3416 computer architecture

8/2/2019 3416 Computer Architecture

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ALLAMA IQBAL OPEN UNIVERSITY, ISLAMABAD

(Department of Computer Science)

Course: Computer Architecture (3416) Semester: Spring, 2011

Level: BS (CS) Total Marks: 100

ASSIGNMENT No. 1All questions carry equal marks.

Q.1 a) Explain block diagram of computer state your answer with the help of a neat

diagram?

Input Unit:

Computers need to receive data and instruction in order to solve any problem.

Therefore we need to input the data and instructions into the computers. The input

unit consists of one or more input devices. Keyboard is the one of the most commonly

used input device. Other commonly used input devices are the mouse, floppy disk

drive, magnetic tape, etc. All the input devices perform the following functions.

Accept the data and instructions from the outside world.

Convert it to a form that the computer can understand.

Supply the converted data to the computer system for further processing.

Storage Unit:

The storage unit of the computer holds data and instructions that are entered through

the input unit, before they are processed. It preserves the intermediate and final

results before these are sent to the output devices. It also saves the data for the later

use. The various storage devices of a computer system are divided into two categories.

1. Primary Storage: Stores and provides very fast. This memory is generally used to

hold the program being currently executed in the computer, the data being received

from the input unit, the intermediate and final results of the program. The primarymemory is temporary in nature. The data is lost, when the computer is switched off. In

order to store the data permanently, the data has to be transferred to the secondary

memory.

The cost of the primary storage is more compared to the secondary storage. Therefore

most computers have limited primary storage capacity.

2. Secondary Storage: Secondary storage is used like an archive. It stores several

programs, documents, data bases etc. The programs that you run on the computer are

first transferred to the primary memory before it is actually run. Whenever the results

are saved, again they get stored in the secondary memory. The secondary memory is

slower and cheaper than the primary memory. Some of the commonly used secondarymemory devices are Hard disk, CD, etc.,

Memory Size:

All digital computers use the binary system, i.e. 0s and 1s. Each character or a

number is represented by an 8 bit code.

The set of 8 bits is called a byte.

A character occupies 1 byte space.

A numeric occupies 2 byte space.

Byte is the space occupied in the memory.


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The size of the primary storage is specified in KB (Kilobytes) or MB (Megabyte). One KB

is equal to 1024 bytes and one MB is equal to 1000KB. The size of the primary storage

in a typical PC usually starts at 16MB. PCs having 32 MB, 48MB, 128 MB, 256MB

memory are quite common.

Output Unit:

The output unit of a computer provides the information and results of a computation to

outside world. Printers, Visual Display Unit (VDU) are the commonly used output

devices. Other commonly used output devices are floppy disk drive, hard disk drive,

and magnetic tape drive.

Arithmetic Logical Unit:

All calculations are performed in the Arithmetic Logic Unit (ALU) of the computer. It

also does comparison and takes decision. The ALU can perform basic operations such

as addition, subtraction, multiplication, division, etc and does logic operations viz, >,


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b) Explain different generations of computers by identifying the main improvement ineach generation?

First Generation (1940-1956) Vacuum TubesThe first computers used vacuum tubes for circuitry and magnetic drums formemory,

and were often enormous, taking up entire rooms. They were very expensive to operate

and in addition to using a great deal of electricity, generated a lot of heat, which wasoften the cause of malfunctions.

First generation computers relied on machine language, the lowest-level programming

language understood by computers, to perform operations, and they could only solve one

problem at a time. Input was based on punched cards and paper tape, and output was

displayed on printouts.

The UNIVAC and ENIAC computers are examples of first-generation computing

devices. The UNIVAC was the first commercial computer delivered to a business client,

the U.S. Census Bureau in 1951.

Second Generation (1956-1963) TransistorsTransistors replaced vacuum tubes and ushered in the second generation of

computers. The transistor was invented in 1947 but did not see widespread usein computers until the late 1950s. The transistor was far superior to the vacuumtube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though thetransistor still generated a great deal of heat that subjected the computer todamage, it was a vast improvement over the vacuum tube. Second-generationcomputers still relied on punched cards for input and printouts for output.Second-generation computers moved from cryptic binary machine language tosymbolic, orassembly, languages, which allowed programmers to specifyinstructions in words. High-level programming languages were also beingdeveloped at this time, such as early versions ofCOBOL and FORTRAN. Thesewere also the first computers that stored their instructions in their memory, which

moved from a magnetic drum to magnetic core technology.The first computers of this generation were developed for the atomic energyindustry.Third Generation (1964-1971) Integrated CircuitsThe development of the integrated circuit was the hallmark of the third generationof computers. Transistors were miniaturized and placed on silicon chips,called semiconductors, which drastically increased the speed and efficiency ofcomputers.Instead of punched cards and printouts, users interacted with third generationcomputers through keyboards and monitors and interfaced with an operatingsystem, which allowed the device to run many different applications at one timewith a central program that monitored the memory. Computers for the first timebecame accessible to a mass audience because they were smaller and cheaperthan their predecessors.

