> According to Allied Ordnance Publication AOP-38-3,[1] a NATO publication, a battleshort is "The capability to bypass certain safety features in a system to ensure completion of the mission without interruption due to the safety feature." It also says, "Examples of bypassed safety features are circuit overload protection, and protection against overheating".
> For example, the electrical drives to elevate and traverse the guns of a combat warship may have "battleshort" fuses, which are simply copper bars of the correct size to fit the fuse holders, as failure to return fire in a combat situation is a greater threat to the ship and crew than damaging or overheating the electrical motors.
> Battleshorts have been used in some non-combat situations as well, including the Firing Room/Mission Control spaces at NASA during the manned Apollo missions — specifically the Moon landings.
As a side note, with great apology to those who may have lost their lives due to the consequences of real-world battleshorts - this is actually a really interesting analogy for the "war room" scenarios we find ourselves in at startups. Risking damage to morale and productivity can be acceptable if the alternative is irrecoverable loss of the startup's reputation. But this also can't be a sustained state of affairs - these types of procedures are meant for a battle, and risk compounds if you don't return to a steady state. Perhaps adding "battleshort" to our lexicon would make it clear that "doing things that don't scale" is often necessary but not without its costs.
Thank you for this, I'll be updating our documentation to include these concepts first thing tomorrow.
... And 6 months later marketing people will have commandeered it, without regard to the original meaning, and they’ll be asking people to battleshort so they can really be agile and lean in on providing air cover via the updated sales deck.
We're now sharpening pitchforks to use on the next salestrooper that comes close to the SalesBell™
/s
Doubly so because I used to be in the US military but now live in a different country, and it's crazy to see how those terms and acronyms infect a lot of US business culture.
A decade ago I would have been fine, even glad, that I could wrap myself in verbiage that would jive with poor career choices I made at 18. Now it just feels incongruous or jingoistic.
In a datacenter though your bets are usually much lower. Nobody is going to die, or lose many millions, if some of your equipment shuts down to prevent it from being damaged, catching a fire, etc.
There are though high-stake situations where you want exactly that: spend the entire amount of the resources of certain hardware to prevent a loss of life, or of untold millions, when you are powering a surgery chamber, or a large stock trading operation.
People who realize that do over-provision and pay top dollar for that when they can afford that. I remember that when a major fire occurred in one of the skyscrapers in the financial district of NYC, traders of a particular financial company were evacuated with their laptops into helicopters on the roof, and ferried to a spare office across Hudson river, in NJ. To minimize the impact of that, they connected to the corporate network via their phones as hotspots, and kept trading while airborne.
Of course one cannot hope to pull such an operation off without extensive preparation and likely regular drills.
Not preparing to a black swan event during a high-stakes event, like translation of a Superbowl match, sounds like either not having enough paranoia which is professionally required, or, more likely, as a cost-cutting after a wrong assessment of risks.
(2) Think about hiring twice as much senior programmes, just in case. Good day traders are even more expensive.
Day traders are expensive? I thought a lot of those folks keep what they kill, and when they screw up they don't get to eat. "Coffee for closers," etc.
If they trade for a large corporation, with the leverage provided by that corporation, it's a whole another ballgame.
The owner of the datacenter's aversion to downtime is not going to be a concern to the building inspector or the fire marshal.
At one of my previous workplaces I learned a bit about our local firecode in relation to electrical code. Mostly that firecode supersedes electrical code. The fire alarm is running of a 230V line (standard) without grounding (non-standard) via a special line from the upstream power transformer that has higher amperage tolerance.
All the fire detectors are powered and wired from this at 40-70V, no ground or if there is a ground, it's grounded at the control panel of the fire alarm system.
In the event of a fire, the entire system is rated about 10X over it's standard ratings. The wires that are allowed to handle 1 Amp before are now allowed to go to 10 Amps, just in case there is a short this might burn it out and allow other equipment to operate.
