IBM PC Network

Jim Brain brain at
Sat May 22 20:12:10 CDT 2021

On 5/22/2021 7:50 PM, Lyle Bickley via cctalk wrote:
> BTW: 16 Mbit Token Ring was much more reliable (especially in "noisy"
> environments) and considerably faster with more consistent performance than 10
> Mbit Ethernet. We won a number of large contracts when other network companies
> used twisted pair 10 Mbit Ethernet in "noisy" environments and their networks
> failed miserably.

I guess that's a selling point of TR, but I loathed it when introduced 
to it after using Ethernet at UIUC.  Having to learn CPI-C, LU-2, 
LU-6.2, APPC, etc. and configure Communications Manager/2 on OS/2 to 
emulate a FEP (3174?, not sure, my mind tended to bury such information, 
and in fact I'm not sure if that's what it did or if it connected to a 
FEP, that info is gone and I've no desire to go review it).

When the network worked, it was fine, of course, but it seemed every 
week someone would do something that would switch a TR card in a PC to 
4Mb, and the entire network would die, "beaconing" for an hour while the 
IT folks ran around trying to figure out where the issue lie.  And, it 
was an office building, so not a ton of noise...

Seeing the 370 (3090, as I recall, nice imposing looking machine) was 
impressive, and I will admit working in a firm with an IBM 370 
architecture machine gave me a new and profound appreciation for the 
staying power of the mainframe (I started the job thinking, as all 
recently minted IT professionals no doubt think, that the mainframe was 
soon to be discarded in favor of UNIX and potentially the newly arrived 
Linux OS. That job changed my mind).

But, I never grew fond of TR, and as soon as IBM supported Ethernet, I 
was happy. (Plus, there was no TR driver in Linux initially, and we all 
desperately wanted to run Linux on our PCs to run a real OS instead of 
Win3.1 or OS/2. OS/2 was nice, to be fair, but it was not UNIX...)


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