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Graphics, File Sizes, Bandwidth and Screen Resolution

Getting connected to the Internet starts with an understanding of the form in which information flows on the Internet.

Bits, Bytes and Bandwidth

The smallest amount of information stored on a computer or transmitted via telecommunications is the bit. A bit is either "on" or "off" in the form of a 0 (zero) or 1 (one). Eight bits make a byte. A byte is the combinations of bits in patterns that represent alpha-numerical characters, A-Z and 0-9.Bits and bytes represent units of memory storage for a computer. Memory increases are measured in increments of the powers of 2: 2 to the tenth power (a kilobyte), 2 to the twentieth power (a megabyte), etc. Units of memory     bit 1 or 0   byte = 8 bits   kilobyte (1K) = 1,024 one thousand bytes 1,024 megabyte (1MB) = 1,024K one million bytes 1,048,576 gigabyte (1GB) = 1,024MB one billion bytes 1,073,741,824 terabyte (1TB) = 1,024GB one trillion bytes 1,099,511,627,776 Computers have drives: hard drives measured in GB's, 40GB's RAM measured in MB's; 16 - 128MB's or more 3.5" floppy measured K's; (Note: double-density = 720K; High-density = 1.44MB) zip drives measured at 100 MB's or 250 MB's other drives The following table allows you to compare the size of the information packages that you might want to send, recieve or store via the Internet. plain text = 44 bits/word text file of 100 characters = 100 bytes double-density = 720K floppy High-density = 1.44MB = 720 pages = 1,440 pages color photo = 1MB and up Complete works of Shakespeare = 5.1 MB 1-minute video = 100MB Stereo CD = 466K/word

Bits and bytes represent units of memory for computer storage. They also represent data flow capacity called bandwidth. Bandwidth represents the amount of data that can be transmitted from one location to another in a given amount of time. Bandwidth in generally expressed as the amount of data that can be transferred in one second. Bandwidth is similar to pipelines. Generally, the larger the pipe, more data can flow faster. Some pipes are like hoses that can only feed data so fast and are only 1 inch in diameter. This would be a 56K modem. Other pipes are like 6 foot diameter sewer pipes where lots of data can flow with almost no speed limit. This would be a T3 line.To improve bandwidth we look for faster/bigger connections. This is acheived through improvement in telecommunications devices and physical connection lines. (more on this later in the section on connections) When Internet data has to flow in "real time", such as streaming audio or video, very high bandwidth is required to allow it to run without perceptible delays, stuttering or interruptions. Plain text 44 bits/word audio 21,000 bits/word streaming video 100,000,000 bits/sec video-conferencing 400,000,000 bits/sec Bandwidth Bottlenecks Most of the Internet backbone runs on very high bandwidth connections like T1 lines or faster. However, your connection (the on-ramp for sending, the off-ramp for recieving information) generally is the bottleneck for communications speed. Even if a 5 MB file moves from server to server and routes from Washington D.C. to Snata Cruz, CA in fractions of a second over high bandwidth Internet backbone connections, if you have a 28K modem it hits the brakes on the off-ramp to your computer and slows to 28,000 bits/second. What slows down Internet data transfer speed and what causes telecommunications bottlenecks? 1. Website Graphics - #, file size, loading, optimization audio, video, animation plugins needed old technology 2. Customer # of customers demanding the page # of customers demanding the server Customer technology - connection, cache. processor speed, browser version, etc. 3.Host Server platform Routing demand Host/Server familiar with URL Host Traffic or server traffic Host Connections # of servers

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