[SystemSafety] Development vs maintenance

[Paul Sherwood]

On 2018-11-16 05:46, Derek M Jones wrote:
> General software has a short lifetime and it is not cost effective
> to invest too much up front:
> https://shape-of-code.coding-guidelines.com/2017/04/20/average-maintenancedevelopment-cost-ratio-is-less-than-one/

Sorry, but this is patently not true. A lot of software has a 
surprisingly LONG lifetime. I'm aware of VAX-based systems and IBM 
mainframe systems still in critical use after several decades.

Much of the stuff Richard Stallman and early unix contributors wrote is 
still in use.

The Linux kernel has been developed and maintained for 25 years or so... 
and on and on.

It's not clear to me how anyone could distinguish, precisely, between 
development and maintenance in any case - if you have a definition I'd 
be interested to read it.

br
Paul