Let’s assume you have administrator access, and that this is a run of mill laptop or desktop. Is it possible to write a program that will result in a fire or something equally as destructive?
EDIT:
To the ”how do you think bombs work” answer: valid answer, but I’m asking about if I have a pocket universe with just a laptop, is it possible to have a program that when run, will set the computer on fire?
It isn't impossible, but with most off the shelf goods, it is unlikely you will find a deterministic way to do it. Groups like CSA, Underwriters, ETL, are pretty careful about what they give the stamp of approval to.
Depending upon that last time you have flown in the US, you may have heard various warnings that you are not to carry a certain brand of Samsung Phone or Apple Laptop on board; further you are not allowed to store them in your luggage, and if you drop one between the seats, to notify the attendants.
These are all precautions because the FAA has determined that these devices pose a fire risk, presumably due to over-heating. So, if you run caffeinate -- which prevents sleeping -- and ran a heavy workload, you could induce the high enough temperatures to cause ignition.
But, heavy on the could. There are a lot of defenses built into the batteries themselves to prevent this; then there are system management components in the computer to prevent this; then there are monitoring components on the CPU to prevent this. So, whatever you do, has to line up some failure mode of all of these systems simultaneously.
Not impossible, but maybe not far from it.
Related
I am trying to figure out way to upgrade software over bus (can/ethernet). While doing this, Safe state suggest to rollback to previous sw.
Please can anyone help me understand how and what are the ways to achieve that?
The only way to roll back is to have enough flash storage, to store the old applications, until the new ones are proven to work.
As applications across ECUs depend on each other, some coordinator, often in a central gateway, has to coordinate that.
In a first step, this coordinator downloads the software release for the whole vehicle, stores it in local memory and does some authenticity and integrity checks.
If not already stored, it can also download the last release, which is flashed currently to it's local space.
The other alternative is to have a second flash area in the ECUs for that, which is usually more expensive.
Then the coordinator ensures that the vehicle is in a safe state, e.g. propulsion system off, no-one inside and doors locked.
If this is ensured, it uses the normal flash procedures to flash all ECUs with the cached software.
After that, it checks every ECU to ensure that flashing was successful.
If yes, it can discard what it stored.
Else, if the ECUs do not just switch back to an internal copy, it flashes the old application again.
For sure, there is a risk that this also fails, why one might want to have this two flash sections in each ECU.
However, the latter is not realistic for smaller ECUs like LIN slaves.
I am learning how to code in C++ and at the moment I am creating some basic programs that calculate something or generally do anything connected with math. So, I am using Code:Blocks for this and every time I compile a harmless program, my antivirus, Bitdefender, detects it as a virus and immediately deletes it. I have tried putting it on whitelist but I often make programs and having to whitelist every directory or program takes too much time. Can somebody explain to me why does Bitdefender, which I bought and which usually works fine is mistakenly detecting a harmless file as a virus? (The virus is described as
Gen:Variant.Ursu.'number'
The vast majority of users (of an anti-virus program) will never run a legitimate/safe program that the anti-virus hasn't seen before (less true for people on this site).
Whereas much malware is polymorphic, altering itself every time it is deployed.
Therefore a useful heuristic for an anti-virus is to block all executables the first time they are seen. Unfortunately this hits software developers rather hard. Fortunately this group is likely to be able to work out how to use exclusions to help themselves.
In my OS class, we use a text book "Operating System Concepts" by Silberschatz.
I ran into this question and answer in practice exercise and wanted to know further explanation.
Q. List the four steps that are necessary to run a program on a completely dedicated machine—a computer that is running only that program.
A.
1. Reserve machine time
2. Manually load program into memory
3. Load starting address and begin execution
4. Monitor and control execution of program from console
Actually, I don't understand the first step, "Reserve machine time". Could you explain what each step means here?
Thank you in advance.
If the computer can run only a single program, but the computer is shared between multiple people, then you will have to agree on a time that you get to use the computer to run your program. This was common up through the 1960s. It is still common in some contexts, such as very expensive super-computers. Time-sharing became popular during the 1970s, enabling multiple people to appear to share a computer at the same time, when in fact the computer quickly switched from one person's program to another.
In my opinion teaching about old batch systems in today's OS classes is not very helpful. You should use some text which is more relevant to contemporary OS design such as the Minix Book
Apart from that if you really want to learn about old systems then wikipedia has pretty good explanation.
Early computers were capable of running only one program at a time.
Each user had sole control of the machine for a scheduled period of
time. They would arrive at the computer with program and data, often
on punched paper cards and magnetic or paper tape, and would load
their program, run and debug it, and carry off their output when done
I would say that the following are valid use cases for Early Media when used for IVRs:
Filtering
Disconnect incoming calls based on certain criteria (such as callers from a specific area code, or to play a message before hanging up on after hour callers).
Rate limiting
For example to limit the number of simultaneous callers, where the excess calls are either disconnected, or placed in a queue. (I'm not sure if the queue example is possible though without answering the call.)
Are there more?
Some links that were helpful:
https://www.dialogic.com/webhelp/csp1010/8.4.1_ipn3/sip_software_chap_-_early_media.htm
https://wiki.asterisk.org/wiki/display/AST/Early+Media+and+the+Progress+Application
https://freeswitch.org/confluence/display/FREESWITCH/Early+Media
3) Legal: in some countries it is illegal for a call center using payed line (caller pay per minute) to accept a call without sending it straight to an agent. So you can't accept the call, give the user some waiting music for 15 minutes (and make them pay for the privilege of waiting as well).
Result: you don't accept the call. However, this creates a new problem: if the caller only hears the ring back tone for those 15 minutes, he/she will assume no one will answer and hangs up.
Using early media, you can give them the traditional "your call is very important to us, please hold on"-type of experience without accepting the call and without starting to charge money. Of course this also depends somewhat on how much the provider is willing to tolerate, as this can also affects their income (depending on their own business model).
4) Comfort: you may not be aware of this, but the sound you hear as caller when the other side is ringing (ring-back tone), is not universally the same throughout the world. A company with a global number may wish to use early media to provide a ring-back tone more familiar to you, depending on where you are calling from. It was always a bit niche of a concept but some target audiences are statistically more likely to hangup if they hear an unfamiliar sound. 15-20 year ago this might have been a concern to some, but in the era of smartphones and internet calls, I doubt anyone really worries about it anymore.
I have a multiplayer project which has some forever loops with checking code inside of them.
The problem is, multiple computers might process this and change crabx or craby due to lag in the variables dvotes, uvotes, lvotes, or rvotes. Only one machine should change this, though.
This can be easily solved by giving each player an ID like many people do in SQL. I would just check if the ID is 1, and that would be the "operating machine". I would then do all of these checks on that one machine. It would do things a Scratch server would do if you could program it...
The problem with this is that there is no way to detect when a player leaves the game. There is no block that is called "on exit" or "on stop button pressed". How would I go about doing this? I have seen people have a button which people click to exit, but some people will not click it/not even see it.
Thanks in advance!
Option 1
I've never been especially successful with cloud data myself, but I've heard the theory on this before:
Essentially, each player gets a "counter". Their computer then constantly increases that counter. If the counter ever stops increasing (which will be detected by the other computers, who are all looking after one another), the project will know that the user has left and one of the computers will take care of removing their ID and other data.
Obviously, this is much easier said than done. (As I said, I've never gotten complex cloud data to work well for myself, but I've seen it done successfully and explained.)
Option 2
Alternatively, you might be better off taking advantage of this cloud api created by MegaApuTurkUltra. I find that stealing from others tends to be the best way of solving problems when it comes to code. ;)