Ok, let me try again, slower. AS/400 and 4300s are/were what we
now call "departmental servers". /370, ES/9000s were relegated to
data centers and are rated for a "class-A" environment only. Note
that "office space" rating isn't exactly harsh either.
I wouldn't exactly call a 4331,41 & 81 class machines a department
server. It was the replacement for 370 M138-158 class machines.
The AS/400 actually out performed that series in black box form.
The word mainframe became fairly ambiguous anyway when they became
nothing more than a rack of RISC cards. It is one reason I left. The
computer business got very boring for a hardware guy. When the CPUs
pumped water and the disk drives pumped oil it was fun to do. The
hardware job became pluck and chuck. The Physical planning rep job
pretty much just went away too. What pass for mainframes these days
would run fine in a warehouse.
BTW offices are still FCC class A environments. B is residential
I was region support for the 4300 and the 138, 148. I don't know of
ONE 370 138/148 customer who went for the 3031
It basically WAS a 158 (as were the service directors) so there would
be no advantage to go 158 to 3031
I was also trained on both the 158 and 3031.
After my time but I bet it is.
CE, Support Specialist then later IPR and Contract Services.
You guys are in semi-violent agreement.
Keith's first response was:
"Not true at all. A high RH contributes to failures in electronics
as well. Even recent equipment is specified from 40-60% RH, over a
fairly narrow temperature range."
I call the "not true at all" part complete bullshit.
What Greg said was 100% true. And the gratuitous
"let me try again, slower" is another detractor.
Bottom line: human comfort and "equipment comfort"
are roughly the same, with the "equipment comfort"
range being wider than the human comfort range.
Think about it - humans operate the equipment, and
would not be willing to work in the thousands upon
thousands of "normal" datacenters if the machinerey
could not function in office-like temperature and
humidity. (Sorry - if you're in the military, you
work where they tell you - but even then, if it's
in a datacenter, it's likely to be comfortable.)
In fact, humans usually get uncomfortable outside
the 68-72 range, on average. Datacenter machinery
functions well outside of that range. The farther
you depart from that 68-72, the more extensive the
steps a human needs to take. Machines can't take
those steps, so they will fail when the conditions
are too far from nominal. What would be interesting
is some real discussion of the specific numbers.
I'll give you five examples:
1) Peat Marwick Mitchell datacenter, early 70's
An airconditioner failure caused DASD (2314) data
errors at exactly 94 degrees on their wall thermometer.
Ran fine at 93.
2) Manufacturers Hanover Trust datacenter began losing
equipment (power down) when temperature went above 90
during a blackout. (Early 80's) They had emergency
power to keep the data processing equipment running,
but nothing to power the conditioners.
3) Bloomingdales (now part of Federated) datacenter,
mid-late 70's. Red lite checks on CPU (3138) whenever
a metal cart carrying cards would touch the CPU;
random red lite cpu checks when loading paper in 1403.
Relative humidity was 16%. Raising it to 40% fixed
the problem. No hardware was damaged. Interesting -
with the lights off, when a new box of 1403 paper was
opened and fanned out, you could see the discharge.
4) Divco Wayne had a building heat failure over the
weekend. On Monday morning, the computer room was
30 degrees F. The damn system powered up and ran,
with no problems - but the 1416 print train ran
audibly slow. (Early-mid 70's)
5) IBM datacenter, early 80's. A disk pack was
transported in the trunk of a car, properly packed,
but in sub zero temperature. Upon arrival it was
immediately placed in a 2314. The idiot who did it
moved the pack to subsequent drives when it didn't
work. 180 heads, 5 VCM's and several days later,
full service was restored. I guess by the 6th pizza
oven, he moved the pack soon enough where the VCM
was not destroyed.
Specifically, the relative humidity spec is for
static/paper "fatness". The equipment couldn't
care less. It will run happily outside the range.
