ISO to USB script for Mac

Writing Linux ISOs to USB drives is always slightly annoying, especially on OSX.  Using OSX, you have to jump through hoops to convert the ISO into some weird format so that disk utility can transfer to the USB drive.  To simplify this 12 step process, I created a script to do the converting and writing process automatically.  All the user needs to do is type one command and the entire process is taken care of automatically. Usage of the script is simple too.  sudo ./convertiso.sh isofile.iso /dev/somedisk

Notice sudo is needed for this to work, as the script uses dd to write to a raw device.  Replace /dev/somedisk with the device path of the flash drive.  I've built in some basic protection, so in the event you make a typo, your hard drive won't be overwritten, but please check the device path before running.  I'm NOT responsible if you use this incorrectly and it breaks your machine. 

Download from my Github page.

Rolling Rant: Web Trends that Need To Die

I'll just keep appending to this list when I find something new on the interwebz that bothers me. 

I am not clicking through 31 pages so you can generate more ad impressions. Bye bye. 

Thank you, I have a scroll wheel that works just fine.   Hooray for no-script.

Scrolljacking: because letting the user scroll for themselves is dangerous

2017: Every website wants to show me notifications.  No, I don't want to clutter my desktop with updates every time someone writes a nonsense article on the internet.  Go to hell.

Migrating from Ubuntu to Freenas

Over the weekend I decided to rebuild my home network.  My NAS machine has been running Ubuntu server 14.04 for the past year hosting a 6TB ZFS array over the network.  I became bored of using Ubuntu on this machine so I switched to FreeNas.  I've used FreeNas in the past and it worked quite well.

I was afraid that installing FreeNas would nuke my entire storage array, so I backed up the important stuff to some external hard drives.  Installing FreeNas (version 9.3.1 at the time of this writing) took less than ten minutes, which was fortunate for me because I had to stand on a stepladder in my freezing cold garage to do this. 

Much to my surprise, the ZFS volumes created under Ubuntu were detected and imported successfully by FreeNas.  I just love it when technology actually works the way it should. 

No rebuilding necessary!!

Setting up an Ubuntu router

Over the last week I scratched an geeky itch that I'd been having for a while.  I wanted to convert away from using SOHO networking equipment.  Instead I configured a Linux based PC to act as a router/firewall/DNS/DHCP server and another linux box to be a media server. This post will cover the setup procedures for the router box.

During the process I learned a lot about networking.  In the past I have always been able to avoid iptables, but this time I could not.  I bit the bullet and decided to read up on how iptables worked instead of just blindly copying and pasting commands and crossing my fingers.  What did I learn?  iptables really aren't that difficult conceptually, they're just not explained well by most tutorials on the internet.  I won't try to explain them in detail in this post.  Here is a link to a site that explains them really well.  Specifically, see section 3 for details about how packets actually traverse iptables.  Reading that section first will help you understand the commands that you will input later.

Here is a basic list of functionality that my router needed to have in order to be a viable replacement for my current SOHO wifi router:

• NAT routing
• firewall
• DHCP
• DNS
• OpenVPN 

Additionally,  my router is configured to handle the PPPOE connection to my DSL provider. This step is only necessary if you have DSL or some other service which uses PPPOE to connect.  As a bonus feature, I also set up a script to automatically update dynamic DNS for the current external IP address of the router.

First, I recommend configuring your new router without exposing it to the internet.  Plug the WAN port of your new router into your existing LAN.  Then plug another computer into the LAN port of your router.  This way you will be able to test all of your configurations without taking down your internet connection. 

Google Drive High CPU usage

Ummm, why does my computer sound like a scaled down jet airplane about to take off?  Oh, just Google Drive running away trying to upload files while I don't have an internet connection.

Google Drive building up pressure with no Intertubes to vent with

As soon as I restore my internet connection by tethering my phone, Google Drive calms down again.  

Google Drive with internet connection

For those interested in collecting bug samples from the wild:
Google Drive OSX App version: 1.24.9931.5480
OSX Version 10.10.4

iPhoto sucked, Photos sucks more, use Unbound instead

 As an aspiring photographer, I take a lot of pictures.   When I'm done shooting I need a place to import and organize my photos.  Like most Mac users, I used iPhoto and later Photos because they were included with the system.  But iPhoto and Photos have been nothing but a pain in the ass for me.

iPhoto started to suck right around the time I started shooting in RAW.  The import process was unbearably slow.  It was a throwback to the dial up days when you'd go make some coffee while waiting for the page to load.  iPhoto often took 10 minutes or more to import less than 100 pictures.  During the import process, iPhoto would peg all my CPU cores to 100% making my Macbook Pro lag like a bargain bin Android tablet.

