Types of Computers

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 and ROM.
• 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.
Types of RAM
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.
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!
Explanation of some important terms:
• Cache Memory
• Registers.
• The Bus.
Cache Memory
• 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.
Registers (Temporary Storage Areas)
• 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.
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 Permanent

Cost(Rs)
Registers Fastest Lowest Highest No
RAM Very Fast Low/ High No

Moderate
Floppy Very Slow Low Low Yes
Disk
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

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PRESENTATION OF INTORDUCTION

 Computer Memory and how computer

In 1964 International Business Machines Corporation (IBM) introduced its

 Minicomputers are smaller than main

 Work stations are specialized single user

 What is computer memory?

Working of computer memory.

 External memory (Secondary storage).

• RAM stores data and program code needed by

• Read-only memory (ROM) is nonvolatile (or

• The CPU accesses each location in memory by

There are two basic types of RAM: dynamic

• Dynamic RAM (DRAM) chips must be

• Static RAM (SRAM) does not need to be

 In DRAM, the circuit for each bit consists of a

• Cache memory is high-speed memory that holds

• Cache is located directly on the CPU or between

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

• The amount of cache memory has a tremendous

• The CPU contains a number of small memory areas, called

• Registers are temporary storage areas for instructions or

• The size of the registers determines the amount of data

Storage. Speed. Capacity Relative Permanent

RAM Very Fast Low/ High No

External memory can generally be classified as:

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