You comb Hacker News daily, marveling at the neatly packaged startup tales, uber-effective best practices, super clever engineering solutions, and lots and lots of links to websites filled with Helvetica, minimalism, and pastel colors. You’ve attended Lean Startup workshops, read Four Steps to the Epiphany, and subscribe to the Silicon Valley Product Group blog.

Honestly, it’s all very intimidating.

My product advice, from one overthinker to another overthinker – throw it all away. I mean, read the articles, enjoy the stories, and try to form your own opinions, but I wouldn’t take it too seriously.

A year into my first startup, my first major product epiphany was to never, never, ever try to build a product you couldn’t be a user for. That may be obvious, but I still read people discussing strategies for building products that they don’t use. There is no better user study, no more accurate persona than asking yourself what is good. There are probably product people out there that can do it, but, no offense, it’s probably not you, and it’s certainly not me.

There are many pros to building a product that you would use. Actually using a product (and I mean really using it), allows you to access the powers of intuition, an infinitely more valuable product tool than reason. Your intuition explains to you in a moment what it takes your reason an hour to break down. Your reason will lead you down a dozen wrong roads.

Another way of saying that is: if you think it’s cool, it’s probably cool. If you think it sucks, it probably sucks.

However, building a product for yourself doesn’t give you a free pass from user research, personas, and all the other things that product gurus tell you to do. Spend a year having the same product discussions with the same group of people, and the discussions will lose all meaning. Talking to five people outside of the company will bring you back to earth real fast.

One last thing…whatever you build, make sure it looks good and is the highest quality possible.

But wait, you say, look at eBay, Amazon, and Craiglist – they look like crap. Implement an MVP with product/market fit, and it doesn’t matter what it looks like. That’s true sometimes, but it also depends on where you are on Maslow’s hierarchy of needs. The lower on the pyramid your product is, the crappier it can look. If your product is core to helping people make money, pirate movies, or sell your useless couch, you don’t need a designer. But if you’re high on the pyramid, ugly/clunky UI makes it impossible to for people to see your vision.

If you read Steve Jobs biography, it talks about one of the three original Apple philosophies: an odd word called impute. It’s basically a philosophy around impressions. On product, they said, “If we present them in a slipshod manner, they will be perceived as slipshod”.

Speaking of the biography, I’ll wrap up with my impression of that book. It’s a story about a product genius, but it’s a story with as many missteps as triumphs. I take the moral of the story to be: forget the experts, the know-it-alls, and the doubters. Trust yourself and your vision, and go build something.

At Miso, we recently launched an integration with AT&T that allows the Miso iPhone app to connect with your TV. Have you ever thought that browsing hundreds of cable channels on your TV was a painful process? Our vision with Miso is that you can turn on your favorite show, see what your friends are watching, or browse additional information about a show, all from your phone.

To make this happen, Miso connects with the AT&T receiver over wifi, and we’re learning from our early adopters that home networks are more complicated than they used to be. Wifi routers are definitely the norm, and it’s not uncommon to have multiple wifi routers cover the living room, the master bedroom, and the guest bedroom upstairs. If you’re plugging in a wifi router that you bought from Best Buy, you’re probably creating a new subnet, which is something you almost never need to care about.

As it turns out, Miso’s integration with AT&T and DIRECTV both assume that a home only has one subnet, which is not always true. This has caused some support issues and prompted some people within Miso to ask, what is a subnet? Good question! As a programmer, I have some basic knowledge of network engineering, but answering this question prompted me to dig a bit deeper.

What is a subnet?

Subnets and IP addresses go hand in hand. Together, they are the building blocks for how computers find each other on a network. For instance, every time you visit a website, you first have to find the computer on the internet that hosts that website.

Addressing on the internet works a lot like mailing addresses for your apartment. The zip code for my apartment is 94105; if you were to Google that, you could see that I live within a certain region of San Francisco. Subnets are like zipcodes – they divide up the internet world into small regions.

The subnet is actually part of the IP address. You’ve probably seen an IP address for a computer. My IP address at this coffee shop is 192.168.5.199. The first three numbers (192.168.5) is the subnet (or network address) and the last number (199) is my laptop’s address (host address). The guy sitting at the next table probably has an address like 192.168.5.198. Because we’re on the same subnet, we could do things like share playlists with iTunes or exchange files on a shared folder. The three numbers that form the subnet are somewhat random, in the same way that zipcodes are somewhat random.

