Computer Systems

Computer Systems

We’ll discuess the following points during our this session:

• Today’s Goal
• Computer Types
• Supercomputers
• Question of the Day
• The Champion: ASCI White
• Mainframe Computers
• Servers/Minicomputers
• Desktop Computers
• Mobile Computers
• Ranking w.r.t. installed number
• Essential Hardware Components
• Input Devices
• What is a Port?
• Processor
• Memory/Storage
• Classifying Memory/Storage
• Output Devices
• What we have learnt Today?

Today’s Goal

1. To learn to classify computers according to their capability and targeted applications
2. To find out about the essential building blocks that make up a modern computer

Computer Types

Computer types according to capability are:

• Supercomputers
• Mainframes
• Servers
• Desktops

• Portables

Super Computers

• State-of-the-art machines designed to perform calculations as fast as the current technology allows
• Used to solve extremely complex and large-scale problems: weather prediction, simulation of atomic explosions; aircraft design; movie animation
• Cost tens of millions of dollars
• Unique in that unlike mainframes & personal computers, designed to focus all their resources and capabilities on a single task at a time
• Early supercomputers used a single or a few processors working in parallel
• Those processors were custom-built for the supercomputers, and were, therefore, very expensive

Modern supercomputers use the same processors that are used in desktop PCs. They, however, are designed to use 1000’s of them working together in parallel

The Champion: ASCI White

• Most powerful computer as of February 2002
• Capable of 12.3 trillion calculations/sec
  - 74,000 times faster than Cray 1 (1976)
  - 1,000 times faster than Deep Blue (1997)
• Designed for complex 3-D simulations required for testing nuclear weapons
• Powered by 8192 microprocessors

• 6 TB of memory; 160 TB of storage capacity

Mainframe Computers

• Also called “Enterprise Servers”
• Designed for performing multiple, intensive tasks for multiple users simultaneously
• Used by large businesses (e.g. banks, e-commerce sites), military, and industrial organizations
• Designed for very-high reliability
• Can be serviced/upgraded while in operation
• Generally consist of multiple processors, GB’s of memory, and TB’s of storage

• Cost in millions of dollars

Servers/Minicomputers

• The name minicomputers used to define the class of computers that lies between personal computers and mainframes
• Then very high-end desktop computers – called low-end or mid-range servers – took over the role that was previously played by minicomputers
• Low-end and mid-range servers are used by small businesses and organizations as file-stores, to run e-mail systems and Web sites
• Generally are more reliable than desktops, but not as solid as the mainframes
• Generally consist of 2 or more processors, GB’s of memory, and TB’s of storage

• Costs in hundreds of thousands of dollars

Desktop Computers

• Also called microcomputers

· Low-end desktops are called PC’s and high-end ones “Workstations”

· Generally consist of a single processor only, some times 2, along with MB’s of memory, and GB’s of storage

· PC’s are used for running productivity applications, Web surfing, messaging

· Workstations for more demanding tasks like low-end 3-D simulations and other engineering & scientific applications

· Are not as reliable and fault-tolerant as servers

• Workstations cost a few thousand dollars; PC around a $1000

Mobile Computers

Laptops, palmtops, and wearable computers are very capable computers but are light-weight and consume very little power

Laptops

• also called notebook computers
• generally weigh around 2kg
• use special low-power processors
• typically have 256MB memory,
• 40GB of storage
• can work for more than 2 hours on battery.
• Their usage is similar to that of PCs
  They cost in the range of $1500-2500

Palmtops,

• also known as PDA’s - Personal Digital Assistants
  Weigh less than a pound
• have very low-power processors
• KB’s of memory
• MB’s of storage capacity
• Can run for many hours on AA batteries
• Used as an electronic version of a pocket diary
• Also for Web surfing and e-mail or even as mobile phones
• Palmtops cost $200-600

Wearables

• are small in size
• carried in a pocket
• worn on the arm, waist
• or head or elsewhere on the body
• Capability similar to PDA’s
• but more expensive
• They are always ON, and always accessible. That is, the user can always enter and execute commands, even while walking around or doing other activities

Each soldier of the future will be fitted with one

Ranking w.r.t. installed number

• PC’s
• PDA’s
• Workstations
• Servers
• Wearables (will take the top spot in future)
• Mainframes

Supercomputers

Essential Hardware Components

At the highest level, two things are required for computing

Hardware: The physical equipment in a computing environment such as the computer and its peripheral devices (printers, speakers, etc.)

