Drivers And Their Purpose

What is the purpose of a device driver?

In short: to drive the hardware.In detail: It talks to the hardware for which it has been written. It writes into the register of the hardware which lets it perform the task as requested by the upper layers. Device driver enables the operating system and the software programs to interact with the hardware device without knowing the hardware detail.For example: A user program requests to open the device, it has just to call the open system call and the device driver's job is to write a method which writes into the register of the device which eventually opens the device.

What is the purpose of a LED driver and how does it work?

An LED driver is needed to run LED's properly.Unlike most electronic devices, LED's are current driven devices, not voltage driven ones. Even a  minuscule change in voltage can lead to a huge change in current. Hence, it is important that the drive current is regulated and not the voltage.LED drivers are usually switching mode devices that convert the input voltage (Typically 120-220 VAC or 12 VDC) into a voltage at which the current drawn by the LED's is equal to its drive current. The drive current is regulated for optimum brightness, led service life, and battery life. A drive current lower than the maximum drive current of an LED can greatly prolong service and battery life.Hope you found this helpful!

Do Uber drivers chose their route?

That depends entirely on whether or not the driver actually knows where they are going or is just following the application blindly. Uber has sold the service to drivers as one that they need no skill to enter and don’t need to know where they are.Knowing your way around entails having a solid grasp of the geography, the order of streets, the way the houses and businesses are numbered and at least roughly where an address might intersect with which cross street. All too often the addresses are given in such a limited way that it is assumed you both don’t know your way around and Uber doesn’t really care, because you should live and breath by the GPS, which suggests you are more interested in the display on the phone than what is on the road ahead.If you do know where you are going you might notice the frequency with which the so called suggested routes resemble a huge crescent taking you on the freeway when in fact you can go in more of a straight line, both saving the customer money and yourself time in order to find another fare.The so called suggested routes are worthy of SNL they are frequently so bad. I use the suggested route most of the time when it coincides with what I already know. Once in a while, in a weird location, in another city I am less familiar with I might refer to it.

What are device drivers?

Nope, Interpreter and compiler don't do the same thing as device driver. Not even remotely. Interpreter - an interpreter is a computer program that directly executes, instructions written in a programming or scripting language, without previously batch-compiling them into machine language.Compiler - A compiler is a computer program (or set of programs) that transforms source code written in a programming language (the source language) into another computer language (the target language, often having a binary form known as object code).Device driver - a device driver is a computer program that operates or controls a particular type of device that is attached to a computer.All of these definitions are from Wikipedia, so you can look up and read the deatils there.You see, Interpreter is a computer program which works purely with the program or a script fed to it (Only SW). It executes the program or the script instruction by instruction without turning it into machine level language. Perl, Python, Ruby are Interpreter based script languages. Compiler is a another computer program which also works with the program fed to it. It compiles, that means preprocesses, parses, does symantic analysis and then generates machine understandable code. Interpreter and compiler work only with SW, they have got nothing to do with the HW or the device. The device driver is a program which can be compiled through the compiler to get a machine understandable executable file or run through the interpreter to get the desired functionality of a hardware executed.Each HW that is connected to a computer (which is the CPU) needs a code which instructs it to perform the activity that it is designed for. This code is the device driver. For. e.g. to communicate to another device, we may use a serial communication device such as UART or SPI. The HW device which is designed for this purpose needs its own driver to perform the desired functionality. Device driver are exclusively specific to the HW for which they have been written. Also, the HW to perform a particular functionality is provided by many different vendors, hence drivers become vendor specific too.