Charles Nadeau: My Software

Continuing the conversion to Gentoo

Wed, 11 Jun 2003 04:29:43 GMT

I finished installing Gentoo Linux on 3 of my old Linux boxes (2 to go). It runs very smoothly. I am really impressed by Gentoo Linux. I am upgrading my OpenMosix kernel to 2.4.20-3 and I face some little quirks. Hopefully they'll be resolved soon.
I also finally configured succesfully distcc. Not every ebuilds use it: MySQL doesn't but ntp does. I guess it's a case-by-case type of thing. Hoepully X and KDE will take advantage of it otherwise it will take a week again to compile everything...
I'll get one more used PC tonight: an IBM PG300GL. It will likely replace one of my old Digital PC5100. Or it may be added to my cluster. I'll see...
I'll probably have to go on a business trip next week, to be confirmed.

Two machines converted to Gentoo

Mon, 02 Jun 2003 04:05:48 GMT

Spent most of the week-end finishing and fine-tuning my installation of Gentoo Linux on two old boxes I have. It is very stable and more responsive than Red Hat 7.3 I used previously on these two boxes. The only drawback is that I now have two OpenMosix clusters: One with three machines running Red Hat 7.3/kernel 2.4.16 and one with two machines running Gentoo 1.4_rc4/kernel 2.4.20. I'll probably start to convert one more Red Hat machine to Gento tonight.
And the rest over the next week-end. I am also discussing with somebody about getting 6 more machines!
The only major problem I had was with distcc. I just couldn't make it work. I followed the instructions, tried many things but it just won't distribute. I'll have to simply rely on OpenMosix to distribute task on the machines of the cluster. This do works. I used it to compile Samba without any problems at all.
I am also thinkering with the idea of installing Blender on all my Linux machines to distribute the load when rendering. I discovered a very nice utility allowing the distribution of a blender job on an OpenMosix cluster. I'll try this one over the week-end too.

I installed the SpamBayes plug-in for Outlook

Tue, 27 May 2003 01:42:16 GMT

I just installed the SpamBayes plug-in for Outlook. Like Jon Udell, I think it just rocks. The fact it relies on the words of the content and their occurences protects me against spam especially well since most of my friends and familly are writing to me in French while 99.9999% of the spam is in English. In this case, ham and spam don't even use the same words corpus!

Installing Gentoo

Fri, 23 May 2003 03:24:18 GMT

I am installing Gentoo Linux on one of my PC at home. Things went pretty well except at the beginning where I was looking for a simpler way to bootstrap the process since I couldn't boot from the CD. I finally found a way using the Slackware boot disks.
On this puny P166MMX/192MB it took almost 36 hours doing scripts/bootstrap.sh then emerge system.
Now I am compiling the OpenMosix kernel. It is not very fast but at the end, I'll have a system completely tailored to my need.

Trying to install gentoo

Mon, 19 May 2003 12:33:21 GMT

I tried to install Gentoo tonight but I have a problem burning a bootable CD from the ISO files available. I posted a message about it on the Gentoo forum. If you read it and have a solution, let me know.

Gzip support for Radio

Tue, 13 May 2003 06:05:11 GMT

It seems there is a gzip plug-in for Radio. Anybody out there with the URL?

Autocompletion in the command prompt!

Sun, 11 May 2003 12:09:07 GMT

Autocompletion in the command prompt!.

Roy Osherove posted a link to some cool Registry settings. One of them I found quite usefull: Enable AutoCompletion in Command Prompt. Once this setting is done, you can use the tab key for autocompleting while typing in the command prompt (cmd)! For example you type "cd c:\progr" (without return) and press the tab key, "progr" will be completed to "Program Files".

To enable this setting, change the following key in the registry:
HKEY_CURRENT_USERSoftwareMicrosoftCommand ProcessorCompletionChar
Change this value (or create the key, DWORD) to 9.

[.NET Weblogs]

Outstanding trick!

Programatically transfering pictures properties

Sun, 11 May 2003 11:23:32 GMT

Transferring properties to a thumbnail image.

