Montecino's CS 103 Course Page

Review WSftp to upload html files - essential when publishing your Web pages.
WSftp is installed in your lab classroom computers.

See these resources:
To configure WSftp to access your local drive and your mason directory.
To download WSftp [FREE for students/educators] to use on your home computer.

Computer Hardware/Software Basics
Lecture 1 - CH 1,5

von Neumann machine (input->memory<-/->processor->output ) An early computer created by Hungarian mathematician John von Neumann (1903-1957), promoted in the 1940s. It included three components used by most computers today: a CPU; a slow-to-access storage area, like a hard drive; and secondary fast-access memory (RAM ). The machine stored instructions as binary values (creating the stored program concept) and executed instructions sequentially - the processor fetched instructions one at a time and processed them. The instruction is analyzed, data is processed, the next instruction is analyzed, etc. Today "von Neumann architecture" often refers to the sequential nature of computers based on this model.


"Chips," made from silicon - a non-metallic element, are an essential part of the computer.

"Silicon" is a "semi-conductor" of electricity.

A "semi-conductor" is any of a class of crystalline solids which has electrical conductivity intermediate between a conductor and an insulator. It can be chemically treated to transmit and control an electric current.

To make a chip, silicon is grown into cylindrical crystals called "ingots." The ingots are sliced into thin "wafers" of silicon. The chip's circuits are etched onto the wafer. The wafer is packaged so that it can be plugged into a circuit board.

The important chips in a computer include the CPU

CPU - central processing unit, the brain of the computer (example: Pentium II Processor). The CPU performs a systematic series of actions when information, "input, " is put into a computer (by a person, another computer or other means of obtaining data).The CPU is divided into two main parts:

CU - control unit - contains program instructions and emits signals to carry them out.

ALU - arithmetic logic unit - performs arithmetic and logical operations on data.

back to top
Hard Disk Drive - The mechanism (drive) that reads and writes data on a hard disk.  Many disk drives improve their performance through a technique using cache, pronounced "cash." Cache is a temporary storage area , often a reserved section of the main memory, where instructions used over and over again are reserved.  The instructions and data are accessed close to the CPU's speed.

Interface Standards - There are several interface standards for passing data between a hard disk and a computer. The most common are

System unit- the "box" which houses the computer's components - power supply, storage devices, main circuit board, processor and memory chips.

Operating System basic operations :

Basic Computer Functions:
back to top
Types of computers:
back to top



data bus - data pathway on which signals are sent between system components. Data is sent back and forth between the memory, RAM,  and the microprocessor, CPU.  The address bus identifies which memory location will be used. The control bus carries the control unit's signal.

expansion bus - segment of data bus which transfers data between the RAM and peripheral devices. (fig 5-23 in text). A printed circuit board that plugs into an expansion slot and extends the computer's ability to control another type of peripheral device. All the boards (cards) that plug into a personal computer's bus are expansion boards, for example display adapters, disk controllers and sound cards.  Support for Stereo sound and VGA display may also be built into
the motherboard, eliminating the need to plug in separate expansion boards.

mhz - megahertz - one million electrical vibrations/cycles per second of instructions

pipelining - a strategy for optimizing processor speed by beginning the next operation before the last is completed

parallel processing - using multiple processors to perform a task.  Parallel processing enables the computer user to have more than one program running at the same time - ie, using a wordprocessor while a spreadsheet program is calculating data and a database is sorting data. A windows environment enables multitasking; DOS does not.

CISC - complex instruction set computer - can recognize 100 or more instructions

RISC - reduced instruction set computer - runs 50 - 75 % faster than a CISC instruction set computer. Cheaper to design, debug and manufacture because they are less complex.  The instructions used the most are emphasized for the fastest possible execution.

back to top


Motherboard -
The main printed circuit board in a computer.  It contains sockets that accept additional boards. In a personal computer, the motherboard contains the bus, CPU and coprocessor sockets, memory sockets, keyboard controller and supporting chips.

See a motherboard at: TechEncyclopedia:

Hard Disk Drive- non removable storage device - usually labelled the C drive.

Storage media- [covered more fully in  Chapter 4]
Storage drives can be removable or non-removable

Monitor- output display device - converts electrical signals into light which is displayed on the screen

Mouse - lets you manipulate icons, data on the screen.

Keyboard- input device (also voice activation technology, pointer activation - useful for handicapped persons) - function keys, shortcuts

Soundcard- not essential for basic computing, but it has become standard on PCs, along with CD-ROMs

Peripherals ( input/output devices):
  • Printer - standard for most computing operations
  • scanners
  • video / graphics card - standard
  • digital cameras, etc

back to top
clock - the computer's internal timing device. Using a quartz crystal, the CPU clock feeds the CPU continuous pulses. For example, a 100 MHz CPU receives 100 million pulses per second. A 200 MHz receives 200 million per second.  A real time clock keeps track of the time of day and provides this data to the software. A timesharing clock interrupts the CPU at regular intervals and allows the operating system to divide its time between user activities and applications.

User Interface - Needs hardware and software.  The software enables the computer to perform specific tasks (ie, Web browsing, wordprocessing, calculations, graphics creation and editing). The hardware controls the way the user can manipulate the computer to allow the software program to perform the functions the user dictates by using the keyboard, mouse,  voice to follow prompts, command the computer to perform functions.  For example, when you use a search engine you type in words at the "SEARCH" prompt.

Non graphical user interface - UNIX operating system. Lynx is a non-graphical browser created at the University of Kansas to access the Web.

