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- Newsgroups: comp.realtime
- Path: sparky!uunet!utcsri!torn!cunews!revcan!quantum!danh
- From: danh@quantum.on.ca (Dan Hildebrand)
- Subject: Re: QNX, network and busses
- Message-ID: <gvmmc2_@quantum.on.ca>
- Date: Tue, 28 Jul 92 14:21:50 GMT
- Organization: Quantum Software Systems
- References: <wJ8koB1w164w@ersys.edmonton.ab.ca>
- Lines: 39
-
- In article <wJ8koB1w164w@ersys.edmonton.ab.ca> kbeau@ersys.edmonton.ab.ca (Kevin Beauchamp) writes:
- > Now that QNX supports an Ethernet interface, does anyone know if one
- > physical net can carry packets from, say TCP/IP and QNX without any
- > determental side effects?
-
- QNX uses a standard packet header ( with a registered subtype ), allowing
- the QNX-native protocol to coexist with other ethernet traffic. Use of a
- standard header allows QNX packets to flow through standard bridge and
- router hardware. The network driver interface in the OS allows QNX to use a
- low-overhead protocol for QNX-to-QNX communications, and the full TCP/IP
- protocol stack for QNX-to-non-QNX communications. The point of having a QNX
- native protocol is that it allows QNX-to-QNX communications to approach 1
- Mbyte / second on 10 Mbit Ethernet. TCP/IP implementations tend not to
- achieve this on PC-class hardware. :-)
-
- > Also, does anyone have experience implementing QNX on a VME backplane?
- > What types of tradeoffs were made WRT the usual (E)ISA/MCA
- > implementations?
-
- QNX runs well on Xycom VME hardware. Since the networking architecture
- already supports multiple network links for load balancing and fault
- tolerance, a natural extension is to add a Net.vme driver to the Net
- manager, allowing it to implement distributed processing across the VME
- bus, just like it does across the network. A VME driver does not yet exist,
- but Xycom should be able to implement one if requested. A Microchannel
- implementation of the VLAN concept is currently in progress ( VLAN = Very
- Local Area Network ).
-
- A paper that outlines how some of this works is available by anonymous ftp
- as /pub/qnx-arch.ps at ftp.cse.ucsc.edu (128.114.134.19). The architecture
- of the QNX microkernel is outlined, and its performance compared to the
- SVR4 UNIX system. A posting should be appearing in comp.newprod shortly.
-
-
-
- Dan Hildebrand email: danh@quantum.on.ca
- Quantum Software Systems, Ltd. QUICS: danh (613) 591-0934 (data)
- (613) 591-0931 (voice) mail: 175 Terrence Matthews
- (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8
-