7 ms·

Back in 1989 I worked as a one-man-IT-department for a bunch of ex-academic economists doing econometric modelling on a Digital VAX 11/750. This mini-computer w

Back in 1989 I worked as a one-man-IT-department for a bunch of ex-academic economists doing econometric modelling on a Digital VAX 11/750. This mini-computer was running VMS - a multi-user operating system. All users had admin rights and each one thought that they could make their models run faster by bumping up the process priority as far as it could go - which of course interfered with the realtime processes needed to manage the effective running of the computer. Unsurprisingly, this had the opposite effect to what they intended. When I discovered this was what was happening, I revoked their privileges and after a system restart, sanity was restored. I was thanked for finally making the system work faster.

havnagiggle 3y ago
A bunch of economists couldn't play nice?
- quickthrower2 3y ago
  Behaving like perfectly rational actors, of course.
  - eru 3y ago
    That's like complaining that real world physicists don't behave like frictionless spheres in a vacuum.
    - dtech 3y ago
      But they were, economic rational actors behave in their own self-interest
      - jychang 3y ago
        Getting his software stuck and then kicked off the computer is his self interest?
- Dylan16807 3y ago
  Wow, you annoyed someone enough to get your comment hidden, impressive.
ycombinete 3y ago
Great example of the economic principle The Tragedy of the Commons: https://en.m.wikipedia.org/wiki/Tragedy_of_the_commons https://en.m.wikipedia.org/wiki/Tragedy_of_the_commons
latchkey 3y ago
Oh, my first internet access was through one of those in 1991 at college! Found a cool exploit that let me anonymously broadcast messages to anyone. Sure freaked out a lot of people. Was fun cause you'd get to see the effects of your action in real time because it was a bunch of people in the same room on shared terminals.
- pdntspa 3y ago
  Reminds me of WinPopup spam on Windows 95
- cheese_van 3y ago
  Around '84 doing seismic data. We just got a terminal in the office that would allow you to monitor the jobs running on the IBM mainframes downstairs. Completely new tech to all of us. It had a command line message capability. Because it was quite easy to send to all instead of just your recipient, one marriage ended rather suddenly. Seeing the effects of your actions with new tech in real time indeed.
  - sokoloff 3y ago
    Working at a hedge fund with multiple locations, the founder insisted that mail to “staff” would reach everyone at the local office and mail to “all” would reach everyone (in all offices). One afternoon (in the middle of the trading day), we got a weird email with an empty body and a bunch of nonsense email addresses. Turns out some poor trader wrote an online dating email, but pasted/wrote the mail in the cc line, resulting in all of us learning that he thought “you don’t seem like all the other girls”, which was sent to you@, don’t@, seem@, and the dreaded all@.
- taneq 3y ago
  “Cool exploit“? Like net send? :)
  - KnobbleMcKnees 3y ago
    I was banned from the school computer suites several times for (ab)using net send. Good times.
idontwantthis 3y ago
If a group of economists can’t coordinate their behavior to prevent tragedy of the commons then they should rethink their career and life choices.
- zer8k 3y ago
  A group of economists couldn't coordinate splitting a bill at Applebee's.
  - yabbs 3y ago
    Applebee's... Does not compute.
- hgomersall 3y ago
  On the contrary, it was a rational attempt to limit their ability to break things.
shagie 3y ago
There was a system that a bunch of students administered (I was one of the students at the time). We would occasionally prank each other. On this DEC station where memory was scarce, one guy ran emacs. Another guy wrote a program that forked 1000 copies of itself, nice itself to 19, did a sleep(0) and then exit. As soon as it got any cpu time, it would exit, but it never would as long as emacs was running. Meanwhile, the load (as displayed by xload) became a solid black box. So the emacs guy would run 'ps -ef | grep procname | xargs kill' as root. This meant that it had to get some cpu time to handle the kill, which took longer than a sleep(0) and was largely ineffective. The second time this prank was done, the process was named 'ema'... which promptly also killed all instances of emacs too. The third time this prank was done, the process was named 'et'. This happened to have also matched /etc/initd and the machine rebooted rather suddenly.
- schoen 3y ago
  Somehow I've never considered what will happen on Unix if pid 1 exits! Even though I'm pretty sure I've run with init=/bin/sh and then typed "exit" at some point in my single-user session, I have absolutely no recollection of the results. I should try it on a few OSes and see!
  - suid 3y ago
    If PID 1 exits, the system usually panics immediately and restarts.
    - rzzzt 3y ago
      "Attempted to kill init!" https://github.com/torvalds/linux/blob/0b5547c51827e053cc754db47d3ec3e6c2c451d2/kernel/exit.c#L843 https://github.com/torvalds/linux/blob/0b5547c51827e053cc754...
      - rollcat 3y ago
        "...and that's why we have to put half a million lines of C in PID 1"
ww520 3y ago
Economy is all about incentives and behaviors. Did they learn any lessons from how they acted during the episode? And hopefully published a whole bunch of papers from it?
jjp 3y ago