Fourth Generation (1971-Present) MicroprocessorsThe microprocessorbrought the fourth generation of computers, as thousands ofintegrated circuits were built onto a single silicon chip. What in the firstgeneration filled an entire room could now fit in the palm of the hand. The Intel4004 chip, developed in 1971, located all the components of the computerfromthe central processing unit and memory to input/output controlson a singlechip.In 1981 IBM introduced its first computer for the home user, and in1984 Apple introduced the Macintosh. Microprocessors also moved out of the
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realm of desktop computers and into many areas of life as more and moreeveryday products began to use microprocessors.As these small computers became more powerful, they could be linked togetherto form networks, which eventually led to the development of the Internet. Fourthgeneration computers also saw the development of GUIs,the mouse and handheld devices.

Fifth Generation (Present and Beyond) Artificial Intelligence

Fifth generation computing devices, based on artificial intelligence, are still indevelopment, though there are some applications, such as voice recognition, thatare being used today. The use ofparallel processing and superconductors ishelping to make artificial intelligence a reality. Quantum computation andmolecular and nanotechnology will radically change the face of computers inyears to come. The goal of fifth-generation computing is to develop devices thatrespond to natural language input and are capable of learning and self-organization.
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Q.2 a) What are different component of computer? Also explain functions

associated with each component.

System unit

The system unitis the core of a computer system. Usually it's a rectangularbox placed on or underneath your desk. Inside this box are many electroniccomponents that process information. The most important of thesecomponents is the central processing unit (CPU), or microprocessor, whichacts as the "brain" of your computer. Another component israndom accessmemory (RAM), which temporarily stores information that the CPU uses whilethe computer is on. The information stored in RAM is erased when thecomputer is turned off.

Almost every other part of your computer connects to the system unit usingcables. The cables plug into specificports (openings), typically on the back ofthe system unit. Hardware that is not part of the system unit is sometimescalled aperipheral device ordevice.

Storage

Your computer has one or more disk drivesdevices that store information ona metal or plastic disk. The disk preserves the information even when yourcomputer is turned off.

Hard disk drive

Your computer's hard disk drive stores information on a hard disk, a rigidplatter or stack of platters with a magnetic surface. Because hard disks canhold massive amounts of information, they usually serve as your computer'sprimary means of storage, holding almost all of your programs and files. Thehard disk drive is normally located inside the system unit.

CD and DVD drives

Nearly all computers today come equipped with a CD or DVD drive, usuallylocated on the front of the system unit. CD drives use lasers to read (retrieve)data from a CD, and many CD drives can also write (record) data onto CDs. Ifyou have a recordable disk drive, you can store copies of your files on blankCDs. You can also use a CD drive to play music CDs on your computer.

Mouse

A mouse is a small device used to point to and select items on your computerscreen. Although mice come in many shapes, the typical mouse does look abit like an actual mouse. It's small, oblong, and connected to the system unitby a long wire that resembles a tail. Some newer mice are wireless.

Applies to all editions of Windows Vista.

Compare editions
http://windows.microsoft.com/en-US/windows-vista/products/compare?T1=tab01http://windows.microsoft.com/en-US/windows-vista/products/compare?T1=tab01http://windows.microsoft.com/en-US/windows-vista/products/compare?T1=tab01


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In this topic

System unit

Storage

Mouse

Keyboard

Monitor

Printer

Speakers

Modem

See also

Introduction to computers

Using your mouse

Using your keyboard

Windows Basics: all topics

Parts of a computer

If you use a desktop computer, you might already know that there isn't any

single part called the "computer." A computer is really a system of many partsworking together. The physical parts, which you can see and touch, arecollectively called hardware. (Software, on the other hand, refers to theinstructions, or programs, that tell the hardware what to do.)

