PRESENTATION OF INTORDUCTION OF COMPUTERS AND PROGRAMMINGS.

PRESENTED BY: NAVEED MUMTAZ.

GROUP MEMBERS:MUHAMMAD NAVEED.MUHAMMAD AWAIS.NAVEED MUMTAZ.

Presentation topics:

Types of computers.

Computer Memory and how computer memory works?

Types of computers.

Computers for organizations.• Super computers• Mainframe computers.• Minicomputers.• Network Servers.

Computers for Individual users.• Workstations.• Notebook computers.• Handheld computers.• Tablet computers.• Smart phones.• Microcomputers.

Early Computers

The earliest computers were so big that they filled entire rooms! This picture shows one of the first computers, UNIVAC I, which was invented in 1951.

Super computers. Supercomputers are the fastest computers currently

available. Supercomputers are very expensive and are employed for

specialized applications that require immense amounts of mathematical calculations (number crunching).

For example, weather forecasting requires a supercomputer.

Other uses of supercomputers scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data.

Recently, some supercomputers have been constructed by connecting together large numbers of individual processing units

Supercomputer (Cray-2 from the 1980’s)

 CM-5 Supercomputer The CM-5 supercomputer is a massively parallel processing computer capable of

many billions of floating point operations per second. The computer contains hundreds of processing units, similar to the central processing units (CPUs) in personal computers. The processing units are linked together in parallel so that

multiple calculations can be carried out simultaneously.                

Mainframe computers.

A powerful multi-user computer capable of supporting many hundreds or thousands of users

simultaneously. Mainframes typically cost several hundred

thousand dollars. They are used in situations where a company

wants the processing power and information

storage in a centralized location. Mainframe computers are used by large

organizations e.g. banks and insurance companies.

Mainframe Computer

In 1964 International Business Machines Corporation (IBM) introduced its revolutionary System/360, the first mainframe computer that used interchangeable software and equipment.

Mainframe computer (this IBM z-series

about 6 feet tall)

Mainframe computers

Minicomputers.

Minicomputers are smaller than main frames but larger than microcomputers.

Minicomputers usually have multiple terminals.

Hundreds of users can use these computers at a time.

Minicomputers may be used as network servers and Internet servers.

Minicomputer.

Workstations.

Work stations are specialized single user computers.

They contain one or more microprocessor CPUs.

They have greater power and processing speed as compared to ordinary PCs.

They have high resolution monitors and enhanced features and graphics.

These computers are mainly used by scientists and engineers.

Workstation.

Notebook computers.

These are extremely lightweight computers.Notebook computers typically weigh less than 6

pounds and are small enough to fit easily in a briefcase.

They run on battery power, but can also be plugged into a wall outlet.

In terms of computing power, modern notebook computers are nearly equivalent to personal computers.

They have the same CPUs, memory capacity, and disk drives as that of microcomputers.

Example is Laptop which costs more than desktop units.

Laptop.

Handheld computers.A portable computer that is small enough to be held

in one’s hand. Although extremely convenient to carry, handheld

computers have not replaced notebook computers because of their small keyboards and screens.

The most popular hand-held computers are those that are specifically designed to provide PIM (personal information manager) functions, such as a calendar and address book.

Hand-held computers are also called PDAs, palmtops and pocket computers.

Handheld computers. (PDA)

Microcomputer. (Personal computers)

Microcomputers are also called personal computers.

The most common types of this computer is desktop computer.

Used friendly by everyone from preschoolers to scholars.

Most common models are:

1) Tower model.

2) Desktop model

Microcomputer

Computer memory and its working.

What is computer memory?

Working of computer memory.

Memory.

Internal storage areas in the computer.The term memory indicates data storage that

comes in the form of chips, and the word storage is used for memory that exists on tapes or disks.

The term memory is usually used as shorthand for physical memory, which refers to the actual chips capable of holding data.

Every computer comes with a certain amount of physical memory, usually referred to as main memory or RAM.

We can think of main memory as an array of boxes, each of which can hold a single byte of information.

Computer Memory. Computer memory can be divided into two

categories: Internal memory (Primary storage).

Internal memory operates at the highest speed and is directly

accessible to the central processing unit (CPU).

For example: RAM(volatile) and ROM (non-volatile).

External memory (Secondary storage). External memory consists of storage on peripheral devices that

are slower than internal memories but capable holding data after the computer’s power has been turned off.

For example: HARD DISC.

Computer system illustration diagram.

• RAM stores data and program code needed by the CPU. The contents of RAM change rapidly and often.

• Read-only memory (ROM) is nonvolatile (or permanent). It holds instructions that run the computer when the power is first turned on.

• The CPU accesses each location in memory by using a unique number, called the memory address.

RAM and ROM.

There are two basic types of RAM: dynamic and static.

• Dynamic RAM (DRAM) chips must be recharged with electricity very frequently, or they will lose their contents.

• Static RAM (SRAM) does not need to be recharged as often as DRAM, and can hold its contents longer.

Types of RAM

Dynamic RAM (DRAM)

In DRAM, the circuit for each bit consists of a transistor, which acts as a switch, and a capacitor, a device that can store a charge.

To store the binary value 1, DRAM places an electric charge on the capacitor. To store the binary value 0, DRAM removes all electric charge from the capacitor.

The transistor is used to switch the charge onto the capacitor. When it is turned on, the transistor acts like a closed switch that allows electric current to flow into the capacitor and build up a charge.

Static RAM (SRAM).

In SRAM, the circuit for a bit consists of multiple transistors that hold the stored value without the need for refresh.

The chief advantage of SRAM lies in its speed. A computer can access data in SRAM more

quickly than it can access data in DRAM or SDRAM.

However, the SRAM circuitry draws more power

and generates more heat than DRAM or SDRAM.

More RAM = Better Performance!

• Cache Memory

• Registers.

• The Bus.

Explanation of some important terms:

• Cache memory is high-speed memory that holds the most recent data and instructions that have been loaded by the CPU.

• Cache is located directly on the CPU or between the CPU and RAM, making it faster than normal RAM.

• CPU-resident cache is called Level-1 (L1) cache. External cache is called Level-2 (L2) cache.

• The amount of cache memory has a tremendous impact on the computer's speed.

Cache Memory

• The CPU contains a number of small memory areas, called registers, which store data and instructions while the CPU processes them.

• Registers are temporary storage areas for instructions or data. They are not a part of memory; rather they are special additional storage locations that offer the advantage of speed.

• The size of the registers determines the amount of data with which the computer can work at a one time.

• Today, most PCs have 32-bit registers, mean the CPU can process four bytes of data at one time. Register sizes are

rapidly growing to 64 bits.

Registers (Temporary Storage Areas)

The Bus

A bus is a path between the components of a computer. Data and instructions travel along these paths.

The system bus or processor bus is an external data bus.

External data bus describes the wires and traces on the motherboard that are used to send and

receive data. The greater the amount of wires, the more data

processer can send and receive.

The Bus.

Working of computer memory.

The following table summarizes the characteristics of the

various kinds of data storage in the storage hierarchy.

Storage. Speed. Capacity Relative

Cost(Rs)

Permanent

Registers Fastest Lowest Highest No

RAM Very Fast Low/

Moderate

High No

Floppy Disk

Very Slow Low Low Yes

Hard Disk Moderate Very High High Yes

External Memory (secondary storage).

External memory can generally be classified as:

Magnetic Media.

It is computer's hard drive.

Optical Media. It is compact disc-read only memory (CD-ROM).

Magneto-Optical Media.

Magneto-optical memory devices use a combination of optical storage coupled with a magnetic medium.

Magnetic Media.

Optical Media