Author Topic: Longest computer up time?  (Read 7141 times)

dfw_pilot

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747-8
« Reply #15 on: June 01, 2016, 05:25:58 PM »
LOL!

Flying the 747-8 is all by wire and we even have a flare-assist module that makes the 32 foot longer airplane flare like it's a -400 model for a common type rating. It's inching closer to the bus, however, when my right and left thumbs both go  "click, click" - "click, click" I can get us outta Dodge if necessary (or so I think).
A clear conscience is a great pillow.


Bull Winkus

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Re: Longest computer up time?
« Reply #16 on: June 01, 2016, 05:45:19 PM »
I love that voice at the end going, "Aaa, oh no, oh no, oh no…"

I think he might be remembering some of his, not ready for prime time, code.

 [biggrin], I mean, poor guy…

EDIT: I just read the text for the video. I thought it was just an errant test flight. I didn't know it was carrying passengers, or I wouldn't have been so flippant. Please forgive me.
Herb

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Foolproofing technology . . . (Re: Longest computer up time?)
« Reply #17 on: June 01, 2016, 11:13:20 PM »
Dear Herb, Blick, dfw, X-Air, and WeatherCat technologists, . . .

Quote
Why am I getting a sinking feeling about now tuning my car with a computer? . . . . .  :o

I think you'll be alright, as long as you don't leave the computer in charge while driving. Aaaa… I can see it now…

*Sigh*, that's a little too late!  My trusty wagon doesn't have 1 computer but 2!  The engine control unit is a computer and the air conditioner is also controlled by a computer.  As long as this thread is hopelessly off-topic, there is a quick video of my trusty wagon starting:

https://youtu.be/bVoqF1zhAHQ

If you look at the far corner of the engine bay behind the air cleaner, you can see the engine control unit and the LED status lights.  When the engine starts you can see all the activity.  So indeed it is too late.  My trusty wagon is definitely computer-controlled at this point.

"You can't make things idiot-proof. There are simply too many idiots around!"

But I thought it was a Murphy-ism that:  "You can't make anything foolproof because fools are so ingenious!" . . .  :o

I'd like to return this thread to its originally scheduled programming , but I fear this might well be impossible! . . . 

Cheers, Edouard  [cheers1]

xairbusdriver

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Re: Longest computer up time?
« Reply #18 on: June 02, 2016, 12:09:12 AM »
OK, nice vid! I especially enjoyed the running commentary! And the magically turning page by the MBP was neat!

What is the pressure gauge(?) on the firewall, just inside of the brake reservoirs/cylinders? Vacuum? AC vapor on the way back to the compressor? Frapilator vapor pressure?

elagache

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When you are a "one-man band" (Re: Longest computer up time?)
« Reply #19 on: June 03, 2016, 12:07:36 AM »
Dear X-Air and WeatherCat technical cinematographers,

OK, nice vid! I especially enjoyed the running commentary! And the magically turning page by the MBP was neat!

I actually have quite a few videos like this - I have no choice.  I have to do all this tuning by myself.  Normally you have one person operate the car and a second person using the laptop making adjustments.  Since I'm the only person can drive the car safely and also the only person who understands the tuning software, I've got make a test, videotape it, and then look over the results afterwards to see what needs to be changed.

What is the pressure gauge(?) on the firewall, just inside of the brake reservoirs/cylinders? Vacuum? AC vapor on the way back to the compressor? Frapilator vapor pressure?

That's the pressure of the gasoline.  In a modern fuel injection system, you run a pump in the gas tank that supplies fuel at a high enough pressure so that when an injector opens, it squirts the fuel into a mist.  The injector dictates the required pressure.  On my trusty wagon, the system requires fuel at 43 psi.

My wagon also shares an unexpected feature with modern cars: the fuel line loop.  Since the injectors aren't opening all the time, what happens to the fuel when the injectors are closed?  On modern cars (and backfitted on my wagon) there is a pressure regulator and when fuel isn't needed by the fuel injection system, it flows down a return line back into the fuel tank.  That way there is always sufficient gas available for the injectors.  Whatever gas isn't used is returned to the fuel tank.

