Re: What's your bus?

["Curtis A. Ridgeway" <curtr@lsil.com>]

Paul,
Thanks for providing information on Spacewire.  It appears to be
somewhat similar with IEEE 1394 which is now a common video
transfer method for consumer devices and some storage devices.
The newer standards like Serial ATA or SCSI provide far more
bandwidth at a low cost.  These have been built on the work done
by the ANSI T11 Fibre Channel group at 1Gbit/sec.  This work
was used by Ethernet for 1Gbit/sec, then Ethernet did the 10Gbit/sec
4-lane XAUI which Fibre Channel also uses.

I did not see when the Spacewire spec was done, but the bandwidth
on the website indicates it is 200 Mbits/sec. Fibre Channel started
in 1997 at about 1000 Mbits/sec and is now at 10K Mbits/sec.
The 8bit/10bit encoding provided by IBM is the common encoding
method uses by most of the high speed connections. I would be interested
in the future planned speed improvements for Spacewire.

I would also like information on Star Fabric since I have not heard of this
one either.

As for the original question about what Bus do I like, I like them all.
I am proposing a common physical layer which can be used by most
of them.  I am the co-editor of the 10GFC spec and have proposed
Fibre Channel be expanded to provide 20 & 40GFC which may also
be used for Infiniband, PCI-Express, Serial RapidIO and Ethernet.
These are all self clocking 8b/10b encoded data protocols.
I am not an expert on Hypertransport, but I thought I heard it is
unencoded and requires a separate clock.  Perhaps someone
can provide feedback on this.

The start of the multilane transfers were proposed within the
IEEE committee as the HARI & SALI interfaces which became
XAUI & XGMII for Fibre Channel and Ethernet.

The various standards had different requirements, so the usage of
the common features diverged.  I believe it is now time them to
converge with a standard XAUI & XGMII interface with different
modes of operation to account for the differences.  I will be
presenting a detailed proposal at the Fibre Channel meeting
in Huntington Beach in February 2003.  Go to WWW.T11.com
for details.  Details on the various standards are contained in
document T11/02-622v0.pdf.

My next document will detail the new illegal k-characters to be
used on the XGMII interface to control the new features used
on the various standards: Beacon, Loss-Of-Signal, Receiver-Detect,
power-down TX/RX/Both, Electrical Idle (D+==D-), alignment
character and a few others.

Thanks - Curt

Paul Walker wrote:

> Alan
>
> A common feature of the ones you mention is that they are not buses,
> they use switch fabric.
>
> So does SpaceWire, a derivative from IEEE 1355, that is simpler and more
> flexible than any of those you mention. It was way ahead of its time,
> but the plethora of new standards, all of which follow it and all of
> which are more complicated, just show that its time will come.
>
> You can reach most of the information about SpaceWire and IEEE 1355 from
> our web site:
> www.4Links.co.uk
>
> Best regards
>
> Paul Walker
>
> In message <OF142CD769.C7EBA262-ON88256C94.000425FB-
> 88256C94.00046007@znyx.com>, Alan Deikman <Alan.Deikman@znyx.com> writes
> >I'd like to hear back from anyone with an opinion on this.  What do you
> >think of as the ultimate bus after PCI and why?
> >
> >1. Hypertransport
> >2. RapidIO
> >3. Star Fabric
> >4. PCI Experss
> >5. Infiniband
> >
> >Any others that will be players?  I get asked this sort of question all the
> >time and I need some new material. :)
> >
> >Alan Deikman
> >ZNYX Networks, Inc.
> >
> >
>
> --
> Paul Walker
> CEO, 4Links Limited,                 Chair of the 1355 Association
> www.4Links.co.uk                                      www.1355.org
> paul@4Links.co.uk
>
> 4Links Limited --- Boards, chips, IP and consultancy ... for Links
> P O Box 816, Bletchley Park                phone  +44 1908 64 2001
> Milton Keynes MK3 6ZP, UK                  fax    +44 1908 64 2011
begin:vcard 
n:Ridgeway;Curt
tel;fax:408-954-4764
tel;work:408-433-7792
x-mozilla-html:FALSE
url:www.lsilogic.com
org:LSI Logic Storage Components;Serial Protocol Development
version:2.1
email;internet:curtr@lsil.com
title:Distinguished I/O Architect, Serial Protocols
adr;quoted-printable:;;1873 Barber Lane=0D=0AMS AH-260;Milpitas;California;95035;USA
note;quoted-printable:=0D=0A
x-mozilla-cpt:;-20840
fn:Ridgeway, Curt
end:vcard