Memory

This note describes the different types of memory units and the features of those types. Memory is the part of the computer system that is used to store data or instruction temporarily and permanently. The memory can be assumed as the set of boxes, the boxes are numbered from zero upwards so that each box can be identified and data can be located.

Summary

Things to Remember

Memory is the part of the computer system that is used to store data or instruction.
The memory can be assumed as the set of boxes, the boxes are numbered from zero upwards so that each box can be identified .
Primary memory is also known as system memory or main memory of the computer.
Secondary memory is also called as Auxiliary memory.

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Q1:

Write a short note on Pharmacology.

Type: Short Difficulty: Easy

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Answer: <h3>Introduction</h3>
Pharmacology is a branch of science which deals with pharmacognosy, pharmaceutics, pharmacodynamics and pharmacokinetics of drugs.
It is the study of the mechanism of drug action and its effect in the living system.
<h3>Branches of pharmacology</h3>
<h4>1) Clinical pharmacology</h4>
The Scientific study of drugs in human is called clinical pharmacology. Clinical pharmacology comprises two major parts:
a) Pharmacology
<ul>
<li>Pharmacodynamics</li>
<li>Pharmacokinetics</li>
</ul>
b) Therapeutic evaluation
2) Pharmaceutics
Deals with preparation and dispensing of drug dosage formulation and suitable
for administration.
3) Therapeutics
Deals with the use of a drug for diagnosis, prevention, and treatment of disease.
4) Toxicology
Study the adverse or poisonous effects of drugs and their treatment.
5) Pharmacogenetics
Concerned with drug responses that are governed by heredity.
<h4>Pharmacokinetics</h4>
Pharmacokinetics deals with the absorption, distribution, biotransformation (metabolism) and excretion of a drug is called pharmacokinetics.
Simply, it means "what the body does to the body". It is the study of the movement of drugs from the site of administration till it reaches its site of action.
<ol>
<li>a) Absorption of drugs</li>
<li>b) Distribution of drug</li>
<li>c) Plasma concentration of a drug</li>
<li>d) Metabolism of drug</li>
<li>e) Excretion of drug</li>
</ol>
<h4>Pharmacodynamics</h4>
The study of biological effects of drugs and their mechanism of action is called pharmacodynamics. It is the study of the biochemical and physiological effect of drugs on the body. As the mechanism of action and its effect is being studied here it is also referred as "what the drug does to the body".
<ol>
<li>a) Action on specific receptors</li>
<li>b) Action on specific enzymes</li>
<li>c) Dose of drugs</li>
<li>d) Factors affecting response to drugs</li>
</ol>
<h4>Pharmaceutical terminologies</h4>
1) Tablet
It is commonly used solid pharmaceutical preparations that are manufactured by punching the granules with the help of dyes and punches or moulded from suitable raw materials, eg: paracetamol tablet, ibuprofen tablet, etc.
 
<img src="http://www.3ders.org/images2014/âpharmaceutical-researcher-create-new-shapes-medicine-tablets-3d-printing-00005.jpg" alt="Image result for single tablet medicine" width="430" height="220" />
 
2) Capsule
Capsules are made from gelatin. They may be spherical, ovoid in shape. The medicines in granules form are present within the capsule. They are useful for unpleasant medicaments. The capsules are of two types: hard capsules and soft capsules.
<img src="https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQxeDxS4g3FJ25svtv7VtBcRLgVUS5XZN5Fp37aPCgMzf09uNRt" alt="Image result for Pharmacology" />
 
 
3) Aerosols
These are a suspension of fine solid and liquid particles in a gas. The aerosols are administered as spray and commonly used to treat a respiratory problem. Eg: salbutamol aerosols.
<img src="http://www.schoolscience.co.uk/site/scho/uploadedresources/productashtma.png" alt="Image result for Aerosols medicine" />
4) Dusting powder
These are usually intended to use externally, which is free flowing and very fine powder that is Nycil dusting powder.
<img src="https://lizzylanefarmbotanicals.files.wordpress.com/2014/09/organic-dusting-powder-in-black-travel-tin.jpg" alt="Image result for Dusting powder" width="410" height="273" />
5) Elixir
It is clear liquid preparation which is pleasantly flavored and usually in attracting color. These are more stable than mixture eg: paracetamol elixir.
<img src="http://exhibits.hsl.virginia.edu/hist-images/nerves/ElixirNormajean.jpg" alt="Image result for Elixir medicine" width="155" height="266" />
 
 
 
 
6) Enemas
These are a suspension, solution or emulsion with a medicament for a rectal administration that is an ezivac enema, soap water enema.
 
