NEETS MODULE 22 - DIGITAL COMPUTING

DISK DRIVE—

A direct-access storage device for recording and retrieving data on hard (rigid) disk or floppy disks (diskettes).

BYTE

A group of bits next to each other that is considered a unit; for example an 8-bit byte.

ADA

A high-level programming language designed by the Department of Defense.

COBOL (COmmon Business Oriented Language)

A high-level programming language designed for business-type applications.

BASIC (Beginners All Purpose Symbolic Instruction Code)

A high-level, general-purpose programming language primarily used on microcomputers. See NAVEDTRA 10079, Introduction to Programming in BASIC.

ASSEMBLY LANGUAGE

A low-level, machine-oriented programming language in which each instruction (written as a mnemonic) translates into a single machine language (computer) instruction.

DISKETTE—

A mass storage device in which information is stored on one or both sides of a flexible disk that can be magnetized. The diskette is rotated by a diskette drive and information is stored and retrieved by one or more magnetically sensitive read/write heads. Diskettes are also called floppy disks because the disk bends easily.

DISK PACK—

A mass storage device in which information is stored on one or both sides of a rigid disk that can be magnetized. The disk is rotated by a disk drive and information is stored and retrieved by one or more magnetically sensitive read/write heads.

BUG

A mistake in a program.

COMPILER

A program that translates source programs written in a high-level programming language (for example COBOL or FORTRAN) into machine language.

COMPUTER

A programmable electronic device that can store, retrieve, and process data.

CHIP

A small piece of silicon impregnated with impurities in such a way as to form transistors, diodes, and resistors. Electrical paths are formed on the silicon by depositing thin layers of aluminum or gold.

What is the most common method to ensure that any stored data lost can be recovered?

Backup files.

What type of applications were most third generation computer systems designed to accomplish?

Both scientific and business data processing applications.

DEBUGGING—

The process of finding errors (bugs) in a program or system and correcting them so that the program or system runs correctly.

In the SNAP II system, how are the different levels of entry defined?

Dependent on a work center's need.

In a digital computer, what does the number of decimal places in the constant depend on?

Design of the computer processing unit.

What can exposure to a magnetic field do to the data on a disk?

Destroy some or all of it.

The work center supervisor can update what items from a user terminal?

COSAL, APL, EIC, SHIP'S FORCE WORK LIST, and CSMP.

When an operating system prompt (A>) is displayed on the screen, what do you enter from the keyboard to load an application program?

The program name.

ALPHAMERIC (ALPHANUMERIC) CHARACTER SET

The set of characters that includes letters, numbers, and special characters.

DATA, REFERENCE—

The source document identification.

DATA REPRESENTATION—

The symbols and codes used by computers to represent letters, numbers, and special characters.

CUSTOM SOFTWARE—

Programs designed and written to the specifications of a user or an organization.

COMPATIBLE SOFTWARE

Programs that can be run on more than one type of computer. These programs come in several different versions so they can be run under several different operating systems.

What does the acronym ROM stand for?

Read-only memory.

APPLICATION (PROGRAMS) SOFTWARE

Programs written to solve user problems.

What does the acronym S-N-A-P stand for?

Shipboard Non-tactical ADP Program.

What does each generation of computer systems indicate?

Significant change in computer design.

CONSOLE

The unit of the computer used by the computer operator to communicate with and control the computer system.

What were computers of the first generation characterized by?

The vacuum tube.

How did vacuum tubes cause a problem for first generation computers?

They were unreliable, required a lot of power to run, and produced so much heat that air conditioning was needed to protect computer parts.

A constant represented by a voltage can be read to what decimal place?

Third.

In first generation computers, internal processing functions were measured by what division of time?

Thousandths of a second (millisecond).

How many systems dealing with accounting applications have been widely accepted?

Six.

What term is used for programs such as assemblers, compilers, and operating systems?

Software.