Software: The set of instructions that operates various parts of the hardware. Also termed as “computer program

All computers have the following essential hardware components:

Input

The devices used to give the computer data or commands are called Input devices. Includes keyboard, mouse, scanner, etc

Processor

A processor is the logic circuitry that responds to and processes the basic instructions that drive a computer.

The term processor has generally replaced the term central processing unit (CPU). The processor in a personal computer or embedded in small devices is often called a microprocessor. Short for microprocessor, the central processing unit in a computer. The processor is the logic of a computer and functions comparably to a human central nervous system, directing signals from one component to another and enabling everything to happen

Memory

Memory is the electronic holding place for instructions and data that your computer's microprocessor can reach quickly. When your computer is in normal operation, its memory usually contains the main parts of the operating system and some or all of the application programs and related data that are being used. Memory is often used as a shorter synonym for random access memory (RAM). This kind of memory is located on one or more microchips that are physically close to the microprocessor in your computer. Most desktop and notebook computers sold today include at least 16 megabytes of RAM, and are upgradeable to include more. The more RAM you have, the less frequently the computer has to access instructions and data from the more slowly accessed hard disk form of storage.

Memory is also called primary or main memory.

Storage

Computer storage is the holding of data in an electromagnetic form for access by a computer processor. It is also called secondary storage. In secondary storage data resides on hard disks, tapes, and other external devices.

Primary storage is much faster to access than secondary storage because of the proximity of the storage to the processor or because of the nature of the storage devices. On the other hand, secondary storage can hold much more data than primary storage.

Output

The devices to which the computer writes data are called Output devices. Often converts the data into a human readable form. Monitor and printer are output devices.

There is another quite essential component that is present in every computer that is BUS

Input Devices

Mouse

A mouse is a small device that a computer user pushes across a desk surface in order to point to a place on a display screen and to select one or more actions to take from that position. The mouse first became a widely-used computer tool when Apple Computer made it a standard part of the Apple Macintosh. Today, the mouse is an integral part of the graphical user interface (GUI) of any personal computer. The mouse apparently got its name by being about the same size and color as a toy mouse.

Keyboard

On most computers, a keyboard is the primary text input device. A keyboard on a computer is almost identical to a keyboard on a typewriter. Computer keyboards will typically have extra keys, however. Some of these keys (common examples include Control, Alt, and Meta) are meant to be used in conjunction with other keys just like shift on a regular typewriter. Other keys (common examples include Insert, Delete, Home, End, Help, function keys, etc.) are meant to be used independently and often perform editing tasks.

Joystick

In computers, a joystick is a cursor control device used in computer games. The joystick, which got its name from the control stick used by a pilot to control the ailerons and elevators of an airplane, is a hand-held lever that pivots on one end and transmits its coordinates to a computer. It often has one or more push-buttons, called switches, whose position can also be read by the computer.

Digital Camera

A digital camera records and stores photographic images in digital form that can be fed to a computer as the impressions are recorded or stored in the camera for later loading into a computer or printer. Currently, Kodak, Canon, and several other companies make digital cameras.

Microphone

A device that converts sound waves into audio signals. These could be used for sound recording as well as voice chatting through internet.

Scanner

A scanner is a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in, and flatbed types and for scanning black-and-white only, or color. Very high resolution scanners are used for scanning for high-resolution printing, but lower resolution scanners are adequate for capturing images for computer display. Scanners usually come with software, such as Adobe's Photoshop product, that lets you resize and otherwise modify a captured image

What is a Port?

On computer and telecommunication devices, a port (noun) is generally a specific place for being physically connected to some other device, usually with a socket and plug of some kind. Typically, a personal computer is provided with one or more serial ports and usually one parallel port.

