Computer books change over time, for obvious reasons. The O'Reilly animal books are always good, but they've removed some useful information in later editions.
For instance, the [sendmail bat book](https://www.oreilly.com/library/view/sendmail-4th-edition/97...) originally talked about all sorts of ways to deal with resource limits, particularly memory, because this was often an issue with servers in the early '90s. Later, memory became cheap and huge, so discussions about this were removed from later editions.
Even when memory ceased being a limitation, though, learning about how to monitor and what to do about heavy resource usage remained important, so the removal was an overall loss. I wish that O'Reilly would make available for free the things they removed from later editions.
I wish I'd've had the money and space to buy the original editions of many of the animal books. I figured they'd live at the bookstore until I did, but then bad things happened, and now bookstores are rare. Perhaps one day I'll find some.
For instance, the [sendmail bat book](https://www.oreilly.com/library/view/sendmail-4th-edition/97...) originally talked about all sorts of ways to deal with resource limits, particularly memory, because this was often an issue with servers in the early '90s. Later, memory became cheap and huge, so discussions about this were removed from later editions.
Even when memory ceased being a limitation, though, learning about how to monitor and what to do about heavy resource usage remained important, so the removal was an overall loss. I wish that O'Reilly would make available for free the things they removed from later editions.
I wish I'd've had the money and space to buy the original editions of many of the animal books. I figured they'd live at the bookstore until I did, but then bad things happened, and now bookstores are rare. Perhaps one day I'll find some.