A computer that is designed to perform a specific operation and usually satisfies the needs of a particular type of problem, is said to be what type of computer?

Special-purpose.

All analog computers are what type of computers?

Special-purpose.

In a general-purpose computer, the ability to perform a wide variety of operations is achieved at the expense of what capabilities?

Speed and efficiency.

BOOT OR BOOTSTRAP

(1) A set of instructions that causes additional instructions to be loaded until the complete computer program is in storage. (2) A technique or device designed to bring itself into a desired state by means of its own action; e.g., a machine routine whose first few instructions are sufficient to bring the rest of itself into the computer from an input device. (3) That part of a computer program used to establish another version of the computer program.

What is the temperature range within which a disk will operate?

10 to 50 degrees Celsius or 50 to 120 degrees Fahrenheit.

ASSEMBLER

A computer program that translates source programs written in assembly language into machine language (object) programs.

DIGITAL COMPUTER—

A computer that solves problems on discrete data using 0's and 1's (OFF and ON states) to represent data and operations.

ANALOG COMPUTER

A computer that solves problems using continuous data from physical quantities like voltage or temperature.

BACKUP FILE

A copy of a program or data file to be used in the event something happens to the original.

AUTOMATIC DATA PROCESSING (ADP)

A general term used to define a system for automatically performing a series of data processing functions by means of machines using mechanical, electromechanical, and electronic circuitry.

COMPUTER PROGRAMMER

A person who designs, writes, tests, debugs, and documents programs.

CURSOR

A pointer (a dot of light) on a crt screen to let you know the next position in which data will be entered. By depressing cursor control keys, the operator can move the cursor from line to line and from character to character.

ASCII (American Standard Code for Information Interchange)

A standardized 8-bit code (originally a 7-bit code) designed for transmitting and processing data.

DIRECT ACCESS—

A storage method that allows the computer to locate and read a particular record without having to search through an entire file. The computer is able to access data independent of its location. Magnetic disks, diskettes, and drums are considered direct access devices.

DATA BASE—

A structured collection of data that can be extracted, organized, and manipulated by a program.

BAUD

A unit for measuring data transmission speed. For practical purposes, it is now used interchangeably with bits per second as the unit of measure of data flow.

BIT

An abbreviation for binary digit; the smallest unit of data, either a 0 or 1.

Mechanical computers are considered to be of what type?

Analog.

Digital computers are generally used for what purposes?

Business and scientific data processing.

How is a general-purpose computer able to perform different operations?

By storing different programs in its internal storage.

How is the accuracy of an analog computer restricted?

By the accuracy with which physical quantities can be sensed and displayed.

How were processing speed and reliability increased in second generation computers?

By the use of small, long lasting transistors.

What are analog computers designed to measure?

Continuous electrical or physical conditions.

What is the great advantage of computers over typewriters?

Correcting errors.

What is the fundamental difference between analog and digital computers?

Digital computers deal with discrete quantities, while analog computers deal with continuous physical variables.

How do electromechanical computers differ from the mechanical computers?

Electromechanical computers use electrical components to perform some of the calculations.

DATA—

Facts represented by numbers, letters, or symbols to which meaning is or can be assigned.

On third generation computers, what results are gained by faster internal processing speeds?

Faster execution of instructions.

What do the smaller circuits in third generation computers allow for?

Faster internal processing speeds.

How are word processing programs used by the Navy?

For manuscript writing, memorandum writing, identification-card application filing, and recordkeeping.

You will most likely be working with what type of computer?

General-purpose digital computer.

Technological advancement is measured by what, in the electronic computer world?

Generations.

The Navy uses analog computers primarily for what purpose?

Gun fire control.

What will be one of the future challenges involving computer power?

How to properly and effectively use the computing power available.

What are computers called that combine the functions of both analog and digital computers?

Hybrid computers.

In electronic computers, vacuum tubes were replaced by transistors and transistors have been replaced by what device?

Integrated circuits.

Other than disk, what is another media used for backup files?

