gtpd3m0hLibrary Guide with Master Index and Glossary

E

EAT
ECB activation table.

EBCDIC
Extended binary-coded decimal interchange code.

ECB
Entry control block.

ECB activation table (EAT)
The structure used by the E-type loader that keeps track of how many ECBs exist for each activation number.

ECB-controlled program
(1) A program that requires an entry control block (ECB) for processing. It must be assigned a name; the BEGIN and FINIS macros must be the first and last source code statements, respectively. (2) A TPF program that is associated with the entry control block that it requires for execution. (Also known as an E-type program.)

ECB control table
The entry control block (ECB) control table keeps track of which ECBs are in use and the system virtual memory (SVM) address of each ECB.

ECB data levels
One of 16 pairs of data fields used by the ECB for I/O or main storage block manipulation.

ECB origin
An identifier that is used with selective activate user exits that allows you to limit the use of an E-type loader (ELDR) loadset. This identifier can be a terminal address, communication line number, port number, user ID, network control program (NCP), adjacent link station (ALS), NCP name, and others.

ECB private area (EPA)
A segment of an address space that is allocated for the exclusive use of an ECB and its application set.

ECB register
The hardware register that contains the address of the ECB for an entry. By convention, the ECB register is register 9.

ECB virtual address (EVA)
A location inside the virtual memory of an ECB.

ECB virtual memory (EVM)
An address space that provides the only view of storage available to ECB-controlled programs. Each ECB runs in its own address space and has its own ECB virtual memory. Control program code may run in the EVM when acting for the ECB. (For example, enter/back is control program code that runs in the address space of the ECB.)

ECR
E-type loader control record.

ECT
ECB control table.

effective group ID
The group ID associated with the last setgid or setegid function. This is the group ID that is used to verify access permissions.

effective user ID
The user ID associated with the last setuid or seteuid function. This is the user ID that is used to verify access permissions.

electronic mail (e-mail)
See e-mail.

element
(1) In TPF collection support (TPFCS), a subunit of a persistent collection. An element can consist of any data type, including binary strings and references to TPF files and other persistent collections. (2) A data object in an array. (3) In Extensible Markup Language (XML) an opening tag, a closing tag, and the contents between the two in an XML document. In the following example, there are three elements: name, first, and last:

<name>
    <first>Mickey</first> 
    <last>Mouse</last>
</name> 	

element equality
A state in which two elements are equal in length and equal in bit sequence for an entire collection.

ELF
Executable and linking format.

else clause
The part of a C-language if statement that contains the word else followed by a statement. The else clause provides an action that is executed when the if condition evaluates to zero (false).

ELT
E-type loader record table.

e-mail Correspondence in the form of messages transmitted between user terminals or workstations over a computer network.
The generation, transmission, and display of correspondence and documents by electronic means. (A)
See Internet mail.

empty directory
A directory that contains, exclusively, directory entries for dot (.) and dot-dot (..).

empty string
A character array whose first element is a null character. (POSIX.1)

EMR
E-type loader master record.

emulator program (EP)
A program that permits 37x5 transmission control unit hardware to run as a 270x transmission control unit.

end-of-message-complete (EOM)
The message delimiter that indicates that the last or only segment of data in a message has been received or sent. Synonymous with EOC (end-of-message-complete).

end-of-message-incomplete (EOI)
The message delimiter that indicates that the message segment currently being sent or received is not the last.

end-of-message/pushbutton (EOP)
The message delimiter, sent from special terminals that have this end-of-message function key, that indicates that the message is complete.

end-of-unsolicited message (EOU)
The message delimiter that indicates that the last character of an unsolicited message has been received or sent.

enter/back macros
Macros used to transfer control to other ECB-controlled programs.

enterprise name
The user-specified name of an enterprise or operations center that forms the first part of the system ID.

entry
The term used to refer to the ECB created for each input message and all the processing required by that message. Entries can also be created by programs using create-type macros.

