Other options with no paywall (or at least a less expensive one).

Although the term "open source" didn’t arrive until the late 1990s, the principle has been around since programming really took off in the 50s and 60s. Early developers shared their code and protocol ...

The popularity of open-source software continues to grow because of the multiple advantages they provide including lower upfront software and hardware costs, lower total-cost-of-ownership, lack of ...