A colleague pointed me to a blog entry on a blog by the VP of VMWare. It talks about a new “replay” feature in the next version of VMWare — you can record the execution of your VM to a file, and then replay that file later. This will reproduce the VM’s execution exactly as it happened the first time. This is an unbelievably cool feature for debugging things like memory stomps and race conditions.

When trying to find a bug, the easiest way is to run it in the debugger, put breakpoints near where you think the problem is happening, and then run it, hoping that it fails the same way that it did before. If it doesn’t, well, try again, or tweak some part of the test case to try to cause it to be more reproducible. If it’s a race condition, it’s highly possible that attaching the debugger or tweaking the test changes the timing enough that the problem never shows up. With this thing, once you’ve reproduced a problem, you could then replay it (in the debugger!) and step through the code, knowing that the problem will reproduce. You can step “back in time” to just before the problem occurred, and then step through the problem as it happens. According to the web site, the recording process has no effect on the speed of the VM. This is not possible according to the Heisenburg Uncertainty Principle, which, strangely, is specifically referenced in the article. Ah, what did he know, anyway?

Apparently it doesn’t have SMP support, so if your problem is SMP-related, this won’t help you. But it looks like a very nice piece of software engineering, so kudos to the VMWare people!

I made the big email switch this week, going from Outlook to the brand-spankin’ new Thunderbird 2.0. My company actually uses Lotus Notes as the “standard” email client, but after a few years of using that, I found that it sucked rocks, so I took a week and switched to Outlook. First I politely asked IT to set me up with an IMAP account, which let me access my network-stored email folders from Outlook. They did that, and I used that to suck down all my archived mail. Then I abandonded IMAP and went to straight POP, and life was good… for a while.

I think it was when I upgraded to Office 2003 that things started to go bad again. Every now and again, I’d go for several hours without receiving any email, and discover that Outlook simply stopped checking, or something. I would shut down Outlook and start it up again, and then it would download all kinds of stuff from the previous few hours. It also took forever to start up Outlook (as much as several minutes sometimes), and the search capabilities were terrible, although I found a tool called LookOut that solved that problem. However, Microsoft bought the company that made Lookout, and changed the product into something called “Windows Desktop
Search”. Apparently Lookout itself is no longer available. I still have an install though – email me if you want it.

I started using Firefox as my default browser several years ago, and I love it, so when I found out that the same team made an email client called Thunderbird, I immediately downloaded it. I tried using it for a couple of days, but I could never get the LDAP stuff working, so searching the company address book for a name would not work. This was a big pain, so I decided to wait until that bug was fixed, and I went back to Outlook. A year or two later, I tried it again, and ran into the same problem. I asked another guy in my department how he got his to work, and he had no idea, it just did. Then we looked at mine, and it just didn’t. We even went so far as to use a packet sniffer and point Thunderbird at a perl script that my boss wrote that acted as a proxy to the real LDAP server, and got nowhere with that either. After more searching, I found that this was a known bug in Thunderbird — the LDAP stuff did not work if IPv6 was installed on the machine. Since I was working on IPv6 for SQL Anywhere, I had it installed, which explained why it didn’t work for me. I followed the progress of the bug for a while, and found that it was not going to be fixed until Thunderbird 2.0, so I had to shelve my plans to switch to Thunderbird yet again, though I did switch to using it as my newsreader at that time, and have been pretty happy with it in that capacity.

When I heard last week that Thunderbird 2.0 was being released, I got all excited, and downloaded it immediately. I tested the LDAP support and it worked, and it (relatively) seamlessly imported all my Outlook contacts and mail, and I’ve been using it for a week now. Honestly though, other than being faster than Outlook, I can’t say I’m noticing much of a difference. It’s better at dealing with junk mail, but I prefer Outlook’s addressing — the To and CC lists consist of a single (expanding) text box where you can enter names separated by semicolons. The names are then expanded, and if more than one match is found, Outlook underlines it and you can right-click to choose the correct one. With Thunderbird, each address is listed on a separate line (so if you’re sending an email to 20 people, you have this huge list of names, rather than one text box). When you enter a short form, it searches your address books until it finds one that matches, and then replaces the name with that address and stops searching. If I type “Kurt” to send an email to the guy in my department named Kurt (who wasn’t in my personal address book), it searched the company directory, found someone named Kurt (probably the first one alphabetically), and used that address. There is no indication that the name wasn’t unique. However, you can click “Contacts”, which opens up a little sidebar that gives you similar functionality. I’m sure I’ll get used to it and it’ll be good enough — I’m just used to the way Outlook did it, not requiring the extra sidebar.

I should probably have waited until 2.0.1, or at least until a patch or two was released, since it crashes now and again, and I’ve even seen the same behaviour that I saw with Outlook — no email downloaded for a long time, but no error messages to say why, or even to indicate that there was a problem. But updates to Outlook were few and far between, while I’m sure there will be fairly regular updates to Thunderbird, so I’m going to continue with Thunderbird on the assumption that these irritations are a bit of short term pain that will eventually result in long-term gain. At least I’m supporting the open source community! That’s good, right?

Maybe I’m naïve, but I just don’t get the big deal with open source software. I think it’s great that people are willing to put their time and effort into writing it, documenting it, and supporting it, but there are people out there that believe that all software should be open source, and that commercial closed source software is generally a Bad Thing. While I can certainly see the advantages of open source software, I make my living writing closed source software. It’s fairly simple: if Sybase didn’t make revenue selling SQL Anywhere, I’d be out of a job.

Thinking about it a little more, I’m quite sure that I am naïve when it comes to open source, because I don’t think I understand how it works. The extent of my knowledge about the process is this: there is a code repository somewhere on the web, and anyone can sync up to it and make changes to the code. But are there regular code reviews? Are there people checking every code submission to see if someone is adding bad code or trojans or anything like that? Who checks all the different platforms? Who runs regression tests to make sure that new features aren’t breaking old features, or that performance isn’t being affected? Who decides which
new features go in and which ones don’t? Surely there must be a full-time team of developers and managers that oversee all of these things, but how do they get paid? Who can afford to take on a full-time job that pays nothing? Is the open source world entirely populated by rich developers who don’t need an income? I doubt it. Is it enough to have advertising on the web site and a “Please donate” button with a link to PayPal?

I just checked the OpenSSL web site, and it says specifically that the project is volunteer-driven. The Apache Software Foundation is a non-profit charitable organization, and their annual reports (complete with financial information) are listed on their website. However, according to the 2006 report, every officer of the company received $0 compensation, and the total revenue of the entire organization was under $150,000. Total compensation, wages, and benefits were $0. Again, are they all rich and don’t need incomes? How do you squeeze in being a director or VP of such an organization if you already have a full-time job elsewhere?

I’ve been a professional software developer for over 15 years, so I probably should know the answers to these questions, and I’m feeling rather stupid that I don’t. If you do, please leave a comment and let me know how this works. Maybe I should stick to blogging about my kids or sports.