Photos was only a slight improvement in that regard.  The import process was much quicker. However, the entire time Photos was open my CPU usage was always around 100% on one or two cores.  This essentially makes Photos useless on a laptop without having a charger nearby.  That kind of power consumption is just not acceptable for a photo viewing app.

Unbound for Mac seems like the best alternative. I don't need the editing features that iPhoto or Photos have.  I just need a simple viewer and organizer that works.  Better yet, Unbound doesn't store the photo files inside of some blackbox folder structure.  It just leaves them the way they were on your machine.  Unbound is fast and simple and it just works.

My perfect nginx config

Setting up web servers is a pain in the ass if you don't do it all the time.  I don't.  So I've spent the last few days trying to figure out how to configure nginx.  I have an Amazon AWS instance running a couple of low traffic sites mainly for fun.  One site in particular had some special requirements. 

• only the index.php file should ever be executed
• no static files are served from this site (css/html/js)

This site has a couple of composer files in the site root, and I didn't want anyone to just be able to download them.  This site also runs on a framework that uses a "front controller", meaning that one PHP file dispatches and handles all the requests.  So here's the nginx config that I came up with to do just that.

With this configuration, here's what works and what doesn't:
These work as expected:
example.com/
example.com/api/who
example.com/index.php
example.com/index.php/api/who

These are 404ed as they should be:
example.com/composer.lock
example.com/SomePHPFile.php


 server {
        listen 80;

        root /var/www/example;

        server_name example.com;

#direct all traffic to the front controller after trying files
    location / {
        index index.php;
        try_files $uri $uri/ /index.php?$args;
   }

#only redirects to the front controller will be processed.
    location ~ index\.php {
        fastcgi_pass   unix:/var/run/php5-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param  SCRIPT_FILENAME $document_root$fastcgi_script_name;

    }

#any path which is an actual file will get a 404
    location ~ (\.[^/]+)$ {
        return 404;
    }

}

rsync WTF

During the process of setting up my NAS box over the weekend, I discovered a curious thing about rsync.  The options that everyone on the internet seems to use, ("-avz") actually slow down the performance of rsync over LAN.  By slow down, I mean 20 MBps over gigabit ethernet. Theoretically, Gig-E can handle ~125 MBps.   Fortunately, the solution was simple.  Dropping the "z" flag (z enables compression) sped up my transfers to around 70 MBps.  

TLDR; use rsync -av, not rsync -avz

For those interested in the relevant details of my setup: I was using rsync to copy files locally from my Macbook to an SMB  mount point.  I'd also tested the speeds of rsync using the rsync protocol (rather than copying to a mounted volume) and they were equally poky.  NFS didn't fare much better.  It seemed to cap out around 40 MBps.   Strangely, SMB seems to be the fastest protocol for copying files in my setup.  Finder copies files even faster than rsync, pulling around 100 MBps.  My NAS box is a dual core Athlon X2 @3 GHz. I've got 4x 2 TB hard drives in RAID Z2 (RAID6) for a total of 4TB usable storage. 

Refresh your Android wallpaper

I get sick of looking at the same background on my phone day after day.  (The same goes for my computer.) Interfacelift.com has always been my go to site for really amazing photography fit for desktop wallpapers.  Unfortunately, they don't have an Android app and going to the website all the time on my phone is a pain in the ass.  Enter my solution: Refresh.

Refresh is a stupid simple Android app that brings all the goodness of interfacelift.com to your Android phone (or tablet).   Simply scroll through a list of wallpapers and pick the ones you like.  Download them to your phone, or set them as your background right away.  The latest version of Refresh will automatically cycle through all the wallpapers you've downloaded.  Every time you turn the screen on, you'll be looking at a different wallpaper.

Check it out on the Google Play store.  I'm open to suggestions for new features and of course bug reports.  (I hate ads as much as the next person, but it's not free to use interfacelift.com's API.  I tried to make them as unobtrusive as possible.)

Beware of commas in For loops

In a C like language, we can declare a for loop as such:
for(pre; condition; post)
where "pre" is something that happens before the loop starts, "condition" is a check that happens before each run of the loop, and "post" happens after each time through the loop. We can get even more fancy and do more than one of each of these. For example, we could have this:
for(pre1, pre2; cond1, cond2; post1, post2)

In this case, "pre1" and "pre2" happen before the loop, "cond1" and "cond2" are evaluated before each run of the loop, and "post1" and "post2" happen after each run of the loop.

