26 Jul
2012
26 Jul
'12
5:54 a.m.
One thing you should also consider is the weight loading you are going to put on your
attic, and how it is distributed, less your ceiling sag over time.
Camiel Vanderhoeven <iamcamiel at gmail.com> wrote:
Hi Everyone,
I'm thinking of a way to move as many of the PDP11 systems I have into
my attic office to a) get them going, and then b) run them
occasionally.
I've stripped the two low corporate racks to the chassis, and if I can
find a helping hand, I'm sure I can get them into the attic, then put
the tabletop of my electronics workbench on top of it (I'm a little
short on space). I'm thinking of bolting two pieces of rack profile to
one side of each rack, which would turn them into a single unit
comprising three racks. That way, I should be able to mount 6 10.5"
PDP's and 6 5.25" PDP's, and have them conveniently close to my
oscilloscope and logic analyzer to work on them.
Now for storage...
I have some RL02 drives, but I'm a bit reluctant to drag those
upstairs. I have Emulex scsi controllers for three of the PDP's (2 x
UC18, 1 x UC08), but the rest is without mass storage.
I read about the TU58 emulator that runs on Linux, and I'm thinking of
putting a DECserver into the rack with the PDP11's, and use virtual
TTY's on a Linux box that connect to the PDP11's over the DECserver,
then run multiple instances of the emulator so each PDP has one or
more emulated TU58's.
I know the "real" TU58 tapes can hold something like 256K of data. Are
the operating systems aware of this limit, or could you get by with
emulating a larger tape?
Thanks for any insight you may have to offer. Warnings like "That's a
really bad idea, because..." are also very welcome.
Cheers,
Camiel
26 Jul
26 Jul
7:34 a.m.
On 7/26/12, Jay jaeger <cube1 at charter.net> wrote:
One thing you should also consider is the weight
loading you are going to
put on your attic, and how it is distributed, less your ceiling sag over
time.
Good point. I hadn't considered that. I figure it'll weigh around 500
kg alltogether. The surface area is 150 x 70 cm = 1,2 m2. That's 416
kg/m2. The floor is made out of concrete, and I'm putting it into a
corner of two load-bearing walls. I'll make a call to the housing
corporation to find out what the maximum load is.
Camiel
8:20 a.m.
Camiel,
Usually 250Kg - 300Kg per m2. Your 500kg on that surface should not be
a problem, there is a large safety margin.
I used to have 6 H960 racks next to each other, with an average of 150Kg
on a concrete floor made of 'kanaalplaten'. Your floor is a reenforced
concrete poured type and an integral part of the walls when the house was
build (gietbouw box constructie, sorry for the Dutch here).
For comparison, the wooden floor in my garage is also designed for 250Kg
per m2, and you have seen how that has been made.
Ed
On 7/26/12, Jay jaeger <cube1 at charter.net>
wrote:
--
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Zeg NEE tegen de 'slimme' meter.
One thing you should also consider is the weight
loading you are going
to
put on your attic, and how it is distributed, less your ceiling sag over
time.
Good point. I hadn't considered that. I figure it'll weigh around 500
kg alltogether. The surface area is 150 x 70 cm = 1,2 m2. That's 416
kg/m2. The floor is made out of concrete, and I'm putting it into a
corner of two load-bearing walls. I'll make a call to the housing
corporation to find out what the maximum load is.
Camiel
11:06 p.m.
If your flooring consists of reinforced Concrete built with standards that
are at least a bit "compatible" with current Eurocodes (construction
Statics and safety margins) and EN 206 (Concrete) the structure should
easily be able to handle your load... From experience people tend to put
much more load on their floors (Aquariums etc.) and I have not seen major
structual damages because of private loads in the last 10 years. Most
damages came from people disregarding plans, standards etc.
If you still have some kind of fear, ping me privately - I have enough
engineers around me at work ;)
2012/7/27 Sander Reiche <reiche at ls-al.eu>
"E. Groenenberg" <quapla at xs4all.nl>
wrote:
For comparison, the wooden floor in my garage is also designed for 250Kg
per m2, and you have seen how that has been made.
Could you rebuild my attic? :)
re,
Sander
27 Jul
27 Jul
8:27 a.m.
The racks will also be providing point loads instead of distributed loads.
Make sure the flooring is strong enough to hold the feet of the racks
without puncturing. In particular, the various manufactured wood products
(flake board, oriented strand board, particle board) can be punctured
easily.
An overlay of 3/4" plywood glued and screwed should provide the needed
support for the feets. If you use ACX grade and put the nice side up, you
can put down a simple floor finish and it looks nice too.
