In bisynchronous communications, a positive acknowledgment character used to indicate that a message was received correctly.
Add-on equipment you can plug into a PC to allow the PC to connect to another device.
Asynchronous data link.
Refers to data represented by a physical variable that varies in a continuous rather than discrete manner and is usually represented by an electrical signal.
American National Standards Institute, Inc. ANSI establishes standards for transmission codes and protocols.
Software that performs a specific application or task, such as word processing, accounting, or financial planning. (Contrasts with a utility or system program that is used to carry out file management and housekeeping functions.)
In SNA, VTAM communicates with many applications. The APPLID is the identifying name of a VTAM application.
American Standard Code for Information Interchange, which specifies a set of 128 graphic and control symbols and their seven-bit codes. Extended ASCII supports 255 symbols. ASCII is used by PCs and PC peripheral devices, such as printers.
A communications technique in which each character is transmitted as a discrete unit. The character transmitted is preceded by a start bit and followed by one or more stop bits. As each character is bracketed by start and stop bits, varying amounts of time can elapse between characters. Contrasts with synchronous communication. Also called start-stop communication.
(1) Parameters that describe files and printers. (2) For 3270 display, characteristics of a field or byte, such as protected or underlined.
A procedure for making a duplicate copy of data that you can use if the primary data is lost or destroyed.
A Barr software product to which options can be added. For example, BARR/RJE is a base software product to which options such as PRINT370 can be added.
A PC DOS file that contains a sequence of DOS commands. When you type the name of the batch file at the DOS prompt, DOS executes all the commands stored in the batch file as if you had typed them from the keyboard.
The number of changes in line condition per second. The term is commonly used as a measure of information transmission speed expressed in bits per second. The use of baud to mean bits per second is valid for the RS232 side of the modem.
A base 2 number system used in computer programming. The binary digits, or bits, are 0 and 1.
A low-level, data-link line protocol for synchronous communications first used by IBM. It only supports half-duplex communications.
In SNA communications, the operation in which the host and remote logical units (LUs) initiate a session and agree upon the protocol to be used within that session.
Basic Input/Output System. Program permanently stored in read-only memory (ROM) chips on your PC’s system board. It is one level below the PC operating system and controls basic hardware operations, such as interactions with disk drives, hard disk drives, and the keyboard. All PCs are shipped with BIOS.
See binary synchronous communication (BSC).
The name of an elementary unit of information that has two states. Usually the two states are called 0 and 1.
A contiguous vector of bits that is read or written as a unit. A block can include one or more records. Blocks usually have a fixed size.
The number of data elements in a block. A measure of the size of a block, usually specified in units such as records, words, or characters.
To prepare a computer for use by loading the operating system. Usually the operating system loads automatically when you power on the computer. See also bootstrap.
At startup of a computer system, the first record read from disk contains a program used to read the rest of the operating system into memory. The first record read is called the bootstrap program.
Bits per second. A unit of measure for the rate that information is transferred.
Binary synchronous communication.
An area of computer memory used for performing input or output operations. The software reads data into a buffer or writes data from a buffer.
A string of bits that, treated as a unit, represent a character. Usually eight adjacent bits represent one character.
Eighty consecutive characters of information, or one line.
Characters used to control vertical spacing of print lines.
See host computer.
A common parallel interface for printers developed by Centronics Corporation.
Color Graphics Adapter, a type of video adapter.
Direct way to connect printers to S/370 mainframes.
A single letter, digit, symbol, space, or punctuation mark.
In SNA communications, commands in character form entered by an end user. These commands, such as Logon and Logoff, must be in the syntax defined in the user’s unformatted system services definition table. Also called unformatted logon.
An electrical signal that occurs at a fixed rate that is used to control the speed of other circuits. In synchronous communications, both send and receive data have a clocking signal.
A heavily shielded and insulated carrier wire with high immunity to electrical interference and a low data error rate. Coax can carry multiple streams of data on one line. This is the same cable commonly used in the cable TV industry.
