[TUHS] Document on BBN's VAX Unix TCP (Noel Chiappa)

Paul Ruizendaal pnr at planet.nl
Fri Aug 5 11:59:50 AEST 2022

> While looking for something else, I found this:
>  VAX-UNIX Networking Support Project Implementation Description
>  Robert F. Gurwitz; January, 1981
>  https://www.rfc-editor.org/ien/ien168.txt
> in a somewhat obscure location. I have no idea if it's already widely known
> or not, but here it is anyway.

Hi Noel,

Thank you for highlighting this document. I had seen it before and the implementation (as found on the tapes from CSRG and now on THUS) follows the plan outlined in IEN168 quite closely. The first snapshot of the code is just a few months after this document.

In a way it is modeled after the UoI Arpanet Unix implementation (and thank you again for finding that source!), with a separate (kernel) process for network activity. In my experiments I have found that it is not all that easy to get smooth network data flow as this network process is difficult to schedule just right. I now better understand why Joy moved to "software interrupts” to get better scheduling of kernel network operations.



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