For nerds only: the tricky part is that which part of the IP address is the subnet actually varies, and it determines how large the subnet is. The mechanisms for dividing up address space has evolved over the years, from classful addressing to classless addressing. We’re at the point where we’re out of IPv4 addresses, thus the creation of IPv6 which has many more available addresses.

So, great, subnets are like zipcodes. They group computers together in some logical way. Laptops in the same cafe are probably on the same subnet and can do stuff like share iTunes playlists, and laptops that are in different cafes probably can’t. Yet, there must be some way to communicate between subnets. The websites that I visit every day are hosted on computers that are all on different subnets.

How does information travel between subnets?

Sending information across subnets is a lot like sending mail across the country. After writing the address on the envelope, I deliver the letter to my local post office. My local post office looks at the zipcode and begins the process of routing the letter through hubs to bring the letter in the general vicinity of the destination address. As the letter approaches the destination address, it will be given to another local post office, which ultimately puts it on a mail truck that goes to the actual address.

In the same way, let’s say that I want to visit google.com. From my laptop, the address for google.com is 74.125.224.114. My laptop has no idea where that address is, so it does the equivalent of delivering my request to the local post office, which is the wifi router of this coffee shop (you may have also heard this referred to as a gateway). The coffee shop’s wifi router also doesn’t know where that address is, so it forwards the request to the internet provider (ISP) of the coffee shop. The internet provider has a better sense for zip codes, so it starts the process of sending the packet in the right direction.

For nerds only: This process is called IP routing and there are several algorithms for doing it and they vary with IPv4 and IPv6. The algorithms differ in how chatty they are and what size network they work well with, among other things. Many algorithms are based on Dijkstra’s algorithm.

So how come I can’t share my iTunes playlist with any computer?

I can access google.com from anywhere, but I can’t access that laptop from the other coffee shop. The reason for that is that there are many more computers (and IP addresses) than there are mailing addresses, so they can’t all be public. If you work in a large business, then your department probably has an internal mail stop that’s handled by your company’s mailroom.

In the same way, internet addresses are divided up into public and private addresses. Public addresses can be reached from anywhere, but private addresses can only be accessed in local networks. Public addresses are handed out by the internet equivalent of the post office called the Internet Assigned Numbers Authority (IANA). If I want a public mailing address, I have to contact the post office. If I want a public IP address, then I have to contact my internet provider. My internet provider is a member of a Regional Internet Registry (RIR), which is a member of the IANA. It’s fairly common that one home will have one public IP address, although you can pay your ISP for more.

So, why doesn’t AT&T and DIRECTV work across multiple subnets?

Hopefully, you have a high level sense for internet addressing, subnets, and routing, although we still haven’t explained why our AT&T and DIRECTV integrations don’t work across multiple subnets yet. We need to understand one more concept – multicast.

Most network communication is two computers talking to each other directly. In some cases, you want to communicate with multiple computers at the same time. Broadcast and multicast are the two ways of doing that. In order for Miso to find the cable receiver, it makes an announcement over multicast asking if there are any cable receivers in the network. That’s the same way your computer discovers printers on your local network.

As you can imagine, multicast announcements can be pretty noisy. Imagine if my laptop made a multicast announcement and every computer in the world had to pay attention; things would get pretty chaotic. Therefore, multicast messages only go out to current subnet. If my cable receiver is on a different subnet, it won’t receive my multicast announcement.

There are a number of ways of overcoming this problem which include adjusting multicast TTL levels, router port forwarding, or configuring routers as bridges. TTL (Time-to-live) tells the multicast message how many hops to take before it should give up. By default, this value is 1, which means that it will deliver the multicast messages to all computers on the local subnet only. Router port forwarding and configuring routers as bridges are other mechanisms for allowing the multicast traffic to hop across to an adjacent subnet; however, for our AT&T integration, they are less ideal because they involve users understanding how to administer their home networks.

Hopefully, you found this high level guide useful. Feedback welcome!

Using and sharing iOS libraries is tragically difficult given the maturity of the framework, the number of active developers, and the size of the open source community.  Compare with Rails which has RubyGems and Bundler, it’s no surprise that Rails/Ruby has a resource like The Ruby Toolbox, while iOS development has…nothing?

Are iOS developers fundamentally less collaborative than Rails developers?  When developing on Rails, if I ever find myself developing anything remotely reusable, I can almost always be certain that there is a gem for it (probably with an obnoxiously clever name).

