Monthly Archives: May 2004

Linux Tip: Scanner not found?

Posted by jmrodri on

After upgrading to Fedora Core 2, I’ve been generally happy with it. I decided to give my HP ScanJet 5p SCSI scanner a shot. I start GIMP 2.0 (nice by the way), and choose “Acquire -> XSane: Device dialog…”. The result is “no devices available”.

ARGH! This is yet another issue with Linux compared with Windows. Linux recognizes my scanner since it it is displayed by dmesg.

  Vendor: HP        Model: C5110A            Rev: 3638
  Type:   Processor                          ANSI SCSI revision: 02

This is odd. So I run xsane from the command line and still the same result. Su to root and run xsane, it finds my scanner. Bingo! Permisions problem. I do:

chmod 666 /dev/sg0

Restart GIMP, and viola, I can scan. Again, from a user’s point of view, I shouldn’t have to do this. It should be automatic or during installation I should be asked “Allow non-root to use scanner?” Personally everyone should be able to use the scanner, so it should’ve been setup correctly by default.

CDRW dies

Posted by jmrodri on

Late last week, while using my Yamaha CRW2100S (SCSI) drive, I started getting SCSI bus errors, like the following ones: 

May 30 15:54:00 firebird kernel: Current sr: sense key Hardware Error
May 30 15:54:00 firebird kernel: Additional sense: Track following error
May 30 15:54:00 firebird kernel: sym0:3:0: ABORT operation started.
May 30 15:54:00 firebird kernel: sym0:3:0: ABORT operation failed.
May 30 15:54:00 firebird kernel: sym0:3:0: DEVICE RESET operation started.
May 30 15:54:00 firebird kernel: sym0:3:0: DEVICE RESET operation complete.
May 30 15:54:00 firebird kernel: sym0:3:control msgout: c.
May 30 15:54:00 firebird kernel: sym0: TARGET 3 has been reset.

Needless to say I was disappointed. Several Google searches for the above error pointed to two things:

1) SCSI bus termination problems
2) Drive going bad

Having figured out the termination many months ago, I ruled that out. But just to make 100% sure, I opened up the case and checked to ensure nothing came loose. Every thing checked out ok. The external zip drive was terminated as was the internal 50-pin cable (with active terminator). The 68 pin side was terminated at the card and the active terminator at the end of the cable. The termination was ok.

After checking the termination I reboot the machine to see what else I can diagnose. Then,’
“Hey what’s that weird @$$ whining noise?” CRAP! CDRW spinning with no disc in it going at all speeds. ARGH! Sure enough the drive is toast.

Now my dilemna is that there aren’t any good SCSI CDRW’s out there anymore. I looked on eBay and no one’s selling a used 2100S or 2200S. This is starting to sound like I’ll need a new IDE drive which I dread because I became a SCSI ho several years ago.

I’ll continue my quest for a SCSI CDRW or just bite the bullet and get a kick @$$ DVDRW :)

Here are a few I’d consider buying:

Sony DRU-700A
Plextor PX-708A
Plextor PX-712A

If I had my P4 machine with SATA, I’d just ditch the SCSI drives and get all new SATA drives.

Oh well, C’est la vie!

Eclipse Tip: Startup Performance

Posted by jmrodri on

I was a bit concerned with Eclipse’s startup performance. It was taking 12 seconds to start up on a machine with dual XEON’s a gig of RAM running Red Hat Enterprise Linux (RHEL). I started digging. I came across a blog which had the following parameters:

-vmargs -Xverify:none -XX:+UseParallelGC -XX:PermSize=20M
-XX:MaxNewSize=32M -XX:NewSize=32M -Xmx160m -Xms160m

Using these parameters my startup went down to 6 seconds!

Sources:
The Blue Pill
Running Eclipse

Sony Clie & Linux (Fedora and Red Hat Enterprise Linux)

Posted by jmrodri on

I’ve been having fun with my Sony Clié. Unfortunately, I could not connect to Red Hat Enterprise Linux (RHEL) using pilot-xfer via USB. I kept getting “no suitable driver” error.