Asynchronous serial ports 1, 2, 3, and 4 on the PC.
Something you instruct the computer to do, such as run a program.
A communication control unit that manages line control and data transfer through a network. Operations are controlled by one or more programs stored and executed in the unit. Examples are the IBM 3705, 3725, and 3745 Communication Controllers.
A communications device that controls the transmission of data over lines in a network, such as transmission control units and communication controllers.
The physical connection and link protocol between the remote workstation and the host computer.
Any physical medium, such as a wire or microwave beam, used to transmit data.
A specification of data and control message formats and their meanings. This specification is followed by both the sender and receiver in a communication link.
In SNA communications, the sender sends two bytes as one byte to increase data transmission throughput. The receiver decompacts the data to the original two bytes.
Programs that convert instructions written in high-level languages to the machine language that the computer can interpret.
To increase throughput in data transmission, the sender substitutes one character for a sequence of duplicate blanks and two characters for a sequence of non-blank characters. The receiver decompresses the data to its original state.
RJE console device. See also console.
(1) A specific combination of hardware that forms a system. for PCs, the term configuration describes characteristics such as the type of monitor adapter, the number and description of printers, the amount of memory, and a description of serial ports. (2) A specific combination of software options used to set up an application program.
The device used to control the operation of a computer, including a keyboard and display or printers.
Any character used to facilitate transmission of data between the PC and the host.
See communication control unit.
Central processing unit. The part of a computer system that controls the interpretation and execution of instructions, input and output units, and auxiliary attachments. It consists of a control unit and an arithmetic logic unit (ALU).
Cyclical redundancy check. A form of error correction that catches all one-, two-, and three-bit errors in a sequence.
The directory where you start BARR/RJE, or the directory you change to when you hot key to DOS after BARR/RJE starts.
A representation of facts, concepts, or instructions in a formalized manner suitable for communication, interpretation, or processing by human or automatic means.
A control block used by access method routines to store and retrieve data.
Communication rules for the orderly exchange of information between two nodes on a data link. The lowest level protocol of SNA and BSC.
An interface that originated with the Dataproducts Corporation used for driving high-speed printers and typesetting equipment.
Direct Access Vertical Forms Unit. A control sequence of characters used to define a vertical print form. The DAVFU convention was first established by Dataproducts Corporation.
Same as a non-switched line. A connection between systems or devices that does not have to be made by dialing.
The reverse operation of modulate. Transforming an analog signal into the digital information it represents. See also modem.
An input and output unit connected to the computer, such as a printer, plotter, or monitor.
A number that uniquely identifies a device.
A software program that controls a specific device, such as a printer or a network connection. Drivers load into memory and stay active while the computer does other work.
A program to detect and isolate errors in programs and faults in equipment.
A telephone line connected to the switched telephone network where the destination is selected by dialing a multi-digit number. Also called a switched line or a dial line. Opposite of leased line or dedicated line.
Terminate a physical connection.
A flexible magnetic-coated mylar disk used to record information. Synonymous with flexible disk or floppy disk.
A TV-like device used to display information.
Direct memory access. A technique for moving data directly between main storage and peripheral equipment without requiring the processing unit to process the data.
Disk operating system. An operating system for computers that uses disks to store programs and data.
See VSE/POWER.
See device driver.
Extended Binary-Coded Decimal Interchange Code, which specifies a set of 256 graphic and control symbols and their eight-bit codes. EBCDIC is used by mainframes and mainframe peripheral devices, such as printers. It was first used with the IBM System/360.
Enhanced Graphics Adapter, a type of video adapter.
Extended Industry Standard Architecture. A 32-bit extension of the 8- and 16-bit internal bus structure developed by IBM. Developed by Compaq Computer Corp. and other PC manufacturers.
Systematic alteration of data that prevents unauthorized persons from viewing and using the data.
A LAN physical standard that allows multiple stations to access the transmission medium.
In a file name, one to three characters that follow the period (for example, STUDY5.JOB).
Forms Control Buffer. A buffer for controlling the vertical format of printed output.