The illustration below shows the most common hardware in a desktopcomputer system. Your system may look a little different, but it probably hasmost of these parts. A laptop computer has similar parts but combines theminto a single notebook-sized package.
http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_1http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_2http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_3http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_4http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_5http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_6http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_7http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_8http://windows.microsoft.com/en-US/windows-vista/Introduction-to-computershttp://windows.microsoft.com/en-US/windows-vista/Using-your-mousehttp://windows.microsoft.com/en-US/windows-vista/Using-your-keyboardhttp://windows.microsoft.com/en-US/windows-vista/Windows-Basics-all-topicshttp://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_1http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_2http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_3http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_4http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_5http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_6http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_7http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#section_8http://windows.microsoft.com/en-US/windows-vista/Introduction-to-computershttp://windows.microsoft.com/en-US/windows-vista/Using-your-mousehttp://windows.microsoft.com/en-US/windows-vista/Using-your-keyboardhttp://windows.microsoft.com/en-US/windows-vista/Windows-Basics-all-topics


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Desktopcomputer system

Let's take a look at each of these parts.

System unit

The system unitis the core of a computer system. Usually it's a rectangularbox placed on or underneath your desk. Inside this box are many electroniccomponents that process information. The most important of thesecomponents is the central processing unit (CPU), or microprocessor, whichacts as the "brain" of your computer. Another component is random accessmemory (RAM), which temporarily stores information that the CPU uses whilethe computer is on. The information stored in RAM is erased when the

computer is turned off.

Almost every other part of your computer connects to the system unit usingcables. The cables plug into specificports (openings), typically on the back ofthe system unit. Hardware that is not part of the system unit is sometimescalled aperipheral device ordevice.

Storage

Your computer has one or more disk drivesdevices that store information ona metal or plastic disk. The disk preserves the information even when yourcomputer is turned off.

Hard disk driveYour computer's hard disk drive stores information on a hard disk, a rigidplatter or stack of platters with a magnetic surface. Because hard disks canhold massive amounts of information, they usually serve as your computer'sprimary means of storage, holding almost all of your programs and files. Thehard disk drive is normally located inside the system unit.

CD and DVD drives

Nearly all computers today come equipped with a CD or DVD drive, usuallylocated on the front of the system unit. CD drives use lasers to read (retrieve)


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data from a CD, and many CD drives can also write (record) data onto CDs. Ifyou have a recordable disk drive, you can store copies of your files on blankCDs. You can also use a CD drive to play music CDs on your computer.

DVD drives can do everything that CD drives can, plus read DVDs. If you havea DVD drive, you can watch movies on your computer. Many DVD drives canrecord data onto blank DVDs.

Floppy disk drive

Floppy disk drives store information on floppy disks, alsocalled floppies or diskettes. Compared to CDs and DVDs, floppy disks canstore only a small amount of data. They also retrieve information more slowlyand are more prone to damage. For these reasons, floppy disk drives are lesspopular than they used to be, although some computers still include them.

Why are floppy disks "floppy"? Even though the outside is made of hardplastic, that's just the sleeve. The disk inside is made of a thin, flexible vinylmaterial.

TMouse

A mouse is a small device used to point to and select items on your computerscreen. Although mice come in many shapes, the typical mouse does look abit like an actual mouse. It's small, oblong, and connected to the system unitby a long wire that resembles a tail. Some newer mice are wireless.

A mouse usually has two buttons: a primary button (usually the left button)and a secondary button. Many mice also have a wheel between the twobuttons, which allows you to scroll smoothly through screens of information.

When you move the mouse with your hand, a pointer on your screen moves in

the same direction. (The pointer's appearance might change depending onwhere it's positioned on your screen.) When you want to select an item, youpoint to the item and then click(press and release) the primary button.Pointing and clicking with your mouse is the main way to interact with yourcomputer. For more information, see Using your mouse.

Keyboard

A keyboard is used mainly for typing text into your computer. Like thekeyboard on a typewriter, it has keys for letters and numbers, but it also hasspecial keys:

The function keys, found on the top row, perform different functions

depending on where they are used.

The numeric keypad, located on the right side of most keyboards,allows you to enter numbers quickly.

The navigation keys, such as the arrow keys, allow you to move yourposition within a document or webpage.
http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#TopOfPageTargethttp://windows.microsoft.com/en-US/windows-vista/Using-your-mousehttp://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer#TopOfPageTargethttp://windows.microsoft.com/en-US/windows-vista/Using-your-mouse


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Monitor

A monitordisplays information in visual form, using text and graphics. Theportion of the monitor that displays the information is called the screen. Like atelevision screen, a computer screen can show still or moving pictures.