Had exactly the same with a bunch of developers who could change the queue priority on a mainframe for their own work. They couldn't work out for themselves that if everybody set their work to the highest priority it had no benefit to any of them. Trying to educate them failed, so we revoked access.
darkclouds 3y ago
> All users had admin rights and each one thought that they could make their models run faster by bumping up the process priority as far as it could go - which of course interfered with the realtime processes needed to manage the effective running of the computer It amazes me what the bios and OS or OS api's let you do, even on modern devices.
- LoganDark 3y ago
  > It amazes me what the bios and OS or OS api's let you do, even on modern devices. Same, but not necessarily in a negative way. I like pushing my hardware and software to the limits, becoming unable to push those limits would be pretty disappointing.
  - Kon-Peki 3y ago
    I'm not sure anyone should call VMS "modern", but that's beside the point ;) VMS has a very comprehensive system of quotas and limits, so a "properly" configured system wouldn't suffer those issues. And furthermore, VMS isn't intended to be used "interactively" as such. You should be submitting work to the built-in batch queues - each with various attributes that can include the priority level. This allows the system to intelligently manage work based on a comprehensive view of the entire system - something a single user in a multi-user system can't have. If you like pushing a multi-user system to its limits, you'd be impressed with what VMS could do even way back in the 1990s.
    - LoganDark 3y ago
      We don't typically use multi-user systems, actually - I'm pretty sure Logan meant our personal hardware. For example, we run an i5-12400F at 5.2GHz and run a fairly customized Windows 11 Enterprise, both of which would become impossible if our BIOS and operating system were too much more locked down. I mean, our motherboard has an external clock generator almost entirely dedicated to pointing and laughing at CPUs with a "locked multiplier". (It's also used for PCIe 5.0) -Emily (see HN profile for details)
infostud 3y ago
I remember going along to a VAX/VMS System Administration workshop. Another bloke and I did a prank where we substituted text of the text editor that would produce blinking "Working" if it got busy. We substituted "or" with "an". The workshop coordinator caught us because we forgot to do something I can't remember and a login was tied to the change in the executable. Happy System Administrator's Day!
bstpierre 3y ago
In 1993 my freshman CS class was taught in scheme. All of our assignments had to be developed and tested on some shared Digital machine running Ultrix. The scheme interpreter was kind of slow to start, especially when there were 20+ users logged in. Helpfully, our TA taught us how to ctrl-z to suspend the interpreter, then edit our program in vi, and then "fg" to get back into the interpreter. Unfortunately the fg part of the equation was lost on about 2/3 of our class... after editing they would start another scheme instance! I recall being in the terminal lab the night one of our first assignments was due, and the machine slowed to an absolute crawl. Can't remember exactly how it was resolved but I do recall being taught how to look for classmates running two or more instances of scheme to remind them about fg. (Also not helpful to machine load: "solutions" to the 8 queens problem with infinite recursion. The real lesson here was, in later years, to not be logged in on nights when CS 401 had assignments due.)
- gte525u 3y ago
  I had a similar story with a friend in college in the 2000's. He would always hit Ctrl-z'd to "close" emacs when logged into the server which would've been fine if he wasn't using screen or tmux as well. At some point, he was using a ridiculous amount of RAM on the server and the admins suspended his login to force him to come in.
- chiph 3y ago
  I had a classmate who did her assignments in Ada. The compiler & linker would bring the school's Data General MV/8000 to it's knees, as it swapped out other processes to make room for it. Every 30-40 minutes we would have a coffee break forced on us.
- donatj 3y ago
  When I was first learning Linux around 2006 I somehow got the idea that Ctrl-Z was the way to exit programs. For maybe 3 years, I would just Ctrl-z my way out of programs. Luckily I worked almost entirely over ssh so I presume the suspended threads died with my ssh session exiting each day.
dghughes 3y ago
That reminds me of a story from a guy I worked with. I'm not sure where he worked but it involved a queue of people. He said someone asked him if they could be given priority for their problem to be looked at before others in the queue. In other words jump to the head of the queue. He said "Sure!" to the surprise of the person asking "But you do realize I will do that for anyone else who asks the same thing?" So they person chose to remain in their place in line.
LorenPechtel 3y ago
I had something of the opposite experience. Digging into the manuals I figured out how to launch the compiler as a background process so I could still have a working system while waiting for it. Brought the whole classroom to a halt. More digging revealed that the background priority was set well above user priority. AFIAK no malice involved, just someone who didn't know how to set the system up and left that landmine for me to find.