Be careful however when placing commas between the conditions.  This may cause unexpected behavior in your program.  When conditions are separated by commas, they are evaluated as OR.  This would be the same as cond1 OR cond2. In my recent C programming adventures, I spent a non-trivial amount of time tracking down this misbehavior. Eventually, I changed the comma to the explicit AND operator and everything worked as expected.  For those interested, the line was as follows:

This causes problems:
for(i = 0; i < index, cur != head; i++, cur = cur->next);
This works the way I want:
for(i = 0; i < index && cur != head; i++, cur = cur->next);

Two loops you didn't know about

Most of us that program are familiar with a few basic types of loops.  We all know the while loop, the for loop, the "for each" loop and the "do while" loop.   Today you'll learn about two little used loops that are built into many modern languages.  I'll show you the pseudo code for the constructs.

Everybody has written some sort of program that got stuck in an infinite loop.  More than likely you wrote a while loop where the condition never became false.  It's possible to write and infinite "for each" loop, but it just takes more work. If you find yourself needing an infinite "for each" loop, you could instead use the special "for ever" loop construct.  This loop is especially handy when you want to iterate through a list infinitely.  The forever loop will iterate through your collection and start right over at the beginning.

forever ( theList : listItem ) {
    //do some stuff
}

The next obscure loop is similar to a "do while" loop.  The do while loop executes the body of the loop once, evaluates the conditional, and executes the body again until the condition is false.  The "don't while" loop is slightly different.  The don't while loop skips over the body of the loop and evaluates the condition.  If the condition is true, the body of the loop is skipped, until the condition becomes false at which point the loop body executes exactly once.

don't{

      //only executes once
     // after the condition is false

}while(condition)

Next time you're trying to write obscure barely functional code, consider using these special loops.  These loops are a really convenient way to confuse new programmers that look at your code.  Experienced programmers will be equally baffled by your decision to utilize such loops.  Happy April 1st!

Keep your OSX workspaces in order

As an OSX user I frequently divide my work up into multiple workspaces.  I keep my email and chat program open on one, IDEs in another, and my browser in a third.  This is especially handy when working without a second monitor, because I can effortlessly swipe between workspace without having to click around to find my windows.

This system works really well until OSX decides to help me out by rearranging my workspaces automatically.  Expecting that my IDE is always to the left of my browser workspace, I swipe left only to find that my email and chat windows are now there.  This can get really annoying when I have 5 or 6 workspaces open, as I end up playing hide-and-seek with windows.

Thanks Mission Control, but I don't need your help.

Fortunately, the solution is simple.  Go into System Preferences >> Mission Control and uncheck the option for "Automatically rearrange Spaces based on most recent use".  Now you can arrange your workspaces without OSX trying to outsmart you. 

I call BS...

A few weeks ago, I bought a pair of jeans from Sears at a local mall.  It has become common practice for retailers to email receipts to customers instead of printing four feet of paper.  Of course, in order to do this, they have to solicit your email address.  And when the cashier asked to my email address, I gave it to her.

In addition to receiving the receipt for my purchase, I was involuntarily signed up for spam.  Over a span of 11 days, I received 6 advertising emails from Sears.  The stupidest thing about the entire situation:  I unsubscribed after the second email.  Why do they keep sending me ads after I've told them I'm no longer interested?

A huge pile of shit

When I clicked the unsubscribe button on the website, I expected to see a message saying that I was unsubscribed and would no longer receive advertising emails.  Instead, Sears showed a popup saying that it would take 7 - 10 days to process my request.  If I weren't a computer science major, I might believe that.  In fact, any logical thinker could figure out that this is just a marketing tactic.

It's highly suspicious of them to quote "7-10 days" to unsubscribe, when it took them about 30 seconds to get me in the system in the first place.  Seriously, my phone was buzzing away with new emails before I reached my car.  I wonder, what about their system causes it to take 20,000 times longer to unsubscribe me for the list than it took to subscribe me in the first place?

Certainly, it's not a technical issue.  I don't know the exact workings of Sears email system, but it wouldn't be unreasonable to think that three or four SQL statements got me in the system.  Unsubscribing should be simpler: I'm thinking one SQL statement ought to drop me from the list.  The last time I checked, it didn't take 7 days to process a SQL command.  Unless they have to send a tech down to the data center to scrub my name off the hard drive with a Q-tip, this practice is inexcusable.

As I've deduced that there's not a technical factor at play here, the logical explanation is that the 7-10 day delay is simply a matter of policy.  This policy only serves one real purpose... to distribute more spam.  From the moment I click unsubscribe to when my name actually goes off the list is a window of opportunity to send me a few more emails.  Admittedly, this a great marketing tactic masquerading as a technical limitation.  It still doesn't make me hate spam any less though.  That four foot receipt might not be so bad after all.

