Using Agile in less-than-perfect situations since Y2K
It’s nearing the end of the year, which is a good time to reflect on things. I have found myself reflecting a bit on adages, axioms, and the like. You know, the “stitch in time saves nine,” “look before you leap” kinds of things. Those little snippets of wisdom that help to convince us to do the right thing.
Software development has a few of these:
- red, green, refactor
- Individuals and interactions over processes and tools
- Don’t break the build
- Perfect is the enemy of the good
That last one really started off a train of thought for me. How do we know when we’ve reached “good” and when we’re trying too hard to reach perfect? This is particularly interesting to me as I often struggle with “leaving well enough alone,” to pull out another cliché. I’m not sure of the exact set of circumstances that led to it, but somehow I started thinking about value versus cost. All of that coalesced to this:
The Best You Can Afford
That’s how you know when to stop. When you can’t afford to keep making it better anymore. That is, when the value of what you’re working on isn’t worth the effort compared to the other things you could spend that effort on. (I’m sure that’s one of the worst-written sentences ever, but it makes the point.)
At first blush this seems obvious. We all apply this every day to an extent right? Well, not necessarily. The best you can afford is very easy to confuse with the worst you can afford. That is putting in the least effort possible to just get by. We see and do this all the time.
What, really, is the difference? The difference is in what these two tactics get you in the long run. Aiming for the worst is attractive because it is, somewhat obviously, the cheaper option. However, that obvious cheapness results in, well, results that are obviously cheap. In physical products this can mean flimsy plastic parts and a shorter life span. In software, this can mean more defects, a hard-to-use product, and upset end users. Worse yet for software, it often also means a harder time performing the maintenance tasks that can be more than 80% of the cost and time spent working on the software.
Aiming for the best is harder to justify up front because so many of those costs are unknown. However, the attention to detail means physical products that people love to use, use for a longer time, and will recommend to others. It mostly means the same in software. Another benefit for software is that maintenance takes less time and is easier for those who must do it.
So now we have a guideline that can tell us when we are spending too much on heading for perfect: when the value of what you are doing is less than the value of doing something else.
I’m going to finish up with an example that a lot of people have used when making similar points. I’m sure a number of readers will roll their eyes as soon as I mention the product, but I urge you to not focus on that, but instead pick some other product or product category and make some comparisons of your own. When has the “worst” product won? How did it win? When has the “best” product won? How did it win? Which of those products started out ahead an then lost?
The product that I think I can most easily make a case for being built using “the best you can afford” mentality is: the iPhone. To see why, we have to go back to before the iPhone was announced or really speculated about. Back in the early 2000s, there were rumors of Apple working on a tablet computer. These rumors persisted ultimately until the iPad was released. It seems, based on all accounts, that these rumors were true. And again based upon what we have heard, Apple was working on what would become the iPad *before* the iPhone.
This is significant because it points out that Apple, whether you decide that means Steve Jobs, Jonny Ive, a host of other folks, or the combination of all of them, Apple was focused on making the best thing they could. At some point, who knows exactly when, someone realized that what they had—a touchscreen computer with a simplified OS—would make a great phone. At that point, the team felt that the iPad was the “best” product, but the “best they could afford” to make at the time was the iPhone.
Further, it is obvious that Apple doesn’t and never did release a version of the iPhone (or iPad) without work already being in progress on the next version. This implies that the “best we can afford” is a philosophy deeply ingrained into Apple. They are continually working on something better, but they release something that is “good enough”.
There are a number of people out there who will point out that the iPhone isn’t the number one phone any longer or that it won’t stay that way for long. I’m sorry, but I don’t buy it. For one thing, there are at most two kinds of iPhones (not counting storage size differences) available for sale at any one time. This isn’t true for any other type of phone. Also, while Apple only has a certain share of the number of devices sold, its share of the profits is much larger. That is, Apple can afford to sell fewer units because it can also manage to charge more for them. Profit is the goal of a company. Selling the most units is worthless if you don’t also have profit.
