APPENDIX A. GLOSSARY

ASCII: Abbreviation for American Standard Code for Information Interchange (pronounced "askee"). A specific binary code of 128 characters represented by 7 bit binary numbers.

ASYNCHRONOUS: The transmission of data between a transmitting and a receiving device occurs as a series of zeros and ones. For the data to be "read" correctly, the receiving device must begin reading at the proper point in the series. In asynchronous communication, this coordination is accomplished by having each character surrounded by one or more start and stop bits which designate the beginning and ending points of the information (see Synchronous).

BAUD RATE: The speed of transmission of information across a serial interface, expressed in units of bits per second. For example, 9600 baud refers to bits being transmitted (or received) from one piece of equipment to another at a rate of 9600 bits per second. Thus, a 7 bit ASCII character plus parity bit plus 1 stop bit (total 9 bits) would be transmitted in 9/9600 sec. = .94 ms or about 1000 characters/sec. When communicating via a serial interface, the baud rate settings of two pieces of equipment must match each other.

DATA POINT: A data value which is sent to Final Storage as the result of an Output Instruction. Strings of data points output at the same time make up Output Arrays.

EXECUTION INTERVAL: The time interval between initiating each execution of a given Program Table. If the Execution Interval is evenly divisible into 24 hours (86,400 seconds), the Execution Interval will be synchronized with 24 hour time, so that the table is executed at midnight and every execution interval thereafter. The table will be executed for the first time at the first occurrence of the Execution Interval after compilation. If the Execution Interval does not divide evenly into 24 hours, execution will start on the first even second after compilation. See Section OV4.3.1 for information on the choice of an Execution Interval.

EXECUTION TIME: The time required to execute an instruction or group of instructions. If the execution time of a Program Table exceeds the table's Execution Interval, the Program Table will be executed less frequently than programmed (Section OV4.3.1 and 8.9).

FINAL STORAGE: That portion of memory allocated for storing Output Arrays. Final Storage may be viewed as a ring memory, with the newest data being written over the oldest. Data in Final Storage may be displayed using the *7 Mode or sent to various peripherals (Sections 2, 3, and OV4.1).

GARBAGE: The refuse of the data communication world. When data are sent or received incorrectly (and there are numerous reasons this happens) a string of invalid, meaningless characters (garbage) results. Two common causes are: 1) a baud rate mismatch and 2) synchronous data being sent to an asynchronous device and vice versa.

HANDSHAKE, HANDSHAKING: The exchange of predetermined information between two devices to assure each that it is connected to the other. When not used as a clock line, the CLK/HS (pin 7) line in the CR10 is primarily used to detect the presence or absence of peripherals such as the Storage Module.

HIGH RESOLUTION: A high resolution data value has 5 significant digits and may range in magnitude from +.00001 to +99999. A high resolution data value requires 2 Final Storage locations (4 bytes). All Input and Intermediate Storage locations are high resolution. Output to Final Storage defaults to low resolution; high resolution output must be specified by Instruction 78.

INDEXED INPUT LOCATION: An Input location entered as an instruction parameter may be indexed by keying "C" before it is entered by keying "A"; two dashes (--) will appear at the right of the display. Within a loop (Instruction 87, Section 12), this will cause the location to be incremented with each pass through the loop. Indexing is also used with Instruction 75 to cause an Input location, which

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