In today’s class, we covered a few basic concepts behind digital technology.
The first was the fundamental building blocks of all digital communication. The binary digit or the bit is the single unit, representing either
off such as a switch. We represent the bit in a more compact way: either as a
0 or a
1. The byte is a minimum string of bits necessary for a computer to assign meaning to those bits. It is usually comprised of eight bits. A byte is equivalent to a single character of text. Two or more bytes constitute a word. For example, a byte representing the Roman character
n becomes a word after the byte representing the Roman character
o is appended to it. The resulting pair of bytes make up the word
no. Similarly adding the
o before the
n results in the word
on. In both cases, the bytes are the same but the order and arrangement are vital to making meaning.
The next building block we discussed was storage. We reviewed three types. The first was the punch card, which encoded the binary digits on paper cards. The second was magnetic storage. Here the bits are stored on metallic particles found on a tape or a disk, such as those found on hard disks and floppy disks. The particles are activated (or not) by a magnet that rearranges the particles. The third was the optical storage, such as DVDs and CDs and those strange hybrids: magento-optical storage. Do you remember how those worked? Hint: it has to do with lasers.
We moved on to electronic processors. We reviewed three kinds. The diode was similar to a light bulb. It is also known as a vacuum tube. Remember how big those were? The next step in reducing the size of processors came with the transistors. Those enabled shrinking computers from room-sized mainframes to cabinet-sized minicomputers. Finally, the biggest step in reducing the size of computers came with microprocessors, which use silicon to shrink the size of a processor to a grain of sand. Without those we wouldn’t have personal computers.
Speaking of PCs, those came about in the 1970s. There were some very important milestones, including:
- Xerox Alto
- Altair 8800
- Apple I
- Apple II
- IBM PC and PC Jr.
- Apple Macintosh
Finally, we covered milestones in networking. While the earliest computer networks were developed for the military, that changed after the launching of Sputnik in 1957. Networks expanded to major universities that would be instrumental in developing new technologies for winning the Space Race and also the Cold War. The result was ARPANet, a distributed network. That network would eventually become the basis for the Internet. Meanwhile, as PCs expanded in the 1980s, early adopters began building new bulletin board systems for connecting to each other. The most basic way to accomplish that was using modems over the existing telephone network. That method would be instrumental in connecting personal computers to the Internet. And while early BBS were interesting, they would pale by comparison to the World Wide Web, a concept developed by Tim Berners-Lee in 1991 at CERN. By 1993, we would have the first graphical web browser, Mosiac, which would become the basis for early web browsers, such as Netscape, and for the current Firefox.