I humbly believe another example of the application of “the best you can afford” is the Improving Podcasts that I co-host with Allen Hurst. This was an idea that Allen and I had around two years ago. We wanted to create a software development podcast and have it associated with our company, Improving Enterprises. We spent several months getting some momentum built and finally realized that it was at a point where we had to release something or risk never publishing an episode. Because of that, the first episodes were more work, and the audio quality was suspect. Over time the best we could afford got better until we found, espeically due to the time involved, recording all audio over Skype was a solid balance of creating something of value without detracting from our other valuable works. This reduced the editing time significantly, allowed for remote participation, and was repeatable by either one of us. However, it also means that occaisionally we are subject to the audio difficulties and other problems associated with remote audio.
I could go on, but at this point this article is as long as I—and probably you as well—can afford. It is also the best I can afford right now. I’m sure I could fix some grammar, make some points more clearly, etc. However, I have other work to do and family to be with. I leave you with this question: How might your life and the lives of those around you improve if you stopped doing the worst you can afford and instead did the best you can afford?
Yesterday, I posted my technique for installing Informix on a Mac. Well, it turns out I wrote just a bit too soon. What I had was indeed working, but only for the “dbaccess” tool that ships with Informix. Trying to connect from a Java (JDBC) application failed.
Thanks to Eric Herber’s comment on that post, the
Reading through the PDF, it notes that the informix user and group are required in order for things to work properly. Examining my install, it seems that the IDS installer tried to create the informix group, but somehow assigned it the same group ID as the _lpoperator group. I believe _lpoperator is the group of people who can use the Mac’s printers. Regardless, it wasn’t the informix group that it should have been.
Important! If you don’t understand what is meant by user and group here, my best advice would be to get someone who does to help you. I don’t want to insult anyone, but making changes to the things I am about to mention could render your machine unusable. Here be dragons!
To fix this issue, I had to do two things. First, create the informix group and make it the informix user’s “primary” group. Second, I had to change the group ownership of everything in my Informix install directory from _lpoperator to the new informix group. The PDF talks about using the Workgroup Manager that is available in the OS X Server Admin Tools. I will let you read that for the details except to say that the correct URL for acquiring the tools depends on the version of OS X you have. Regardless, the URL in the PDF is outdated, as is one I found in a search on MacOSXHints. The best means I have found is to go to the Apple Support site’s Advanced Search, enter “server admin tools”, select the radio button to match all keywords, use the drop-down to restrict the document type to “Downloads”, and pick the version you want from the results. I am far from certain, but it would make sense to pick the one closest to your version of OS X.
Once you have the Server Admin Tools download, it is a simple, and typical Mac install. Once installed, you can run the Workgroup Manager tool more or less as stated in the PDF. Do not skip the step that asks you to select “Show All Records” from the “View Menu”. This may be “Show System Records” depending on the version of the tool. If you know a little about Unix user management, the tool is fairly intuitive. If you know a lot about Unix user management, you may prefer the command line tools that can do the same thing. Regardless, I simply had to create the informix group and make it the informix user’s primary group.
It is worth noting that if I had created the informix user and group using this tool before running the installer, I probably would not have had the _lpoperator nonsense nor would I have had to do the next step: changing the group ownership of all the files in my Informix install.
To change the group ownership, I went back to the command line and did the following:
$ cd /Applications/IBM/informix $ ls -l total 11656 drwxr-xr-x 3 root staff 102 Aug 15 2008 CSDK drwxr-xr-x 5 root staff 170 Aug 15 2008 DBLD drwxr-xr-x 3 root staff 102 Aug 15 2008 ICONNECT -rw-r--r-- 1 root staff 5904 Aug 14 2008 README.html drwxr-xr-x 7 root staff 238 Aug 15 2008 SERVER drwxrwxr-x 4 informix _lpoperator 136 Jan 13 15:50 aaodir drwxr-xr-x 109 informix _lpoperator 3706 Jan 13 15:54 bin ... -rwxr-xr-x 1 root _lpoperator 29713 Aug 14 2008 uninstallserver $ sudo chgrp -R informix aaodir ...
