Skip to main content

SD West: Software Requirements: 10 Traps

Next up: Karl Wiegers talks about the 10 Traps of Software Requirements.  I plan to check out processimpact.com  for sample documents and spreadsheets (the requirements prioritization example spreadsheet sounds especially useful). 

Lots of good advice and pointers to resources in the talk.  He had somevaluable points regarding the different views of what a 'requirement'is to different stakeholders.  He presented a frameworkfor separation into business (why), user (what), and functional(high-level how) requirements, and how to categorize requirements intothis framework to help avoid confusion.  This becomes particularlyimportant when doing incremental development (which is what almosteverybody does):  It's OK to be fuzzy on some of the functionalrequirements before starting a project, but the business requirementshad better be very clear and solid.

Regarding change control boards, I asked how one can scale a CCB so itdoesn't become a bottleneck in a large program.  He said (interpretinga bit) that the way to scale a CCB is to identify policies so that youcan distribute responsibilities among CCBs -- only escalating changerequests up to a central CCB if its scope truly warrants it. 

The slightly depressing part about this talk was that I knew most ofthe solutions presented; however, none of them helped to solve thereally hard people problems that actually are the root cause ofmost requirements issues. 

On a side note, the wireless network stopped working for me during thistalk.  I started seeing packet round-trip times of >>1sec to reachwhat was supposedly our DNS server.  I think this highlights one of thenonfunctional requirements that should have been part of the requirements for the Santa Clara Convention Centernetwork:  When you build a wireless network for a convention center inthe middle of Silicon Valley, make sure that it can handle a fewthousand software engineers with laptops!

Popular posts from this blog

Personal Web Discovery (aka Webfinger)

There's a particular discovery problem for open and distributed protocols such as OpenID, OAuth, Portable Contacts, Activity Streams, and OpenSocial.  It seems like a trivial problem, but it's one of the stumbling blocks that slows mass adoption.  We need to fix it.  So first, I'm going to name it:

The Personal Web Discovery Problem:  Given a person, how do I find out what services that person uses?
This does sound trivial, doesn't it?  And it is easy as long as you're service-centric; if you're building on top of social network X, there is no discovery problem, or at least only a trivial one that can be solved with proprietary APIs.  But what if you want to build on top of X,Y, and Z?  Well, you write code to make the user log in to each one so you can call those proprietary APIs... which means the user has to tell you their identity (and probably password) on each one... and the user has already clicked the Back button because this is complicated and annoying.

XAuth is a Lot Like Democracy

XAuth is a lot like democracy:  The worst form of user identity prefs, except for all those others that have been tried (apologies to Churchill).  I've just read Eran's rather overblown "XAuth - a Terrible, Horrible, No Good, Very Bad Idea", and I see that the same objections are being tossed around; I'm going to rebut them here to save time in the future.

Let's take this from the top.  XAuth is a proposal to let browsers remember that sites have registered themselves as a user's identity provider and let other sites know if the user has a session at that site.  In other words, it has the same information as proprietary solutions that already exist, except that it works across multiple identity providers.  It means that when you go to a new website, it doesn't have to ask you what your preferred services are, it can just look them up.  Note that this only tells the site that you have an account with Google or Yahoo or Facebook or Twitter, not what the…
Twister is interesting.  It's a decentralized "microblogging" system based on putting together existing protocols:  Bitcoin, distributed hash tables, and Bittorrent.  The most interesting part for me is using Bitcoin for user registration and spam control.  Federated systems handle this with federated trust, which is at least conceptually simple.  The Twister/Bitcoin mechanism looks intriguing though I don't know enough about Bitcoin to really comment.  Need to read further.