Building the System/360 Mainframe Nearly Destroyed IBM

TIL that not only the software side was chaotic (served as the backdrop of Fred Brook's "Mythical Man Month"), but also the hardware side almost failed.

the article here ends around 1971 --- the mainframe would later save IBM again, twice, once when they replaced aluminum with copper in interconnects, and then when some crazy IBM Fellow had a team port Linux to s390. Which marked the birth of "enterprise Linux", i.e. Linux running the data centre, for real.

> [Porting Linux to s390] marked the birth of "enterprise Linux", i.e. Linux running the data centre

Did it though? Or was it the gradual phasing out of mainframe-class hardware in favour of PC-compatible servers and the death of commercial Unices?

well, IBM very publicly invested 1Bn USD into supporting Linux on all their hardware with all their software. so db/2 on s390 on Linux, likewise websphere, etc. it gave the customers the promise of one run time environment on anything. and SUSE and shortly later Red Hat provided truly source compatible environments for software vendors. "code once run anywhere", for real. and then IBM and Oracle and Co forced suse and red hat to become binary compatible at the kernel/libc and basic system libs level, so Oracle and all could provide one binary under /opt on any Linux...

and that pulled all other vendors along, HP, Dell, Fujitsu, likewise for software...

and it all started with IBM officially supporting and pushing the hobbyist student project Linux on the holy Grail of enterprise compute, (of 1999/2000): s390