There are two basic types of monitors:CRT(cathode ray tube) monitorsand LCD (liquid crystal display) monitors. Both types produce sharp images,

but LCD monitors have the advantage of being much thinner and lighter. CRTmonitors, however, are generally more affordable.

RamRandomaccessmemory, a type of computer memorythat can

be accessed randomly; that is, any byteof memory can beaccessed without touching the preceding bytes. RAM is the mostcommon type of memory found in computersand other devices,such as printers.
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b) What is meant by a bus? Explain different types of buses used in computer.

BUS:

A bus is a group of conducting lines that carriers data, address, & controlsignals. A bus is two or many wire communication method. A bus whichcommunicates between two active devices, it may transfer address, data, etc.Buses are the set of wires that carry special information to or from the cpu.

There are three types of buses

They are:Control Bus: The control bus is used by the CPU to direct and monitor the

actions of the other functional areas of the computer. It is used to transmit avariety of individual signals (read, write, interrupt, acknowledge, and so forth)

necessary to control and coordinate the operations of the computer.

The individual signals transmitted over the control bus and their functions arecovered in the appropriate functional area description.

Address Bus: The address bus consists of all the signals necessary to defineany of the possible memory address locations within the computer, or for

modular memories any of the possible memory address locations within amodule. An address is defined as a label, symbol, or other set of characters

used to designate a location or register where information is stored. Beforedata or instructions can be written into or read from memory by the CPU or

I/O sections, an address must be transmitted to memory over the addressbus.

Data Bus: The bidirectional data bus, sometimes called the memory bus,handles the transfer of all data and instructions between functional areas of

the computer. The bidirectional data bus can only transmit in one direction ata time. The data bus is used to transfer instructions from memory to the CPU

for execution. It carries data (operands) to and from the CPU and memory asrequired by instruction translation.

The data bus is also used to transfer data between memory and the I/Osection during input/output operations. The information on the data bus is

either written into memory at the address defined by the address bus orconsists of data read from the memory address specified by the address bus.


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Q.3 a) Explain the use of DMA controller in a computer system with a neat diagram.

Direct Memory Access (DMA): - Whether or not a system has memory-

mapped I/O, its CPU needs to address the device controllers to exchange data

with them. The CPU can request data from an I/O controller one byte at a

time but doing so for a device like a disk that produces a large block of data

wastes the CPUs time, so a different scheme, called DMA (Direct Memory

Access) is often used. The operating system can only use DMA if the hardwarehas a DMA controller, which most systems do. Sometimes this controller is

integrated into disk controllers and other controllers, but such a design

requires a separate DMA controller for each device. More commonly, a single

DMA controller is available (e.g., on the parent board) for regulating transfers

to multiple devices, often concurrently. No matter where it is physically

located, the DMA controller has access to the system bus independent of the

CPU, as shown in Fig. It contains several registers that can be written and

read by the CPU. These include a memory address register, a byte count

register, and one or more control registers. The control registers specify the

I/O port to use, the direction of the transfer (reading from the I/O device orwriting to the I/O device), the transfer unit (byte at a time or word at a time),

and the number of bytes to transfer in one burst.

First the controller reads the block (one or more sectors) from the drive

serially, bit by bit, until the entire block is in the controllers internal buffer.

Next, it computes the checksum to verify that no read errors have occurred.

Then the controller causes an interrupt. When the operating system starts

running, it can read the disk block from the controllers buffer a byte or a

word at a time by executing a loop, with each iteration reading one byte or

word from a controller device register, storing it in main memory,

incrementing the memory address, and decrementing the count of items to be

read until it reaches zero. When DMA is used, the procedure is different. First

the CPU programs the DMA controller by setting its registers so it knows what

to transfer where.

(Step 1 in fig.) It also issues a command to the disk controller telling it to

read data from the disk into its internal buffer and verify the checksum. When

valid data are in the disk controllers buffer, DMA can begin. The DMA

controller initiates the transfer by issuing a read request over the bus to the

disk controller

(Step 2) This read request looks like any other read request, and the disk

controller does not know or care whether it came from the CPU or from a DMA

controller. Typically, the memory address to write to is on the address lines of

the bus so when the disk controller fetches the next word from its internal

buffer, it knows where to write it. The write to memory is another standard

bus cycle.

