1.0 A Brief History of Computing
In 1642 Pascal invented the first mechanical adding machine. It could add and subtract. In 1832 Charles Baggage from England built the first general purpose mechanical digital computer. Ada Byron, Countess of Lovelace, suggested Baggage program his machine with punch cards like those used in weaving looms. She also wrote programs for his early computer. In 1890 an American, Herman Hollerith invented a machine that used punch cards to count the information collected in the census. He was so successful he started a company, which later became IBM. In 1944 IBM built the Mark 1, a big mechanical computer. It was 55 feet long, used 500 miles of wire and had about 1 million parts. The Mark 1 could do two additions a second.
On February 14, 1946 scientists working at the University of Pennsylvania turned on the first big, general-purpose electronic digital computer. They called it ENIAC for Electronic Numerical Integrator and Computer. ENIAC used 18,000 vacuum tubes, weighed 30 tons and filled a room the size of a school gym. It had more than 3,000 tiny light bulbs which told the operator what the machine was doing. ENIAC could not store programs. It was programmed by turning knobs and plugging and unplugging cables. ENIAC could do 100,000 additions a second when it worked.
In the 1970s integrated circuits on tiny chips brought down the size and price of computers, enabling people, rather than companies, to buy them. These small computers can do at least 100,000,000 additions a second.
1.1 Early Comments about Computing
Here are what some early experts thought about the future of computers.
1. Popular Mechanics, forecasting the relentless march of science, 1949.
"Computers in the future may weigh no more than 1.5 tons."
2. Thomas Watson, Chairman of IBM, 1943
"I think there is a world market for maybe five computers."
3. The Editor in Charge of Business Books for Prentice Hall, 1957.
"I have traveled the length and breadth of this country and talked with the best people, and I can assure you that data processing is a fad that won't last out the year."
4. Engineer at the Advanced Computing Systems Division of IBM, 1968,
commenting on the microchip.
"But what . . . is it good for?"
5. Ken Olson, President, Chairman and Founder of Digital Equipment Corp., 1977.
"There is no reason anyone would want a computer in their home."
It's supposed to be fun
It's not your fault if you're confused
You can't do it all
Make the Mac your own
A file saved is a file saved
Two, three, many backups
Murphy's Law will happen
All computers process data. These data may be pictures, numbers, words, symbols, letters, symbols or sound.
To process data, four activities must take place:
1. The data must be put into the computer by an input device. The most common input devices you will use when you begin to work with the computer are a keyboard, a mouse, and a disk. Later on you may work with other devices such as a microphone, a video camera, or an electronic pH meter.
2. The data are then stored in the memory of the computer.
3. After the data are in the memory, the data are processed according a set of instructions called a program. This occurs in the central processing unit or CPU.
4. The data are sent to an output device such as a monitor or a printer.
The following diagram illustrates the flow of data between the parts of a computer:
Hardware is the physical parts of the computer. The printers, the screen, the disk drives, the memory, the CPU or anything else you can touch. Software is the instructions or program. Some programs are built into the computer. Other programs are put into the computer by a process called loading.
These terms are often confused, and are confusing. The memory resides inside the computer on little silicon chips. There are two types of memory inside the computer. One is called ROM (Read Only Memory). This type of memory can not be changed, increased or decreased. The other type of memory is called RAM (Random Access Memory). You are most interested in RAM. The data and instructions from the program are kept in the RAM. When the computer is turned off, the data in the RAM are lost. In addition, the RAM of a computer can be increased by adding chips to the central processing unit.
If you want to keep the information that resides in the RAM, the information must be transferred to a storage device. The most common storage device you will use in this course is the 3.5 inch, Double Sided, High Density floppy disk capable of storing about 1.4 MB of information.
The other common storage device is a hard drive. Although you will not save information on the hard drive in this course, you would save information on a hard drive on your personal computer. You move information from memory to storage by a process called ÒsavingÓ.
The computer stores and manipulates data by turning things on and off. Therefore, Òon and offÓ is one piece of information to a computer. It is call a bit (BInary digiT). Eight bits make a byte. A kilobyte (KB) is about 1000 bytes (actually 210 bytes or 1064 bytes), a megabyte (MB) is about 1,000,000 bytes. The computers in the Macintosh laboratory have about 16.0 Megabytes (MB) of memory. This is enough memory to hold all of the information in about 40 medium size books. The storage devices you use most often, the floppy disks, hold about 1.4 megabyte (MB) of storage, or 1,400 kilobytes (KB) Ñ about the same amount of information in 2 medium size books. Current Hard Drives store more than a Gigabyte (GB) of information. A Gigabyte is about 1,000 Megabytes.
Some people will refer to the amount that a storage device can hold as the ÒmemoryÓ of the storage device. This practice causes confusion between memory and storage.
People write programs to tell a computer what to do. There are three types of programs. The first is called freeware. These are programs that you may copy and use without restrictions. The second type is called shareware. These are programs you may copy and use. If you find them useful, please support the person(s) who wrote the program by sending them the money or the item they request. The third type of program is commercial. These may not be copied.
You can obtain programs in several ways. The instructor may give you disks that have programs on them that you may copy. Some of the programs are freeware, others are shareware. You may also obtain freeware or shareware from some companies or user groups at a modest cost. You will use some freeware and shareware products in this course.
If you want to use a commercial program you must buy it. Many companies will let you return a program after thirty days. This policy lets you try out a program to see if it fits your needs. At CSUB you can use commercial programs in the Macintosh laboratories in two ways. First, you can access the programs from a central computer on campus that is connected to the computer you have in front of you. Second, you may check out a commercial program from the instructor or the computer center for use in the laboratory. These commercial programs have been purchased. Because computers transfer information quickly, it is easy to copy programs. However, do not copy any program unless the instructor tells you it is O.K. Use commercial programs as you would use a book from the library - that is, do not copy them for your personal use.
Some of the programs you will use are bundled together and are given the name of a disk operating system, or simply OS. These programs are needed by the computer to run correctly, and carry out basic functions. From time to time, the system is improved. The current version of the system is 7.5.3. You may work just as well with an older version of the system.
Other large programs you will use in this course include a word processing program, a spreadsheet, a drawing program, a communication program and a paint program.