Determined to sync my new Clié, when I got home, I booted up my crusty Windows XP partition. Installed the Sony Clié software. I did a Hotsync, and installed two trial games. Worked great. Say what you will about Windows, it definitely has a leg up on Linux.

Now that I’ve successfully synced my PDA, I decided to boot Fedora Core 2 to try my luck. Hopefully, I fair better than I did with RHEL 3.


I tried using gnome-pilot, filled in /dev/pilot as the port, and click on USB. I then click the Forward button, and chose “Yes, I’ve used sync software with this pilot before.”, and clicked Forward again. I pressed the Hotsync button on my PDA, and gnome-pilot sits there. No activity. I waited until the Sony timed out.

So I remember reading somewhere that if gnome-pilot doesn’t work use pilot-xfer.

As me (not root), I try

pilot-xfer -l

. Hmm. so /dev/pilot doesn’t exist. I remember that I didn’t run /sbin/modprobe (from my experience with RHEL). So I su to root, run

/sbin/modprobe visor

Then I look at /var/log/messages and notice the following message:

May 25 22:48:38 firebird kernel: usb 1-2: Handspring Visor /
Palm OS converter now attached to ttyUSB0
(or usb/tts/0 for devfs)

Lightbulb! Ok I run

pilot-xfer -p /dev/ttyUSB0 -l

as me again. Tells me I need to chmod 0666 /dev/ttyUSB0. ARGH! I become root and do as stated. Now as me again, I re-run pilot-xfer. BINGO! Success! I get back the list of items on my Sony Clié. So I take it a step further,

pilot-xfer -p /dev/ttyUSB0 -backup /home/jmrodri/palm

and I have 75 file files (.prc & .pdb). Now we’re rockin’ and rollin’.


WHEW! That was tiring. Ok let’s see if we can get gnome-pilot to work now that we know to use /dev/ttyUSB0. And again, it sits there. So I’m going to guess that gnome-pilot sucks :) At least pilot-xfer works. I’ll keep toying around with it until I’m satisfied.

In general Linux has potential, but it is still years behind Windows in usability. The fact that I had to deal with the /dev file system (which a normal user should not have to worry about) and use a command line application to sync my PDA, is beyond a regular desktop user. Hopefully, Red Hat Desktop has the ability to sync with PDAs, and other consumer (and business) devices, if it hopes to unseat Windows in the enterprise.

Nautilus & Fedora Core 2

Posted by jmrodri on

So far I’m loving the new “spatial” navigation in Nautilus. It reminds me a lot of the OS/2 days.

My only gripe is with the default association of java files to a java compiler. I will figure out how to change this tomorrow night, but 99% of the time when I double click a java file I want to open it. The 1% of the time I want to compile it, I have a script or IDE to do it since most files need to be compiled in context with other files.

Hibernate not suited for normalized databases

Posted by jmrodri on

On my current project our database is highly normalized to support high volumes of data. We decided to investigate persistence frameworks with a bias towards Hibernate which has a reputation for being the best persistence framework at current. While it is well suited for a situation where you have one object per table (seems like a typical paradigm for web applications), it is not suited for heavily normalized tables.

In the past, I’ve posted about recommending Hibernate (see my JavaLobby article), but couldn’t find a proper use of it in our application. We have several tables sometimes upto three for a given object. Hibernate doesn’t seem to do this. Many have said “Hibernate can handle multiple tables per object” but few have actually explained how to do it. Many have also said, “Why don’t you make use one object per table” because we can’t change our database tables.

We’re going to roll our own mapping and hope for the best. In the process, I will checkout iBATIS as well as OBJ.

Other Hibernate entries

Angsuman’s Blog

If you have examples of an object being loaded from multiple tables and the ability to use hand tuned SQL queries (without the use of HQL) feel free to comment.