A while back, I created a simple console app for thumbnailing photos for posting on my family Web site. The application simply asks for a directory and a reduction percentage, then looks for any images in the directory provided and reduces them by the requested percentage.

This was fine as far as it went, but I realized after a colleague, Ryan Trudelle-Schwarz, requested copies of some of the photos I'd thumbnailed with this app, that I had neglected to correctly transfer the properties from the old image to the newly-created thumbnail. Given that digital cameras like mine (a Nikon CoolPix 4500) provide a lot of information in the properties, from photo info like focal length, exposure time, and ISO speed to important stuff like the date the photo was taken (as opposed to the date the file was last copied/altered).

Given that the app did mostly what I wanted, I didn't tackle the property transfer until recently. I was pleased to find that as with most stuff in .NET, it was pretty easy, once I stopped trying to fight the platform (I initially tried doing a For loop with a counter variable, but wasn't getting the PropertyItems populated that way). My initial successful code took advantage of a neat feature of arrays (the properties of an image are stored in an array called PropertyItems) called Enumerators. Enumerators, which implement the IEnumerator interface, allow you to easily traverse the members of an array or collection much the same way as you would a recordset or a DataReader. The code below gets an enumerator for the PropertyItems array of an instance of System.Drawing.Image that is created from the image being thumbnailed, and then calls the SetPropertyItem method of a new instance of System.Drawing.Bitmap that will contain the thumbnail version of the image:

        Dim imgPropEnum As System.Collections.IEnumerator = img.PropertyItems.GetEnumerator
        While imgPropEnum.MoveNext()
            bmp.SetPropertyItem(imgPropEnum.Current)
        End While

In a subsequent email, Ryan suggested the following code, which is a little cleaner, and perhaps more like what a VB programmer would expect to use:

        Dim PropItm As PropertyItem
        For Each PropItm In img.PropertyItems
            bmp.SetPropertyItem(PropItm)
        Next

Either will work, and both are examples of how simple tasks graphics-related tasks are in the .NET Framework. The trick, as I discovered, is to work with the framework, rather than against it.

As an aside, while I was playing with the code above, I also took a look at the GetThumbnailImage method of the Image class, but found that the method appears to both reduce the size of the image and compress it, such that the resulting image quality is fairly poor. In all fairness, the MSDN docs for the GetThumbnailImage method does warn that

GetThumbnailImage works well when the requested thumbnail image has a size of about 120 x 120. If you request a large thumbnail image (say 300 x 300) from an Image object that has an embedded thumbnail, there could be a noticeable loss of quality in the thumbnail image. It might be better to scale the main image (instead of scaling the embedded thumbnail) by calling DrawImage.

but I was hoping that the code for creating a decent thumbnail would've been as simple as a single method call, perhaps one overloaded to allow both compressed and non-compressed thumbnails. Not that it's all that difficult to scale an image in .NET, of course. I guess I've just gotten spoiled by how much the framework classes do for the developer that now I expect them to do everything. Perhaps in version 2.0.

[Listening to: How Blue Can You Get? - B.B. King - The Best of B.B. King [MCA] (05:09)]

[.NET Weblogs]

This is a very cool trick as I take tons of pictures that I shuffle around and manipulate a lot. I could use this trick in a script that is applying a series of "steps" to a fixed set of pictures.

T-SQL trick

Wed, 07 May 2003 04:11:57 GMT

T-SQL Tip of the day.

Just to test the w.bloggar tool with this blog and because it's always nice to have something to say, I thought why not post a nice T-SQL Tip. (It works on Oracle too btw)

Optional parameters
When you have a table, say Orders (as in the Northwind database which comes with SQLServer), which has more than 1 foreign key (FK), it is typical that developers will query the Orders table based on a combination of these FK fields. However, as with the Orders table, this can be quite cumbersome when there are a number of FK fields. It would be nice if you could pass along any combination of these FK fields to a single stored procedure which would use these parameters to query the table in a uniform manner, so there will be no recompiles (most people who try to use optional parameters end up concatenating SQL strings in a stored procedure, which is not that good).