<img src="https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQiAnR4WOiq-217nMDCpXPEzVohzEBiTYtkxlBpnlbxPW9Lnj7n" alt="Image result for Enemas medicine" />
 
 
 
7) Suppositories
These are solid preparation for insertion into the rectum or vaginal where they melt and exert local action eg: Bisacodyl suppositories.
 
<img src="http://image.slidesharecdn.com/suppositories-150825062849-lva1-app6892/95/suppositories-7-638.jpg?cb=1440484272" alt="Image result for Suppositories" width="389" height="292" />
 
8) Pessaries
These are solid medicated preparation, which is use to introduce inside the vagina, where they melt and exert local action. Pessaries are something use to keep for a long time.
 
<img src="https://incostress1.files.wordpress.com/2013/02/milex-range.jpg" alt="Image result for Pessaries" width="323" height="252" />
 
9) Solution
The solution is common to use externally as well as through mouth. It includes syrup solution and other medicament solution used by nebulizer eg: salbutamol solution.
 
10) Cream
These are semisolid emulsion for external use eg: betamethasone cream.
 
11) Paints
These are liquid preparation for the application to the skin and mucosa eg: gentian violet paint.
 
12) Ointment
These are semisolid greasy for the application in concerned parts, it is thicker than cream eg: Neosporin ointment, betadine ointment.
 
13) Paste
These are harder and thicker than ointment that is magnesium sulphate paste.
 
14) Mixture
These are a most common form of liquid oral preparation. They should shake before use that is magnesium trisilicate mixture.
 
15) Lotion
These are external preparation without friction eg: gamma benzene hexachloride lotion.
 
<h4>Ween human body and drugs</h4>
1) Drink LOTS of water. Nothing better than to filter the body and help get rid of the junk in your body faster. The more the better!
2) Tea without Caffeine help. There is a tea called "Sleepytime" that really does wonders and will help you sleep as insomnia is a side effect of withdrawal.
3) Alcohol has been known to help somewhat because it is a depressant and keeps the body slowed down but I would be careful not to overdo it. Alcohol also dehydrates the body so this could be a negative thing. Watch what you mix it with as well (such as sodas). Caffeine is a stimulant and can increase withdrawal effects as well as dehydrate you.
4) Vitamins and natural herbs help. Anything you can do to give the rest of your body what it has been deprived of is a good idea. Watch out for herbs or vitamins that increase metabolism as the goal is to keep the body slow and slowly let it speed back up.
5) Food is a great idea. Food has never tasted better after quitting pain medication. I've heard that fruits with lots of citruses are a good idea.
6) The last piece of advice would be to stay active. It is easy to want to sleep all day or sit in bed when quitting pain medication. While this can make the time pass I think it is better to stay active. I personally started lifting weights again when I was going through my withdrawals. Probably not the best idea but find something that can take your mind off of the whole thing. It also helped to have people around me. As much as I wanted to be alone when going through hell, I am very glad my wife was here to support me. Nothing beats depression like a good friend to talk to.

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Basic Pharmacology

Memory

MEMORY

Memory is the part of the computer system that is used to store data or instruction temporarily and permanently. The memory can be assumed as the set of boxes and the boxes are numbered from zero upwards so that each box can be identified.

Once data is stored in the memory of memory box, it holds there till it is replaced by other data in the computer system. The computer cannot function without the memory. So, memory is the key factor of the computer to run smoothly and nicely and it is used to store data.

CPU (Central Processing Unit ) contains necessary data processing and controlling other components of the computer. It does not have any other place to store programs and data during data calculation and data processing. We also know that the CPU obtain several registers for storing data and instructions.

On the basis of technological point of view, memory can be classified as below:

Semiconductor memory
It is the memory that is built by using transistor and IC. It is faster, lighter, has smaller storage capacity and consumes less power. It is used as the main memory of the computer. It has an access time of about 50ns. Examples: ROM, RAM, Cache memory, etc.
Magnetic memory
It is the memory that consists of magnetic property for storing data. It stores data in the form of magnetized dots. It is slower for read / write and cheaper than semiconductor. It is used as the secondary or backup memory of the computer. Examples: Hard disk, Floppy disk, Tape drive, etc.
Optical memory
It is the memory that uses optical property (light) to the read-write operation of the data. It is slower and cheaper than semiconductor memory and used for mass storage and backup. Example: CD, DVD, BD, etc.

