[Info-vax] booting vaxstation off alpha

[Hans Vlems]

On 12 feb, 13:31, Bart Zorn <Bart.Z... at Gmail.com> wrote:
> On 12-Feb-2013 08:48, Hans Vlems wrote:
>
>
>
>
>
> > On 12 feb, 01:31, Johnny Billquist <b... at softjar.se> wrote:
> >> On 2013-02-11 13:44, Stephen Hoffman wrote:
>
> >>> On 2013-02-11 07:54:11 +0000, Hans Vlems said:
>
> >>>> DECnet over DSSI works fine, provided you get the incantations right.
> >>>> All I tried was CTERM and FAL and both worked as expected (reliable
> >>>> albeit slow).
> >>>> Another example of an undocumented, unsupported feature that works
> >>>> alright.
>
> >>> Not that there is even a remote chance of seeing DSSI gear around, nor
> >>> any likelihood of IP over FC nor connections, but...
>
> >>> If you ran any tests[1] with that, how well does that "albeit slow"
> >>> connection perform as compared with slow Ethernet?  CI wasn't known for
> >>> its network performance, as compared with DECnet over even then-current
> >>> 10 Mb Ethernet, and usual recommendations back then had CI at higher
> >>> cost as a backup connection.  I can't see DSSI being much better in that
> >>> regard.
>
> >> That sounds weird. Do you know why?
> >> I mean, CI was after all two redundant full duplex 70 Mbit/s channels,
> >> compared to the half-duplex 10Mbit/s ethernet. Not to mention the fact
> >> that the MTU of CI is much larger.
>
> >>          Johnny
>
> >> --
> >> Johnny Billquist                  || "I'm on a bus
> >>                                     ||  on a psychedelic trip
> >> email: b... at softjar.se             ||  Reading murder books
> >> pdp is alive!                     ||  tryin' to stay hip" - B. Idol
>
> > Yes, I know what you mean Johnny. I don't think the CI was full duplex
> > though.
> > But it clocked a lot faster than ethernet. The cables BTW were
> > physically remarkably similar,
> > other than the colour. Won't say much for the electrical
> > characteristics of the two of course.
> > The CI bus was a lot more restricted in length than a 10BASE5 cable
> > which probably
> > explains the higher speed.
> > The DECnet driver for the CI bus (CNDRIVER) may have something to do
> > with the speed.
> > Perhaps DECnet slowed down the regular CI traffic too much so its use
> > was discouraged?
> > Anyway, speed wasn't a designfactor. Within the cluster all disks were
> > visible via the CI so
> > why use DECnet in the first place. Any other disk lived behind a host
> > on ethernet or another
> > DECnet link.
> > Hans
>
> The CI as a whole is full duplex, but the individual cables are not.
> Normally a CI connection consists of four cables, an A and a B path,
> each a send and a receive cable.
>
> HTH,
>
> Bart

Of course, that was it. The green and red labels identified the
transmit and receive paths
and there was room to put a sticker with an A of B on the label.
Lots of thick blue unyielding cables....
Hans