Study On Processor Functions And Memory Types Computer Science Essay

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This report based on operating systems and the topic covers generally about the Processor functions, Memory types such as Primary or Secondary, Input & Output e.g. To/From the User & To/From the network, Support Elements, Conclusion and References at the end. For the section Processor student will be gathering information about the Central Processing Unit (CPU).There are two primary manufacturers of computer microprocessors which are Intel and Advanced Micro Devices AMD which lead the market in terms of speed and quality. For the process function research will be involved about operation, instructions, registers, cache memory finally a diagram to show the internal structure of processor (CPU). The memory type�s researches will involve research on such as Ram, Rom, Cache, hard drive, optical storage devices such as CD-ROMs, DVD-ROMs, as well as read - only memories. The input & Output device will cover the key board, mouse, printers, monitor and the components will be expanded with main use, advantages, disadvantages plus few points the need of this components. The support elements will cover the motherboard, CPU fan, PCI slots which enable computer to work effectively.

The conclusion will cover the overall explanation of the report and any recommendations in improvements.

The processor is the brain of the computer and it�s called the central processing unit carries out instructions of a computer program and is the main component carrying out computer functions. The CPU allows the processing of numeric data, which tells the user that information entered in binary form and the execution of instructions stored in memory.

The need of the CPU is without CPU desktop PC will not run and CPU is the component that runs the computer. CPU runs all of the operating systems software such user application Word, Excel, games, and any other operating system like Unix, Linux, OS2, assembler, everything. The physical two images shown below are the most know effective processor (CPU) brand, which is Intel and AMD.

The diagram shown below is the elements that make up the processor:-


The processor which is an electronic circuit, which works in the same speed of inside clock which should be credited to the quartz crystal which, after subjected to an electrical currant, send pulses, called peaks. The clock speed has the other know name as cycle, links to number of pulses per second, written in Hertz Hz. Therefore a 200 MHz computer has a clock that sends 200,000,000 pulses per second. The clock speed normally several of the system frequency front side bus FSB and meaning several of the motherboard frequency.

With each clock peak, the processor performs an action that corresponds to an instruction or a part thereof. A measure called CPI (Cycles Per Instruction) gives a representation of the average number of clock cycles required for a microprocessor to execute an instruction. A microprocessor's power can thus be characterized by the number of instructions per second that it is capable of processing. MIPS (millions of instructions per second) are the unit used and correspond to the processor frequency divided by the CPI.


An instruction is an elementary operation that the processor can accomplish. Instructions are stored in the main memory, waiting to be processed by the processor. An instruction has two fields:

� the operation code, which represents the action that the processor must execute;

� theoperand code, which defines the parameters of the action. The operand code depends on the operation. It can be data or a memory address.

Operation Code Operand Field

The number of bits in an instruction varies according to the type of data (between 1 and 4 8-bit bytes).

Instructions can be grouped by category, of which the main ones are:

� Memory Access: accessing the memory or transferring data between registers.

� Arithmetic Operations: operations such as addition, subtraction, division or multiplication.

� Logic Operations: operations such as AND, OR, NOT, EXCLUSIVE NOT, etc.

� Control: sequence controls, conditional connections, etc.


When the processor executes instructions, data is temporarily stored in small, local memory locations of 8, 16, 32 or 64 bits called registers. Depending on the type of processor, the overall number of registers can vary from about ten to many hundreds.

The main registers are:

� the accumulator register (ACC), which stores the results of arithmetic and logical operations;

� thestatus register (PSW, Processor Status Word), which holds system status indicators (carry digits, overflow, etc.);

� the instruction register (RI), which contains the current instruction being processed;

� the ordinal counter (OC or PC for Program Counter), which contains the address of the next instruction to process;

� thebuffer register, which temporarily stores data from the memory.

