system unit

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A computer system unit is the enclosure that contains the main components of a computer. It is also referred to as computer case or tower. Read on to learn about the functions and components that go into a computer system unit.

Definition

A typical desktop computer consists of a computer system unit, a keyboard, a mouse, and a monitor. The computer system unit is the enclosure for all the other main interior components of a computer. It is also called the computer case, computer chassis, or computer tower. Cases are typically made of steel or aluminum, but plastic can also be used. While most computer cases are rather dull, black, metal boxes, some manufacturers try to give the unit some flair with color and special design elements.

Computer system unit

Functions

The primary function of the computer system unit is to hold all the other components together and protect the sensitive electronic parts from the outside elements. A typical computer case is also large enough to allow for upgrades, such as adding a second hard drive or a higher-quality video card. It is relatively easy to open up a computer system unit to replace parts and install upgrades. In contrast, it is quite difficult to open up a laptop computer, which is not designed with replacements and upgrades in mind.

In most computer system units, the front side contains the elements a user needs frequently, such as the power button, an optical disk drive, an audio outlet for a pair of headphones, and a number of USB connections. The back side contains all other connections - for power, monitor, keyboard, mouse, Internet connection, and any other peripheral devices. There are typically more connections than the minimum necessary to allow for expansion.

Front (left) and back (right) of a computer system unit.

Inside the Computer Case

Once you open up a computer case, it can initially be difficult to recognize the various components, especially all the different wires. However, if you look closely, you will probably start to recognize a number of components.

Major components inside a computer case

In this particular example, the motherboard is placed vertically, which is quite common. One side of the motherboard is accessible from the back of the computer case - this includes the variousconnectors for input and output devices as well as expansion slots for additional peripherals. The motherboard also contains the central processing unit (CPU), although it can be difficult to see. A largefan is often placed on top of the CPU to avoid overheating. The motherboard also contains thehttp://study.com/academy/lesson/what-is-a-computer-system-unit-function-components-definition.html

The system unit, sometimes called the chassis, is a box-like case housing the electronic components of a computer that are used to process data. System unit components include the processor, memory module, cards, ports, and connectors. Many of the system unit’s components reside on a circuit board called the motherboard. The motherboard contains many different types of chips, or small pieces of semiconducting material, on which one or more integrated circuits (IC) are etched. An integrated circuit is a microscopic pathway capable of carrying electronic current. Each IC can contain millions oftransistors, which act as switches for electronic signals.

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Explain How The CPU Uses The Four Steps Of A Machine Cycle To Process Data

The central processing unit (CPU), also called a processor, significantly impacts overall computing power and manages most of a computer’s operations. The CPU contains the control unit and the arithmetic/logic unit. The control unit directs and coordinates most of the operations in the computer. For every instruction, the control unit repeats a set of four basic operations called the machine cycle: (1)fetching the instruction or data item from memory, (2) decoding the instruction into commands the computer understands, (3) executing the commands, and, if necessary, (4) storing, or writing the result to memory. The arithmetic/logic unit (ALU) performs the execution part of the machine cycle. Specifically, the ALU carries out three operations:

Arithmetic operations – performing calculations, which include addition, subtraction, multiplication, and division

Comparison operations – comparing data items to determine if the first item is greater than, equal to, or less than the other item

Logical operations – working with conditions and logical operators such as AND, OR, and NOT

Compare and contrast various personal computer processors on the market today

A personal computer’s CPU usually is contained on a single chip, which some call a microprocessor. Intel is a leading manufacturer of personal computer processors. Most high-performance PCs use a processor from Intel called the Pentium® processor. A second Intel brand, called the Celeron™, is designed for less expensive PCs. Two more brands, called the Xeon™ and Itanium™ processors, are ideal for workstations and low-end servers. Intel-compatible processors have the same internal design as Intel processors and perform the same functions, but are made by other companies and often are less expensive. An alternative design to the Intel-style processor, the Motorola processor, is found in Apple Macintosh and Power Macintosh systems. A new type of processor designed for lower-costing personal computers and Internet appliances, called an integrated CPU, combines functions of a processor, memory, and a video card on a single chip. Today’s processors are equipped with MMX™technology, a built-in set of instructions that manipulates and processes multimedia data more efficiently. Intel’s SSE instructions and AMD’s 3DNow!™ are two other technologies that improve a processor’s performance of multimedia, the Web, and 3-D graphics. To optimize and extend battery life for notebook computers, Intel® mobile processors use SpeedStep™ technology and AMD processors use PowerNow!™ technology.

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Define A Bit And Describe How A Series Of Bits Represents Data

Most computers are digital, meaning they understand only two discrete states: on and off. These states are represented using two digits, 0 (off) and 1 (on). Each on or off value is called a bit (short for binary digit), the smallest unit of data a computer can handle. Eight bits grouped together as a unit form a byte. A byte provides enough different combinations of 0s and 1s to represent 256 individual characters including numbers, letters of the alphabet, punctuation marks, and other characters.

The combinations of 0s and 1s used to represent data are defined by patterns called coding schemes. Popular coding schemes are ASCII, EBCDIC, and Unicode. Coding schemes make it possible for humans to interact with a digital computer that recognizes only bits. Every character you type on a keyboard is converted into a corresponding byte, a series of on/off electrical states the computer can process.

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Differentiate Between The Various Types Of Memory

Memory is a temporary storage place for data, instructions, and information. Memory stores the operating system, application programs, and the data processed by application programs. A byte is the basic storage unit in memory. Memory size is measured by the number of bytes available for use. A kilobyte (KB or K) of memory is approximately one thousand bytes, a megabyte (MB) is approximately one million bytes, and a gigabyte (GB) is approximately one billion bytes. The system unit contains several types of memory.

RAM (random access memory) consists of memory chips that the processor can read from and write to. Most RAM is volatile memory, meaning that its contents are lost when the computer’s power is turned off. Two basic types of RAM chips are dynamic RAM and static RAM. Dynamic RAM (DRAM) must be re-energized constantly or it loses its contents. Static RAM (SRAM) is faster and more reliable than DRAM and has to be re-energized less often, but it is much more expensive.

Memory cache, also called a cache store or RAM cache, improves processing time by storing frequently used instructions and data. ROM (read-only memory) refers to memory chips that only can be read and used; that is, they cannot be modified. ROM is nonvolatile memory (NVM), meaning that its contents are not lost when the computer’s power is turned off. A variation of the ROM chip, calledprogrammable read-only memory (PROM), is a blank chip on which you can place items permanently.

Flash memory, also known as flash ROM or flash RAM, is nonvolatile memory that can be erased electronically and reprogrammed. Complementary metal-oxide semiconductor (CMOS) memory, another type of memory chip, stores configuration information about the computer and uses battery power to retain information when the power to the computer is off.