The time to fetch and load data from the storage space into CPU must be very small to that from disk storage to reduce the speed mismatch problem with CPU speed. Every computer has a storage space called main memory or primary memory. It is temporary area built into the computer hardware.

Memory consist of IC (Integrated circuit), chips either on the motherboard or on a small circuit board attached to the motherboard of a computer system. Hence, the rate of data fetching from the main memory is faster than that from high-speed secondary storage like a disk.

Primary Memory

Primary memory is also known as system memory or main memory or primary storage or internal memory. Primary memory is the working area for the computer's processor.

It holds data for processing. It holds instructions for processing data. It holds data after it is processed waiting to be sent to an output or storage device.

Features of Primary memory

It is used for storing data and programs for temporary.
It is normally used for smaller storages.
It is expensive and faster for read / write operations than secondary memory.

Here are some of them that comes under the primary memory

RAM (Random Access Memory)

RAM is the read/write memory of the computer. It is used for both purpose read and write. It possesses random access property that means CPU can access any memory location in a random sequence form.

It is a volatile memory. It stores data or information as long as power supply is on. But ,after power supply is off,data will be gone. There are two types of RAM.

Types of RAM

Static RAM (SRAM)

SRAM stores data and programs as long as the computer is in ON state. It is expensive but faster for read/write than DRAM.it is typically used for CPU cache while DRAM is used for a computer's main memory.

Fig: Static RAM

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Dynamic RAM (DRAM)

The data stored in DRAM will be lost after a few milliseconds even if the computer is on. It is cheap but slow for read/write than SRAM.

Fig: Dynamic RAM

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Read Only Memory (ROM)

ROM stands for Read only memory. It can be used only to perform the read operations. It does not have write access. It is non-volatile memory i.e, the information stored in it is permanent and is not lost even if the power supply is cut down.

Fig:Read Only Memory

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It is used for permanent storage of programs. It is cheaper than RAM on per unit basis but while compared to storage ROM is expensive than RAM.

Types of ROM

PROM (Programmable Read Only Memory)

It is a programmable memory that users can write data at once only. The user can store permanent programs, data or any kind of information in PROM.

Fig: Programmable Read only Memory

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EEPROM ( Electrical erasable programmable read only memory)

It is a memory that can also be erasable via electric. It can be erased and reprogrammed on the byte by byte basis single data or the entire chip can be erased.

Fig: Electrical erasable programmable read only memory

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EPROM ( Erasable Programmable Read Only Memory)

It is an erasable memory. Data stored on it can be erasable via passing the Ultra-Violet light so that entire data will be erased.

Fig: ErasableProgrammable Read Only Memory

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Secondary Memory

Secondary memory is non-volatile and has a lower cost per bit. It generally has an operating speed far slower than that of primary memory. Secondary memory is also called as "Auxiliary Memory". It is primarily used to store a large volume of data on the permanent basis that can be partially transferred to primary storage.

Secondary storage is the storage device that is designed to store data and instructions (programs) in a computer relatively in permanent form. It is non-volatile storage.ie. stored data and instructions can be retained even if the power supply is cut off. It is also known as backup memory.

Features of secondary memory

It is not directly accessible to CPU; it requires primary memory for its operation.
It is usually non-volatile memory.
It is usually cheaper and slower for read /write operation than primary memory.

Cache Memory

Cache memory pronounced as cash, is a special high speed and expensive memory used in CPU, so that CPU doesn`t have to wait for data to be delivered. The most frequently used instructions are kept in the cache memory.

Cache memory computer runs fast and smoothly. It doesn`t have to swap instruction in and out of RAM. Hence, the cache memory is placed in between CPU and RAM so that the speed of operation of main memory and cache memory together can meet speed requirements.

There are usually two levels of cache memory. They are:

Level 1 (L1)

L1 is smaller and the faster. Multi-level caches generally operate by checking the L1

cache first If it hits the processor proceeds at high speed.

Level 2 (L2)

L2 is larger and the slower. If the smaller cache misses the next larger cache L2 is checked and so on.

Buffer

It is a temporary holding area for data; unlike register it stores more than one piece of data. It is normally used between the CPU and the input/output devices. The purpose of a buffer is to hold data prior being used by CPU.

(Shrestha, Manandhar, and Roshan)

Bibliography

Shrestha, Prachanda Ram, et al. Computer Essentials. Kathmandu: Asmita's Publication, 2014

Gurung,Juddha Bahadur et.al.,computer science-XI,Bhundipuran Pakashan.

Lesson

Computer System

Subject

Computer Science

Grade

Grade 11

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