(Step 3) When the write is complete, the disk controller sends an

acknowledgement signal to the disk controller, also over the bus


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(Step 4) The DMA controller then increments the memory address to use

and decrements the byte count. If the byte count is still greater than 0, steps

2 through 4 are repeated until the count reaches 0. At this point the controller

causes an interrupt. When the operating system starts up, it does not have to

copy the block to memory; it is already there.


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b) Describe the working principles of USB?

The USB (for Universal Serial Bus) is a low cost serial bus which initially

provided up to 12 Mb/S. That's about 100 times faster than the RS-232 style serial

interfaces used in earlier generations of computers. In June 2002, Intel and others

started to demonstrate USB 2.0, which increases the speed of the peripheral to PC

connection from 12 megabits per second (Mbps) on USB 1.1 to up to 480 Mbps

on USB 2.0, or 40 times faster than with the older technology.

USB pen drives are typically portable USB flash memory devices as it is the

incorporation of technology of flash memory that allows you to rewrite or erase

the data stored in these devices. And also flash memory is responsible for the high

durability of the compact removable disk. Like any other electronic gadget, USB

flash memory devices contain a collection of cells or chips and can be either NOR

or NAND type flash depending upon the way it is connected. Both of them use

floating gate transistors to which electrons are tunneled for erasing the data.

In the NOR type the initial values will be 00, and a current of opposite polarity is

induced for erasing the data whereas in the NAND type, the initial values are

maintained at FF. The NAND flash has found its applications in digital cameras,memory sticks, cards,USB pen drive and so on. The major success of the USB

flash memory device lies in its increased capacity to store high amount of

information together with its shock proof and dust proof nature which were the

major limitation witnessed in the floppies of the earlier years. Thus these tiny

devices have definitely created a revolution in the field of information technology.
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Q.4 a) Describe the functional characteristics that are common to build main

and secondary computer memory?

Primary Memory:

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 isaccessed 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.

o 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 secondarymemory is much slower and also less costly. It stores the data permanently unless it is

erased.

Secondary Memory Characteristics:

Secondary memory is not directly accessible to the CPU. Input/output

channels are used to access this nonvolatile memory. This memory does not

lose the data when the system is powered off. The most familiar form of

secondary memory that is widely used is Hard Disk. Some examples of

secondary memory are USB sticks, floppy drives and Zip drives.

Optical Disc Storage

Optical Disc Drives use electromagnetic waves or laser light to read and write

information to optical discs. There are drives that only read while on the other

hand some drives are also there that performs both reading and writing.

These devices include CD, DVD and Blue-ray Disc.

Magnetic Tape Storage

The device that performs reading and writing of data on magnetic tapes is a

tape drive. Tapes can be cost effective while storing large amounts of data.

Today they are largely used for backups and archives.

Hard Disks

A Hard Disks Drive (HDD) is a nonvolatile secondary storage device whichstores digitally encoded data on the magnetic surface of it.


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b) Give a brief description of computer memory organization?

Volatile memories Volatile memories are memories that lose their contents

when the poweris turned off. A semiconductor memory is an example. Nonvolatile memories Nonvolatile memories are memories that donot lose

their contents when power is removed. Core memory is an example.

MEMORY ORGANIZATION

Memory organization is two-fold. First we discuss the hardware (physical)organization, then the internal architecture. The type of computer and

its size do not reflect the type of memories that the computer uses.

Some computers have a mixture of memory types. For example, theymay use some type of magnetic memory (core or film) and also a

semiconductor memory (static or dynamic). They also have a read-

only memory which is usually a part of the CPU. Memory in acomputer can vary from one or more modules to one or

more pcbs, depending on the computer type. The larger mainframe

computers use the modular arrangement, multiple modules (four or

more), to make up their memories. Whereas, minicomputers

and microcomputers use chassis or assemblies, cages or racks, andmotherboard or backplane arrangements. Minis and micros use

multiple components on one pcb or groups of pcbs to form thememory.

Magnetictapes

Magneticdisks

I/Oprocessor

CPU

Mainmemory

Cachememory

Register

Cache

Main Memory

Magnetic Disk

Magnetic Tape


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Q.5 a) Explain how the processor is interfaced with memory with a neat block

diagram and explain how they communicate?

In a memory read operation the CPU loads the address onto the address bus. Mostcases these lines are fed to a decoder which selects the proper memory location. TheCPU then sends a read control signal. The data is stored in that location is transferred tothe processor via the data lines.