GUI  (graphical user interface) - Windows - incorporates icons, pull-down menus and a mouse. Allows for multitasking - operations can be performed among various applications. Netscape has a GUI interface to access the Web.

back to top

Prompts -

"Enter your name"

Using a wizard

commands - DOS, UNIX


Dialogue boxes (for example - a print dialogue box -  how many pages, no of copies)

Graphical objects: icons, buttons - "save" icon, "home" icon in browser,Paint program tools

Manipulating onscreen objects - dragging items to the trash can or moving files, etc.

Function keys - F1 - "help" in many programs , shortcut keys CTRL-ALT-DEL
to shut down a "frozen" computer.  Holding down the SHIFT and ARROW keys at the same time will highlight text to copy or move.

back to top

Resources to learn computer applications:

Course related, GMU resources
back to top

MEMORY - ROM - read only memory, non-volatile memory (can't read and write)  - storage.  contains essential system programs that ordinarily can't be erased when the computer is shut down.

RAM - random access memory, volatile memory (Sometimes called SDRAM or DRAM - dynamic random access memory.) It is actually "direct access" memory in which the program instructions and data stored are directly accessible to the CPU - Central Processing Unit.

RAM is "read and write" memory. A portion of RAM is set aside as a temporary workspace. YOU LOSE ALL WORK IN RAM IF YOU HAVE NOT SAVED IT.  Todays computers generally have between 16 and 128 megs of RAM.

RAM cache - fast memory that stores information for DRAM - serves as a buffer between the CPU and the disk drive.

Virtual memory - (using hard disk space as an extension of RAM) - If you are running a number of software programs at the same time, which can take a lot of your memory, your computer can use space on your hard disk as an extension of RAM.  How fast your machine can run your programs depends upon how fast your processor works.

CMOS - (complimentary metal oxide semiconductor) - memory which allows the computer to store configuration/boot data so there is always a place where essential data is stored.   CMOS needs to be updated if a new hard drive is installed - more pemanent than RAM - less permanent than ROM.

port - The serial and parallel ports on a personal computer are external sockets to plug in communications lines, modems, printers, etc. to a computer via cables. The Macintosh uses the serial port to attach a printer, whereas the PC uses the parallel port.

Pixels - small dots of light that make up the images displayed on a monitor.  The higher the pixel resolution (the more rows and columns of pixels), the more information can be displayed.  The bit depth (also called color depth and pixel depth) determines the number of colors displayed at one time. Digital video requires at least 15 bits, while 24 bits produces photorealistic colors.

back to top

Color depth Number of colors
             4-bits 16
             8-bits 256
             15-bits 32,768
             16-bits 65,536
             24-bits 16,777,216
             32-bits 16,777,216

Some operating systems:

    Windows 95/98
    Mac OS

Bootstrapping - When the computer is turned on, the permanent instructions stored in ROM tell the computer how to find the disk containing the operating system. The operating system is then copied from the disk into RAM for quick access. Hardware diagnostics are run and the system may check itself for viruses.

back to top
Bootstrap process:

1. Turn the machine on - power goes to the internal fan and otherboard.  The light comes on when this process is started.

2. The CPU (microprocessor) executes the instructions stored in ROM (read only memory).  The programs stored in ROM are activated.

3. The computer performs self test - disgnostics of critical system components.
Checks graphics card -> tests RAM->checks keyboard-> tests drives.  Throughout this process on most computers you will see lights flash on keyboard and various drives.

4. The OS (operating system) is copied from a disk to RAM.  Computer locates the default drive ->

5. The CPU (microprocessor) reads configuration data and performs start up routines residing in Autoexec.bat or Windows startup group.  Customized routines can be set by the computer user - for example a virus check, a utilities program to check performance.

6. The computer is ready to accept commands from the user and let the user enter data.  The interface (Windows or other desktop configuration) appears,  from which the user can access applications.

Digital Data Representation - a computer doesn't use symbols such as the alphabet or numbers other than 1 and 0 to represent data.  A computer is a digital device chich uses various combinations of 0s and 1s.  The circuits in a digital computer only have on and off states. Number 1 represents the ON state.  The digit 0 represents the OFF state.  Each 1 or 0 = 1bit.

Bits and Bytes

Bit stands for binary digit: 0 or 1

A byte is made up of 8 bits

It takes 1 byte to store one ASCII character

ASCII stands for the American Standard Code for Information Interchange

        A       0100 0001
        B       0100 0010
        C       0100 0011

K stands for kilo and = 1024 (2 to the tenth power)

M stands for mega. A MB, megabyte is about a million bytes (1024x1024)

G stands for giga. A GB, gigabyte is about a billion bytes (1024x1024x1024)

T stands for tera. A TB, terabyte is about a trillion!

RAM is usually measured in MB

Hard disk spaces is usually measured in gigabytes

(Digital Data Representation from Dr. Marchant's lecture notes:
bits and bytes

back to top

Software -   Instructions to the computer - includes system and utility programs in computer-readable language.

Firmware - the system software permanently stored in the computers ROM (read-only memory) or elsewhere in the circuitry.  Is not modified by the user.

Applications- special purpose software

Some special purpose applications:

    Web Browser/Editor - Netscame, Internet Explorer
    FTP - file transfer protocol
    MS Word, Wordperfect  - wordprocessing
    MS Excel, Quatro Pro - spreadsheets
    MS Access - database management
    Adobe Photoshop, Paint Shop Pro, LView - Graphics creation/editing programs
    Money management - MS Money, Quicken

back to top

Montecino's CS 103 Course Page