Note: The “…” on line 11 means there were a lot of other entries. The one at the end means that I repeated that “sudo chgrp” for all of the files and directories that had group ownership of _lpoperator.
The “sqlhosts” File
That group information was annoying and tedious to fix, but it was not really the problem. If you recall from the earlier post, there are some environment settings that need to be loaded. One points to a file that is very important to enabling clients to connect to the server: INFORMIXSQLHOSTS. The whole purpose of the file is to define the mechanisms by which clients can connect, this means whether they must be using shared memory space or can use sockets and what port they use to connect. The one created by the installer for the demo database has a single line that looks like this:
demo_on onsoctcp yoda.local 9088
The first is the dbservername and is correct for the demo database. The second is a three-part string that identifies how clients can connect. In short, “on” means a regular database server (short for on-line as in OLTP maybe), “soc” means sockets as opposed to “shm” for shared memory, and “tcp” means the network protocol. So, this seems right as well. The other two entries are the machine hostname and the port. However, although my Mac is named “Yoda” (yes, I’m a Star Wars geek), that is not listed in the /etc/hosts file. I changed this to “localhost” which is in the hosts file. Finally, that last entry is meant to be the service name from the /etc/services file, not the port number. To figure out how to change this, I used the following command:
$ cat /etc/services | grep Informix sqlexec 9088/tcp # IBM Informix SQL Interface sqlexec 9088/udp # IBM Informix SQL Interface sqlexec-ssl 9089/tcp # IBM Informix SQL Interface - Encrypted sqlexec-ssl 9089/udp # IBM Informix SQL Interface - Encrypted
My final file still contains one line, which looks like this:
demo_on onsoctcp localhost sqlexec
And now, everything is working smoothly. Whew!
Update: I had some problems connecting to Informix via Java. Also, the process below led to an issue with the “informix” user’s group settings. I have created a “part 2″ post to detail what happened and how I managed to fix it. Please read that before using these instructions to perform your own install.
I have recently started a project with a group that uses Informix as the database. To set up my development environment to match production as closely as possible, I have installed IDS for Mac. The instructions that you can find on the web caused me some difficulty. There is a video available from IBM that would be great, but it seems to be outdated slightly. (Viewing it may still give you some benefit, so you can find it here.) To save myself time in the future if other Mac users need to join the project, I have documented what I believe to be the final process here.
- Do not start this process without a current system backup. System settings are going to be modified.
- I tried to document this as I went, however I did make some discoveries late and then inserted them where I believe I should have done them. Those have not been retested.
- It is likely there are better/faster ways to do some of these things.
- There may well be additional steps needed to add additional databases or if your usage is heavier than mine to date.
If you try this out and find some things that don’t work or ways to make it faster or easier, please let me know in the comments. I will happily incorporate them.
One quick formatting note, when command examples are given, the “$” at the beginning of a line is in place of the command prompt. By default in the Mac Terminal app, this is usually of the form “hostname:current_directory username$”. If you copy and paste the commands, remove the “$” and the space after it.
- Download IDS here
- Mount the downloaded IDS disk image (iif.11.50.FC2DE.macosx64.dmg)
- Double-click the install package (iif.11.50.FC2DE.macosx64.pkg) and follow the prompts.
- Enable root user and log in as root. Note: It might be possible to follow the steps using only sudo, but most on-line instructions say to use the root account method. As such, this is what has been tested. Instructions provided below are for Snow Leopard 10.6.2.
- Open System Preferences
- Click “Accounts”
- Click “Login Options” (just above the lock in the bottom-left)
- Click the button next to “Network Account Server:” (near bottom-middle)
- Click “Open Directory Utility…”
- Click the lock (bottom-left) and enter admin password
- In the menu-bar, choose “Edit” then “Enable Root User”
- Enter a password for the root user
- Quit Directory Utility.
