About me
Technical details

About me

My name is Cvetan Ivanov and I'm the sole developer and maintainer of this site.

I've spent the past 12 years working as a System Administrator/Network Engineer in a major ISP/Telecom company. There I've been doing many things ranging from mail and web server administration to configuration of interconnections with other telecoms over SS7 protocol and developing billing systems.

But around the end of 2008 I've decided that it's worth at least trying to see what it's like to be your own boss and quit my job.

There are a lot of things that I can do, but it boils down to either doing consulting/contracting type of work or developing something from scratch (or getting another permanent job, but that probably won't happen for some time).

I got addicted to the VOR game in the meantime, and then came the idea of developing some software for it. Writing code to try and win the game is not exactly my cup of tea, so I thought about some kind of service. But developing subscription - based service did not look like very good idea either, for various reasons.

So I just decided to see if it would be possible to create something useful that people really like, and see what comes out of it.

It has been a great experience so far. Remembered some forgotten programming and administration skills and got some insight on things technical people don't usually care too much about - marketing, customer care, planning, and project management in general. And have met a lot of interesting people too.

This site is built entirely with open source software (linux, lighttpd, perl, postgresql, gcc, postfix and many other tools and libraries) and publicly available data (GFS Weather model and GSHHS shoreline data, both provided by NOAA.gov), but large part is still written from scratch - like the optimizer itself, the map and wind tile rendering and the client-side javascript.

I have some real sailing experience too - I've spent few summers as charter yacht skipper 15 years ago. Now more into windsurfing, but should try the real thing again some day.

Thanks to my web designer friend. The site would not be the same without the clean look. Drop me a note if you like the graphic design and want to hire her to do something like it for you.

And thanks to all the people who have helped with bug reports, suggestions, corrections, donations or even a brief "Thank you" note.

Fair winds in the game and in the real sea.


P.S. You can find me at Facebook and LinkedIn

Technical details

2009-05-20 11:30 CET

The site hit its performance limit and became a bit sluggish for the first time today at 11AM after the wind change when the fleet was rounding the mark.

I received a kind offer for help during that time, and had written brief answer about hardware, performance tricks that I've used and possible scaling options. There probably are more people who will be interested about those things, so here is the answer (with few changes):

It may sound funny, but the site still runs on the same machine on which I'm typing this message right now - my home workstation. 3.16GHz E8500 Core 2 Duo CPU with 8G of RAM and single hard drive, running 64-bit Linux.

The real bottleneck is the CPU. Each simulation run takes up to 2 seconds, so the limit is serving 1000 people in the first 10 minutes after the wind change, and I think that this limit was reached for the first time 20 minutes ago when the mouse pointer became a bit unresponsive.

2500 hits on the chart page in the last 30 minutes, but not all of those run the simulation, as same data is used for the different zoom levels (cached in a database).

I've applied expiration times to the image files very carefully, and they are also small - 1-bit for the winds and 2 or 3-bit for the background chart PNG files, so the bandwidth is relatively low - about a 1 Megabit at the last peak after the wind update when all browser caches expired simultaneously and started loading the new forecast.

The internet connection itself is PON Fiber to the home by my former employer, Spectrum Net Jsc and should be able to easily handle 10 times more traffic than this.

The simplest way for scaling up is probably running the optimizer and maybe the fastcgi perl scripts, on remote machines. The only problem is that the generated image files are stored like disk files right now, but they can easily go to the database.


The site is becoming quite popular and needs hardware upgrades now and then. Donations allow me to keep up to date and provide reasonable performance and response times even during peak load.

Collecting some donations also allows me to continue developing and supporting the service for a while without feeling guilty for staying unemployed for months or going back to dull things like debugging SS7 stacks ;).

PayPal, amount in EUR
PayPal, amount in $ US
PayPal, amount in £ GBP
Bank TransferI've always thought that international bank transfers are prohibitively expensive for smal amounts with their initial fees of 15-20 EUR.
This has changed for countries in the EU, but the news of Bulgaria joining the union may have not made it to the bank sector. At least the banks here act like they've never heard about it.
Please let me know if I'm wrong and I can provide BIC+IBAN numbers.
ePay is the largest Bulgarian online payment operator. Verified by Visa.
Accepts Visa/MasterCard without user registration.
20 BGN is around EUR 11 / $15 USD at the current exchange rate and you can change the amount.

Any amount is greatly appreciated. Thanks.

Copyright 2009 by ZEZO.ORG. All Rights Reserved.