Different terms in embedded system

Embedded system

Embedded system is different from that with the general purpose system. This system is generally of resources constrained. The resources refer to the hardware components.

 

 Embedded system may or may not require an RTOS, whereas general purpose systems always do have to have an OS.

Difference between RTOS and OS

 In general we hear the term OS which is nothing but the Operating System. Most of us are familiar in making use of the Operating Systems such as Windows 98, Windows XP etc. There can be a new term utilized from the embedded systems named RTOS which can be a Authentic Time OS.

Embedded system OS

 Operating systems are broadly applied in general purpose systems which may be LINUX or Windows. All operating systems use an important idea called Time Sharing.

 Time Sharing is nothing but performing several operations at a time, this has been take care from the OS.

 The idea of time sharing could be very best understood from the following figure.

 The notion of DMA also comes into the picture in time sharing. In general purpose systems the tasks are allocated at different time slots. The user does not have any idea when the task will be completed.

Embedded RTOS

 The RTOS are similar towards the operating system but has smaller kernel (core with the operating system) size. It also uses the time sharing idea.

 In general purpose the allocation of time is usually adjusted from the OS, but in RTOS the time cannot be adjusted.

Processors

 The General purpose systems use x86 processor.

 Embedded systems use controllers or processors such as ARM, FPGA and so forth.

Compiling and Cross Compiling

 The RTOS cannot be employed as such like an operating system. It has being cross compiled for the particular processor. Other packages such as BIOS programming, Boot loader and Root file system also has to be applied in Embedded system linux environment.

BIOS

 Basic Input Output System is the firmware that initializes the system. BIOS Programming has to become written and stored in for the flash memory.

Boot loader

 An essential package which is responsible for the kernel within the memory.

In General Purpose System Linux uses GRUB boot loader whereas the Embedded Linux system uses the U-boot bootloader.

Linux kernel

 Lot of Linux kernel versions are available which is usually cross-compiled for particular processor.

Root file system

 Root file system contains all the binaries with the operating system.