- Close System Preferences
- Log out
- Choose “Other” from the log-in menu and provide the root as the username and the password entered previously.
- Kernel options:
- Kernel options should be as follows per the IDS README files. (To avoid issues, system settings can be higher, but not lower):
kern.sysv.shmmax=4398046511104 kern.sysv.shmmin=1 kern.sysv.shmmni=512 kern.sysv.shmseg=512 kern.sysv.shmall=1073741824 kern.sysv.semume=10 kern.sysv.semmsl=87381 kern.sysv.semmnu=87381 kern.sysv.semmns=87381 kern.sysv.semmni=87381 kern.maxfiles=2147483647 kern.maxfilesperproc=40000 kern.maxvnodes=150000
- To check them, use the following command:
$ sysctl kern.sysv.shmmax kern.sysv.shmmin kern.sysv.shmmni kern.sysv.shmseg kern.sysv.shmall kern.sysv.semume kern.sysv.semmsl kern.sysv.semmnu kern.sysv.semmns kern.sysv.semmni kern.maxfiles kern.maxfilesperproc kern.maxvnodes
- Compare the output to the list above.
- To adjust any that need to be changed, use the following command (may not work for kern.sysv.shmmni):
$ sysctl -w
And copy the key-value from the list above (ex. kern.sysv.shmmax=4398046511104)
- Those command-line changes will disappear after a reboot. To make them permanent, edit /etc/sysctl.conf and simply paste the desired key-values. This is an important system file. Make a backup of the file first!
- Kernel options should be as follows per the IDS README files. (To avoid issues, system settings can be higher, but not lower):
- Two options (the first runs a CLI installer, the second may run a GUI installer):
- Open a terminal window, navigate to /Applications/IBM/informix and run “ids_install”
- Open the finder, navigate to /Applications/IBM/informix and double-click “ids_install”
- Follow the installer prompts. Accept defaults as much as is possible except for the demo server installation and terminal emulator. Be sure to select “Yes” for the demo server and do not use the terminal emulator option.
- Launch a terminal window.
- Execute the following command (assuming a Bash shell):
$ . /Applications/IBM/informix/demo/server/profile_settings
- If desired, copy the settings in that profile_settings file to your profile (as well as the profile of root and/or the informix user created by the installation).
- Run the following command to load the demo database, which will not be in your path (actual location: /Applications/IBM/informix/bin):
- Run the following command to connect to the database:
- The interface is navigable using the arrow keys on the keyboard, go to “Table”
- Select the database “storesdemo@demoon”
- Select “Info”
- Select the “‘root’.stock” table
- Select “Columns”
- View the information (no more detail will be gone into here on using the tool)
- Select “Exit” and repeat until the tool quits.
- You can now log out as root and back in as your normal user.
- If you want to use the informix user to start/stop your database, continue. Otherwise, you can use the root user. Both will work from a terminal.
- Open Terminal and navigate to the /Users directory.
- By default, the install creates the informix user’s home directory but leaves it owned by the root user. To change the owner use (enter your password when prompted):
$ sudo chown informix informix
- Use “su” command in the Terminal to log in as the informix user (enter the informix user’s password when prompted):
$ su - informix
- Use the command below to print the contents of the needed settings to the terminal:
$ cat /Applications/IBM/informix/demo/server/profile_settings
- Select the text (using the mouse) and copy it using Command-C.
- Edit (or create) a .profile file in the informix user’s home directory:
$ cd ~ $ vim .profile
- Enter VI’s insert mode by pressing “i”, and paste the copied settings using Command-V.
- Save and exit VI by pressing Escape, then entering “:wq” (without the quotes).
- Log out as informix and setup is complete.