Magnetic tape.

Rather than using a stored program, a special-purpose computer's applicability to a particular problem is a function of what?

Its design.

What is a drawback to the special-purpose computer?

Lack of versatility.

Early analog computers were what type of devices?

Mechanical or electromechanical.

What type of computers are small and inexpensive yet provide a lot of computing power?

Microcomputers and minicomputers.

If disks are stored horizontally, how many can be stacked?

No more than ten.

DATA ELEMENT—

One item of information; the smallest unit of data that can be referenced.

BLOCKED RECORDS

One or more logical records grouped and treated as a unit (physical record or block) for input/output processing.

CHARACTER

One symbol; for example, A, Z, a, z, 0, 1, 9, !, ".

What does user friendly mean in computer terms?

Operating instructions are written in everyday English.

What is a central set of programs called that manages the execution of other programs and performs common functions like read, write, and print?

Operating system.

The data cell had a storage capacity of how many characters?

Over 100 million.

With improvements in software, what kind of computer languages could be used on second generation computers?

Symbolic machine languages or assembly languages.

CRT (Cathode-Ray Tube)

TERMINAL—A computer terminal that displays its output on a television like screen that may be black and white or color.

How are computers classified?

Technology (mechanical, electromechanical, electronic), purpose (special or general), type of data they handle (analog or digital), cost, physical size (handheld to room size).

ACCESS TIME

The amount of time between the time a request for data from a storage device is made and the time the data is delivered.

ARTIFICIAL INTELLIGENCE

The capability of a machine to perform human-like intelligence functions, such as learning, adapting, reasoning, and self-correction.

When you see the error message NO SYSTEM, what does it mean?

The computer is reading a properly inserted floppy disk, but it does not have an operating system on it.

COMPUTER SYSTEM

The cpu (mainframe) with its console, input, and output devices, and secondary (auxiliary) storage devices. COMPUTER USERS—See users.

DATA COMMUNICATIONS—

The means by which data is transmitted electronically from one location to another over a communications channel.

DENSITY, RECORDING—

The number of bits, bytes, characters, or frames per linear inch on a recording medium, like tape or disk.

BLOCKING FACTOR

The number of records stored in a record block.

The accuracy of a digital computer is governed by what factor?

The number of significant figures carried in the computations.

CENTRAL PROCESSING UNIT (cpu)

The part of the computer hardware that directs the sequence of operations, interprets the coded instructions, performs arithmetic and logical operations, and initiates the proper commands to the computer circuits for execution. It controls the computer operation as directed by the program it is executing.

ARITHMETIC-LOGIC UNIT

The part of the cpu that contains the logic capability and performs all the arithmetic functions (addition, subtraction, multiplication, and division).

CONTROL SECTION

The part of the cpu that directs the flow of operations and data, maintains order in the computer, and initiates execution of the instructions.

AUXILIARY EQUIPMENT

The peripheral equipment or devices that may or may not be in direct communication with the central processing unit of a computer.

COMPUTER OPERATOR

The person who sets up and operates the computer system.

What is the function of a built-in program called a bootstrap loader?

To load an external operating system into the computer's internal memory.

A general-purpose computer is designed for what purpose?

To perform a wide variety of functions and operations.

For what purposes is the SNAP II system designed?

To support shipboard and intermediate level maintenance, supply, financial, and administrative functions.

BINARY

Two values (0 or 1) or states (ON or OFF); the number system used in computers.

What does a password prevent?

Unauthorized entry into the main computer's program.

At present what type of classified use is allowed for SNAP II?

Unclassified.

The software (computer program) used on first generation computers was what type?

Unsophisticated and machine oriented.

The most common method of creating a backup for a microcomputer is what?

Use a floppy disk and the diskcopy procedure.

In second generation computers, how was the storage capacity greatly increased?

With the introduction of magnetic disk storage and the use of core for main storage.

What is one of the more widespread uses of the computer?

Word processing.