kontrawize

Printing with CUPS in openSUSE 10.3 (Linux)

abcoates — Tue, 29 Apr 2008 00:06:53 +0100

It's been ages since I've posted. In February I started a new company (Londata), and that has been keeping me very busy. I've not had enough time to read the blogs I like to read, let alone find the time to write anything.

However, I've finally solved a problem that has been gnawing at me, so that seemed like a good reason to take the time to write. I installed openSUSE 10.3 back in October, and since that time I haven't been able to print anything from openSUSE! Now, that might seem intolerable to some of you, but I don't print a lot of stuff, so it wasn't enough to put me off openSUSE 10.3, but it has been inconvenient.

I couldn't print from my deskside PC, which is my print server. So no surprise that I couldn't print remotely from my laptop. However, the big surprise was that I could print remotely from Windows XP (using Samba), either from machines running XP directly, or from VMware virtual machines running XP (we don't run any other variety of Windows here at Casa Coates at present). How galling is that? I had a Linux print server running, but could only print if I printed from Windows. Anyway, that is what I have been doing, copying files across to Windows on those occasions when I actually needed to print something.

Today, I decided to look around for a solution. I was sure I couldn't be the only one with this issue; at least, I hoped I wasn't the only one. I quick search suggested other people have this problem, but I didn't come across an obvious solution. However, I solved my problem anyway. Here is what I did.

My printer is a USB printer, set up with CUPS so that it can be accessed remotely. On my print server, you can access the CUPS printer information using the URL

http://localhost:631/printers/

I went into the entry for my printer (which is called “printer”), and vainly tried to print a test page, just to see if any recent openSUSE updates had changed anything. However, I then noticed a “Modify Printer” button that I hadn't tried before. When I tried it, it asked for the same information that YaST asks for when setting up a printer. I went through and set things up this way, then tried to print a test page again. This time it worked! So, it seems that YaST doesn't quite get the printer setup right in openSUSE 10.3. That's frustrating, but I'm glad there is a solution. It worked for me; if you are having the same problem, I hope it works for you too.

Dilbert on kontrawize

abcoates — Wed, 23 Jan 2008 12:50:52 +0000

As a reader of the Dilbert blog, I have added the new Dilbert widget to the sidebar of my weblog pages. So, if you visit my weblog site, you can catch up with Dilbert there. There are many other places you can catch up with Dilbert, of course. The choice is yours.

Miley Watts XML File Lister for Apache Ant

abcoates — Fri, 18 Jan 2008 18:02:26 +0000

I have updated the open-source XML file listing task that I have written for Apache Ant. This is useful, in particular, when you want to apply an XSLT stylesheet to a number of files together (not individually). You use the file listing task to create an XML file listing containing the file URLs, then you load the files into your XSLT stylesheet using the URLs and the XSLT “document()” function.

Version 1.0 created an XML file listing with an XML hierarchy that mirrored the directory hierarchy. The new version 1.1 has two other options. You can produce a flat listing without the directory hierarchy, and you can create a “collection” XML listing that works with the “collection()” function in the Saxon XSLT/XQuery engine.

For details and examples, please visit the download site. I hope you will find it useful.

Doritos in Japan

abcoates — Fri, 18 Jan 2008 10:58:40 +0000

I was reading a blog post about falling domestic car sales in Japan, but what really caught my eye was the accompanying photo (go on, have a look). I'm not sure what the two guys on the packet of Doritos are supposed to be doing, but perhaps it's an aid to digestion. It reminded me a bit of how, when tea was first brought to England, people didn't know what to do with it, and some people just boiled it up, threw away the liquid, and ate the soggy tea leaves. I'm starting to wonder what people actually do with Doritos in strange corners of the world.

xmlcatalog.net

abcoates — Fri, 04 Jan 2008 10:27:39 +0000

A few years ago now, I was a (junior) member of the OASIS Entity Resolution TC, which produced the OASIS XML Catalogs specification (HTML, PDF). XML Catalogs are used to specify simple rules for re-writing or re-directing URIs in XML documents. This work was based on the catalogues used for SGML (from which XML is derived), so there was a lot of genuine long-term user experience factored into the design.