Forms Control Buffer Load. A record sent from a host to a remote to specify vertical forms control.
Federal Communications Commission.
Used to mark the end of a file.
Transfer of files between two computer systems.
In SNA communications, an eight-bit character used to introduce and end SDLC transmission frames. It is coded in binary as 01111110.
Mechanism to control the rate that data is sent to devices (such as printers) so that data is not sent faster than it can be accepted. See also pacing and virtual route pacing.
In SNA communications, a logon message coded into fields, including the remote name, password, LOGMODE table, and APPLID.
In SNA communications, a consecutive string of bits sent as a unit. The frame begins with a flag followed by an address and control byte, data, and Cyclical Redundancy Check (CRC), and ends with a flag.
A processor that relieves the host computer of certain processing tasks, such as line control, message handling, code conversion, and error control. Examples include the 3725 and 3745.
File Transfer Protocol. In TCP/IP, an application protocol used to transfer files to and from host computers. FTP requires a user ID and perhaps a password to allow access to files on a remote host system. FTP assumes that TCP is the underlying protocol.
A communications link that allows for the simultaneous transmission of data in both directions (in contrast to half duplex).
The 40 key combinations — F1 to F10, SHIFT+F1 to F10, CTRL+F1 to F10, and ALT+F1 to F10 — on the left or top of the keyboard.
A device that uses protocol conversion to connect dissimilar communications systems. For example, BARR/RJE serves as a gateway between a LAN and a mainframe. (In contrast, a bridge connects systems or networks with similar architectures.)
Symbols represented by a picture (in contrast to symbols with an alphabetic name such as carriage return).
A communications link that allows for transmission of data in only one direction at a time (in contrast to full duplex).
The physical or hard components in a computer system, such as a processor, memory, display, and printer. (Contrasts with the soft information components that include programs and data processed by the computer.)
A small device used for software protection that plugs into the computer’s parallel port. You can attach a printer cable to the other end of the key. The key comes with the BARR/RJE 802.2 software.
Houston Automatic Spooling Priority system. A popular enhancement to the IBM operating system that was used for many years as a job entry system for local readers and printers as well as RJE terminals.
See spool header.
A base 16 number system that uses the digits 0 to 9 and letters A to F.
A large computer that controls the communications network, stores databases, and has a large computing and memory capacity. Other computers can connect to the host to share its resources.
International Business Machines Corporation.
International Business Machines Personal Computer.
In SNA communications, identification data used for dial-up devices. See also Xid.
Information that is read into a computer.
Installation program for entering BARR/RJE configuration options.
The connection between any two hardware or software components in a system.
Mechanism used to stop a program for an event needing immediate attention.
Input/Output. Represents data transfer between a computer and peripheral equipment.
See Novell IPX.
Interrupt request. A request for processing on a particular priority level.
Industry Standard Architecture, a standard for the PC’s expansion bus (where you plug in add-on adapters). The IBM AT bus became a 16-bit ISA bus.
Job Control Language. A language interpreted by the operating system.
Job entry subsystems of the IBM MVS operating system. These subsystems are used for entering jobs into the MVS operating system and dispensing the output from the jobs. JES2 and JES3 are replacements for the HASP II program that was used for this same purpose.
An independent unit of work that is processed by the host operating system. A job consists of JCL statements, programming language statements, and data to be processed. The output of a job includes printed output and updates to files on disk or tape.
Kilobyte.
See hardware key.
A unit of computer memory that is 1,024 bytes. Each byte is eight bits long. 1,024 in decimal notation is the same as 10000000000 in binary notation. In computer literature, the kilo prefix means "times 1,024."
See local area network.
A language consists of a set of symbols, the rules that define which sequences of symbols are syntactically correct, and the meanings attached to various parts of the language. Examples of computer languages include FORTRAN, C, COBOL, and ALGOL.
Local Area Transport, an early networking protocol used by DEC. (DECNET is the newer protocol.)
A communications link provided by the telephone company that is dedicated for use by one customer. It is also called a private line service and can be a privately owned cable between two points.