In the memory write operation after the address is loaded the CPU sends the writecontrol signal followed by the data to the requested memory location.

The memory can be classified in various ways i.e. based on the location, powerconsumption, way of data storage etc

The memory at the basic level can be classified as1. Processor Memory (Register Array)2. Internal on-chip Memory3. Primary Memory4. Cache Memory5. Secondary Memory

Processor Memory (Register Array)

Most processors have some registers associated with the arithmetic logic units. Theystore the operands and the result of an instruction. The data transfer rates are muchfaster without needing any additional clock cycles. The number of registers varies fromprocessor to processor. The more is the number the faster is the instruction execution.But the complexity of the architecture puts a limit on the amount of the processormemory.

Internal on-chip Memory

In some processors there may be a block of memory location. They are treated as thesame way as the external memory. However it is very fast.

Primary Memory

This is the one which sits just out side the CPU. It can also stay in the same chip as ofCPU. These memories can be static or dynamic.

Cache Memory

This is situated in between the processor and the primary memory. This serves as abuffer to the immediate instructions or data which the processor anticipates. There canbe more than one levels of cache memory.
http://1.bp.blogspot.com/_1neq2KSL4SE/TH5B6whFGII/AAAAAAAAAL0/lOFLcvXYSpE/s1600/memory+interface.png


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Secondary Memory

These are generally treated as Input/Output devices. They are much cheaper massstorage and slower devices connected through some input/output interface circuits. Theyare generally magnetic or optical memories such as Hard Disk and CDROM devices.The memory can also be divided into Volatile and Non-volatile memory.

* Volatile Memory

The contents are erased when the power is switched off. Semiconductor Random AccessMemories fall into this category.

* Non-volatile Memory

The contents are intact even of the power is switched off. Magnetic Memories (HardDisks), Optical Disks (CDROMs), Read Only Memories (ROM) fall under this category.
http://1.bp.blogspot.com/_1neq2KSL4SE/TH5EpCt8PWI/AAAAAAAAAL8/dA_H6rQCrQw/s1600/internal+reg.pnghttp://1.bp.blogspot.com/_1neq2KSL4SE/TH5EpCt8PWI/AAAAAAAAAL8/dA_H6rQCrQw/s1600/internal+reg.png


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b) Write a note on static memories?

The Static Random Access Memory (Static RAM) is a high speed memory.

Static RAM is a type ofRAM that gets its data without an external refresh. For as long as

power is supplied to the circuit.

SRAM has many differences to Dynamic RAM (DRAM). The first of all is duty to refresh

memory many times per second to hold its data contents. The second one is that SRAMs

are also used for specific applications within the PC, where their strengths outweigh their

weaknesses compared to DRAM

Static memory allocation refers to the process of allocating memory at compile-time before the associated program is executed, unlike dynamic memoryallocation orallocation where memory is allocated as required at run-time.

The only connection with static electricity that I can think of, is that static electricity is areal threat to extra RAM that you can plug into your PC or, for that matter, many parts ofyour PC if you open it up for any reason.

Other than that, static means staying in one place, staying the same, whereas dynamic isobviously something that changes all the time. Once you put a file somewhere on yourhard disc, it stays in the same place and does not change (unless of course youdefragment your hard drive). The contents of the RAM etc. changes all the time.
http://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/DRAMhttp://simple.wikipedia.org/wiki/PChttp://simple.wikipedia.org/wiki/DRAMhttp://en.wikipedia.org/wiki/Compile_timehttp://en.wikipedia.org/wiki/Compile_timehttp://en.wikipedia.org/wiki/Dynamic_memory_allocationhttp://en.wikipedia.org/wiki/Dynamic_memory_allocationhttp://en.wikipedia.org/wiki/Run_time_(program_lifecycle_phase)http://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/RAMhttp://simple.wikipedia.org/wiki/DRAMhttp://simple.wikipedia.org/wiki/PChttp://simple.wikipedia.org/wiki/DRAMhttp://en.wikipedia.org/wiki/Compile_timehttp://en.wikipedia.org/wiki/Compile_timehttp://en.wikipedia.org/wiki/Dynamic_memory_allocationhttp://en.wikipedia.org/wiki/Dynamic_memory_allocationhttp://en.wikipedia.org/wiki/Run_time_(program_lifecycle_phase)

3416 computer architecture

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