entry control block (ECB)
A control block assigned to each input message/entry. It defines all resources allocated to process that entry and allows programs to be reentrant.

entry life
The amount of time an entry exists, measured from when the entry is made until its ECB is deleted.

entry point (EP)
In TCP/IP offload support, a program entered by TPF CLAW system services when an asynchronous (unsolicited) event is generated by a CLAW workstation.

enumeration constant
An identifier (that has an associated integer value) defined in an enumerator. You can use an enumeration constant anywhere an integer constant is allowed.

enumeration data type
A type that represents integers and a set of enumeration constants. Each enumeration constant has an associated integer value.

enumeration tag
The identifier that names an enumeration data type.

enumerator
An enumeration constant and its associated value.

Environmental Record Editing and Printing (EREP) program
A program that makes the data (such as machine checks) contained in a system recorder file available for further analysis.

environment block
In TPF collection support (TPFCS), a temporary block that is created and returned by the TO2_createEnv C function. A pointer to this block must be passed on every TPF collection support function call. The environment block specifies which data store and application to use to access collections.

EOC
End-of-message-complete. Synonym for EOM (end-of-message-complete).

EOCF/2
Extended Operations Console Facility/2.

EOI
End-of-message-incomplete.

EOM
End-of-message-complete.

EOP
End-of-message/pushbutton.

EOU
End-of-unsolicited message.

EP
Emulator program. Entry point.

EPA
ECB private area.

EPD
E-type loader program directory.

epilog
The code that gets executed each time a return from a function is processed. The epilog deallocates the storage allocated by the prolog, restores the calling program's registers, and returns to the calling function.

equate macros
Declarative macros that assign values to system parameters during the assembly process.

ERA
Error recovery action.

ERD
E-type loader rules database.

EREP
Environmental Error Record Editing and Printing.

error monitor mode
The condition that causes all errors that occur on a terminal interchange to be logged as they occur.

error recovery action (ERA) code
A code returned by a tape control unit describing the recommended error recovery action.

escape sequence
A representation of a character. An escape sequence contains the \ symbol followed by one of the characters: a, b, f, n, r, t, v, ', ", \, or followed by one to three octal digits.

E-type loader
A program that loads E-type programs to the online system. It consists of an online and offline portion. Unlike the general file loader and the auxiliary loader, once you have loaded programs with the E-type loader, you can begin using the newly loaded programs without a re-IPL of the TPF system.

E-type loader control record (ECR)
A processor-unique record containing the active loadsets for a processor.

E-type loader master record (EMR)
A structure that is a type of work list used to serialize and keep track of E-type loader operations. The EMR is also used as a communication vehicle between processors.

E-type loader program directory (EPD)
A structure used by the E-type loader that contains information about each program in a particular loadset.

E-type loader record table (ELT)
A structure that contains the ordinal number of each available #OLDx fixed file record that can be dispensed to the E-type loader.

E-type loader rules database (ERD)
A record that contains the default values for the E-type loader. These values can be altered to change the E-type loader for different environments.

E-type loader working record table (WRT)
A structure that resides in main storage and acts as a cache for the E-type loader #OLDx fixed file records that are being dispensed or returned.

E-type program
An ECB-controlled program.

EVA
ECB virtual address.

event facility
A method for ECB-controlled programs to define an event that can be waited for or posted by all ECBs knowing the name of the event.