The idea is this: for every parameter you do not need, you pass in 'NULL' as value. For every parameter you do need, you pass in the value you want to filter on. Let's get back to the example table, the Orders table in the Northwind database. This table has 3 foreign keys: CustomerID, EmployeeID and ShipVia. If we want all Orders of a given CustomerID which are taken by a given Employee we normally wouldn't be able to use the same stored procedure which would query for all Orders for a given Customer which are shipped via a given ShipVia value. But you can! Here's how:

CREATE PROCEDURE pr_Orders_SelectMultiWCustomerEmployeeShipper
 @sCustomerID nchar(5),
 @iEmployeeID int,
 @iShipVia int
AS
SELECT  *
FROM Orders
WHERE CustomerID = COALESCE(@sCustomerID, CustomerID)
 AND
 EmployeeID = COALESCE(@iEmployeeID, EmployeeID)
 AND
 ShipVia = COALESCE(@iShipVia, ShipVia)

That's it! This stored procedure will query for Orders on any given combination of CustomerID, EmployeeID and ShipVia. If we f.e. want to select all Orders for Customer 'CHOPS' and ShipVia '1', pass these 2 values to the stored procedure and pass NULL for @iEmployeeID. This will result in the requested rows.

Caveats.
Of course there are drawbacks. One of them is that this is slower than a query which is taylored to the columns you want to filter on. It also needs a clustered index to work well, but every table should have a clustered index anyway to support fast retrievals of data.

[.NET Weblogs]

This kind of situation happen often in my kind of usage of databases.

Copying and backing up under Linux

Sat, 26 Apr 2003 12:53:52 GMT

Backing up with tar and ssh. bbum: I found myself in a situation where I really needed to copy some files from a remote OS X box to my local system, but the only access I had was via SSH. Unfortunately, the files all have resource forks that contain pertinent information.

You can probably do this all at once:

  ssh remote.server.com -c 'gnutar cvp file1 file1/rsrc file2 file2/rsrc file3 file3/rsrc' | gnutar -x -v -p --overwrite

Here are some other handy ones:

- back up a remote directory to a local tarfile over a slow link

  ssh remote.server.com -c 'tar -cz /path/to/dir/to/back/up' > backup.tar.gz

- back up a remote directory to a local tarfile over a fast link, where the remote PC is very slow

  ssh remotehost -c 'tar -c /path/to/dir/to/back/up' | gzip > backup.tar.gz

Also rsync is great for this sort of thing:

  rsync -vr remote.server.com:/path/to/dir/to/back/up localbackupdir

Comment

[Second p0st]

Useful trick

Back Up Exec 8.6 incompatible with Adobe Premiere 6.0

Sat, 26 Apr 2003 12:00:39 GMT

While backing up with Veritas Back Up Exec 8.6, it is impossible to either capture or render with Adobe Premiere 6.0: tried 4 times, crashed the machine 4 times...

MSDN newsfeed

Thu, 17 Apr 2003 15:33:52 GMT

MSDN Magazine RSS feed. I just noticed that MSDN Magazine has an RSS feed, in addition to the feeds that Tim Ewald already mentioned. Cool!... [Incessant Ramblings (Technology Entries)]

It doesn't work now but should later...

Problem solved with BackUp Exec 8.6

Fri, 11 Apr 2003 07:48:00 GMT

I finally solve my OFO problem with BackupExec. It seems it is incompatible with Roxio EasyCD creator. I got rid of Roxio and boom, problem solved. I am testing it intensively to make sure I ironed out any problems left.

Outlook anti-spam add-on

Fri, 11 Apr 2003 03:00:18 GMT

SPAM, SPAM, SPAM, Baked Beans, and SPAM.

I just bumped into an Anti-Spam tool that actually seems to work. It has caught 100% of the Spam coming into my In-box for the last 48 hours without ANY interaction on my part.

It is an Outlook Add-in so it is seamless (no external program to scrub your email first, nothing server side required). This was something I've wanted for a while now.

And at $0.00, the price is just right. :)

Check out SpamNet from Cloudmark.

[.NET Weblogs]

I am using it since 2 weeks and it works flawlessly too. Try it. Recommended!

"Null or empty"'s neat trick

Thu, 10 Apr 2003 05:37:17 GMT

NullOrEmptyString.

