23 May
2021
23 May
'21
12:18 p.m.
On Sat, 22 May 2021 23:00:31 -0600
Grant Taylor via cctalk <cctalk at classiccmp.org> wrote:
On 5/22/21 6:50 PM, Lyle Bickley via cctalk 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OSA-2 Token Ring feature (feature code 5201) is superseded by the OSA-Express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
for a period make a "High-Speed 100/16/4 Token- Ring PCI Management Adapter" It
was NOT popular - and not many were sold. (For more detail, see:
ftp://ps-2.kev009.com/incoming/timc/PDFS/IBM/Networking/IBM_C_TR.pdf)
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, that was
the "death knell" of Token Ring ;)
As a networking company we never installed any 100Mbps Token Ring networks -
and weren't aware of any implemented by our competitors.
Cheers,
Lyle
--
73 NM6Y
Bickley Consulting West
https://bickleywest.com
"Black holes are where God is dividing by zero"
Wow, never heard of "Tokenray" ;)
Nor have I.
BTW: 16 Mbit Token Ring was much more reliable
(especially in "noisy"
environments) and considerably faster with more consistent performance
than 10 Mbit Ethernet.
I've heard tell that Token Ring worked MUCH better on extremely busy
networks. Purportedly Ethernet starts having problems when there are
more and more systems and / or a higher and higher percentage of
utilization is happening. I seem to remember that Ethernet had problems
starting about 80% utilization while Token Ring could easily handle 95%
utilization or higher.
plus IBM never upgraded Token Ring past 16 Mbit.
Sure they did.
You can find commercial Token Ring cards that support, 4 Mbps, 16 Mbps,
/and/ *100* Mbps. I see them on eBay monthly.
I heard that IBM developed 1,000 Mbps / 1 Gbps Token Ring in the lab.
But that no commercial products were ever made.