Cache Memory

Cache memory (also called buffer memory) is local memory that reduces waiting times for information stored in the RAM (Random Access Memory). In effect, the computer's main memory is slower than that of the processor. There are, however, types of memory that are much faster, but which have a greatly increased cost. The solution is therefore to include this type of local memory close to the processor and to temporarily store the primary data to be processed in it. Recent model computers have many different levels of cache memory:

� Level one cache memory (called L1 Cache, for Level 1 Cache) is directly integrated into the processor. It is subdivided into two parts:

o the first part is the instruction cache, which contains instructions from the RAM that have been decoded as they came across the pipelines.

o the second part is the data cache, which contains data from the RAM and data recently used during processor operations.

Level 1 caches can be accessed very rapidly. Access waiting time approaches that of internal processor registers.

� Level two cache memory (called L2 Cache, for Level 2 Cache) is located in the case along with the processor (in the chip). The level two cache is an intermediary between the processor, with its internal cache, and the RAM. It can be accessed more rapidly than the RAM, but less rapidly than the level one cache.

� Level three cache memory (called L3 Cache, for Level 3 Cache) is located on the motherboard.

All these levels of cache reduce the latency time of various memory types when processing or transferring information. While the processor works, the level one cache controller can interface with the level two controller to transfer information without impeding the processor. As well, the level two cache interfaces with the RAM (level three cache) to allow transfers without impeding normal processor operation.

The term "memory" applies to any electronic component capable of temporarily storing data. There are two main categories of memories:

� internal memory that temporarily memorises data while programs are running. Internal memory uses microconductors, i.e. fast specialised electronic circuits. Internal memory corresponds to what we call random access memory (RAM).

� auxiliary memory (also called physical memory or external memory) that stores information over the long term, including after the computer is turned off. Auxiliary memory corresponds to magnetic storage devices such as the hard drive, optical storage devices such as CD-ROMs and DVD-ROMs, as well as read-only memories.

Technical Characteristics

The main characteristics of a memory are:

� Capacity, representing the global volume of information (in bits) that the memory can store

� Access time, corresponding to the time interval between the read/write request and the availability of the data

� Cycle time, representing the minimum time interval between two successive accesses

� Throughput, which defines the volume of information exchanged per unit of time, expressed in bits per second

� Non-volatility, which characterises the ability of a memory to store data when it is not being supplied with electricity

The ideal memory has a large capacity with restricted access time and cycle time, a high throughput and is non-volatile.

However, fast memories are also the most expensive. This is why memories that use different technologies are used in a computer, interfaced with each other and organised hierarchically.

The fastest memories are located in small numbers close to the processor. Auxiliary memories, which are not as fast, are used to store information permanently.

Types of Memories

Random Access Memory

Random access memory, generally called RAM is the system's main memory, i.e. it is a space that allows you to temporarily store data when a program is running.

Unlike data storage on an auxiliary memory such as a hard drive, RAM is volatile, meaning that it only stores data as long as it supplied with electricity. Thus, each time the computer is turned off, all the data in the memory are irremediably erased.

Read-Only Memory

Read-only memory, called ROM, is a type of memory that allows you to keep the information contained on it even when the memory is no longer receiving electricity. Basically, this type of memory only has read-only access. However, it is possible to save information in some types of ROM memory.

Flash Memory

Flash memory is a compromise between RAM-type memories and ROM memories. Flash memory possesses the non-volatility of ROM memories while providing both read and write access However, the access times of flash memories are longer than the access times of RAM.

The primary memory or the main memory is part of the main computer system. The processor or the CPU directly stores and retrieves information from it. This memory is accessed by CPU, in random fashion. That means any location of this memory can be accessed by the CPU to either read information from it, or to store information in it.

The primary memory itself is implemented by two types of memory technologies. The first is called Random Access Memory (RAM) and the other is read only memory (ROM). A more appropriate name for RAM is RWM (Read Write Memory), the CPU can write and read information from any primary memory location implemented using RAM. The other part of primary memory is implemented using ROM which stands for Read Only Memory.