Many Types of Ports

1. Parallel
2. Serial
3. SCSI
4. USB
5. Firewire

Parallel

An interface on a computer that supports transmission of multiple bits at the same time; almost exclusively used for connecting a printer. On IBM or compatible computers, the parallel port uses a 25-pin connector.

Serial

It is a general-purpose personal computer communications port in which 1 bit of information is transferred at a time. In the past, most digital cameras were connected to a computer's serial port in order to transfer images to the computer. Recently, however, the serial port is being replaced by the much faster USB port on digital cameras as well as computers.

SCSI

A port that's faster than the serial and parallel ports but slower and harder to configure than the newer USB port. Also know as the Small Computer System Interface.

A high-speed connection that enables devices, such as hard-disk drives and network adapters, to be attached to a computer.

USB

USB (Universal Serial Bus) is a plug-and-play hardware interface for peripherals such as the keyboard, mouse, joystick, scanner, printer and modem. USB has a maximum bandwidth of 12 Mbits/sec and up to 127 devices can be attached. With USB, a new device can be added to your computer without having to add an adapter card. It typically is located at the back of the PC

Firewire

FireWire is simply a really fast port that lets you connect computer peripherals and consumer electronics to your computer without the need to restart. It is a simple common plug-in serial connector on the back of your computer.It has the ability to chain devices together in a number of different ways without terminators for example, simply join 2 computers with a FireWire cable for instant high-speed networking.

Processor

• Pentium
• Celeron
• Athlon
• PowerPC
• StrongARM (PDA)
• Crusoe (Laptops)
• SPARC (Workstations)

Memory/Storage

RAM

RAM (random access memory) is the place in a computer where the operating system, application programs, and data in current use are kept so that they can be quickly reached by the computer's processor. RAM is much faster to read from and write to than the other kinds of storage in a computer, the hard disk, floppy disk, and CD-ROM. However, the data in RAM stays there only as long as your computer is running. When you turn the computer off, RAM loses its data. When you turn your computer on again, your operating system and other files are once again loaded into RAM, usually from your hard disk.

Punch cards

A card on which data can be recorded in the form of punched holes.

ROM

ROM is "built-in" computer memory containing data that normally can only be read, not written to. ROM contains the programming that allows your computer to be "booted up" or regenerated each time you turn it on. Unlike a computer's random access memory (RAM), the data in ROM is not lost when the computer power is turned off.

The ROM is sustained by a small long-life battery in your computer.

Hard disk

Hard disk is a computer storage device which saves and retrieves the data when required. Its capacity is much greater than the computer memory (RAM, ROM). Data on hard disk is stored and retrieved from electromagnetically charged surface.Today we can save huge amount of data on a single hard disk. Now hard disks can contain several billion bytes.

Floppy disk

A diskette is a random access, removable data storage medium that can be used with personal computers. The term usually refers to the magnetic medium housed in a rigid plastic cartridge measuring 3.5 inches square and about 2 millimeters thick. Also called a "3.5-inch diskette," it can store up to 1.44 megabytes (MB) of data.

Tape

In computers, tape is an external storage medium, usually both readable and writable, can store data in the form of electromagnetic charges that can be read and also erased. A tape drive is the device that positions, writes from, and reads to the tape.

CD

A compact disc [sometimes spelled disk] (CD) is a small, portable, round medium for electronically recording, storing, and playing back audio, video, text, and other information in digital form.

DVD

DVD (digital versatile disc) is an optical disc technology that is expected to rapidly replace the CD-ROM disc (as well as the audio compact disc) over the next few years. The digital versatile disc (DVD) holds 4.7 gigabyte of information on one of its two sides, or enough for a 133-minute movie.

Classifying Memory/Storage

• Electronic (RAM, ROM)
• Magnetic (HD, FD, Tape), optical (CD, DVD)
• Volatile (RAM), non-volatile (HD)
• Direct access (RAM, HD), serial access (Tape)
• Read/write (HD, RAM), read-only (CD)

Output Devices

• Printer
• Plotter
• Speakers
• Monitor

Modem is output as well as input device at the same time. It receives the data (analog signal) coming through telephone line, converts them to digital signals and sends them to computer to which it is attached. It also receives the data from computer and changes it to analog signals.