Cheers, Edouard

xairbusdriver

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Re: Longest computer up time?
« Reply #20 on: June 03, 2016, 03:27:07 AM »
Quote
...fuel line loop... ...pressure regulator...
Thanks for the explanation. Probably safe than a simple accumulator and more accurate/constant pressure. I had no idea that the pump in the tank put out that much pressure! :o

Michel

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Re: Longest computer up time?
« Reply #21 on: June 14, 2016, 06:59:06 PM »
Hi xairbus,

after a long period of absence from this forum  I stumbled across your uptime question and couldn't resist...

Maybe should be a Poll?

Good idea  [tup]

Quote
So, the question is; What is the longest time you've had a nonstop running computer?

Since you are not referring to a particular hardware or OS, here are the first lines of the
output of my DIGITAL AlphaServer DS10 running OpenVMS 8.3 - the uptime is shown in days,
hours, minutes and seconds in the upper right corner...

 


Quote
Second question might be, who cares?!

A lot of people in manufacturing, health care, electric power plants, banks, stock exchanges etc. do...
And I do as well :-) I simply prefer the beasts to run and do the work for me over having to play nanny for them.

  Regards !

   Michel

xairbusdriver

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Re: Longest computer up time?
« Reply #22 on: June 15, 2016, 12:48:55 AM »
I'll agree, restarts/reboots can be a drag, but I'm willing to bet that most  systems demanding continuos time stamping will be running duplicate/triplicate/multi-cate systems with non-conflicting, single system maintenance schedules. Or, maybe not!  [banghead]

I notice that this system decided to disregard such things as "months" and "years", possibly for the same reasons I did. ;)

However, based one questions about "time" in another thread here (<time measuring difficulties>), even using "day" may be fraught with inconsistencies! Exactly what is the definition of a "day" on these systems?


dfw_pilot

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Re: Longest computer up time?
« Reply #23 on: June 15, 2016, 12:50:26 AM »
Seconds from the Epoch?
A clear conscience is a great pillow.


xairbusdriver

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Re: Longest computer up time?
« Reply #24 on: June 15, 2016, 01:32:24 AM »
Quote
Seconds from the Epoch?
Probably, but considering the fact that a day is actually longer than the "standard" 86400 seconds, ererz accumulate like dust on my desktop! :blush: That's why I removed my original calculations that included Years/Months/Days/Hours/Seconds. With even a day being not an integer value in a "day", how can we then interpolate a "month" or even a "year"?! Even in the 17th Century, it became obvious that the 24/7/365 "standard" wasn't working correctly. The "solution" was to create a "leap day" every so often. [banghead]

It seems the "DIGITAL AlphaServer DS10 running OpenVMS 8.3" didn't bother with trying to go further than "Days", even though it could end up with a rather large number! ;)

Michel

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Re: Longest computer up time?
« Reply #25 on: June 15, 2016, 05:51:55 AM »
Oh well... What have I done ? :-)

To answer the more or less simple question regarding epoch and its friends first:

With Unix applications, the epoch begins 1-Jan-1970 00:00:00.00 UTC. (1970-01-01T00:00:00Z)
With OpenVMS, the system base date is 17-Nov-1858 00:00:00.00 (local) (1858-11-17T00:00:00)

OpenVMS uses local time as the system time, unlike Mac OS X. This design flaw
dates back to software and hardware decisions made when the platform was conceived,
back in 1975. A 64-bit value for the time was quite foresighted for that time.
Unix has an analogous error in its use of a longword for its basic time value —
but the lack of timezone support is definitely among the larger design flaws in
OpenVMS.

It should be clear how the system clock's seconds evolve from a particular
number of processor cycles - and subsequently minutes, hours and days.

If I got you right, the question is how this systems does handle days or to be
more precise "calendar days". This arises the question :

"To leap or not to leap..."