Tired of doing this: "if(s == null || s == String.Empty)"...

public class NullOrEmptyString
{
 public static NullOrEmptyString Value = new NullOrEmptyString();

 public static bool operator==(NullOrEmptyString s1, string s2)
 {
  return ((object)s1) == null || s1.Equals(s2);
 }
 public static bool operator!=(NullOrEmptyString s1, string s2)
 {
  return !(((object)s1) == null || s1.Equals(s2));
 }
 public override int GetHashCode()
 {
  return String.Empty.GetHashCode();
 }
 public override bool Equals(object o)
 {
  return((o is string) && (o == null || (((string)o) == string.Empty)));
 }
 public static implicit operator string(NullOrEmptyString s)
 {
  return s.ToString();
 }
 public override string ToString()
 {
  return String.Empty;
 }}

[.NET Weblogs]

Neat trick

Calling stored procedure from within a loop

Wed, 09 Apr 2003 02:52:39 GMT

Running a stored procedure in a loop.

My two picks for the NCAA Finals came true. Let's see if Kansas wins tonight.

Okay, this bit of code iterates through a loop, running a stored procedure for each pass. The only item that differs from the normal use of a stored procedure is the line that reads objComm.Parameters.Clear(). Without this line, the parameters would continue to be added and not reset as they should be.

Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
â€˜Db declarations and such

            For i = intFirst To intLast
                    objParam = objComm.Parameters.Add("ID", OleDbType.Numeric, 7)
                    objParam.Direction = ParameterDirection.Input
                    objParam.Value = Session("ID")

                    objParam = objComm.Parameters.Add("strOne", OleDbType.Numeric, 7)
                    objParam.Direction = ParameterDirection.Input
                    objParam.Value = strOne

                    objParam = objComm.Parameters.Add("strTwo", OleDbType.Numeric, 7)
                    objParam.Direction = ParameterDirection.Input
                    objParam.Value = strTwo

objComm.ExecuteScalar()
objComm.Parameters.Clear()

                End If
            Next
    End Sub

[.NET Weblogs]

Very good trick to remember!

From ArrayList to Array

Sat, 05 Apr 2003 03:09:03 GMT

Cool blog entry from Craig Andera.

[Craig Andera]

Building an Array

A question that comes up occasionally on the mailing lists revolves around how to manipulate arrays of things. The problem is that once created, arrays can't change size. But what if you don't necessarily know how big it'll be right off the bat. Here's my favorite way to deal with arrays.

ArrayList al = new ArrayList();

for (loop over some set of things)

{

al.Add(thing);

}

Thing[] things =

(Thing[]) al.ToArray(typeof(Thing));

In other words, System.ArrayList is a convenient way to keep track of a list of things that you can later turn into an array.

Even better is the fact that you can construct an ArrayList from any array, like so:

ArrayList list = new ArrayList(things);

And you can remove a particular item like this:

list.Remove(particularThing);

Combine these three things, and you have a convenient way to remove an item from a list: turn the array into an ArrayList, remove the item you care about, then turn it back into an array. Or use Add instead of Remove, and you've got a convenient way to append things.

For those who've never used the ArrayList for this purpose, you will be amazed at the convenience of this. I use this technique all time. One case where I especially like it is where I have a class for which I don't want to go through creating a type safe collection. I just use this technique to return an array of the type of the class back from the method where I use the ArrayList internally. Obviously, you lose the benefit of checking at compile time type safety. However, for an internal function where I know what I'm getting myself into, using this technique well worth it to me.

[.NET Weblogs]

Another useful trick to remember.

Free ASP.NET hosting

Sat, 05 Apr 2003 03:03:27 GMT

.NET hosting for free?.

http://www.dotnetplayground.com/

Great for testing stuff!
No banners. Supports code behind. Has support for MS Access but no SQL Server.

Can't beat the price!

[.NET Weblogs]

Could be useful

.NET architecture videos

Fri, 04 Apr 2003 02:15:32 GMT

Dot Net Architecture Videos.