havnagiggle 3y ago

A bunch of economists couldn't play nice?

quickthrower2 3y ago
Behaving like perfectly rational actors, of course.
- eru 3y ago
  That's like complaining that real world physicists don't behave like frictionless spheres in a vacuum.
  - dtech 3y ago
    But they were, economic rational actors behave in their own self-interest
    - jychang 3y ago
      Getting his software stuck and then kicked off the computer is his self interest?
Dylan16807 3y ago
Wow, you annoyed someone enough to get your comment hidden, impressive.

ycombinete 3y ago

Great example of the economic principle The Tragedy of the Commons: https://en.m.wikipedia.org/wiki/Tragedy_of_the_commons https://en.m.wikipedia.org/wiki/Tragedy_of_the_commons

latchkey 3y ago

Oh, my first internet access was through one of those in 1991 at college! Found a cool exploit that let me anonymously broadcast messages to anyone. Sure freaked out a lot of people. Was fun cause you'd get to see the effects of your action in real time because it was a bunch of people in the same room on shared terminals.

pdntspa 3y ago
Reminds me of WinPopup spam on Windows 95
cheese_van 3y ago
Around '84 doing seismic data. We just got a terminal in the office that would allow you to monitor the jobs running on the IBM mainframes downstairs. Completely new tech to all of us. It had a command line message capability. Because it was quite easy to send to all instead of just your recipient, one marriage ended rather suddenly. Seeing the effects of your actions with new tech in real time indeed.
- sokoloff 3y ago
  Working at a hedge fund with multiple locations, the founder insisted that mail to “staff” would reach everyone at the local office and mail to “all” would reach everyone (in all offices). One afternoon (in the middle of the trading day), we got a weird email with an empty body and a bunch of nonsense email addresses. Turns out some poor trader wrote an online dating email, but pasted/wrote the mail in the cc line, resulting in all of us learning that he thought “you don’t seem like all the other girls”, which was sent to you@, don’t@, seem@, and the dreaded all@.
taneq 3y ago
“Cool exploit“? Like net send? :)
- KnobbleMcKnees 3y ago
  I was banned from the school computer suites several times for (ab)using net send. Good times.

idontwantthis 3y ago

If a group of economists can’t coordinate their behavior to prevent tragedy of the commons then they should rethink their career and life choices.

zer8k 3y ago
A group of economists couldn't coordinate splitting a bill at Applebee's.
- yabbs 3y ago
  Applebee's... Does not compute.
hgomersall 3y ago
On the contrary, it was a rational attempt to limit their ability to break things.

shagie 3y ago

There was a system that a bunch of students administered (I was one of the students at the time). We would occasionally prank each other. On this DEC station where memory was scarce, one guy ran emacs. Another guy wrote a program that forked 1000 copies of itself, nice itself to 19, did a sleep(0) and then exit. As soon as it got any cpu time, it would exit, but it never would as long as emacs was running. Meanwhile, the load (as displayed by xload) became a solid black box. So the emacs guy would run 'ps -ef | grep procname | xargs kill' as root. This meant that it had to get some cpu time to handle the kill, which took longer than a sleep(0) and was largely ineffective. The second time this prank was done, the process was named 'ema'... which promptly also killed all instances of emacs too. The third time this prank was done, the process was named 'et'. This happened to have also matched /etc/initd and the machine rebooted rather suddenly.

schoen 3y ago
Somehow I've never considered what will happen on Unix if pid 1 exits! Even though I'm pretty sure I've run with init=/bin/sh and then typed "exit" at some point in my single-user session, I have absolutely no recollection of the results. I should try it on a few OSes and see!
- suid 3y ago
  If PID 1 exits, the system usually panics immediately and restarts.
  - rzzzt 3y ago
    "Attempted to kill init!" https://github.com/torvalds/linux/blob/0b5547c51827e053cc754db47d3ec3e6c2c451d2/kernel/exit.c#L843 https://github.com/torvalds/linux/blob/0b5547c51827e053cc754...
    - rollcat 3y ago
      "...and that's why we have to put half a million lines of C in PID 1"

ww520 3y ago

Economy is all about incentives and behaviors. Did they learn any lessons from how they acted during the episode? And hopefully published a whole bunch of papers from it?

jjp 3y ago

Had exactly the same with a bunch of developers who could change the queue priority on a mainframe for their own work. They couldn't work out for themselves that if everybody set their work to the highest priority it had no benefit to any of them. Trying to educate them failed, so we revoked access.

darkclouds 3y ago

> All users had admin rights and each one thought that they could make their models run faster by bumping up the process priority as far as it could go - which of course interfered with the realtime processes needed to manage the effective running of the computer It amazes me what the bios and OS or OS api's let you do, even on modern devices.