The most common use case for XML Catalogs is re-directing an HTTP URL for an XML Schema or DTD reference to a local copy of the file on your own file system. This aids both performance (HTTP is comparatively slow, and the remote HTTP server is usually that much slower again) and security (you don't have to trust that URLs in an incoming XML document are pointed at the correct schema, or the correct version of the schema). It also means that your different users or different systems can have their own catalogue file that controls where they get their schemas from, and there is no need to try and force one single configuration (a setup of HTTP URLs or a set of file locations) to work for all situations.

XML Catalogs is implemented now by a variety of software tools, e.g. Java, oXygen and XML Spy. However, I needed an implementation to use for a .NET application, and couldn't find a suitable implementation, so I have written one, called “xmlcatalog.net”. You can download it from

http://secure.mileywatts.com/confluence/display/CMSW/Miley+Watts+XML+Catalogs+for+.NET+and+Mono+(xmlcatalog.net)

(or alternatively from http://xmlcatalog.net, once the domain re-direction kicks in properly).

As an example, suppose I have the following (trivial) XML document:

<?xml version="1.0" encoding="UTF-8"?>
<schemaTest xmlns="http://www.example.com/schema/test"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.example.com/schema/test schematest.xsd">
  <a><c/></a>
  <b><d/></b>
</schemaTest>

Note that the “xmi:schemaLocation” attribute indicates that the relative path to the Schema is “schematest.xsd”. This is a common situation that people end up in; not being able to specify a relative or absolute Schema URL that works for all users, they just assume that the Schema is in the same directory as the XML file (i.e. simplest possible relative path), and let end users sort out the problem for themselves.

Alternatively, you can use the following XML Catalog file:

<?xml version="1.0" encoding="UTF-8"?>
<catalog xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">
  <systemSuffix systemIdSuffix="schematest.xsd"
uri="../xsd/schematest.xsd"/>
</catalog>

which contains one rule: if you see a system ID (i.e. a physical schema location) which ends in “schematest.xsd”, then use the file whose path is “../xsd/schematest.xsd”, relative to the catalogue file. So, this one short XML file gives your users the ability to have their schemas in any location that best suits them – if the XML applications that they use are “ catalogue aware”, all they have to do is keep their catalogue file up-to-date.

In the .NET/Mono XML API, absolute and relative URLs that need to be used by parsers and such (e.g. schema locations) are passed to an XmlResolver. The standard version only provides the ability to convert relative URLs to absolute URLs. xmlcatalog.net provides a derived “ XmlCatalogResolver” class that uses your XML Catalog file(s) to re-write or re-direct the URIs that are being resolved. You can re-direct URIs to local files (using “file:///” URIs or relative paths that are relative to the catalogue file), or to alternative URLs. It is straightforward to configure a .NET/Mono XML parser to use XmlCatalogResolver:

using System.Xml;
using System.Xml.Schema;
...
XmlReaderSettings settings = new XmlReaderSettings();


// These two statements are important for W3C XML Schema validation.
settings.ValidationType = ValidationType.Schema;
settings.ValidationFlags =
        XmlSchemaValidationFlags.ProcessSchemaLocation
        | XmlSchemaValidationFlags.ReportValidationWarnings
        | XmlSchemaValidationFlags.AllowXmlAttributes
        | XmlSchemaValidationFlags.ProcessIdentityConstraints;


settings.ValidationEventHandler +=  new ValidationEventHandler(ValidationHandler);
settings.XmlResolver = new XmlCatalogResolver(catalogPath);


XmlReader reader = XmlReader.Create(xmlPath,settings);


// Read (parse) and validate the file.
while (reader.Read());

By the way, my intention is that xmlcatalog.net should support both .NET and Mono, but I'm having some trouble getting NUnit to run under openSUSE 10.3, so I don't have my test suite running. It may already work under Mono (if you try it, let me know); when I get it tested against Mono, I will post an update.

