# 9/5; Computer connectivity and geologic research and teaching

## How do you get information out of the computer?

What is our perception of reality? Analog...
How do we handle it in the computer? Digital... (bits and bytes)

What are these words? Look it up.

## Binary numbers and computers

How do we count? One method might be to use a single character to each object we count:
|||| is 4 sticks.
But that is a bit unwieldy when we talk about 20 sticks:
||||||||||||||||||
So we use the decimal system normally (it uses 10 characters--0-9):
1 is 1
11 is 1+10
213 is 200+10+3
Computers use the binary system which only has two characters: 0 and 1.
so each place represents twice as much as the place to its right. 1 is 1
10 is 2
11 is 3 (1+2)
111 is 7 (1+2+4)
101 is ??
1011 is 11 (1 + 2 + no 4 + 8)
101101 is ??
11111111 is 255 (1 + 2 + 4 + 8 + 16 + 32 + 64 + 128). That is the biggest 8 bit number (a byte) we can make.
Most computers that we use can handle 32 bit numbers which is the decimal equivalent of 4,294,967,295.
We can also use the binary system to represent comands and letters of the alphabet.
The reason binary notation is used in computing is that the electronics need only two types of electrical signals in different combinations to represent any number. The transistor is ideal for this because if we apply a current flow, we get a 1. Reverse the polarity, and we get a 0.

## Input and output (I/O)

All data/command input is analog to digital conversion.
All computer operations are digital.
All data/result output is digital to analog conversion.

The subject of today's exploration is to look at the different manifestations of data/command input and data/result output in computing.

### Standard I/O

Keyboard
Digitizer
Scanner
Video camera
Digital camera
Microphone

#### Input/Output connections

Serial ports (printer and modem ports on the mac)
Parallel port (old printer port on the PC)
SCSI
Infrared
Microphone jack or speaker jack
Network

Printer
Monitor
Speakers

### More interesting I/O

#### Laptops and mobile computing

If computers are useful tools, then why not get them out into the field with you to help with work that is beyond the computer lab?
Several innovations make mobile computing possible:
1) The development of decent LCD screens.
2) The development of cpus that can run cool with low power draw.
3) The development of battery technology
and for I/O
4) the PCMCIA standard. What is that?

##### The ideal field set up
Let's have a look at Lenin, the amazing Tecra 700ct, that my students and I use. The ideal set up is to have the battery powered computer and printer set up in the field and set up a ncie field office. Why not have the modem hooked to the cellular or satellite phone and transfer data??
##### Computers and teaching with multimedia
Another interesting thing that is not limited to laptops but is conveniently done with them is to make multimedia presentations. Let's take a look at the Geology Department's set up for displaying laserdisc videos in Geology classes as an example of computer I/O that is not so common, but quite useful. Schematic of the equipment

## When is a calculator a computer?

Calculators->Palm Pilot->Apple Newton-> Computer

## Buying all of the parts

Where can you get all of these tidbits to make these things work?
You can do it online at:
MicroWarehouse
Also take a trip to the new Frys at Baseline and I-10.

## Finally, where is all of this going?

Let's look at a bit of Bill Gates view of things from the multimedia CD that goes with his book: The Road Ahead, 1995, Viking Press.

## Assignment 3

Some of this lecture comes from the book How Macs Work, 1993, by John Rizzo and K. Daniel Clark, Ziff-Davis Press.

Pages maintained by
Prof. Ramón Arrowsmith