But if the RH is too low, static discharge can
occur, and that discharge can interfere with
equipment operation. The equipment does not mind
the low humidity, but it does mind the discharge.
"Wet" paper, due to high humidity, does not do
well in paper handling machinery in the datacenter.
Feed the equipment "dry" paper & it performs flawlessly.
I do not have statistics on "wet" paper - perhaps
one of you can discuss that in more detail.
Ah - we run something comparitively smaller in our office with a pretty
even mix of *nix to Windows servers. All total there are roughly 50
Room is supplied with power by an APC Symmetra that gives us nominally
15 minutes of backup power. That Symmetra also has a kill switch for
emergency and its wired into the fire alarm system so that when the
sprinklers go off, all power to the room is cut.
The Symmetra also powers the cubes in the IT space. Right now we get 40
minutes time out of it, but that's only because two of our employees
like to have their heaters going full tilt. Otherwise it's over an hour.
Overhead lighting and air conditioning are not on the UPS. However there
is a 125kW natural gas fired generator out back that backs up the UPS,
and also supplies power to not only the overheads, but to the HVAC
system and we even ran a line out to the MDF int he building so Cox
could take advantage of our generator in the event of a building wide
power failure. We weren't being altruistic, we just wanted to make sure
our network connection stays up.
We also do quarterly tests of the power system, as well as having the
system set to do regular exercise runs on the generator.
That data center was my baby. And the redundancy built in shows it.
If you bring a pallet of paper in from outside in Florida (80-90 RH)
and put it in a 3800 it will wad up so bad you can't stack more than
about 200 pages without taking it out. Forget trying to run it through
They usually tried to keep it in the A/C for several days before using
Reminds me of an incident that occurred in the late 80s/early 90s when I
worked for the Navy. I managed a Tandem TXP system that shared a computer room
with a Honeywell 66. One holiday weekend, the air conditioning system failed
in the wee hours of Saturday morning after the second shift operators had gone
home. (There was no third shift.) Monday being a holiday, the problem wasn't
discovered until the first shift operators arrived at about 6am Tuesday to
find the data center at about 110 degrees. The Honeywell had gone down only
about three hours after the air conditioning did... but the Tandem was still
up. The DASD cabinets were painfully hot to the touch, and one of the drives
had gone down -- but since Tandem uses mirrored drives, and the mirror was
still ok, it did no harm. I measured the exhaust air at the back of the
processor cabinet at 134 degrees... but the Tandem was still up.
Doug Miller (alphageek at milmac dot com)
Back in 1993 I was responsible for managing a Data General MV9600U
running AOS/VS II. Loved that machine, and still remember alot about it.
In any case, these were machines that could take abuse. We knew of one
located in a non-ventilated closet that just continued to run until
Any of the air cooled machines could run damn near anywhere. When I
got to Florida (From the glass house data centers of DC) I saw it
happening. A "computer room" was a bay in a strip mall or industrial
center. That was also the first time I ran into red leg delta power
and the first time I saw "no raised floor" since the 1401 and mod 30
We stipulated a raised floor because we could. And it has come in handy,
from snaking a power whip over to the telephone switch (An Avaya
Prologix) or running network cabling to server racks, etc.
We had a bunch of them but I tried to stay away from them. When they
merged GSD and FE it got harder to do. I ended up working on the 3x
and was trained on the RS6000 and AS/400. I was the 7800 (TP support)
guy so mostly I did the communication end.
All of those boxes were basically solid except the DASD and that was
just a software nightmare, not a hardware problem. Once they started
using RAID5 they were a no brainer.
My boss had a real sense of humor and sent me to Series 1 school the
week after I got back from 3090 support school. It was the only school
I walked out of.
I've been in some places, like computer rooms, which were kept like
that. Also the generator room at Glen Canyon Dam was kept at 50F.
Interestingly, I didn't find it that cold. That house (where 65F was
too cold) may have had too many leaks.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.