New Elephans On The Block
Karsten
http://www.cyberlotto.dk/720/3803.jpg
The seller asked less than 40 dollars for the one to the left. It has no
front door and no pedestal. All drives included are 2 GB. Both have 16 x 8
MB RAM. The one to the left is up and running on two 166 MHz processors.
There is only one processor in the other, I still don't know what speed
(most likely the same: 166). Otherwise it seems to be alive & kicking.
The IBM site really sucks. Even though I have a FRU (76H6875) and a P/N
(12J4753), I cannot locate the ServeRAID adapter. I don't understand their
policy. It should be rather straightforward: Please enter your FRU here and
we will take you to all available information about your product. Why are
they deleting and omitting? Do they really need more disk space? Sorry, -
back to the RAID adapter: what is of interest is the empty slot in the
middle - memory? The other 720 is equipped with a PCI DAC960 (doing OK, but
apparently with a logical drive limit of 30GB).
I have questions to the bridge adapters (allow me to quote BradBoot):
"You can tell the 33Mhz card from the 25 Mhz card by a notch in the front
(towards you looking at the card installed) 33Mhz card. The 25Mhz C-bus card
is even all the way across the front. "
http://www.cyberlotto.dk/720/3804.jpg
Then it would seem that the above link (3804) shows the 33MHz card and the
link below (3807) leads to the 25MHz card, or ..?
http://www.cyberlotto.dk/720/3807.jpg
The latter (3807) is working now. Both PCI and Microchannel run perfectly.
Is the 33MHz highly superior to the older version?
Also note the structural differences with the plastic support for the
processor cards in one machine, and the metal retainer in the other. Both
machines are labeled 8642-M0Z.
It seems that I am in the market for RAM and processor cards (and info on
how to use it).
: - ) k
PS - I have noted the words of the Don:
I -personally- don't like the 720 that much.It took them (IBM and Corollary)
too long to get a stable design, the early bridgecards were a weak point on
them and the machine came too late anyway tofind much response. So the parts
situation is a bit "constrained". Not manyparts fit from other machines -
the most of the inards is "720-only", thereforemaintenance of these machines
will come rather tricky in a short period of time(unless you buy stock parts
from IBM for horrible prices). I think the 720 willbe history when others
are still able to service Mod. 95A or Server 500 withlittle or no problems.
David L. Beem
> I paid approx. 200 dollars for these guys (including shipping).
> http://www.cyberlotto.dk/720/3803.jpg
another member here. Plus I have very many parts now.
> The seller asked less than 40 dollars for the one to the left. It has
> no front door and no pedestal. All drives included are 2 GB. Both
> have 16 x 8 MB RAM. The one to the left is up and running on
> two 166 MHz processors. There is only one processor in the
> other, I still don't know what speed (most likely the same: 166).
> Otherwise it seems to be alive & kicking.
As long as it is not the low-end 100MHz level that has some operational
constraints. Some time ago there was a run on the optimal 200MHz cards (Dr.
Jim has modified the slower cards to operate at a higher speed as I recall)
with it's greater cache, but I really haven't followed the ups & downs
lately. In fact I don't even think I've powered on my 720 since a time
before my deployment (maybe 2002).
The pedestal is common to the 500 & both 520 models, although I don't
think I have any spares left. Maybe Bill, but I think he has had events
force him to purge. Even the front bezel can be used from the others I think
(except for the slimline CD-ROM Server 500 models).
> The IBM site really sucks. Even though I have a FRU (76H6875) and a
> P/N (12J4753), I cannot locate the ServeRAID adapter. I don't
> understand their policy. It should be rather straightforward: Please enter
> your FRU here and we will take you to all available information about
> your product. Why are they deleting and omitting? Do they really need
> more disk space? Sorry, - back to the RAID adapter: what is of
> interest is the empty slot in the middle - memory? The other 720 is
> equipped with a PCI DAC960 (doing OK, but apparently with a logical
> drive limit of 30GB).