I don’t think the spirit of collaboration is lacking in the iOS developer community; rather, there are a few fundamental challenges with iOS library development:

• Libraries are hard to integrate into a project.  Granted, it’s not *that* hard to follow a brief set of instructions, but why can’t this process be more streamlined?
• No standardized versioning standard.  Once a library is integrated into a project, there is no standard way of capturing which version of the library was used.
• No dependency specification standard (this is a big problem).  Why does facebook-ios-sdk embed it’s own JSON library when there are better ones available?  So many libraries come embedded with common libraries that we all use – and worse than that, who knows what version they’re using!  Not only can this lead to duplicate symbols, but library developers essentially have to start from scratch instead of leveraging other existing libraries.

Of course, coming up with a naming, versioning, and dependency standard for iOS libraries and convincing everyone to adopt it is a daunting task.  One possible approach is follow the example of Homebrew, a popular package manager for OS X.  Homebrew turned installing and updating packages on OS X into a simple process.  Instead of convincing everyone to comply to some standard, Homebrew maintains a set of formulas that helps describe commonly used packages.  These formulas allow Homebrew to automate the installation process as well as enforce dependencies.  This works well for Homebrew, although it puts the burden of maintaining package specifications in one place, rather then distributed as it is with Ruby gems.

There seems to be a need for some type of solution here.  When we write Rails libraries, we write the readme first to help us understand what problem we’re trying to solve (Readme Driven Development).  Below is the readme for an iOS packaging system called Vendor.

Vendor – an iOS library management system

Vendor makes the process of using and managing libraries in iOS easy.  Vendor leverages the XCode Workspaces feature introduced with XCode 4 and is modeled after Bundler. Vendor streamlines the installation and update process for dependent libraries.  It also tracks versions and manages dependencies between libraries.

Step 1) Specify dependencies

Specify your dependencies in a Vendors file in your project’s root.

source "https://github.com/bazaarlabs/vendor"
lib "facebook-ios-sdk"  # Formula specified at source above
lib "three20"
lib "asi-http-request", :git => "https://github.com/pokeb/asi-http-request.git"
lib "JSONKit", :git => "https://github.com/johnezang/JSONKit.git"

Step 2) Install dependencies

vendor install
git add Vendors.lock

Installing a vendor library gets the latest version of the code, and adds the XCode project to the workspace.  As part of the installation process, the library is set up as a dependency of the main project, header search paths are modified, and required frameworks are added.  The installed version of the library is captured in the Vendors.lock file.

After a fresh check out of a project from source control, the XCode workspace may contain links to projects that don’t exist in the file system because vendor projects are not checked into source control. Run `vendor install` to restore the vendor projects.

Other commands

# Updating all dependencies will update all libraries to their latest versions.
vendor update
# Specifying the dependency will cause only the single library to be updated.
vendor update facebook-ios-sdk

Adding a library formula

If a library has no framework dependencies, has no required additional compiler/linker flags, and has an XCode project, it doesn’t require a Vendor formula. An example is JSONKit, which may be specified as below. However, if another Vendor library requires JSONKit, JSONKit must have a Vendor formula.

lib "JSONKit", :git => "https://github.com/johnezang/JSONKit.git"

However, if the library requires frameworks or has dependencies on other Vendor libraries, it must have a Vendor formula.  As with Brew, a Vendor formula is some declarative Ruby code that is open source and centrally managed.

An example Vendor formula might look like:

require 'formula'

class Three20 < Formula
  url "https://github.com/facebook/three20"
  libraries libThree20.a
  frameworks "CoreAnimation"
  header_path "three20/Build/Products/three20"
  linker_flags "ObjC", "all_load"
  vendors "JSONKit"
end

Conclusion

Using iOS libraries is way harder than it should be, which has negatively impacted the growth of the open source community for iOS.  Even if I was only developing libraries for myself, I would still want some kind of packaging system to help me manage the code.  Vendor essentially streamlines the flow described by Jonas Williams here.  Unfortunately, programmatically managing XCode projects isn’t supported natively, but people have implemented various solutions, such as Three20, Victor Costan, and XCS.

Open Questions

• Is there an existing solution for this?
• Would this be a useful gem for your iOS development?
• Why hasn’t anyone built something like this already? Impossible to build?

Miso (and I) had our first Hackathon last week, and both of us survived! Our goal: conceive of an idea and build it within 3 days. We built Listify – an iPhone app that let’s you create, browse, and upvote lists of TV show and movies. Also with accompanying web landing pages.