In fact, there are not only leap years, there are also leap seconds.
DIGITAL once (1983) was asked by a customer why they considered the year
2000 to be a leap year - because he suspected this was wrong. Here's
the answer which points out that OpenVMS makes use of the Gregorian calendar
and hence also clarifies how this system does handle (calendar) days:


                   ******DEC INTERNAL USE ONLY******             
 
SPR NUMBER:                  11-60903
 
ANSWER CATEGORY:             UE
MAINTENANCE HOURS:           1
DUPLICATE PROBLEM:           N
DUPLICATE SPR NUMBER(S):     
 
OPERATING SYSTEM:            VAX/VMS             
O.S. VERSION:                V3.2
PRODUCT:                     VAX/VMS
PRODUCT VERSION:             V3.2
COMPONENT:                   Run-Time Library
SUB-COMPONENT:               LIB$ routines
 
DATE ANSWERED:               13-Oct-1983
 
MAINTAINER:                  Stanley Rabinowitz
 
ATTACHMENT:                  N
 
PUBLICATION INSTRUCTIONS:    N
 
SPR PROBLEM ABSTRACT:        User claims year 2000 should not be a leap year.
 
TITLE:                       -
PUBLICATIONS:                -
ADDITIONAL O.S. VERSIONS:
ADDITIONAL PRODUCT VERSIONS:
COMPONENT SEQUENCE NUMBER:   
SUPERSEDES:                   
TYPE OF ARTICLE:             
 
                            ANSWER CATEGORIES
 
CG=1=CORRECTION GIVEN       RS=5=RESTRICTION              SG=9=SUGGESTION
FN=2=FIXED IN NEXT RELEASE  CS=6=CUSTOMER SUPPORTED       IQ=10=INQUIRY
DE=3=DOCUMENTATION ERROR    NR=7=NON-REPRODUCIBLE         HW=11=HARDWARE
UE=4=USER ERROR             II=8=INSUFFICIENT INFORMATION
 
                            TYPE OF ARTICLE
 
F=OPTIONAL FEATURE PATCH    N=NOTE
M=MANDATORY PATCH           R=RESTRICTION
 
                         FOR MAINTENANCE USE
 
 
 
 
 
                     ******END OF DEC USE ONLY******
 
                            D I G I T A L
 
                           SPR ANSWER FORM
 
SPR NO. 11-60903
 
 
           SYSTEM   VERSION   PRODUCT   VERSION   COMPONENT
SOFTWARE:  VAX/VMS  V3.2      VAX/VMS   V3.2      Run-Time Library
 
 
 
PROBLEM:
 
The LIB$DAY Run-Time Library service "incorrectly"  assumes  the  year
2000 is a leap year.
 
 
RESPONSE:
 
Thank you for your forward-looking SPR.
 
Various system services, such as SYS$ASCTIM assume that the year  2000
will  be  a  leap  year.   Although one can never be sure of what will
happen at some future time, there is strong historical  precedent  for
presuming  that the present Gregorian calendar will still be in affect
by the year 2000.  Since we also hope that VMS will still be around by
then, we have chosen to adhere to these precedents.
 
The purpose of a calendar is to reckon time in advance,  to  show  how
many  days  have  to  elapse  until a certain event takes place in the
future, such as the harvest or the release of VMS  V4.   The  earliest
calendars,  naturally,  were  crude  and  tended  to be based upon the
seasons or the lunar cycle.
 
The calendar of the Assyrians, for example, was based upon the  phases
of  the  moon.  They knew that a lunation (the time from one full moon
to the next) was 29 1/2 days long, so their lunar year had a  duration
of [354] days.   This  fell  short of the solar year by about 11 days.
(The exact time for the solar year is approximately 365 days, 5 hours,
48  minutes,  and  46  seconds.)  After 3 years, such a lunar calendar
would be off by a whole month, so the Assyrians added an  extra  month
from  time  to time to keep their calendar in synchronization with the
seasons.
 
The best approximation that was possible in antiquity  was  a  19-year
period, with 7 of these 19 years having 13 months (leap months).  This
scheme was adopted as the basis for the religious calendar used by the
Jews.   (The  Arabs  also  used  this  calendar until Mohammed forbade
shifting from 12 months to 13 months.)
 
When Rome emerged as a world  power,  the  difficulties  of  making  a
calendar  were  well  known,  but  the  Romans complicated their lives
because of their superstition that even numbers were  unlucky.   Hence
their  months were 29 or 31 days long, with the exception of February,
which had 28 days.  Every second year, the Roman calendar included  an
extra  month  called  Mercedonius of 22 or 23 days to keep up with the
solar year.
 