Avoid carpet (hard to move racks after they have sat for a while),
linoleum (dimples never go away), and soft woods (pine).
Clint
On Thu, 26 Jul 2012, E. Groenenberg wrote:
Camiel,
Usually 250Kg - 300Kg per m2. Your 500kg on that surface should not be
a problem, there is a large safety margin.
I used to have 6 H960 racks next to each other, with an average of 150Kg
on a concrete floor made of 'kanaalplaten'. Your floor is a reenforced
concrete poured type and an integral part of the walls when the house was
build (gietbouw box constructie, sorry for the Dutch here).
For comparison, the wooden floor in my garage is also designed for 250Kg
per m2, and you have seen how that has been made.
Ed
On 7/26/12, Jay jaeger <cube1 at
charter.net> wrote:
--
Dit is een HTML vrije email / This is an HTML free email.
Zeg NEE tegen de 'slimme' meter.
One thing you should also consider is the weight
loading you are going
to
put on your attic, and how it is distributed, less your ceiling sag over
time.
Good point. I hadn't considered that. I figure it'll weigh around 500
kg alltogether. The surface area is 150 x 70 cm = 1,2 m2. That's 416
kg/m2. The floor is made out of concrete, and I'm putting it into a
corner of two load-bearing walls. I'll make a call to the housing
corporation to find out what the maximum load is.
Camiel
10:04 a.m.
On 27 Jul 2012 at 9:27, cctech at vax-11.org wrote:
An overlay of 3/4" plywood glued and screwed
should provide the needed
support for the feets. If you use ACX grade and put the nice side up,
you can put down a simple floor finish and it looks nice too.
Avoid carpet (hard to move racks after they have sat for a while),
linoleum (dimples never go away), and soft woods (pine).
When we installed a VAX 11/750 system in the second floor of a wood-
frame office building, we constructed a frame of 2x4 lumber to
distribute the weight of the system that sat right on the existing
floor. A double layer of 3/4" subfloor grade plywood (T&G) on top of
that (glued and screwed) and finished off with vinyl composition tile
(very tough stuff and easy to renew the surface if scratched, or if
necessary, to replace a damaged tile).
Not expensive to build and very sturdy.
FWIW,
Chuck
10:28 a.m.
On 07/27/2012 01:04 PM, Chuck Guzis wrote:
Good heavens, an 11/750 isn't THAT heavy.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
An overlay of
3/4" plywood glued and screwed should provide the needed
support for the feets. If you use ACX grade and put the nice side up,
you can put down a simple floor finish and it looks nice too.
Avoid carpet (hard to move racks after they have sat for a while),
linoleum (dimples never go away), and soft woods (pine).
When we installed a VAX 11/750 system in the second floor of a wood-
frame office building, we constructed a frame of 2x4 lumber to
distribute the weight of the system that sat right on the existing
floor. A double layer of 3/4" subfloor grade plywood (T&G) on top of
that (glued and screwed) and finished off with vinyl composition tile
(very tough stuff and easy to renew the surface if scratched, or if
necessary, to replace a damaged tile).
Not expensive to build and very sturdy.
10:53 a.m.
On 27 Jul 2012 at 13:28, Dave McGuire wrote:
Good heavens, an 11/750 isn't THAT heavy.
Oh, I knew that and so did the DEC salesman. But the landlord
refused to be mollified. He insisted on floor reinforcement to 100
lbs./sq. ft. The guy was also an architect, so maybe he refused to
trust computer people with their awful boxes.
I suppose we were grateful at that point that he didn't make us
spring for extra HVAC as well...
At some point, it's simply cheaper to capitulate than be right.
--Chuck
11:31 a.m.
On 7/27/12 12:53 PM, Chuck Guzis wrote:
On 27 Jul 2012 at 13:28, Dave McGuire wrote:
Ralphie May, quoting his late father on hearing Ralphie was getting
married:
"Just remember, son, you can be right, or you can be happy."
Words to live by.
Doc
Good heavens, an 11/750 isn't THAT heavy.
Oh, I knew that and so did the DEC salesman. But the landlord
refused to be mollified. He insisted on floor reinforcement to 100
lbs./sq. ft. The guy was also an architect, so maybe he refused to
trust computer people with their awful boxes.
I suppose we were grateful at that point that he didn't make us
spring for extra HVAC as well...
At some point, it's simply cheaper to capitulate than be right.
2:50 p.m.
On 07/27/2012 01:53 PM, Chuck Guzis wrote:
Yeah. People really suck sometimes. :-(
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
Good
heavens, an 11/750 isn't THAT heavy.
