g.Ryland@SU-SCORE.ARPA (07/27/83)
From: Chris Ryland <g.Ryland@SU-SCORE.ARPA> Omninet seems to be the dominant "cheapo" LAN for the micro world right now (they claim over 20,000 networks, of average size 4 (stations)). It's a 1MB twisted-pair RS422 network, using two proprietary chips (they sell) and a Motorola 6801 (with their custom code burned in) to accomplish the link-level, and little of the transport level. Thus, for the IBM PC, their board is very simple, and low-cost (about $300, I believe), as well as reasonably efficient, as they DMA from the network to waiting buffers in the CPU. It's really a wonderful network from the point of view of cabling: the "transceivers" cost $10, and can be wired by anyone with a screwdriver. 1MB isn't bad for a small cluster of workstations. There are some limitations on the number and type of connections a given workstation can have open: only one "remote disk" connection at a time is allowed, and only three more other connections of non-remote-disk type are allowed simultaneously. I've been looking into Omninet lately for other reasons, and, as far as I can tell, there isn't much activity with interconnection to VAXes, or, for that matter, with other networks. Omninet DOES have an XNS packet encapsulation protocol, which they and Xerox agreed to (it's published in the Omninet protocol handbook). There is, I believe, a Unibus Omninet board just announced or to be announced, though I can't find the information right now. With that, I suppose you could write a VMS driver for Omninet. /Chris Ryland