Category Archives: Personal

100Mb/s glassfibre to my home

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In our Nijmegen area glassfibre has recently been installed. Last weekend the new connection to our home was activated. According to the specification the speed should be 100Mbps both ways, i.e. up and down. That is the same speed that I (and most people probably) have on my desk at the university. I have done some preliminary tests that I want to report on.

According to http://speedtest.net, the down speed is ~95Mbps and the up speed is ~60Mbps. I have repeated that a couple of times, and the throughput varies over the day. These numbers are the best ones observed.

I have also tested using ftp, sending/receiving a 100MB file to/from the ftp server of the Donders Centre for Cognitive Neuroimaging. This results in 7.22MB/s or 60Mbps upstream and 7.77MB/s or 65Mbps downstream (see below for details).

The same test from my PowerBook G4, which is connected over 802.11g wireless to an Airport Extreme router, resulted in 2.5MB/s or ~20Mbps upstream and 1.56MB/s or 13Mbps downstream. The bottleneck here clearly is the wireless connection, and not the glassfibre.


ftp> put testfile.bin
local: testfile.bin remote: testfile.bin
200 PORT command successful. Consider using PASV.
150 Ok to send data.
100% |*************************************| 100 MB 7.23 MB/s 00:00 ETA
226 File receive OK.
104857600 bytes sent in 00:13 (7.22 MB/s)

ftp> get testfile.bin
local: testfile.bin remote: testfile.bin
200 PORT command successful. Consider using PASV.
150 Opening BINARY mode data connection for testfile.bin (104857600 bytes).
100% |*************************************| 100 MB 7.79 MB/s 00:00 ETA
226 File send OK.
104857600 bytes received in 00:12 (7.77 MB/s)

Overall I am pretty happy with these initial results of 60Mbps up and downstream in a realistic test, i.e. 60% of the theoretical throughput. I am not sure whether I have been able to connect to a server that does not introduce a bottleneck itself, and there is some variance in the tests itself that is due to other traffic over the network. I might post some more tests later.

More information can be found on http://www.glazenkamp.nl

Moved homepage

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UPDATED on 28 October 2012.

My personal homepage has moved to a new webserver and can now be found at http://robertoostenveld.nl.

Some other and older homepage addresses that over the years have disappeared, or that hopefully would refer you to the most up-to-date location of my homepage are:

  • http://sccn.ucsd.edu/~roberto
  • http://www.mbfys.kun.nl/~roberto
  • http://www.mbfys.ru.nl/~roberto
  • http://miba.auc.dk/~roberto
  • http://smi.auc.dk/~roberto
  • http://oase.uci.ru.nl
  • http://robertoostenveld.ruhosting.nl
  • http://oostenveld.net
  • http://oostenveld.org

Mac Mini with EyeTV

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After a long period of doubt, last December I finaly decided to buy a Mac Mini as home entertainment system. It arrived soon and sofar it completely lives up to my expectations. I am using it together with a NEC LCD screen at the moment (which will be replaced by a 23″ Apple Cinema Display soon) and Elgato EyeTV. The EyeTV software can be controlled with the Apple remote, and resembles the FrontRow interface. However, EyeTV is not completely integrated with FrontRow: the two full-screen menus are seperate from each other. A small nuisance is that pressing the “menu” button on the remove short opens FrontRow, pressing it long opens the full-screen EyeTV menu interface opens. When watching TV, I sometimes accidentally press short instead of long, resulting in the FrontRow menu opening instead of the EyeTV menu.

I am using EyeTV together with a Plextor M402U Convert-X tuner. The Plextor tuner is one of few tuners that connects through USB and that is also compatible with both Linux and Mac OS X. I originally bought the tuner to be used with my old Dell laptop and Linux PVR software like MythTV. After fiddling around for multiple evenings, I got it to work but I found the software not of sufficient quality. The Dell laptop works fine with linux, but it did not convince me to be usefull on a daily basis. I did not even dare to try to convince my girlfriend . What a difference when I installed Elgato EyeTV op my Apple PowerBook: just plug-and-play and it works like a charm. Also the electronic program guide in EyeTV (using tvtv) works well. Actually, I consider this EPG to be quite important for serious PVR use.

To test out the dual tuner support in EyeTV, I borrowed a second tuner from a German friend: a Miglia TV-Mini. It is a DVB-T tuner for digital through-the-air broadcasts. In the Netherlands these broadcasts are carried out by Digitenne. I had previously read somewhere on the internet that Digitenne would not work at all with such a device, since all all stations (including Nederland 1, 2 and 3) would be scrambled. However, after doing the auto-setup, it did find a list of ~30 TV and ~20 radio channels! It gives a very sharp picture and has less of a delay than the Plextor tuner. So also digital trough-the-air TV works fine with the MacMini/EyeTV setup. Note that most of the channels are actually scrambled, only the public stations (Nederland 1, 2, 3 and TV Gelderland) are not scrambled. Regarding radio, the same applies: only Radio 1-5, the Concertzender and Radio Gelderland are available unscrambled. The others are listed with a “$” sign behind them, but this is already more that I had expected. To decode the scrambled signals you probably have to get a Digitenne subscription for the smartcard. This Miglia TVMini is a USB-stick sized decoder and cannot be used with a smartcard for decoding, but there are other tuners that can (e.g. Elgato 410).

