Worthless Precision

Calculations show that Earth’s oil reserves will cease to exist at 20:58 on Oct 22, 2047. It is scary figure to see and it is probably as good of an guess as any. Saying this, it is also just rubbish. I will explain on example of thermometer.

My new kitchen thermometer shows me temperature of 19.3 °C. I think that all thermometers that you can buy show results with one decimal digit (with resolution of 0.1 °C). However, once I checked specification, I was puzzled. Precision of measurement is only ±2°C. Simply said it means that actual temperature is anywhere from 17.3 to 21.3 °C.

It is in human nature to assume that all that is shown actually matters. I can bet you that people would trust thermometer with five decimal digits more (e.g. 19.24133 °C) than one without them (e.g. 19 °C). It just looks better when our numbers have higher resolution. Real truth is hidden in precision. And that number is not always easy to find.

Time of oil exhaustion is nonsense for same reason. They showed it with resolution of one minute just to make it more believable. Real precision is probably give-or-take few years if not more.

P.S. Yes, we will run out of oil one day. We just cannot pinpoint date.

BIOS Feature

I have mandatory BIOS password on my work computer. Some Catbert character thought of it as good security feature. Now, whenever I need to reboot my computer, I need to sit next to it.

I used to grab cap of coffee while it was rebooting and all I needed to do was to log into Windows once that is done. Now I need to sit next to it through whole shutdown process waiting for BIOS password and only then I can get a coffee. If there is some update in progress, that waiting period usually puts me in “I will kill this guy” state. I really hate waiting…

During that useless time my mind often wonders to my first Pentium-class computer. There you could set “stealth” BIOS password (I forgot official name of that feature). If such password was set, system would boot up without asking for anything. Everything seemed normal until you tried to use keyboard or mouse - they were locked. Only once you entered your password BIOS would release control of PS/2 ports and Windows would take over. Since Windows worked normally even without password, you could rely on this feature even across reboots.

I have pretty good idea why that feature is gone - USB. BIOS can intercept and handle PS/2 keyboards quite easily even once Windows are up and running. Since Windows talk with keyboard over BIOS, it can choose whether to pass characters or not. With USB things get complicated.

Once Windows take over USB control (and that is fairly early in boot process) there is no simple way BIOS can restrict it. Only approach that would work in that case would be some hardware virtualization. BIOS would have control over physical USB and Windows would get virtualized version controlled by BIOS.

I am quite sure that someone would do it if there weren’t three big problems - compatibility, performance and cost. Compatibility would be easiest to solve. Performance (latency) could be lowered by employing ASICs. However cost to do that would be high. And all that because of feature that is not that necessary to begin with.

Sometimes I long for simpler times… :)

Full Width Toolbar

As I ventured into WPF world, some things annoyed me more than others. One of those things was inability of toolbar to have no grip and to be full width.

After some time I found solution for grip problem. Just put toolbar in toolbar tray and set IsLocked attribute to true.

<ToolBarTray IsLocked="True">
    <ToolBar>
        ...
    </ToolBar>
</ToolBarTray>

Extending it’s width proved to be little bit more engaging. It took me a while to notice ActualWidth property of ToolbarTray control. As name says, it will return you actual width of ToolbarTray.

Since we want toolbar to span whole window, it should be inside DockPanel (and docked to top). Synchronizing ActualWidth of ToolbarTray and our Toolbar is then solved by simple data binding:

<DockPanel?
    <ToolBarTray IsLocked="True" DockPanel.Dock="Top">
        <ToolBar MinWidth="{Binding RelativeSource={RelativeSource AncestorType={x:Type ToolBarTray}}, Path=ActualWidth}">
            ...
        </ToolBar>
    </ToolBarTray>

    <Grid>
    </Grid>
</DockPanel>

Sample with everything done (and few things more) is here.

Got a Key?

Starcraft II has it’s release date confirmed. It will be available for general public on 27th July. Of course that probably means that I (a resident of Croatia) will not get it until some time later.

Detecting 64-Bit in .NET 4.0

In previous versions of .NET we could check whether process is 64-bit or not. It is not obvious solution - we check length of pointers.

With .NET 4.0 there are two new properties in Environment class. Is64BitProcess returns true if we are currently running in 32-bit mode. It is equivalent to our old-style check of IntPtr.Size == 4.

Is64BitOperatingSystem is something completely new. It will return true if operating system is capable of running 64-bit programs. This opens possibility of detecting 64-bit environment even if we run in 32-bits ourself. It will not be used often but it is good thing to have when e.g. running other processes.