What is an embedded system? Can Mobile be considered as an embedded product?
This is a question that even embedded systems experts often ask and discuss. There is as with many things a spectrum, and simple definitions are difficult.
My preferred definition is: a system containing one or more computing or processing element that is not a general purpose computer.
Some systems are inarguably embedded within that definition, and include such things as washing machine controllers, telephone switches, satellite navigation equipment, marine chart-plotters, automotive ECUs, laser printers etc.
Some are less easily categorised. A first generation digital mobile phone, is probably certainly an embedded system while more modern feature and smart phones however are somehow different. They can run apps chosen and installed by end-users allowing them to perform tasks not determined by the manufacturer. With increasing capabilities they are essentially hand-held computers and the range of apps sufficient to be able to regard them as "general purpose".
With these more ambiguous systems, it is useful to ask perhaps not what is an embedded system, but rather what is embedded systems development? For example, the manufacturer of your smart-phone deployed on it an operating system, the signal processing and communications stack required for it to operate as a telephone, all the device drivers and stacks for WiFi, USB, data storage etc., and this is certainly embedded systems development. However the guys writing apps for PlayStore or AppStore etc. are writing to a defined common platform abstracted by all that embedded code - that is not embedded systems development by any definition that I would accept, unless perhaps the application were for some bespoke vertical market application - like the delivery signature apps UPS drivers have on PDAs for example - in that environment the "general-purpose" device has been re-purposed as a "special-purpose" device.
With respect to a PC; a PC can be the embedded computing element in a system that is not a general purpose computer. Industrial PCs are commonly found embedded in manufacturing and packaging machinery, CNC machine tools, medical equipment etc. Although they share hardware architecture with desktop PCs they do not necessarily look like desktop PCs and come in many different form factors of both boards, and enclosures. Even within a desktop PC however, there are many examples of embedded computing elements, and embedded software such as the BIOS responsible for bootstrapping the system, the keyboard controller and disc drive controllers for example.
Generally an embedded system is one placed into operation for a specific, narrow purpose, and lacking the kind of general purpose user interfaces you would find on an ordinary desktop/laptop.
That is not to say though that an embedded system cannot have these - I've seen test equipment such as network analyzers running desktop operating systems, with mouse/keyboard ports. One could probably hack one of those to use it for general purpose computing, but it would not be cost effective.
Going the other way, you can take a general purpose computer and shove it into an embedded application. However, systems optimized for embedded use may be more robust, support better real-world I/O (often retaining legacy ports), and use parts expected to be available over longer lifetimes than used in commodity PCs (if one fails, you want to be able to replace it with the exact same thing).
Often embedded systems are smaller - 8 bit processors (even 4-bit or serial-core historically) with limited memory; though 32 bit cores such as the arm family are now inexpensive and commonplace. Nor are tens to hundreds of megabytes of memory unknown.
Older cellphones would have a lot in common with embedded systems, but rather obviously contemporary smartphones are catching up in power and versatility, though still often constrained by user interface. Software wise some "think small" habits endure - for example, Android's compact bionic C library and toolbox shell have similar design goals to embedded C libraries and busybox. In other ways though, expansive resource-gobbling user experiences are now the norm on phones. Toss tablets based on the same processors and accessorized with keyboard into the mix, run a kernel designed originally for desktop computers on them, and the real difference is between UI software stacks designed to run segregated "apps" on a touch interface, vs one designed to run more traditional programs.
Embedded system are devices that do some specific job not like our laptops which can play music, click pictures and format documents. They are devices like water filter , washing machines, vending machine etc. They are programmed for some specific work and they do that work in a super loop depending on the user input.Like the vending machine always perform same thing when you opt for coffee in it with the help of button provided in it.
So in that way mobile phone is not an embedded system because it has no super loop and it can do various general purpose things just like a computer.
An embedded system has memory constrain, timing constrain and they do things in limited space.
An embedded system is any electronic system that uses a CPU chip, but that is not a general-purpose workstation, desktop or laptop computer. An embedded system is a special-purpose computer system designed to perform a dedicated function. Unlike a general-purpose computer, such as a personal computer, an embedded system performs one or a few pre-defined tasks, usually with very specific requirements, and often includes task-specific hardware and mechanical parts not usually found in a general-purpose computer.
Read more: http://romux-loc.com/tutorials/embedded-system#ixzz3113gchPt