LoganDark 3y ago
> It amazes me what the bios and OS or OS api's let you do, even on modern devices. Same, but not necessarily in a negative way. I like pushing my hardware and software to the limits, becoming unable to push those limits would be pretty disappointing.
- Kon-Peki 3y ago
  I'm not sure anyone should call VMS "modern", but that's beside the point ;) VMS has a very comprehensive system of quotas and limits, so a "properly" configured system wouldn't suffer those issues. And furthermore, VMS isn't intended to be used "interactively" as such. You should be submitting work to the built-in batch queues - each with various attributes that can include the priority level. This allows the system to intelligently manage work based on a comprehensive view of the entire system - something a single user in a multi-user system can't have. If you like pushing a multi-user system to its limits, you'd be impressed with what VMS could do even way back in the 1990s.
  - LoganDark 3y ago
    We don't typically use multi-user systems, actually - I'm pretty sure Logan meant our personal hardware. For example, we run an i5-12400F at 5.2GHz and run a fairly customized Windows 11 Enterprise, both of which would become impossible if our BIOS and operating system were too much more locked down. I mean, our motherboard has an external clock generator almost entirely dedicated to pointing and laughing at CPUs with a "locked multiplier". (It's also used for PCIe 5.0) -Emily (see HN profile for details)

infostud 3y ago

I remember going along to a VAX/VMS System Administration workshop. Another bloke and I did a prank where we substituted text of the text editor that would produce blinking "Working" if it got busy. We substituted "or" with "an". The workshop coordinator caught us because we forgot to do something I can't remember and a login was tied to the change in the executable. Happy System Administrator's Day!

bstpierre 3y ago

In 1993 my freshman CS class was taught in scheme. All of our assignments had to be developed and tested on some shared Digital machine running Ultrix. The scheme interpreter was kind of slow to start, especially when there were 20+ users logged in. Helpfully, our TA taught us how to ctrl-z to suspend the interpreter, then edit our program in vi, and then "fg" to get back into the interpreter. Unfortunately the fg part of the equation was lost on about 2/3 of our class... after editing they would start another scheme instance! I recall being in the terminal lab the night one of our first assignments was due, and the machine slowed to an absolute crawl. Can't remember exactly how it was resolved but I do recall being taught how to look for classmates running two or more instances of scheme to remind them about fg. (Also not helpful to machine load: "solutions" to the 8 queens problem with infinite recursion. The real lesson here was, in later years, to not be logged in on nights when CS 401 had assignments due.)

gte525u 3y ago
I had a similar story with a friend in college in the 2000's. He would always hit Ctrl-z'd to "close" emacs when logged into the server which would've been fine if he wasn't using screen or tmux as well. At some point, he was using a ridiculous amount of RAM on the server and the admins suspended his login to force him to come in.
chiph 3y ago
I had a classmate who did her assignments in Ada. The compiler & linker would bring the school's Data General MV/8000 to it's knees, as it swapped out other processes to make room for it. Every 30-40 minutes we would have a coffee break forced on us.
donatj 3y ago
When I was first learning Linux around 2006 I somehow got the idea that Ctrl-Z was the way to exit programs. For maybe 3 years, I would just Ctrl-z my way out of programs. Luckily I worked almost entirely over ssh so I presume the suspended threads died with my ssh session exiting each day.

dghughes 3y ago

That reminds me of a story from a guy I worked with. I'm not sure where he worked but it involved a queue of people. He said someone asked him if they could be given priority for their problem to be looked at before others in the queue. In other words jump to the head of the queue. He said "Sure!" to the surprise of the person asking "But you do realize I will do that for anyone else who asks the same thing?" So they person chose to remain in their place in line.

LorenPechtel 3y ago

I had something of the opposite experience. Digging into the manuals I figured out how to launch the compiler as a background process so I could still have a working system while waiting for it. Brought the whole classroom to a halt. More digging revealed that the background priority was set well above user priority. AFIAK no malice involved, just someone who didn't know how to set the system up and left that landmine for me to find.