Oh, I knew that and so did the DEC salesman. But the landlord
refused to be mollified. He insisted on floor reinforcement to 100
lbs./sq. ft. The guy was also an architect, so maybe he refused to
trust computer people with their awful boxes.
I suppose we were grateful at that point that he didn't make us
spring for extra HVAC as well...
At some point, it's simply cheaper to capitulate than be right. 
28 Jul
28 Jul
1:51 p.m.
Good point. I hadn't considered that. I figure it'll weigh around 500
kg alltogether. The surface area is 150 x 70 cm = 1,2 m2. That's 416
kg/m2. The floor is made out of concrete, and I'm putting it into a
corner of two load-bearing walls. I'll make a call to the housing
corporation to find out what the maximum load is.
Camiel
--
Dit is een HTML vrije email / This is an HTML free email.
Zeg NEE tegen de 'slimme' meter.
This conversation has started to worry me about the PDP-11/23 system in my
29 Jul
29 Jul
12:32 a.m.
You are not even remotely in dangerous territory here.
For some perspective, think of a sofa with "feet", with two or three fat
people on it.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
On Jul 28, 2012, at 4:51 PM, Earl Evans <earl at retrobits.com> wrote:
This
conversation has started to worry me about the PDP-11/23 system in my
daylight
basement/family room. It's the largest single room in our home,
and on the bottom of three floors. It is a wooden floor, with (large)
crawl space underneath.
The configuration is a PDP-11/23 in a BA23 chassis, 2 RL02 drives, and the
standard DEC rackmount cabinet (which is pretty heavy itself). The entire
cabinet has been placed on a 2 foot by 4 foot piece of half-inch plywood to
evenly distribute the load. It is located near one of the load-bearing
external walls of the home.
RL02 drives weigh 75 lbs by themselves. Does anyone have a rough guess on
what the total weight is for the system I described, and whether or not
this would be safe for residential basement wood flooring? I realize there
are a lot of factors - I'm just trying to get a wild guess before I start
getting panicked.
Thanks,
- Earl 
26 Jul
26 Jul
3:14 p.m.
Camiel Vanderhoeven <iamcamiel at gmail.com> wrote:
Good point. I hadn't considered that. I figure it'll weigh around 500
kg alltogether. The surface area is 150 x 70 cm = 1,2 m2. That's 416
kg/m2. The floor is made out of concrete, and I'm putting it into a
corner of two load-bearing walls. I'll make a call to the housing
corporation to find out what the maximum load is.
Concrete should take 150 kg/cm2. My wooden house probably maxes
out at 75 kg/cm2, hence no H960 on my attic ;)
re,
Sander
27 Jul
27 Jul
3:10 a.m.
IIRC the raised floor here is specified for 600 kg/m?...
On Fri, 27 Jul 2012, Sander Reiche wrote:
Concrete should take 150 kg/cm2. My wooden house
probably maxes
out at 75 kg/cm2, hence no H960 on my attic ;)
...and your house then for 750 tons/m? ? That's impressive :-o
(I've implied that you don't mean the pressure of the entire house on the
terrain, but instead the supported weight of the floor)
Christian
5:56 a.m.
depends on the classification of your concrete. fairly typical is c20/25
which means characteristic 20n per mm2 or more on a test cylinder or 25 n
per mm2 or more on a test cube until the material breaks. in most cases the
concrete will take even more load.
conclusion: if you have a conrete floor which is about 20-25 cm in height
and pile your stuff in a corner of the room you will not run into problems.
i talked to one of our engineers at work today, he did not see a problem
too. he is the head of our concrete test lab for over 15 years now and i
tend to trust him.
if anyone is interested i have some training materials and papers according
concrete (exposition classes, usage, testing etc.). the stuff is mostly in
german, but i can translate a bit if desired.
2012/7/27 Christian Corti <cc at informatik.uni-stuttgart.de>
IIRC the raised floor here is specified for 600
kg/m?...
On Fri, 27 Jul 2012, Sander Reiche wrote:
Concrete should take 150 kg/cm2. My wooden house
probably maxes
out at 75 kg/cm2, hence no H960 on my attic ;)
...and your house then for 750 tons/m? ? That's impressive :-o
(I've implied that you don't mean the pressure of the entire house on the
terrain, but instead the supported weight of the floor)
Christian
4529
days inactive
4532
days old
15 comments
11 participants
participants (11)
-
cc＠informatik.uni-stuttgart.de -
cclist＠sydex.com -
cctech＠vax-11.org -
cube1＠charter.net -
doc＠vaxen.net -
earl＠retrobits.com -
iamcamiel＠gmail.com -
mcguire＠neurotica.com -
quapla＠xs4all.nl -
reiche＠ls-al.eu -
wolfgang＠eichberger.org