At the download site

http://secure.mileywatts.com/confluence/display/CMSW/Miley+Watts+XML+Catalogs+for+.NET+and+Mono+(xmlcatalog.net)

you can register to get access to our JIRA issue tracking system, if you need to search the existing issues or log new issues (bugs, feature requests, etc.). We are already using xmlcatalog.net as part of a customer project, and it's working well. If you use .NET or Mono for your XML, give it a try and let me know what you think.

Updated openSUSE 10.2 to 10.3 under VMware Server 1.0.4 (a bit of a tale)

abcoates — Sun, 30 Dec 2007 15:50:08 +0000

I hesitated on upgrading my openSUSE 10.2 VMware virtual machine to 10.3, because it is the system on which I do most of my work, so I can't afford to have any significant down-time with it. However, there weren't a lot of new issues on the openSUSE newsgroups , so I thought it might be safe now.

Initially, the upgrade went OK. As usual for an openSUSE upgrade in a VMware virtual machine, you do it in text mode, and you don't test the internet connection or select any options that require network access. However, openSUSE 10.3 won't install unless your boot partition (if you have a separate "/boot" partition like I do) is at least 64M, so I had to use a bootable "gparted" CD to increase my boot partition's size by taking some of the space from the adjacent swap partition. Also, during the set-up phase of the update, I had to agree to remove some packages (e.g. Firefox and Java 6) to make the package manager happy. I made a note to re-install these later.

After the upgrade finished, I ran "vmware-config-tools.pl" to rebuild the VMware tools (has to be done whenever the kernel version changes). This is needed to get network connectivity in the virtual machine, among other things. After installation, I removed obviously out-of-date software repositories from my list of repositories (using YaST), did an online registration (to get the details for the appropriate online update repository), and then added my favourite repositories. Then I ran the online update. It told me to reboot, so I did.

Unfortunately, after the reboot, my windowing system wouldn't start. Running "yast2" and redoing the display settings didn't help, so I re-ran the openSUSE 10.3 upgrade, this time not adding extra repositories until after the initial online update had been completed. Quite a number of package dependencies couldn't be satisfied, especially packages that were part of the GNOME desktop. For the most part, I set the package manager to ignore those dependency issues, hoping that I would get it all resolved later.

In retrospect, perhaps I should have just disabled the extra repositories and just have re-run the online update, but I didn't think of that at the time. That said, re-running the openSUSE 10.3 updater on a system that already has 10.3 restored is pretty quick. Unfortunately, the re-installation didn't help, I still couldn't get my windowing system running.

So, I went in and disabled all repositories except the installation disk and the main update site, and re-ran the online update using "yast2" in text mode, and then rebooted as instructed. I then re-ran "vmware-config-tools.pl", and rebooted.

No luck. Using "vmware-config-tools.pl" to change the screen resolution (from 1280x800 to 800x600) also didn't help. At this stage I had to give up. The screen had been OK before my original online update, so I restored my openSUSE 10.2 VMware virtual machine from my backup, and started the update all over again.

During this, I noted that VMware Tools was doing something in "/usr/X11R6/bin", where the only file by default is "xauth". VMware tools seemed to expect to find "X" there. After a quick search, I found that some other tools are fooled by this, and the suggestion is to do

ln -s /usr/bin/Xorg /usr/X11R6/bin/X

In addition, I also did

ln -s /usr/bin/Xorg /usr/X11R6/bin/Xorg

This certainly fixed the minor issue with "vmware-config-tools.pl", but after rebooting again, the windowing system was still crashing as before.

