Private office for yourself?

Question

Android

I am writing a technical task and I have a few questions. Is it worth ordering a personal account for the administrator (application owner (me)) in order to edit design elements and monitor all statistics of complaints and surveys, and in case of technical work, it would be possible to stop the application from working for all users with the following functions
: authorization background
Possibility to act as a moderator (three-click moderation)
Editing the donation page
Possibility to send messages for each of the companies
Editing polls
Displaying statistics on the results of polls
Displaying statistics of violations by users
Displaying statistics on donations
Possibility to pause/start the general operation of the app
Possibility to pause/start donation fundraiser
Swapping images for interests
Two-factor authentication via SMS
What's extra? What to replace? What other features should be added based on other personal accounts? (Google what?) How
much will it cost?
I don't know much about programming myself.
Thank you in advance.

Answer 1

What to google?

google "how to hire an analyst to collect initial requirements for product development"

Answer 2

The presence or absence of a signal in the wire was in the days of telegraph devices, i.e. about two hundred years ago. Since then a lot has changed. In a modern network cable (let's take only copper as an example), pulses with a frequency of 100, 250, 500 or more MHz are transmitted through the cable, and not in one, but in 2, 4 or even 6 pairs. (Actually, everything is somewhat more complicated there, but to understand the essence, it is quite enough to consider pairs as parallel transmission lines.) It is customary to talk about pairs of wires, because. there is no level (potential) in itself; level - it is always relative to something else, for example, in one wire relative to another wire. Hence the pairs, and why they are called twisted - google it yourself. The transmitted signal is modulated by the so-called. Pulse Amplitude Modulation (PAM), i.e. the transmitting and receiving parties distinguish 3, 5 or even 16 different signal levels, which, roughly speaking, are encoded respectively. bits.
In this way, several "different bits" can be transmitted over the cable at the same time. Well, and the situation when at the same moment in time there is one potential in one place of the conductor, and another one in another, in general, should be familiar even for school physics ... this is how any antenna works and, in general, any conductor with a variable current. If you answer the question literally, then in the "same place" of each pair at any time there is only one transmitted pulse , but this can mean many different bits .
Now about speed and distance. The speed of signal propagation in a conductor at the level of school physics (if, of course, they talk about it at all now) is considered to be equal to the speed of light in vacuum, about 3m per 1 ns, but in practice it is less, because the conductor is not perfect and, as a rule, is not in a vacuum, but in isolation from a dielectric. The parasitic capacitance introduced by the dielectric reduces the speed of signal propagation in the conductor (not to be confused with the speed of field propagation!) But those who have not skipped physics and mathematics may well estimate the order of numbers for a 1000 km long conductor, as for a train going from A to B or even "distance" between two adjacent bits transmitted over one pair :)
True, the results obtained by such a simple calculation (even if taking into account the wave characteristics of the cable) are still far from reality for distances of thousands of km, because even in the best cable of this length, all the signal energy of the transmitting side would turn into heat and radiation, and the receiving side would be left with only a donut hole. The length of a real network cable between two devices (twisted pair!), Roughly speaking, cannot exceed 100m. Then the signal gets to another device, which introduces its own delays, and so on. etc. from Taganrog, and to YouTube itself. Of course, not all of these devices are connected by copper, but we will not go into the intricacies of the propagation of light in different optical media, and radio waves in the ionosphere, so that the average Toaster audience does not inadvertently blow away. The only thing that matters here is
It was not even an introduction, but a popularly simplified cheat sheet on the topic of "how bits travel on wires", or, to put it more simply, what happens in the network at layer 1 of the seven-layer ISO / OSI model. Packets, as well as frames, datagrams, etc. abstract agreements on exactly how to count bits - this is already from a different opera, more precisely, at other levels, moreover, each has its own, and one in the other. Given that inside the processor and memory (where we are dealing with the data from these packets) everything is the same as in the cable, at any level of the model it is quite correct to assume that a packet of this level is delivered "at once".

Answer 3

The ISO/OSI networking model will cover this in detail. Maybe even pictures.

Answer 4

If this is trolling, then I give a standing ovation! =)
THE ANSWER IS: no one knows how it works! It `s Magic! Really! Everyone just pretends, they talk about all sorts of models, transmission media, but this is all garbage! MAGIC!!
www.youtube.com/watch?v=Hu6MVnwPClA

Answer 5

nah horror! my brain exploded in the middle of a question. call the paramedics for me.

Answer 6

Read in Olifer's book on networks the device of physical connections, everything is written in detail there.

Answer 7

The Internet network consists of many networks, modern networks use packet switching technology. At a time, the packet exists only on a small section of the network; after arriving at the router, it is transmitted to the next network (network segment).
As for packages, there is such a thing as Encapsulation .
I recommend to read the book "Computer networks. Principles, technologies, protocols" by the authors: Victor Olifer, Natalia Olifer.

Answer 8

As far as I know, "zero" is not the absence of a signal, but simply the smaller brother of "one". That is, this is the same signal, but with a smaller charge, or something like that.