Category Archives: Development

Books, Development

The Mythical Man-Month

The Mythical Man-MonthFrederick Brooks wrote this classical book already back in 1975 and added a few extra chapters for the twenty years anniversary 1995…

Large portions of it feels of the age and there’s a lot of talk about Fortran, System/360 and PL-1 as if we should know about them (which made me fast forward over some chapters). But there are gems as well, and the most significant things people seem to remember Brooks’ book for are still pretty valid and fine.

Adding more people to a project leads to the need for more communication and thus it may slow down development rather than speed it up. Also known as Brooks’s law.

Given the complexity of software and software development, there’s no single method or concept that will lead to an improvement by an order of magnitude – within a decade. There’s No Silver Bullet. (This section was not in the original edition of the book.)

The risks involved when rewriting something and wants to fix everything that was wrong in the previous version so you over-work and over-design the successor. The so called Second system effect.

A lot of the book is spent on thoughts and theories around how to manage really really large software projects, like when you involve thousands of persons. Is it even possible to make such huge projects successful and if so, what does it take? The extra chapters do indeed add value since they offered Brooks a chance to re-evaluate his earlier claims and ideas and to check what seemed to be truths and what mistakes he did in the original edition.

A very interesting read that I’m glad I finally got time to get through!

Development

Food Calendar

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MatkalendernFacing the every day problem with what to eat, planning and shopping food for the family I took the familiar route: I wrote a web site (the site is in Swedish!) and service for it to ease this boring work!

Using this site, you enter the recipes of the dishes you tend to eat, you assign meals to days and then you can get the site to produce a nice and handy shopping list of all the ingredients that the planned meals require.

With multiple users, you can bookmark other users’ recipes to avoid having to enter them yourself. With top-lists and statistics you can see what meals you plan to eat the most and the least and so on. It actually works pretty neat. We have a set of user logins handed out as well, but I don’t think very many people other than me and my wife actually use it…

It still has lots of room for improvements to make it even easier to plan and to make the grocery store shopping list easier and quicker to deal with, but it scratches my itch already and I’m improving it slowly over time. I started the development of this in early 2006 and we’ve been using it in my family for well over a year now.

cURL and libcurl, Development, Open Source

ABI Breakage

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Domenico Andreoli, the Debian curl and libcurl maintainer posted to the curl-library list about the recent libcurl soname bump and the related issue of ABI breakage.

I responded, explaining my view on why the soname bump from 3 to 4 was valid, but I’ve also gone back in my mail archives and checked out a private discussion I had with Bjorn Reese over this subject a long time ago and I feel it is about time it hits the air.

An ABI breakage occurs when one or more of the following changes are made

Functions:

  • Change function names
  • Remove existing functions
  • Change parameters
  • Change behavior
  • Change undefined behavior
  • Add dependence on other functions (e.g. A() must be called before B())

Data structures:

  • Change the order of elements
  • Add elements
  • Remove elements
  • Change the data type or size
  • Change alignment
  • Change element values (e.g. change bits in flag variables)

Global variables:

  • Change variable names or types
  • Remove variables

Update: Dan Fandrich posted on the curl-library list and mentioned Mike Hearn’s great related page: Writing shared libraries.