Cups Printing Delay

So you’re running Ubuntu 12.10, 12.04, or a recent version of Debian Linux. And you’ve tried to print from another Linux client running cups. And what you’ve noticed is that there’s a nasty 10 second delay (or maybe 5 second, 7 second, etc) before your next print job starts.

A-hah, you think Maybe it’s an issue with some sort of delay between reprints. And you’re right. But good luck trying to find the setting to force that down to a lower interval.

And here’s why. It’s not there. There is no setting to retry the remote system’s print job without the wait. But there is a setting you can change.

For the issue I was having, everything was set up properly on the client and the print server. The only message it was returning was something about Dirty Jobs. Which led me to this.

What needed to be changed was the cupsd.conf file, and it needed the following options set.

DirtyCleanInterval seconds
Specifies the delay for updating of configuration and state files. A value of 0 causes the update to happen as soon as possible, typically within a few milliseconds.

And that was it. With “DirtyCleanInterval 0” the system now prints sequential print jobs as quickly as possible.

What I assume going on there is that there are more settings altered by that option than listed. Because there was an 8 second delay, but that setting defaults to 30 seconds which is certainly longer than the print delay I was seeing.

In some cases it might cause other issues due to unintended consequences of the rapid check. But it certainly seems to fix the issue on a wait between prints on our receipt printers.

Testing Auto Coolant with a Multimeter

Ran across this on the bob is the oil guy forum. There’s a note half way down the posts stating:

So, test the corrosion protection. With a digital voltmeter, put one probe in the cool coolant in the radiator neck (not touching metal). Put the other probe on the battery negative post. If you read 0.1 volts DC to 0.3 VDC, you’re good. If you read 0.5 VDC or more, your coolant had depleted corrosion inhibitors and is due (or overdue) for a change. You’re reading the voltage generated by the galvanic action of the dissimilar metals and the electrolyte (the coolant).

That’s certainly something I never thought of. Hopefully it’ll help you out the next time you’re stuck trying to figure out if someone’s coolant is good and are short a hydrometer.

CK Back, Working on Bitcoin Client

So I just noticed -ck attached to a bitcoin client and low, behold, it’s the same Con Kolivas who used to maintain the -ck Linux scheduler. Check out the CGminer bitcoin number crunching client if you’re interested.

Con’s done some outstanding work in scheduler development on the Linux kernel. He’s always backed up his claims with actual graphs and numbers unlike so many (not specifically Linux) developers who take a “well it should work” attitude. It’s interesting to see all that applied math going into tweaking a number cruncher.

Ubuntu 11.04 CUPSD Not Printing to ttyUSB0 Fix

So you’ve got a serial device that needs printing output sent to it and you’ve installed Ubuntu 11.04. Cups responds with an Unable to open device file … Permission Denied. Well!

Ubuntu has thoughtfully explicitly denied access to /dev/ttyUSB devices through apparmor. No reason you’d ever print to serial devices in Ubuntu, eh?

So to get your receipt printer, Okidata 320ML serial printer, or whatever working you’ll either need to uninstall apparmor (I imagine) or change a line in the file /etc/apparmor.d/usr.sbin.cupsd from “deny /dev/ttyUSB*” to “/dev/ttyUSB*”.

That should do it.

Puzzle Agent 2 Review

Game: Puzzle Agent 2
Publisher: Telltale Games

Puzzle Agent 2 from Telltale Games brings us back to Scoggins, Minnesota to delve into the unresolved secrets of the first installment. The FBI’s sole agent in charge of the US Department of Puzzle Research, Nelson Tethers, has decided there’s a puzzle left unsolved.

Graham Annable returns with his sketch-art animation and folk-lore hidden people. The animation and story board are a good bit of the selling point for the Puzzle Agent series, with Graham’s ability to pack emotion into a fairly low-detail form of art. The art’s fun, unpretentious, and surprisingly engaging.

Audio in the game sets the mood nicely, complementing the gameplay and settings without being overbearing. Voice acting is on par with anything I’ve watched. The best complement I can pay any game not about music is that I don’t remember the soundtrack, only recalling that it was good.

And that’s the case here.

Too many titles wedge in music that undercuts the gameplay rather than underscoring it because someone “did music” or they’re trying to get an extra sales angle in.

Puzzles in Puzzle Agent 2 are slightly easier than in the first game. Some of the aspects that could make solving puzzles irritating have been altered. I really didn’t find them hard, more along the lines of a brain-teaser or Saturday newspaper puzzle than MENSA material.

There are also abundant hints available if riddles are a bit too challenging. Or if you don’t have knowledge of a particular subject.

Coming in at about 4 hours of playtime, Puzzle Agent 2 is a bit longer than an episode but shorter than a traditional long-format game. Which is about right for a ~10$ pricetag.

I liked the game. It was fun all the way through. With the sketch animation style, puzzles, and clean content Puzzle Agent 2 delivers.

Footnote: you should play Puzzle Agent first, since Puzzle Agent 2 is somewhat of another episode. It’s not going to hurt to start on the second chapter, but why would you want to?

SSHd Server On Android

Android devices are great unless they’re not. One of the ways they’re not-great is when you don’t have Android Marketplace installed for whatever reason and need to get applications to them for install.

So if you’re looking for a solution to getting files over to your android device in relatively secure style, an SSH server is probably the way to go.

Two of the options that I’ve picked out that that work are:

SSHDroid: A free ad-driven application that allows you to open up a somewhat configurable compile of the Dropbear SSH daemon.

DroidSSHd: this one is ad-free but doesn’t include sFTP support. It also didn’t like SCP running through it, but that may have been due to where it dumped the client in the directory structure. If you’re looking for a clean compile of Dropbear sshd for android, they’ve also got that, along with instructions on how to cross platform compile sshd for android yourself.

Minecraft Server Start, Stop, and Auto Save Scripts

If you’re running a Minecraft server on Linux and you want a simple way to automate starting, stopping, and backing up the server with a single command-line option this might be for you.

These scripts are something I cracked out for the Minecraft server we run here. Feel free to grab a copy and modify them for your own use.

You’ll need basic unix utilities and “screen”, which may not be installed by default. If you’ve got all that, the only thing that it’s necessary to change should be the startup directory setting in the main file.

If you’d like the backups to be run automatically, put the backup script in your crontab file. If you need help doing that, look up “edit vixie crontab how-to” on google. If you’re not using Vixie Cron.. well.. you probably know what you’re doing.

Also note that this was created to be the absolute bare-bones of what you’d need to effectively run and back-up the server. There certainly could be more options, wrappers, MOTD on entry daemons, etc. But they won’t be in these scripts.

If you need to pop into the Minecraft server command line once it’s up and running, type “screen -r” as long as you’ve only got the single screen session running. When you want to leave the server, and exit back to your prompt without closing it down, press CTRL-A CTRL-D.

Hopefully they help, and good luck!

Minecraft Start/Stop/Backup Scripts