I agree. The purge really set me back a ways. ServeRAID does have it's
own section, just make sure you don't upgrade yourself out of existance (my
720 currently won't find the correct boot drive among the populated bays,
although I haven't fully investigated it).
Cache RAM goes in the slot. I think all my ServeRAID adapters of that
type have it empty. Dunno if it is something like the DRAM card of a
750-series Thinkpad.
> I have questions to the bridge adapters (allow me to quote BradBoot):
> "You can tell the 33Mhz card from the 25 Mhz card by a notch in the
> front (towards you looking at the card installed) 33Mhz card. The
> 25Mhz C-bus card is even all the way across the front. "
> http://www.cyberlotto.dk/720/3804.jpg
> Then it would seem that the above link (3804) shows the 33MHz card
> and the link below (3807) leads to the 25MHz card, or ..?
> http://www.cyberlotto.dk/720/3807.jpg The latter (3807) is working
> now. Both PCI and Microchannel run perfectly.
Yes, you have it right. You are lucky; It took quite a bit of digging
for me to get the 33MHz version. Maybe it would be nice to benchmark the two
against each other sometimes.
> Is the 33MHz highly superior to the older version?
It's faster PCI (33MHz) than the older version is the only difference I
am aware of. Smaller card, with reduced chip count as I recall; The irony of
upgrades as always. PCI cards may like it a little better too.
> Also note the structural differences with the plastic support for the
> processor cards in one machine, and the metal retainer in the other.
> Both machines are labeled 8642-M0Z.
I have the metal version that I need to improve upon. As Peter states
gravity is a big problem in these systems by dragging all the cards down.
Occasionally I reseat the foam card holder in it's placement since it seems
to slip no matter how I tack it in position.
> It seems that I am in the market for RAM and processor cards
> (and info on how to use it).
Ok, I can be a source for some 16Mb modules I think. Full of 32Mb
sticks (which I may eventually have a spare set) gives 1Gb RAM. The
acquisition of my second 720 was mainly to get a full set of 200MHz cards
(meaning I may even have a couple spare for almost all speed levels).
You might keep an eye on the 880 watt PSUs that are cropping up now for
very low prices (they also have adapters to work in the 500 & both bus
models of 520). There was a recent thread by a passer-by that wanted to
adapt one to ATX connections (with the 520 adaptations you would have a very
powerful AT PSU though). From the only pic you have showing a PSU it looks
like the 440 watt without the auxiliary (providing another 220 watts).
I'm looking to unassemble the driver diskette included with the 880
watt PSU for the 720, because it may have a way of writing characters to the
second line of the 720 info panel display (four times the character space as
the 8595/9595/500 info panel). WBST did some legwork on it back in the day,
which I should have mostly documented on
http://www.gilanet.com/David/Interrupts/INT15hCB.html. It would be nice to
get it eventually figured out.
> PS - I have noted the words of the Don: "I -personally- don't like
> the 720 that much.It took them (IBM and Corollary) too long to
> get a stable design, the early bridgecards were a weak point on
> them and the machine came too late anyway tofind much response.
> So the parts situation is a bit "constrained". Not many parts fit from
> other machines - the most of the inards is "720-only", therefore
> maintenance of these machines will come rather tricky in a short
> period of time(unless you buy stock parts from IBM for horrible
> prices). I think the 720 will be history when others are still able to
> service Mod. 95A or Server 500 with little or no problems.
The Corollary bus is different from all other SMP designs in that you
are supposed to be able to mix speeds (but mixing CPU steppings & speeds
would be avoided for me I'm sure). I do agree with Peter about the bad
design of the cards plugging into the planar (the same shortcomings that
doomed the Server 195 & 295) & that the 720 owners out there seem to be
dwindling when other systems are going strong. But in no other system do you
have eight microchannel slots alongside eight PCI slots (although it is not
able to run some modern cards from what I hear), all shared space of course.
David
Da...@IBMMuseum.com