IBM PC Network

On Sat, 22 May 2021 23:00:31 -0600 Grant Taylor via cctalk <cctalk at classiccmp.org> wrote: Here's IBM's "Redbook" on Token Ring: "IBM does not view high-speed Token Ring as a requirement for the majority of its customers, and therefore the decision has been made not to provide 100 Mbps high-speed Token Ring uplinks on its products..." Also: "Note: IBM Statement of Direction, effective October 2001: For z900 server, this feature is called the OSA-2 Token Ring feature, and can only be configured as two 4/16 Mbps Token Ring ports. Note: Effective October 2001: OSA-2 Token Ring feature (feature code 5201) is superseded by the OSA-Express Fast Ethernet feature (feature code 2366), and OSA-Express Token Ring feature (feature code 2367), as required. OSA-2 Token Ring feature (feature code 5201) is not carried forward on G5/G6 server to z900 server upgrades." To download the Redbook: http://www.redbooks.ibm.com/redbooks/pdfs/sg245975.pdf Interestingly, in spite of their statement of direction, for a time, IBM did make a "High-Speed 100/16/4 Token- Ring PCI Management Adapter" (Token Ring PDF attached...). It was NOT popular - and not many were sold. Ethernet had "won" the hearts and minds of IT folks (plus Ethernet by that time was full duplex - at both 100Mbps and 1000Mbps, potentially doubling it's capabilities). Ethernet also could be implemented for a fraction of the price of Token Ring. When IBM began to support Ethernet on mainframes, Token Ring "died" ;) As a networking company we never installed any 100Mbps Token Ring networks - and weren't aware of any implemented by our competitors. Cheers, Lyle