I've seen some systems that are "optionally fused", they have an internal relais that's held by external power and if the fused lines fail, it automatically switches to unfused power, where the alarm system can evaluate the condition and decide to go back to the fused line if power returns. That's on top of having it's own backup batteries. Some of the more modern systems have watchdogs systems built in so that in case the fire alarm computer is on fire, it won't switch to the unfused line once the computer is no longer operational.
At to amperage ratings, don't you just mean that they have a 10x safety factor? Probably using current limiting supplies that can handle a short circuit. Fire circuits (and the feed from the main panel) should use fire rated cabling -- generally mineral insulated copper sheathed cables. Most of the standards (NFPA 75/76) are moving away from being prescriptive to being risk or performance based though, so it is possible they used normal conduit if the overall risk was small.
Incidentally, hospitals also make extensive use of isolation transformers for wet areas (like emergency / ICU), to provide a local point for resetting breakers (electronically), identifying which point is tripping, etc, see IEEE 602-2007. Much better filtering for medical equipment too. You also tend to see positive retention plugs (in the US, green dot UL 817).
Looks like there's a drop in replacement for Halon.
Older systems, before Halon was invented, are typically CO2 or Argon. They require a lot more agent to accomplish the job, but they're very simple.
I worked briefly in a CO2 datacenter. It dated from the mainframe era, and had some gorgeous mementos on the walls. There were SCBA packs in the hallway outside, and everyone got a brief safety lecture before being allowed into the facility. The point I remember was basically "The alarm will sound intermittently for twenty seconds, then go solid for five, before discharge. If it goes off, do not stop to save your files, just run for the door. If you're not outside yet when the solid tone sounds, hold your breath and run on what's in your lungs."
Apparently the CO2 is considerably nastier than Halon to get a lung-full of...
- The Stratus supposedly had fault tolerant duplexing of boards - pull one out and the other keeps working. A famous demo where local consultant pulls out the only board which wasn't duplicated!
- The machine room was also fire proofed with Halon gas (if I recall correctly), but due to security concerns the door was locked from inside by operators when present (luckily as programmers we weren't expected to work inside with doors locked!). Luckily also, it was my first exposure to "paired programming"/"paired operating" as in there were invariably 2 of them.
- A couple of the operators became too interested in how to work things, and wrote a quite comprehensive manual. They were "moved on" within the bank, because for security, management only wanted "people who could follow instructions", not "who can think for themselves".
- the whole headquarters building was in a guarded compound, where ultimate protection against "red brigade terrorists" (https://en.wikipedia.org/wiki/Red_Brigades) were the armed guards. We used to meet them in the ground floor cafe every mid-morning, with a revolver on their hip, while they drank an espresso with brandy chaser. Really inspired confidence that they would be there to protect us should the need arise!
And this is why we cannot have nice IT security practices.
Wow!
Funnily enough I believe the SR-71 has the opposite problem, where the engines would merrily go above Mach 3.5 with no issue but the airframe and everything attached to it would get torn apart by the intense heat if the pilot tried to go any faster
Additionally, there's the Mach Cone. The shock wave off the nose forms a cone shape, with the angle determined by the speed of the aircraft. From the nose to the wingtip forms an angle of about 17.5 degrees, which corresponds well with the max speed from the CIT of Mach 3.3.
That both methods of determining max speed agree shouldn't be surprising. Skunk Works was filled with good engineers.
The airframe, however, will get bent from temperature and you better hope the missile cooling loops don't fail.
The power isn't dialed down at lower speeds in order to provide thrust for maneuvering and climb.
The boost controller has a "scramble" button which overrides the preset boost targets and allows you to run a higher (and unsafe) boost level as long as the button is pressed.
This is useful when you're in the middle of a $10,000 race and you're losing by a few feet.
The "scramble" button I'm talking about is for "boost", which is the amount of positive air pressure inside the intake manifold.
Both "boost" and nitrous can dramatically increase power by essentially getting more oxygen into the combustion chamber, but nitrous is a much more dramatic effect.
This mode is pretty much reserved for go around or post V1 takeoff when one engine on twin engined airliner had failed.