Even this algorithm was very poor, so that in 45 BC,  Caesar,  advised
by  the  astronomer Sosigenes, ordered a sweeping reform.  By imperial
decree, one year was made 445 days long to bring the calendar back  in
step  with  the  seasons.  The new calendar, similar to the one we now
use was called the Julian calendar (named after Julius Caesar).   It's
months  were  30 or 31 days in length and every fourth year was made a
leap year (having 366 days).  Caesar also decreed that the year  would
start with the first of January, not the vernal equinox in late March.
 
Caesar's year was 11 1/2 minutes short of the calculations recommended
by  Sosigenes  and  eventually the date of the vernal equinox began to
drift.  Roger Bacon became alarmed and sent a note to Pope Clement IV,
who  apparently  was  not  impressed.   Pope  Sixtus  IV  later became
convinced that  another  reform  was  needed  and  called  the  German
astronomer,  Regiomontanus,  to  Rome  to  advise him.  Unfortunately,
Regiomontanus died of the plague shortly thereafter and the plans died
as well.
 
In 1545, the Council of Trent authorized Pope Gregory XIII  to  reform
the  calendar  once  more.   Most of the mathematical work was done by
Father Christopher Clavius, S.J.  The immediate  correction  that  was
adopted  was  that Thursday, October 4, 1582 was to be the last day of
the Julian calendar.  The next  day  was  Friday,  with  the  date  of
October  15.   For  long  range  accuracy,  a formula suggested by the
Vatican librarian Aloysius Giglio was adopted.   It  said  that  every
fourth  year  is  a  leap  year  except for century years that are not
divisible by 400.  Thus 1700, 1800 and 1900 would not be  leap  years,
but  2000  would  be a leap year since 2000 is divisible by 400.  This
rule eliminates 3 leap years every 4 centuries,  making  the  calendar
sufficiently  correct  for  most  ordinary purposes.  This calendar is
known as the Gregorian calendar and is the one that we now use  today.
(It  is  interesting  to note that in 1582, all the Protestant princes
ignored the papal decree and so many countries continued  to  use  the
Julian  calendar  until either 1698 or 1752.  In Russia, it needed the
revolution to introduce the Gregorian calendar in 1918.)
 
This explains why VMS chooses to treat the year 2000 as a leap year.
 
Despite the great accuracy of the Gregorian calendar, it  still  falls
behind very slightly every few years.  If you are very concerned about
this problem, we suggest that you tune in  short  wave  radio  station
WWV,  which  broadcasts  official  time  signals for use in the United
States.  About once every 3 years, they declare a leap second at which
time  you  should be careful to adjust your system clock.  If you have
trouble picking up their signals, we suggest you  purchase  an  atomic
clock (not manufactured by Digital and not a VAX option at this time).
 
 
                         END OF SPR RESPONSE
 
Mon 17-Oct-1983 11:15 EDT / Nina Eppes, R2ME2::EPPES, 381-2175, ZKO2-3/K06
--

Is that enough of an explanation ? :-)

 Regards !
 
    Michael



Michel

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Re: Longest computer up time?
« Reply #26 on: June 15, 2016, 07:07:09 AM »
I overlooked this one with my previous answer:

I'll agree, restarts/reboots can be a drag, but I'm willing to bet that most  systems demanding continuos time stamping will be running duplicate/triplicate/multi-cate systems with non-conflicting, single system maintenance schedules. Or, maybe not!  [banghead]

Hook, line and sinker, xairbus !

In the VMS world the related heading is "Cluster".
There are identically named functions in the *nix and Win world which must not be
confused with VMS clustering. VMS clustering means full access to any ressource
(no matter if hard- or software) on any node worlwide being a member of a given
VMS Cluster. Say you can access a remote system's HDD or DVD or tape drives just
as if they would be sitting in the computer beneath your desk. Furthermore you can
upgrade single Cluster members while the other nodes will continue to service  the
users without any sign of downtime.

The above is a tad abstract, so here is a report from real life:

=======================================================

If cluster uptimes are going to be boasted about, here is our story.

We are running several major applications for the Regio Politie Amsterdam-Amstelland
(compare Greater Amsterdam Police). Call room, Criminal Investigation,
Recognation Service etc. are really in demand 7*24!