Connection between one computing unit and another computing unit, such as a host computer and a remote terminal. In this manual, line usually refers to a line coming out of a communications controller that is connected to a modem by an RS232 cable.
The number of binary digits that can be sent over a communication line in one second. Line speed is usually expressed in bits per second (bps).
A recording of the frames sent and received on a communication line that is useful for diagnosing communications problems.
A high-speed communications network within a limited geographic area. Typically, several PCs are linked together within a single building or campus. (In contrast, a wide area network might span hundreds or thousands of miles.)
Directly connected to the mainframe without use of a telecommunication line.
In SNA communications, an independent stream of data that is multiplexed with other streams within a physical unit.
In SNA communications, a list of parameters specifying the type of session to establish between a mainframe application and a remote workstation. VTAM uses the LOGMODE during the Bind operation.
In SNA communications, to terminate a session.
In SNA communications, to initiate a session or to initiate a session between an application program and a logical unit.
In SNA communications, a logical unit sends a message in response to the logon. The entire logon sequence or message is called the logon data.
A testing procedure in which transmitted data is returned as received data.
Line printer daemon. The remote printer server that allows other hosts to print on a printer local to your host.
Line printer request.
PC parallel ports 1, 2, and 3.
Logical record length.
See logical unit.
An instruction in a source language that points to a sequence of instructions in the same language to replace it. The macro can also specify values for parameters in the replacement instructions.
Term used for a large central computer that offers a full set of computing services. The term originated in the days when the central processor, memory, and input/output channels were located in one central housing called the mainframe.
Megabit.
Megabyte.
One million bits (more accurately, 1,048,576 bits).
One million bytes (more accurately, 1,048,576 bytes).
The longest unit of information transmitted as a consecutive series of bits. In asynchronous communication, a message is a single character. In synchronous communication, a message is a block of characters preceded by some sync characters and terminated by an end-of-block marker.
See multiple logical unit RJE.
In SNA communications, the macro that defines the LOGMODE table.
Modulate/Demodulate. A device designed to interface between a digital communication link and an analog communication link. Usually the digital communication link is a computer or terminal and the analog communication link is a telephone line. Modulate means convert a digital signal from the computer into an analog signal capable of being transmitted by the telephone system. Demodulate is the opposite of modulate.
In SNA communications, a table of LOGMODE definitions.
See multipoint line.
In HASP communications, a BSC communications protocol that allows one communications link to send data in both directions at the same time. In each direction, multiple streams of data can flow to several printers or disk files.
The most sophisticated RJE protocol supported by SNA communications. It enables several logical units to simultaneously send and receive multiple streams of data.
See multiple logical unit RJE.
To concentrate multiple streams of data on one medium.
In SNA and 3780 communications, a line that has more than one physical unit communication with the host computer. These physical units share the line, but only one unit sends on the line at a time. Also called multidrop line.
A centrally located unit to which token ring nodes are connected. The MAU repairs the ring by removing non-functioning nodes from the ring, and thus maintains the integrity of the ring even if there is a malfunction.
Multiple Virtual Storage operating system. A large IBM operating system that operates on System/370, 3081, and 3091 processors.
In bisynchronous communications, a Negative Acknowledgment character used to indicate a problem with receiving a message.
In SNA communications, a program that controls the operation of a communication controller. It is generated by the user from a library of IBM-supplied modules.
Network Basic Input/Output System is a standard interface between PC software and LAN adapters such as token ring, Ethernet, or Arcnet adapters.
An arrangement of nodes and connecting branches for information interchange.
In bisynchronous communications, an obsolete standard that does not allow transmission of all 256 characters.
See dedicated line. (Contrasts with switched or leased line.)
Novell Internet Packet Exchange comes with the Novell LAN. Novell has implemented IPX for most LAN adapters, including Ethernet, Arcnet, and token ring.
In SNA communications, a method of coding data transmission so that the sender changes the signal for a binary 0 to the opposite state and leaves the signal for binary 1 in the same state. Also known as invert on zero coding.