So, I ran the online update utility in text mode, and found there were outstanding updates. I decided to keep updating (and re-running "vmware-config-tools.pl" in the case of a kernal update) until there were no more updates left. I should mention that there was (and is) a network issue. My experience of recent openSUSE upgrades is that network device information doesn't get carried over correctly, and needs to be fixed. However, I couldn't get the network to start working by itself on boot-up. Even now, I can only get it to work by running the following script (as root or using "sudo"):

#!/bin/bash
/etc/init.d/network stop
/sbin/rmmod pcnet32
/sbin/rmmod vmxnet
/sbin/depmod -a
/sbin/modprobe vmxnet
/etc/init.d/network start

Anyway, installing all of the online updates didn't fix things. I used YaST's "Software Management" app to select all packages with "xorg" in the name (X-Windows), and tried updating those again. A quick Web search showed that X.org 7.3 is available (7.2 ships with openSUSE 10.3), so I found the openSUSE repository for version 7.3 of X-windows

http://download.opensuse.org/repositories/xorg73/openSUSE_10.3/

I added it as a repository, and then did yet another online update of the installed "xorg-*" packages. That worked!

With that major problem over, I added my favourite repositories (Packman, GNOME stable, OpenOffice, etc.) and updated with no problems. The update is done, but that X.org problem almost had me reverting to openSUSE 10.2. It's a pity these things can't run more smoothly, but it's done now, I can just get on with things.

Finding software for openSUSE

abcoates — Sun, 23 Dec 2007 17:14:27 +0000

openSUSE Linux doesn't have the “apt-get” command that users of Debian Linux and its derivatives provide as a simple mechanism to download some application that you've heard of, but don't have installed. However, it isn't hard to find most things that you might want for openSUSE, it's just that the process is different.

The best place to start is http://software.opensuse.org/. You can download openSUSE from here, but you can also find applications that you need for your openSUSE installation. In the left-hand column are the “Software” links. The Software Search link returns a list of URLs for repositories that contain the application that you want, while the other “Software” links take you to lists of repositories. In both cases, you need to add the repository or repositories that you need to your list of openSUSE sources.

To do this, start YaST, then from the “Software” group select “Installation Source” (openSUSE 10.2 or earlier) or “Software Repositories” (openSUSE 10.3 or later). Press “Add”, then “Specify URL...”, and then paste in the repository URL that you found earlier. Once you have done this, you can use YaST's “Software Management” to locate and install the software that you want from the repository that you have added.

You rarely have to add new repositories once you have added a few, as each contains many packages. So, this isn't something that you will need to do every time you are looking for a new application, but you will have to do it sometimes.

I hope that helps, if you have been looking for software for openSUSE.

Genericode – 3rd public review, and XML 2007

abcoates — Sat, 24 Nov 2007 14:36:02 +0000

The 3^rd public review of genericode, the OASIS XML format for code lists, began yesterday and runs for 15 days. This is likely to be the last review before genericode 1.0 is published as a committee specification (it will then start the process to be voted as an OASIS specification).

At the XML 2007 conference, on the 4^th December, there will be an evening of lightning rounds on standards. Each speaker presents 20 slides for 20 seconds each. I will be there for the OASIS Code List Representation Technical Committee (CLRTC), with 10 slides on genericode, and 10 slides on the CLRTC's new work, context value association. This allows you to associate particular elements in an XML document with a genericode code list; it's a piece you need if you are using genericode remove code lists from your XML schemas, so you aren't forced to republish your schemas every time a code list changes.

See the “ Genericode News” section at genericode.org for more details.

XML 2007 – last chance for conference hotel

abcoates — Mon, 19 Nov 2007 17:58:05 +0000

The XML 2007 Conference is on in Boston from Monday 3 December to Wednesday 5 December 2007. The special hotel rate has been extended until 21 November (Wednesday this week), so make your booking now! It should be a great conference.

I'm speaking on the Tuesday at 9am on “ Semantic data models and business context modelling”. I will be discussing the ways that “Semantic Web” technologies are becoming of interest for more traditional data modelling activities, making use of their expressive power rather than the more “gee-whiz” features like automated inference.

I hope to see you there! If you are there, please feel free to find me and have a chat.

Holy Cow! Flying Cow!

abcoates — Wed, 07 Nov 2007 16:46:22 +0000

Can I get those rump steaks delivered? Via Jalopnik.