- Open a terminal and use the “su -” command to log in as root or the informix user. The “-” is important, as it ensures the user’s profile is loaded. If the informix user was enabled to start/stop the database according to the optional steps during installation, this loads the appropriate settings and “informix$” will now be the command prompt. Otherwise, the settings in /Applications/IBM/informix/demo/server/profile_settings must be loaded manually using this command:
$ . /Applications/IBM/informix/demo/server/profile_settings
- Run the commands below. The output should match:
$ oninit $ onstat - IBM Informix Dynamic Server Version 11.50.FC2DE — On-Line — Up 00:00:09 — 41756 Kbytes
- Open a terminal and use the “su -” command to log in as root or the informix user. (Note: “informix$” is now the command prompt.)
- Make sure the settings in /Applications/IBM/informix/demo/server/profile_settings are part of the environment.
- Run the commands below. The output should match.
$ onmode -ky</blockquote> $ onstat -</blockquote> shared memory not initialized for INFORMIXSERVER ‘demo_on’
For Father’s Day this year, my family gave me the gift of a stereo Bluetooth headset. I had been asking for one since the iPhone announced support for A2DP headsets. (Basically, simple stereo headphone support.) The one I got was the Plantronics Voyager 855. I can’t speak highly enough about it. There may be sets with better sound or build quality, but I haven’t had any problems with the set itself. And at just over $30 it is far cheaper than most. Listening to podcasts or music while mowing the lawn or whatever else is fantastic. The combination of in-ear buds that block out external noise and the wireless connection to the phone—I can’t believe I lived without it for so long.
However, the iPhone’s Bluetooth support is not the best. I have an 8GB 3G, and had a lot of trouble with the audio cutting out. Worse, the same was true when I was on a call. I could usually hear just fine, but folks on the other end would tell me that my voice was cutting out. I was starting to blame the headset and was preparing to buy a more expensive model.
Fortunately, I noticed two important things. First, the podcast/music audio cutting out tended to only happen when the screen locked. This was true whether or not I pressed the lock or let the phone auto-lock. Second, I noticed that Apple’s iPhone OS 3.1 update mentioned attempting to fix problems with Bluetooth and wireless (Wi-Fi). In their case, they were trying to improve Wi-Fi performance.
Because of this, I decided to experiment a bit. I disabled the Auto-Lock feature and disabled Wi-Fi. Suddenly, I had no more skipping and cut-out problems. People said calls did not cut out either. I tested this way for about a day. I was able to get the audio to cut out by launching a CPU-intensive app, but only during the launch. Once the app was running, the audio came back with no more problems.
After that, I re-enabled the auto-lock. I locked and unlocked the phone. Still no cut-out problems. I then turned Wi-Fi back on. No cut-out problems. Then I locked the phone. Bingo! Audio started cutting out again. I disabled auto-lock, but the problem was still there when I locked the phone. Finally, I disabled Wi-Fi and turned auto-lock back on. No more skipping or cut-out problems.
It turns out that the iPhone is built such that Wi-Fi and Bluetooth share an antenna (presumably to share space). This causes problems when both are on. Apple seems to have found a way to manage this most of the time and even released updates to improve Wi-Fi performance. However, as has been true of iPhone Bluetooth support all along, they seem to have neglected to do the same for Bluetooth. Specifically, something seems to happen to the Bluetooth power (and possibly the Wi-Fi power) when the phone is locked. The combination of signal degredation from both being on and the phone being locked causes the problem.
The moral of the story? If you want to use a Bluetooth headset, disable Wi-Fi. If you want to use Wi-Fi, disable Bluetooth. That will get you the best performance. Now back to enjoying my wireless music while refactoring.
The one or two of you who actually come to the site to read these posts may have noticed that a few weeks ago, I added a link to Improving Podcasts in my sidebar. Allen Hurst, I, and a few other Improving employees have started producing a bi-weekly (every other Tuesday) podcast covering software development topics.
We have three episodes produced, and the latest was posted just this afternoon. (It may take some time for it to show up in iTunes.) The topics to date have centered around Agile projects management and development practices. Head over there, listen, subscribe, and please provide feedback. We really would love some positive feedback in iTunes, but to suggest topics, ask questions, or invite yourself to join us, the best place is the web site itself.