Device that deletes output.
Disconnected from the system. Processing that is performed in isolation.
Connected to the system. Processing that is performed during direct communications between a workstation and a host computer.
A JES2 command used to modify a command or identify the job or system facility to act upon.
A master program that manages the resources of the computer. The operating system provides a set of services to all programs for input/output, data management, program loading, memory allocation, and communication facilities for job entry and output dispatching.
Commands sent to the host computer.
See operating system.
Data produced by a computer program.
In SNA communications, a method to control the flow of data from VTAM to the remote.
A device interface to the computer that reads and writes groups of bits at the same time. A common way to connect printers to the PC.
A variable that is given a constant value for a specified application.
A bit appended to a group of binary digits to ensure that the sum of bits is either even or odd. Serves as an error-detection scheme for data communications.
Personal computer or microcomputer.
Pulse Code Modulation code. A coding scheme used for digital transmission of telephone calls. The analog telephone signal is sampled 8,000 times a second. For each sample an eight-bit code is constructed. This digital code is sent within the telephone system. The eight-bit code is converted back to the analog signal prior to being put on the local telephone line.
FTP Software, Inc.’s kernel that interfaces between Barr software and the TCP/IP network.
Equipment attached to the computer that is controlled by the computer or serves as memory or a source of information. Examples of peripheral devices include disk drives, printers, and communications devices such as modems.
In SNA communications, an independent unit attached to an SDLC line.
One of the conducting contacts of an electrical connector.
Output from the host to be written to a graphics plotter device.
A PC connector for attaching peripheral devices to PCs.
RJE printer 1.
Data used to specify the operating mode of the printer.
Commands sent to the host to manage printing special forms.
A list of items waiting to print.
A program or processor attached to a LAN that manages file printing.
Managing a queue of files to be printed on one or more printers.
A disk used in daily PC operation.
A set of instructions that gives step-by-step details for performing a task. Computer instructions can be written in a high-level language like FORTRAN, BASIC, or PASCAL. Instructions in a form directly usable by the computer are called machine language instructions.
See communications protocol.
Translation between two computer protocols (such as ADLC and SDLC) so that two dissimilar systems can communicate.
See physical unit.
RJE punch device 1. Typically, data received on the punch is processed rather than printed.
Output from the host computer that consists of a file of lines up to 80 characters long.
A list of items waiting for service in a system.
RJE reader device 1.
A logical device that reads jobs from the RJE workstation and sends them to the host system. At the host, jobs are placed in a job queue for processing.
To obtain data from a communications line (in contrast to send).
Options that control the format of files that are received.
Record format. The definition of how data is structured in the records contained in a file. The definition includes record name, field names, and field descriptions such as length and data type. Record formats can be fixed length, variable length, or unspecified length.
A logical grouping of data, such as all information relating to a particular account.
A terminal attached via a communications link to a mainframe computer.
To connect equipment to the mainframe via a telecommunication line.
Remote Job Entry. A computing environment in which you can create programs and data offline on the PC, transmit them to the mainframe, receive the printouts at high speed on disk or printers, and control the status of jobs with remote operator commands.
Refers to EIA Standard RS232C for connecting data communication equipment (DCE) to data terminal equipment (DTE), including connecting terminals and computers to modems. Many computer peripheral devices also use this interface for connecting to the computers. See also serial interface port.
Remote Spooling Communications Subsystem of the IBM VM operating system. RSCS is a remote job entry system that is compatible with BARR/HASP.
Request-To-Send signal.
IBM mainframe machine architecture. See also channel attached.
Synchronous Data Link Control is a low-level communications protocol for synchronous communications. It is defined for both full-duplex and half-duplex operation. SNA uses SDLC as its low-level communications protocol.
Data describing an I/O error.
Interface ports that send and receive data one bit at a time using the RS232 standard.
Files read from a serial port (COM1 to COM4) and sent to the host. These files can be printed, sent to the host, or routed on the LAN.
