Del Boy versus Turing

This post is more than 15 years old.

Posted at 22:00 on 25 November 2008

It seems that in the world of software development, it is quite common for sales guys to come up with totally unrealistic quotes when pitching to potential clients. First get the contract, then let the developers worry about fulfilling it afterwards.


I call it the Del Boy approach to marketing, after the character of that name in Only Fools and Horses, who would do things such as sweet talking his way into cleaning antique seventeenth century chandeliers using Windolene and old handkerchiefs. The big problem is that you run the risk of delivering late, over budget, incomplete and buggy software -- if indeed you deliver anything at all -- and you then have to rely on having sufficient social skills to be able to blag your way out of a corner when everything hits the fan.

One particularly juicy example is this project request on

The purpose of this project is to create a debugger program. This program will take as input the source code another program, and will analyze that other program and determine if it will run to completion, or have an error, or go into an infinite loop.

To state that another way, given a function f and input x, determine if f(x) will halt.

At present, there are eighteen bids, with serious offers ranging from US$300 to US$1800, with time estimates between 10 and 25 days.

I just love the way one bidder says, “Its about doing it professionally exactly according to the requirements.” All I can say to him is good luck because you’re going to need all the social skills you can get with this one. This particular assignment is called the Halting Problem, and it was proven in 1936 by Alan Turing that it is, in actual fact, unsolvable.

(Update: It seems that the nice folks as got wise to the fact that this item was a joke and deleted all the responses. However, not before it had received several apparently serious bids from the Del Boy types.)