Brandon Savage is talking about Validation Blind Spots

When I read Brandon’s post – Validation Blind Spots Hurt Real Users – I was immediately reminded of a book I read back in Jr. high school, “The Man Whose Name Wouldn’t Fit”. In it, a man’s name did not fit into his company’s new payroll system. (Kiddies, that there on the cover of the book is a Punch Card; real Old-school tech.) To exact his revenge for being let go because of this anomaly, he wreaks havoc on the computer system using a variety of delivery methods for a magnetic tape eating bacteria. It was a fun romp.

Brandon’s article starts by describing a similar, real-world problem. Here’s a little taste.

A friend of mine lives on Bonieta Harrold Drive. I live on a Windsor Hill Drive. Both of us have a problem in common, which is that poorly designed software is incapable of accepting the length of our street address. For me, American Express refuses to accept more than “WINDSOR HILL D”, which still arrives at our home. I can’t imagine if my friend ever got an American Express card, since given the maximum length available for an address, he would live on “BONIETA HARROL”. If you live in a place where direction (e.g. NW, SW, SE) matter, not having enough space can be extraordinarily problematic to the proper delivery of mail and packages if there is not enough room for the whole address.

As Brandon (and the book) both point out, companies need to be careful when setting artificial limits and validations on incoming data. Unlike the book however, Brandon does not advocate attacking the computers, instead he offers advice to the developers building the systems.

Brandon gives 4 very valid pieces of advices to developers (and system architects for that matter) on dealing with data and validation. You will have to visit his blog however, to find them. While you are there, feel free to leave a comment. Tell Brandon what points you agree on, what points you disagree on, and share some of your own personal experiences. Blog posts are great, but conversations are greater.

While “The Man Whose Name Wouldn’t Fit” had a great cover – I just love that 70’s OCR font – Validation Blind Spots Hurt Real Users has better advice on how to deal with the problem. Click on through and give it a read.

About Cal Evans

Many moons ago, at the tender age of 14, Cal touched his first computer. (We're using the term "computer" loosely here, it was a TRS-80 Model 1) Since then his life has never been the same. He graduated from TRS-80s to Commodores and eventually to IBM PCs.   For the past 10 years, Cal has worked with PHP and MySQL on Linux OSX, and when necessary, Windows. He has built on a variety of projects ranging in size from simple web pages to multi-million dollar web applications. When not banging his head on his monitor, attempting a blood sacrifice to get a particular piece of code working, he enjoys building and managing development teams using his widely imitated but never patented management style of "management by wandering around". Cal is happily married to wife 1.33, the lovely and talented Kathy. Together they have 2 kids who were both bright enough not to pursue a career in IT. Cal blogs at and is the founder and host of Nomad PHP