-time big-mouthed Facebook-selfie heroes. The world needs polite people who can discretely hand over a napkin without asking what’s it for.
Print posters on a regular printer with Excel.
I recently needed to print out a big schematic diagram of the RX/TX board of a Kenwood TS50 Transceiver. This did not fit on a single piece of paper. Instead of downloading all kinds of crappy tools or uploading the image to some “free” site which is going to use it for whatever they think justifies their definition of “free”, I found out you can do this in Excel. Here’s how:
- Make sure the image you want to print out as a poster has a decent resolution
- Open Excel (maybe this will work in LibreOffice too, I haven’t tested, let me know)
- Drag the image into a new worksheet so that it is top-left of the sheet.
- Open the “Print preview” (the little icon in the bottom left of the window)
- Resize the image so that it covers more than one page, up to the number of pages you’d like the poster to be. Your screen should now look somewhat like this:
- Optional: Adjust the page margins.
- Print.
After this, you’ll be gluing the pages together, but I think you already figured that out beforehand.
Have fun!
Open a port in OSX Mavericks’ Firewall
The new firewall in Mavericks is great. For the common user. For a developer, not so much. If you are a Java developer like me, and you just need to open one port (say, 8080) so that the web application you’re working on is accessable from another computer, you can’t. I disabled the Firewall altogether for a few days, but it didn’t feel right.
I googled around and to make a long story short, here’s how to open port 8080 on any interface to any application on your OSX Mavericks installation in 3 steps:
sudo vim /etc/pf.conf
Then add the following lines at the end of the file:
# Open port 8080 for TCP on all interfaces
pass in proto tcp from any to any port 8080
Test (and, according to the documentation, load) your edits with:
sudo pfctl -vnf /etc/pf.conf
Reboot.
(I have found at least 5 pieces of voodoo to make the Firewall restart and reload, but none of them seemed to work reliably, so pardon the reboot)
You can close it by commenting out the lines in pf.conf and reboot again. If anybody knows of an easier way to do this, preferably in one terminal command, and without rebooting, let me know.
Hope this helps.
There’s life without Google. Or iCloud. Or Facebook.
Regular readers of this blog already know that I am not using dropbox, and I was an Evernote user, but recently decided it became to dangerous and replaced it with my own scripts. I had an interesting discussion on Twitter which made me decide to show you how I run my digital life without the help of Google, Facebook, Dropbox, Whatsapp or iCloud, and still be able to have all the functionality these services offer.
The search was hard and sometimes I need to reconsider some of the choices, but the last few years the selection of products was very stable and the setup has worked flawlessly. Searching for a secure replacement for Whatsapp or Google? It’s in here.
Read More “There’s life without Google. Or iCloud. Or Facebook.” »
Replace Evernote with Spidernote
In the past I have used Evernote extensively, it really helped me in my research for this blog and keeping track of meeting notes, todo lists and even making pictures of whiteboards at work searchable. As a product, there is no note taking app that can beat Evernote. But there is a little problem that has become a deal breaker for me, and that is basically the NSA and the way Americans, and particularly the American government seems to think about people’s privacy and online security.
Evernote is an American company, which sadly has to comply with whatever ridiculous request by the U.S. government to turn over data of innocent people all over the world (yes, even outside the U.S. border, I know, it’s amazing). This, combined with the fact that Evernote clearly can not use zero-knowledge encryption because of the services it provides, makes that all the data you and I put into Evernote are at NSA’s fingertips at all times. If you find that as scary as I do, and you have a Mac, there is a way to solve this.
From the Finder to the Shell (and back)
A quick tip for OSX users out there who frequently need to open a Terminal window for the current location in the finder, or the other way around:
Install the free application from the App Store: Go2Shell. It will give you an icon on the toolbar of your Finder, and pressing it will open a Terminal window and automatically change it’s directory to match the Finder’s location.
The other way around is easier; you can already do that on any Mac. Simply type “open .” (that’s the word “open”, followed by a space and a period). This command will open a Finder window for the directory location your Terminal window is in.
Bonus tip: Also check the “open -t [filename]” command, it will open your system’s default text editor with the given file.
Anonimatron: Quick Start
After reading my last blogpost on Anonimatron, you must have asked yourself “Great, but how do I actually use Anonimatron to de-personalize my database”? I tried my best to make basic Anonimatron configuration as self-explanatory as possible, just start it without any command line arguments and it will tell you.
Less adventurous or in a big hurry? This blogpost will show how simple it is to install and configure Anonimatron on an example MySQL database.