(1) SNA communications between two logical units that start with a logon and end with a logoff. (2) A BARR/RJE screen dedicated to a particular activity.
Systems Network Architecture. A description of the IBM communications network, a multilayered communications environment that usually uses SDLC as its lowest level communications protocol. The description includes the logical structure, formats, protocols, and operational sequences for transmitting units through and controlling the configuration and operation of networks.
The programmable instructions for operating the physical machinery of a computer system, such as programs, databases, and files. (Contrasts with hardware components such as the processor, printer, and disk drive.)
See disk.
Start-of-header, a character in the binary synchronous communications protocol.
The directory where files are queued while they wait for printing or routing from the Barr print spool.
Data at the start of a file that describes the file and how the file is to be printed.
Simultaneous Peripheral Operations Online. Spooling denotes a system that allows several independent flows of data to proceed concurrently. For example, files can be sent from disk to the host computer while other files are being printed. See also print spooling.
See System Services Control Point.
A set of rules established by an industry or governmental organization. Usually implies an extensive review process.
See dial-up line.
Character sent before a bisynchronous communications protocol message or block.
Communications adapter that allows connection to a synchronous modem.
Mode of communication in which blocks of characters are sent as a unit without start and stop bits for each character. Unlike asynchronous communication, the timing for data is obtained from the carrier signal and is not a function of the time-from-the-start bit.
In SNA communications, a focal point within an SNA network for managing session services for end users of the network. SSCP includes configuring, coordinating network operator and problem determination requests, and providing directory support.
A character that causes the printer to advance to a tab stop.
Transmission Control Protocol/Internet Protocol. A suite of protocols designed to allow communication between networks regardless of the technologies implemented in each network.
The end of a communication line. A simple terminal is a keyboard and a TV-like display. More powerful terminals include disk storage, a computer, printers, and plotters.
An elapsed time period without a transmission or other expected event occurring.
An interface adapter installed in the 3745 or 3725 to connect to a token ring network.
High-speed communication network that consists of physical equipment and architecture. This is the IBM architecture for LANs. The network is characterized by ring structure with a single token continuously circling the ring.
See line trace.
Process of converting from one coding convention to another.
To send data from one place to another for reception.
A variation of binary synchronous communication that allows transmission of all 256 characters.
Terminate and Stay Resident.
Transmission in the reverse direction, that is, reversal from send to receive or from receive to send. This usually refers to a half-duplex communication channel.
Universal Character Set. Some printers (such as the IBM 3203 and 3211) require that you load a UCS buffer to match the print train or band installed.
An operating system for workstations developed by Bell Laboratories that features multiprogramming in a multi-user environment. It was originally developed for minicomputers but can now be used on mainframes and microcomputers.
Unformatted System Services Definition Table. A mainframe system table that defines character-coded commands.
A super-minicomputer made by Digital Equipment Corporation.
Specification for spacing of lines on print form.
Video Graphics Array, a type of video adapter.
In SNA communications, pacing used to control data flow of the application and VTAM.
IBM’s Virtual Machine operating system. A popular operating system for interactive computing. It creates a computing environment in which users appear to have their own IBM 370 computer.
Virtual Machine/Remote Spooling Communications System.
An S/370 operating system program that simultaneously operates many readers, printers, and remote communications devices.
Virtual Telecommunications Access Method. An IBM operating system program that resides on the mainframe controlling SNA communications between the mainframe applications software and remote terminals.
No glossary entries.
An International Telegraph and Telephone Consultative Committee (CCITT) recommendation for a general-purpose interface between data terminal equipment and data circuit-terminating equipment for synchronous operations on a public data network.
An International Telegraph and Telephone Consultative Committee (CCITT) recommendation for a general-purpose interface between data terminal equipment and packet-switched networks.
In SNA communications, an SDLC command and response passed between a host and remote that provides initial identification of the remote to the host. Contains IDNUM and IDBLK data.
A control character used to restore (XON) or suspend (XOFF) the flow of data.
Xerox Printer Access Facility.
No glossary entries.
No glossary entries.