To conclude, I am very happy with my Mac Mini. It works great for watching movies and listening to music (both using FrontRow) and for watching and recording TV using EyeTV and the Plextor tuner. The dual tuner support is still in beta stage (I am using EyeTV version 2.3.1) but the first impression is OK. I only hope that Apple will open up the FrontRow interface so that other high-quality products like EyeTV can be integrated in it, which would even improve the user experience as a “audio-visual media appliance” instead of as computer.

Prevent spam when giving your email address

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There are a couple of usefull web services that I want to share with you.

http://www.spamgourmet.com. Create disposable email addresses on the fly. You only have to create an account once on the Spamgourmet website, and from then on you can create disposable email addresses whenever needed. E.g. when you have to register on a website and are required to give your email address for a confirmation mail, you can at that moment think of and fill in a new email address. The confirmation email that is sent to your spamgourmet account will then be forwarded to your real account. The sender never sees your real address and after a ceirtain number of emails (that you specify), further undesirable email (spam) from that sender will be blocked.

http://www.mailinator.com. Create disposable email addresses on the fly. You can read the emails on the Mailinator website, no mail is forwarded to your real account. Your temporary email account will be automatically deleted after a few hours. It usage is similar to Spamgourmet, except that you do not have to register. The difference is also that anyone who can guess your temporary email address is able to read it (no passwords) and that mail is deleted after a few hours, whereas Spamgourmet forwards it to your real mail account.

http://www.yousendit.com. Share large (up to 1GB) files with other people. No passwords to share, no software to install, no accounts to create, and no full mailboxes. Your file is uploaded to their website and the recipient gets an email address with the obfuscated link where he/she can dowload your file.

Backing up my iPod mp3’s

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Note: prior to applying the script below, read all the way through to the bottom. There you will find an important update!

I recently bought a 60GB iPod photo, and encountered the problem that the iTunes “synchronisation” does not really work for me: I can store many more files on my iPod than I have space available on the hard disk of my PowerBook. Therefore, I decided not to use the “synch” option in iTunes and to do it manually … so far, so easy…

Recently I accidentally pressed the “automatically update” button in the iPod preferences in iTunes. To my horror suddenly it started deleting 20GB of mp3’s that I copied on my iPod and that I did not have on my hard disk any more 🙁

To prevent this accidental deletion of the files on my iPod, I made the following backup script. It uses low-level unix command line tools, and creates a “hard link” for each file on the iPod. The hard link does not prevent the file from being deleted using iTunes, but at least it ensures that the mp3 data itself is not erased. I.e., it is simple to add the mp3 back to your iTunes music collection on your iPod.

The hard link is similar as a copy of the file, except that only the pointer to the file is copied, the data is left alone. Therefore a hard link does not occupy additional space on your iPod. If you edit the ID3 tags of a file, the iD3 content of both the original file and of the hard-linked copy will be updated.

The following script creates the hard links in a subdirectory with today’s date as the name. Copy and paste it into a text file with the name “ipodbackup”, set the permissions to “execute” (e.g. chmod +x ipodbackup) and you can execute it from the terminal command line to make a backup of all files on your iPod prior to adding new mp3’s.

#!/bin/sh

IPOD="/Volumes/Robert Oostenveldâ~@~Ys iPod"
SOURCE="$IPOD"/iPod_Control/Music
TARGET="$IPOD"/Backup/`date +'%Y%m%d'`

# create the directory that will contain the backup
mkdir -p "$TARGET"
cd "$TARGET"

# create the subdirectories that conatin the mp3's
find "$SOURCE" -type d -mindepth 1 -exec basename {} ; | xargs mkdir

# create the hard links in each subdirectory
for subdir in F* ; do
echo linking `ls "$SOURCE"/$subdir | wc -l` music files in directory $subdir
ln "$SOURCE"/$subdir/* "$TARGET"/$subdir
done

Important update (12 Aug 2005): After applying the script and making all the hard links, I discovered that they confuse the software on the iPod. It will not play the songs any more, although they still appear correctly in both iTunes and on the iPod when disconnected. Also, iTunes is still able to play the songs. To solve this, I had to copy all the songs off and reimport them in iTunes and on the iPod. So the backup script does not work as I hoped 🙁