April 13 1997 (sunday morning) after a lot of planning and preparing to allow
for offline-police services, there was a 'big bang' total network upgrade,
which interrupted the online services for several hours. We (the VMS group)
took the opportunity to go down and do various changes that are so much more
cumbersome to perform "rolling". At that time the cluster consisted of 2
Alpha 2100's and a VaxStation 4000-90, running VMS 6.2-1H3 (some sopporting
programs were available only on VAX, they were to be replaced by different
ways to do them). In june 1997 a third 2100 was added. In march 1999 we did a
rolling upgrade from V6.2 to 7.1-1H2. A major change came in may 1999 when a
second location (7 KM away) was activated. An FDDI ring was established.
A test system (Alpha 1200) was configured into the cluster, and moved to the
other (the "dark") site. Then 2 2100 were removed, tranported over, and added
again. The 1200 left again.

The hardest part was explaining to management that we didn't go down for the move.

September 2000 an ES40 was added. February 2001 VMS went from 7.1-1H2 to 7.2-1;
the VaxStation was no longer needed and left. In may the "intestines" of the
2100's were moved into 2100A's to satisfy more PCI need. December 2002/january
2003 saw the upgrade to VMS 7.3-1, to prepare for the big change: the 2100A's
were to be replaced and a SAN deployed. After adding 2 ES45's and an ES40,
the data was moved from the HSZ40-connected SCSI disks to (HSG80-connected)SAN.
Over 850 concealed devices, moved at moments when a specific device was unused.
Only 5 of those had to be forced by deliberately breaking availability during
the SLA-specified "potential maintenance window", 0:30-1:00.
Thereafter the 2100A's and the old disks were removed. So now we are running a
cluster with uptime 2420 days, in which the oldest hardware (FDDI concentrators)
is only 1650 days, and the oldest system's age is less half that of the cluster
uptime. Daily peak concurrent usage is some 600+ interactive users, 50+ batch
jobs, 30+ network jobs, and 180+ detached processes ("other mode", mostly
call-room service processes and the server-end of the radio-connected
MobileDataTerminals in the policecars) Even more interesting, because the
signify the need to not go down: weekly LOW usage is some 50+ interactive,
40+ batch, 20+ net, and 170+ detached. The total environment is far from
unchanging: about twice a month some or other application is upgraded (most
support rolling upgrades), and there are about 100-150 mutations in personnel,
and some 200-300 application (de-)autorizations per week.
All this is maintained by only 3 people: Frank Wagenaar (full time)
Anton van Ruitenbeek (40%) and myself (full time).

=======================================================

I think this shows what well-thought hardware and OS design is able to accomplish
and that you are right in that it takes more than a single Computer to deliver permanent
service...

In this connection... the "disaster proof video" is a must see:
http://brightcove.vo.llnwd.net/e1/uds/pd/1160438707001/1160438707001_3492507031001_Disaster-Proof-MPEG2-3BZ7.mp4?pubId=4119874060001&videoId=4657542628001


 Regards !
 
   Michel


xairbusdriver

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Re: Longest computer up time?
« Reply #27 on: June 15, 2016, 05:14:24 PM »
Which one of those guys was you?! [lol]

BTW, Ouachita County, Arkansas is the home of the <Arkansas Law Enforcement Training Academy>, probably the actual location for this "disaster".

I'm impressed (even though no macOS [note new designation protocol] software was used)! However, the credulity of the video is stretched a bit by the claim that "no animals" were harmed, despite Blaze, Sparky, and Little Smokey 'returning' to their aquarium. I find it extremely hard to believe that those fish were not harmed by having such horrible 'puny' names!!! Obviously, HP has no concern for the mental cruelty to Animalia: Chordata: Pisces!!

Blicj11

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Re: Longest computer up time?
« Reply #28 on: June 15, 2016, 05:55:29 PM »
Great video. So happy for the fish.
Blick


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Re: Longest computer up time?
« Reply #29 on: June 15, 2016, 09:46:06 PM »
That video reminded me of the TV show, Dragnet for some odd reason.

Great thread, guys! Enjoyed the read on "why VMS chooses to treat the year 2000 as a leap year." Best and most detailed explanation I've seen, so far.

 [cheers1]
Herb