A Little Bit of Context

At Miso, we’ve been working on making fun things for people watching TV, starting with check-ins, but experimenting with synchronized trivia, exclusive content, live Q & A. However, over the last three months, we’ve been focusing on ideas that connect friends around what they watch.

Why a Hackathon?

Entrepreneurs seem to be drinking heavily from the “Lean Startup” and “customer development” kool-aid.  One basic tenet is that product ideas/assumptions can be proven in days, not weeks or months.  Common tactics include applying MacGyver-like strategies to challenge product assumptions.  For example, create a splash page (this was our first attempt – http://playredzone.herokuapp.com) for a product before writing any code.

Generally speaking, it can be challenging to apply their methodologies consistently, but Hackathons certainly seem to intrinsically embody the spirit of Lean Startup.  Also, as most engineers will understand, creating something new from end to end is a very rewarding experience.

On to the Main Event

As we were deciding what to build for the Hackathon, we set the following constraints:

• Should be consistent with the “connect friends around what they watch” theme.
• Should be built on the Miso API (i.e., not as a feature in our main product).
• We have to want to use it.
• Must be finished in 3 days.

After some happy hour brainstorming, we came up with the basic motivation and mechanics behind Listify.

The need: People need help discovering what movies and TV shows to watch.

The underlying psychologies:

• People want to express themselves. Lists are a structured and easy way to do that.
• People take pride in their sense of taste. The band they “discovered”, the new (or old) indie film, are all worthy Facebook posts.
• People enjoy communities of like-minded people. They’re hard to create, but when it works, it’s unbeatable.

Implementation

Over the course of a few hours, we defined a minimum (and a reach) feature set, then designed and sketched an iPhone application, with accompanying web landing pages for the lists. We also spec’d the RESTful API that would support the iPhone app.

Over the next two (long) days, Josh and I built the iPhone app, while Nathan and Nico implemented the API (which utilized the Miso API, RABL, and Padrino) and the web splash pages. Nico served double duty as our art director.  Aside from some idle discussion that a little thought and investment in library development could make building iPhone apps that are fairly straightforward views of a RESTful API much faster, the implementation went without much incident.

While we’ve been happily using the app in beta for a week or so, we hope to release the app to the iPhone App Store after about a day of cleanup work, as soon as we find the time.

Conclusion

Overall, putting aside all the business rationalizations for doing a company hackathon, building something that we were only imagining a few days before was a ton of fun and a testament to why we’re engineers in the first place.  I’ll be sure to update this blog post when we actually submit to the App Store.

Our goal: we currently spend about 150-180 ms in Ruby for an average web request, and we think it’s reasonable to improve that to be around 100 ms.

Two of the most expensive operations in Ruby are: object allocation and garbage collection. Unfortunately, in Ruby (unlike Java), garbage collection is synchronous and can have a major impact on the performance of requests. If you’ve ever noticed that a partial template rendering occasionally randomly takes a couple of seconds, you’re probably observing a request triggering garbage collection.

The good news: it’s easy to quickly (< 10 min) see how much your app is impacted from garbage collection. You’re likely to improve your performance by 20-30% just by tuning your garbage collection parameters.

If you have a production Rails app, and you’re even remotely interested in performance, I’m going to assume you’re using the excellent New Relic service.  If you’re using REE or a version of Ruby with the Railsbench GC patches, it’s easy to turn on garbage collection stats that will be visualized by New Relic.

You’ll get pretty charts like this:

by adding:

GC.enable_stats

somewhere in your initialization.  After enabling garbage collection stats in our application, we can see that approximately 20% of our Ruby time is spent in garbage collection, which implies that there’s also a not-so-insignificant portion of time spent in object allocation.

What’s next

We last tuned our Ruby garbage collection parameters about 5 months ago and, after an initial performance boost, we’ve seen the application time spent in Ruby creep back up.  To try to bring the response time back down, our next steps are to:

• Consider taking another pass at garbage collection parameter tuning.  Since we’ve already taken one pass at this, I’m not sure if we’ll be as impactful the second time around, but we’ll see.
• Identify the slowest controller actions via New Relic and profile them using ruby-prof or perftools.

Performance tuning using ruby-prof is likely going to vary a lot depending on the code, but if we find techniques that might apply more broadly, we’ll be sure to blog about it here.

Links

• Garbage Collection is Why Rails is Slow
• Guerrilla’s Guide to Optimizing Rails Applications