28 Oct
2001
28 Oct
'01
11:01 a.m.
Plz see comments inline below.
Dick
----- Original Message -----
From: "Eric Dittman" <dittman(a)dittman.net>
To: <classiccmp(a)classiccmp.org>
Sent: Sunday, October 28, 2001 5:34 PM
Subject: Re: VLB SCSI?
compatible.
Perhaps that one wasn't firewire, but it was ADAPTEC. The FC is what has me
buzzed up right now and I've seen no 64-bit slots in motherboards offered
recently. I hadn't even considered an Apple product, and it may take a while
for me to accept that notion. I've certainly never seen a high-bandwidth card
of any sort for sale that wasn't a 64-bit card. The abundance of 64-bit cards
against the dearth of motherboards with 64-bit PCI slots is what I've been
focusing on. Surely ADAPTEC and others are selling their products into
something with full 64-bit capacity.
despite
> > 64-bit PCI cards will work in a 32-bit PCI
slot. I've got a four-port
64-bit
> > Ethernet card in a 32-bit PCI slot in one of
my systems.
> >
> I really don't see how they could work, since the connector is not likely to
> fit. I recently had a peek at the standard for PCI, and I didn't seen any
way
in which this
could work.
They have been designed from the start to be forward- and backward- The 64-bit has a slot where the end of the 32-bit
connector is located, and
the
correct connector does not have a wide end. All the
32-bit connectors I've
seen
have been the correct size (and I've seen a lot of
them). A 64-bit PCI card
in
a 32-bit slot steps down to 32-bit transfers. A 66MHz
card in a 33MHz slot
steps
down to 33MHz.
That wouldn't work too well when you need 99% of the bandwidth. The few
64-bit
cards I've seen up close don't seem to have a wide enough slit to allow them to
be plugged into a short PCI slot. The standard references to features such as
this one seemed quite iffy. I wish I could justify a current copy of the
standard. I just returned one to the local library, which had to get it on ILL.
> Since there apparently aren't any serious SCSI boards being made for 32-bit
PCI
> any longer, and since most fibrechanel and
firewire boards are 64-bit, I'd
think
> it desirable to have most PCI mothers support the
64-bit PCI, which,
according
> to what I've read so far, does support the
32-bit cards. If you want the
250+
> MBPs transfer rates, no short PCI slot is going
to handle that. The 10Gb
> ethernet will demand that the system process sustained, meaning for years
and
> years, not just for bursts of a few hundred
picoseconds, transfer rates of
> 10Gb/sec, and who knows what will come along after that. What's more, it's
got
> to work faster than all that at the system level,
since the traffic has to
go
somewhere and
the responses have to come from somewhere as well.
I've seen 32-bit FC and firewire cards. I've seen FC cards that come in both
32- and 64-bit configurations, although the 32-bit cards I've seen look like
they are the 64-bit version with only a 32-bit edge connector.
I've never seen a 64-bit firewire card.
ALPHA boards aren't relevant any longer, are
they?
I think so. The Alpha will be around for a while, with EV7 on the way, what some people think. Compaq announced the Alpha
would be winding down, not
stopping dead in its tracks.
Yes, but they're controlled by someone else, now, and they're a fickle
master.
I'd put no faith in that statement at all.
--
Eric Dittman
dittman(a)dittman.net
Check out the DEC Enthusiasts Club at http://www.dittman.net/