The case contains and protects the electronics of the computer or mobile device from damage. Inside the case has motherboard, processors, cloud computing, data representation,  memory and adapters.

The motherboard is the main circuit board of the computer . It is a computer chip contains integrated circuits. The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer. Its Contain a control unit and an arithmetic logic unit (ALU). A multi-core processor is a single chip with two or more separate processor. The control unit is the component of the processor that directs and coordinates most of the operations in the computer.The arithmetic logic unit (ALU) performs arithmetic, comparison, and other operations. For every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle. The processor contains registers, that temporarily hold data and instructions. The system clock controls the timing of all computer operations. The pace of the system clock is called the clock speed, and is measured in gigahertz (GHz). The leading manufacturers of personal computer processor chips are Intel and AMD. A processor chip generates heat that could cause the chip to malfunction or fail. Require additional cooling such as heat sinks, liquid cooling technology, and cooling mats.

Home and business users choose cloud computing for a variety of reasons such as  accessibility, cost savings, space savings, scalability. In Data Representation, Analog signals are continuous and vary in strength and quality. Digital signals are in one of two states: on or off.Most computers are digital.  The binary system uses two unique digits (0 and 1) bits and bytes.

Memory consists of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data. The stores three basic categories of items are the operating system and other programs, applications, data being processed and the resulting information.Each location in memory has an address. Memory size commonly is measured in gigabytes (GB) or terabytes (TB). The system unit contains two types of memory that are Volatile memory and Nonvolatile memory. Volatile memory will loses its contents when power is turned off. Example includes RAM. Nonvolatile memory does not lose contents when power is removed. Examples include ROM, flash memory, and CMOS. Two common types of RAM chips exist are Dynamic RAM (DRAM) and Static RAM (SRAM). RAM chips usually reside on a memory module and are inserted into memory slots. Memory cache speeds the processes of the computer because it stores frequently used instructions and data. Read-only memory (ROM) refers to memory chips storing permanent data and instructions.Flash memory can be erased electronically and rewritten.  Access time is the amount of time it takes the processor to read from memory and measured in nanoseconds.

An adapter card enhances functions of a component of a desktop or server system unit and or provides connections to peripherals such as sound card and graphics card. An expansion slot is a socket on a desktop or server motherboard that can hold an adapter card. With Plug and Play, the computer automatically can recognize peripheral devices as you install them.   Adapters for mobile computers are in the form of a removable flash memory device such as USB adapter and ExpressCard module.

buses

A bus allows the various devices both inside and attached to the system unit to communicate with each other data bus and address bus. Word size is the number of bits the processor can interpret and execute at a given time. Three types of buses are System bus, Backside bus, and Expansion bus.

batteries

 The power supply or laptop AC adapter converts the wall out AC power into DC power. Mobile computers and devices can run using either a power supply or batteries. Batteries typically are rechargeable lithium-ion batteries.