How programing language control hardware ? please read what i mean

[desertsolider]

i mean like how we press shutdown and it switch off the computer ... how assebmly or watever any language control the hardware .i dun kno if i am really stupid asking this but i am goin crazy =D
thxx

[joeprogrammer]

Well, generally-speaking, the system's BIOS does nearly all the talking to the hardware. The software you normally write usually sends messages to the operating system when it needs to control the hardware. The operating system in turn sends the instructions to the BIOS, which carries out the actual hardware instructions.

There are situations where the OS can somehow get around the BIOS, but I don't really know much about that.

[joeprogrammer]

Ah, here is some more information from Wikipedia's article:

Older operating systems such as DOS relied on the BIOS to carry out most input-output tasks within the PC. A variety of technical reasons eventually made it inefficient—especially for more recent operating systems written for the Intel 80386 such as Linux and Microsoft Windows—to invoke the BIOS directly. Such operating systems instead used their own better-performing native drivers and were also much easier to extend to support new hardware. As such, the BIOS was mostly relegated to bootstrapping to the point where the operating system's own drivers could take control of the hardware.

This explains what I was talking about before.

Another interesting bit:

In recent years, however, by way of systems such as ACPI, the BIOS has taken on more complex functions such as power management, hot swapping and thermal management. This has led to renewed reliance on the BIOS by operating system producers, and an increase in complexity of BIOS code. This in turn has led to invention of Intel's modern Extensible Firmware Interface (EFI) which in itself incorporates BIOSes extended options. Linux supports EFI via elilo boot loader since early 2000. Microsoft announced that support for EFI in Windows Vista is only available for the 64-bit versions.

Here's the link to the entire article: http://en.wikipedia.org/wiki/BIOS

[Peterwkc]

I guess the OS/kernel might switch between on and off from 1 to 0 to switch off the pc but before shutdown the pc the kernel needs to unmount the file system. I have no idea how this is done.

[desertsolider]

ikinda this explain but still didn get my point :D like u write with keyboard it writes its a software and this is hardware u kno never mind its complicated and i feel stupid askin this thhxx soo much