Clements points out that the entire architecture seminar is online. Very nice stuff!

http://www.dotnetmaailma.com/dotnetmaailma/seminaarit/online/EMEA+Architects+Tour.htm

[via Jesse Ezell Blog]

Really cool stuff. [.NET Weblogs]

Very interesting!

Dynamically generating "facetted" RSS feeds.

Fri, 04 Apr 2003 01:46:28 GMT

DRSS?.

On the OT list, folks have been ranting about RSS. I think what they're ranting about is the way that the various idiosyncrasies of blogs' RSS feeds box them into a corner, in various ways.

The more I think about it, the more I think that the one-RSS-endpoint-per-blog model is just not right. In my limited experience, I've encountered at least 3 different dimensions to RSS:

1) Version: 0.91, 1.0, 2.0, etc.

2) Category: All, technical-only, personal-only, etc.

3) Fidelity: Full content, summaries and links, etc.

Just considering those options, I'd have to expose 3x3x2=18 different RSS endpoints, to satisfy my readers. And that number would grow, as new versions of RSS emerge, or I define new categories, or...

This is madness. RSS is almost always dynamially-generated anyway -- why not generate it in whatever specific format the clients request?

http://www.myblog.com/rss.aspx?version=2.0&;category=technical&fidelity=full

Such a "DRSS" (think: DHTML) scheme would also allow RSS providers to punt questions like "how many items, or how far back into the past, should my feed expose?" back to the readers.

http://www.myblog.com/rss.aspx?version=2.0&;category=technical&fidelity=full&numitems=15

To be sure, a lot of folks are already doing things like this to manage the versioning-madness that is RSS. I'd love to see this convention grow to include support for filtering on categories, fidelity, and history.

[.NET Weblogs] This is a great idea. If I had time, I would try to cobble together my own blogging platform but I do not have enough... Maybe the next version of Radio could implement this...

Reflection trick with .NET

Thu, 03 Apr 2003 01:37:27 GMT

Cool Method You Never Knew Existed.

Ever needed to get the method description for the currently executing method? You can do this pretty easily by calling: "ConstructorInfo.GetCurrentMethod()."

[.NET Weblogs]

Pretty cool trick

Fawcette has a RSS feed!

Thu, 03 Apr 2003 00:18:07 GMT

Matt Carter at Fawcette sends a pointer to their new RSS feed. He says it contains "all of our magazine articles, online stuff, code, interviews etc, updated twice a day." The subject of the message is Bandwagon Jumping. The bandwagon here is Microsoft, and I think I must write a DaveNet piece about this. A remarkable movement, and a remarkable move by MS. They didn't reinvent RSS as they jumped in. This is a new idea for a BigCo. Of course there's still plenty of time for them to reinvent it. Praise Murphy! [Scripting News]

Very good stream of Java and .NET articles

Reading with TextReader

Wed, 02 Apr 2003 23:08:27 GMT

design choices in .NET. Chris has some great comments about the design decisions around some of the -Reader classes in the BCL:TextReader is a base class for things that read text. You can read text from a String (StringReader) or from a Stream (StreamReader). What about... [Incessant Ramblings]

Interesting comments there.

WinForms FAQ

Wed, 02 Apr 2003 12:50:31 GMT

An amazing Winforms FAQ.

I just discovered this site, and plan to use it often!

http://www.syncfusion.com/FAQ/WinForms/default.asp

great job!

Check out the very thorough DataGrid FAQ here:

http://www.syncfusion.com/FAQ/WinForms/FAQ_c44c.asp

[.NET Weblogs]

Excellent FAQ indeed!

Bruce eckel blog

Tue, 01 Apr 2003 06:21:08 GMT

Bruce Eckel blog.

I have no problem admitting that I learnt object oriented programming with Bruce Eckel's Thinking in Java. Even more, I am absolutely convinced that if from time to time I manage to look "solidly backgrounded" in O-O it is due to what I learnt in Thinking in Java. Third edition just received a Jolt award (I learnt while moving from 1st to 2nd Ed, time do fly, sigh). Thinking in C# is in the works and I am looking forward to it. In the mean time, Bruce has started his web log and it's got some mind opening content, go browse around, you won't repent.

[.NET Weblogs]

Interesting but no RSS feed.