Making an endless list load smoothly in Android

In my latest Android app endeavor, I needed to create an endless list.  There's no built in class that does this, so I had to create something that would approximate one.  There are plenty of tutorials on the basic ideas behind endless lists, but none of them worked very well for my application.

My app is a viewer for interfacelift.com, which provides high quality wallpaper downloads.  The app displays a list of wallpapers in descending chronological order.  The user can continue scrolling indefinitely (until the site runs out of wallpapers).   The standard way of approaching the infinitely scrolling list tends to be glitchy when the next set of wallpapers loads.  I've come up with a simple solution to solve the glitchy-ness problem.

When the app loads a set of wallpapers, it adds them to an ArrayList, which is displayed by the ListView.  However, the list adapter doesn't know about the new wallpapers until it is explicitly told that the data set has changed with a call to notifyDataSetChanged().  When this happens, the list adapter is forced to update all of the views.  In my app's case, issuing a new view sets the ImageView's drawable to a placeholder, which is almost immediately replaced with the real image.  This causes the entire list to "jerk" when the existing images are updated.

Continue reading to see code solution.

The quest for the perfect writing spot

Normally, I don't need any extra motivation to write an article here.  I enjoy writing techie articles that four people a month read.  Writing papers for English class is a bit different.  It's more challenging.  I have no aversion to being challenged, it just takes a bit more motivation to get going.  Today I set out leaving the comfort of my own apartment and find the perfect spot in Spokane to jump start my writing mojo.

As a coffee lover, it was only natural that I seek out a coffee shop to conduct my work.  I tossed my Macbook in my backpack and set foot toward the nearest bus stop.  My bus trip ended in downtown Spokane, near River Park square.  I didn't have any predetermined coffee destinations in mind, the only criteria was to avoid Starbucks.  I realize that these establishments are businesses, not temporary offices, and thus limited my stays to around an hour.

The first stop of the day: Thomas Hammer in downtown Spokane.  I ordered my favorite non-latte drink, the Fireball (no, it doesn't have Fireball whiskey in it).  This drink is essentially a mocha, with a shot of orange syrup in it.  It is weirdly delicious.  The barista even made latte art in the drink, but sadly I wasn't able to admire its beauty as she covered it with the lid immediately after pouring it, though the imprint of the art was visible through the lid for a few fleeting moments.  Aside from a few noisy patrons, the environment was fine for productivity.  I didn't need to squirm in the chair, as the seating was quite comfortable.  There were no power outlets to be found. Fortunately, my machine had enough charge to get me through an hour, after which I left to avoid overstaying my welcome.  Thomas Hammer had Wi-Fi, but it was password protected, so I used my Nexus 4 as a hotspot instead.

About three blocks away, I found the Brews Brothers coffee shop, a place with a friendly atmosphere and chatty customers.  The barista there seemed to know a lot of the customers by name, indicating that many of them were regulars, a good sign indeed.  This time I ordered a chai latte, and that's all I have to say about that.  This time, I was able to situate within reach of a power outlet.  Again, Wi-Fi was password protected, so I whipped out my phone once again.  The atmosphere here was much more conducive to writing.  There space was large enough to dissipate the individual conversations and native noises of a coffee shop.

Finally, after wandering the blocks for a few minutes after lunch, I located Atticus.  This joint was by far the busiest of three I had visited today, and it was 2 PM.  Admittedly, much of the traffic in the store was on the gift shop side, but there was still about 20 people occupying tables and enjoying coffee.  I ordered a plain latte this time, which was the cheapest drink I bought at $2.99 after tax.  Atticus expects a certain volume of sit down customers, serving drinks in ceramic mugs if you choose to stay.  Props to them for saving the environment and saving money on cups.  Now that I had my latte, I needed a place to sit.  All of the individual tables were taken, leaving me to take a chair at one of the large group tables.  These tables are an open invitation for group activities, as every time I've been to this establishment, there were groups of teenagers doing homework at the tables.  Atticus even posts signs on the tables to the tune of "We are a business, not a study hall or an office. Please don't hog the seating."  Despite the bustling atmosphere, I was able to get some work done here.  And the latte was decent.

It should be noted that none of these places had open Wi-fi, though it was free at all of them.  It seems that coffee houses are either WPA protecting their Wi-Fi to stop people from squatting or give patrons better security.  If I owned a coffee shop, I'd probably do the same.

Of the three shops I sampled today, I would be most likely to return to Brews Brother to get some work done.   Lots of seating options and a large(ish) room made this place desirable for getting work done.  Naturally, I'd order a drink that wasn't a pre-made chai tea, as pre-made chai is just too sweet for my taste.