EVM
ECB virtual memory.

exchange identification (XID)
During link activation for an SNA physical unit (PU-PU) session, IDs are exchanged for node identification. Negotiated link characteristics are then established.

exception handler
A catch block in a C++ application that catches an exception when it is thrown from a function enclosed in a try block. Try blocks, catch blocks, and throw expressions are the constructs used to implement formal exception handling in C++ applications. A set of routines used to detect deadlock conditions or to process abnormal conditions. An exception handler allows the normal running of processes to be interrupted and resumed.

exclude
The process by which a program is marked as being excluded from an E-type loader loadset. This effectively removes the program from the loadset.

exclusive lock
A means to inform a process that another process has access to a file and does not want to share access.

exclude function
The E-type loader function that removes 1 or more programs from a specified loadset.

executable and linking format (ELF)
A portable object file format that is used to standardize the binary object interface across multiple operating environments.

executable file
A file suitable for execution. An executable file may be a program that has been compiled and link-edited, or it may be a shell script. A file that contains programs or commands that perform operations on actions to be taken. A regular file acceptable as a new process image file by the equivalent of the POSIX.1 exec family of functions, and, thus usable as one form of a utility. The standard utilities described in POSIX.1 as compilers can produce executable files, but other unspecified methods of producing executable files may also be provided. The internal format of an executable file is unspecified, but a conforming application shall not assume an executable file is a text file. (POSIX.2) A REXX exec.

executable script
In the TPF system, a type of executable file that can be used by the tpf_fork function to start a TPF application. An executable script is a file that contains readable text and statements that are interpreted. When the tpf_fork function is used to call an executable script, the first line of the executable script is parsed for the name of the TPF segment. The line must start with the #! characters, which is a UNIX shell convention. The access permission for the file must be set to execute. Internet servers typically use tpf_fork and executable scripts to run TPF applications.

exit vector
A user exit vector can consist of a SWISC expansion to an E-type program or an entry point address to a C-type program. User exit vectors are specified by MPIF functions (such as IDENTIFY and CONNECT).

exponent
A number, indicating the power to which another number is to be raised.

export
To make a function or variable available for dynamic access by other load modules. Dynamic link libraries (DLLs) export functions and variables. Exporting is accomplished in three ways: by specifying the EXPORTALL compiler options, by coding the #pragma export recompiler directive, or by qualifying a function or variable declarator with the _Export keyword.

expression
A representation of a value. For example, variables and constants appearing alone or in combination with operators.

extended binary-coded decimal interchange code (EBCDIC)
A set of 256 8-bit characters.

extended locales
The locale definition files based on the localedef utility that is supplied with IBM C/C++ compilers on the IBM System/390 platform.

Extended Operations Console Facility/2
An IBM licensed program designed to provide licensed customers of the TPF system with enhanced console operations, such as the capability for automation and the ability to control and monitor multiple TPF host systems using a single workstation in an IBM Operating System/2 (OS/2) environment.

extended resident
A description for a collection in which TPF collection support (TPFCS) stores data using an extended structure. See also extended structure.

extended structure
An object containing only control information and pointers that TPF collection support (TPFCS) uses to sort or retrieve the data elements that an application has stored in a collection. The data elements themselves are contained in pool file records that are chained to the extended structure. The DASDINDEXPool object of the StructureDasd class is just one example of several kinds of extended structures.

Extensible Markup Language (XML)
A metamarkup language that is used by the universal data display (UDD) to describe record layouts. It specifies each variable name, type, and length. XML uses user-defined tags and is similar to HTML. However, it addresses some of the limitations in the HTML language and is ideal for marking up data without regard to presentation. (The presentation is defined separately.) XML can be used for both publishing and data retrieval. Go to the W3C Web site at http://www.w3.org/ to view the XML specification.

external data definition
A definition appearing outside a function. The defined object is accessible to all functions that follow the definition and are located within the same source file as the definition.

external function
A TPF E-type file resident application program written in C language.

external locking facility (XLF)
A facility that is used by the TPF system to synchronize the updating of data records on its shared DASD database. The XLF has to be connected to and shared by all CPCs in a TPF loosely coupled complex. There are currently 2 XLFs supported by the TPF system. They are hardware features for the DASD control units. One of the features is the limited lock facility (LLF) and the other is the multi-path lock facility (MPLF) RPQ. TPF software support for MPLF is the concurrency filter lock facility (CFLF).