Primary memory is much faster and also it is more cost effective. But the secondary memory is much slower and also less costly. It stores the data permanently unless it is erased. The secondary memory is usually available in the form of floppy disk storage media, hard disk, CD, DVD, Pen drive (i.e. Mass storage devices), memory chips. A 5 and1/4 inch floppy disk typically stores 1.44 mb of data. The data on the floppy disk is organized in terms of tracks and sectors. Hard disk can have large capacity something like 80-300 GB's or higher. Hard disk itself is made up of, large number of platters. Hard disk is usually much faster compared to floppy disk. CD can store up to 750 mb of data. Information on CD ROM is organized in terms of a spiral track. A DVD is digital Versatile Disk and can store 4.6 Gigabyte of information. All these CD disk are usually write ones and read many times (if the disk is not multisession and re writable). So are the DVDs.

An input device is any device that provides input to a computer. There are lot of possible input devices, but the two most common ones are a keyboard and mouse. Every key you press on the keyboard and every movement or click you make with the mouse sends a specific input signal to the computer. These commands allow you to open programs, type messages, drag objects, and perform many other functions on your computer.

Since the job of a computer is primarily to process input, computers are pretty useless without input devices. Just imagine how much fun you would have using your computer without a keyboard or mouse. Not very much therefore, input devices are a vital part of every computer system.

While most computers come with a keyboard and mouse, other input devices may also be used to send information to the computer. Some examples include joysticks, MIDI keyboards, microphones, scanners, digital cameras, webcams, card readers, UPC scanners, and scientific measuring equipment. All these devices send information to the computer and therefore are categorized as input devices. Peripherals that output data from the computer are called output devices.


A keyboard produces letters, numbers, signs, other keys and the user physical key press can produce actions to the computer commands. The command key board will perform is to operating system of computer, such as Windows Control-Alt Delete together, which shows up a task window or shuts down the machine. The use of keyboard can lead in word processor, text editor or other program. The keyboard can also be attached to the computer by wire or it can be wireless. It is a flat and curved keyboard. The second keyboard is slightly divided and wider design. The Keyboard is designed similar to rectangle shape.


A mouse it�s an input device designed for the help of the user in controlling the screen and it also have two or three buttons. It is a palm design. Mouse is used for navigation and can be used for shortcut to programs.

Any device that outputs information from a computer is called, not surprisingly, an output device. Since most information from a computer is output in either a visual or auditory format, the most common output devices are the monitor and speakers. These two devices provide instant feedback to the user's input, such as displaying characters as they are typed or playing a song selected from a playlist.

While monitors and speakers are the most common output devices, there are many others. Some examples include headphones, printers, projectors, lighting control systems, audio recording devices, and robotic machines. A computer without an output device connected to it is pretty useless, since the output is what we interact with. Anyone who has ever had a monitor or printer stop working knows just how true this is. Of course, it is also important to be able to send information to the computer, which requires an input device.


A monitor is a component that displays images created by devices such a computers, without producing a permanent record. Monitor includes the display device, circuitry and area. The display device for the current monitors is thin film transistor liquid display and this shows up is in TFT, LCD. The display device for old version of monitors is cathode ray tube and this is for CRT


In computing, a printer is a peripheral which produces a hard copy (permanent readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a USB cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless and/or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time. In addition, a few modern printers can directly interface to electronic media such as memory sticks or memory cards, or to image capture devices such as digital cameras, scanners; some printers are combined with a scanners and/or fax machines in a single unit, and can function as photocopiers. Printers that include non-printing features are sometimes called Multifunction printers (MFP), Multi-Function Devices (MFD), or All-In-One (AIO) printers. Most MFPs include printing, scanning, and copying among their features.


Input devices are needed so that data can be entered into a computer system, to be stored or processed. Some input devices are manual, such as a keyboard or mouse, and some are automatic, such as a barcode reader or a webcam. Automatic input devices are generally more reliable and accurate than manual devices because there is less risk of human error. Without output devices it would not be possible to get information out of computer systems or use computer systems to control devices. Some output devices such as monitors and speakers are designed to communicate information to humans. Others such as motors are designed to control devices such as automatic cooling fans.

Mother Board


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