gtpd3m0kLibrary Guide with Master Index and Glossary

H

handle
A number that uniquely identifies an object. For a dynamic link library (DLL), the number uniquely identifies the requested DLL for subsequent explicit requests for that DLL. A different handle is returned for each successful call to the dllload function.

hardening
In TPF transaction services, the process in which data is written to DASD and any locks that were held by the commit scope are released.

hard error
An error condition detected by hardware or software that remains an error after a predetermined number of retries. Contrast with soft error.

hard link
A directory entry to a file. A directory must have one, and only one, hard link to it other than dot (.) and dot-dot (..). Other files must have one but may have more hard links to each of them.

hard IPL
The loading of the TPF system; activated from the service processor. Contrast with software IPL.

HCT
Hotcon table.

head
The first of a chain of records.

header file
A file that contains commonly used definitions and declarations. The file is included in application source code by means of the #include preprocessor directive. The #include statement is replaced with the contents of the header file (also known as the include field) at compile time.

heap private area
Contiguous storage above the 16-MB line that is available to ECBs through the use of the CALOC, MALOC, REALLOC, and FREEC assembler macros and their corresponding C language functions.

heap storage
The total memory pool from which an application may obtain memory through a dynamic allocation request. The TPF system uses heap storage for the heap private area in the ECB virtual memory above the 16-MB line.

heterogeneous collection
A collection in which all elements have the same displacement to the persistent identifier (PID) or file address and can be recouped in the same way.

hexadecimal
A base sixteen numbering system; hexadecimal digits range from 0 through 9 and uppercase or lowercase A (ten) through F (fifteen).

hexadecimal constant
The characters 0x or 0X (zeroX) followed by any digits 0 to 9 and uppercase or lowercase letters A to F.

hierarchical file system
A file system where each directory must have one, and only one, hard link to it and, as a result of this restriction, the directories are organized in a hierarchy (rather than a mesh).

High Performance Option (HPO)
A TPF feature that consists of the loosely coupled facility and the multiple database function (MDBF).

high-performance routing message table (HPRMT)
A core-resident table used to save output messages sent over rapid transport protocol (RTP) connections so the output messages can be retransmitted if the remote RTP endpoint makes this request.

High-performance routing session address table (HPRSAT)
A core-resident table used to map the session address (SA) from a network layer packet (NLP) to the appropriate session resource vector table (RVT) entry. There is one entry in the HPRSAT for each LU-LU session started using HPR support.

high-performance routing (HPR) support
An addition to TPF Advanced Peer-to-Peer Networking (TPF/APPN) support that enhances data-routing performance and session reliability.

high-speed
High-speed lines are used in the TPF system to refer to ALC and SLC lines that operate at 9600 baud, in contrast to low-speed lines that operate at rates as low as 75 baud.

home page
The initial Web page that is returned by a Web site when a user specifies the uniform resource locator (URL) for the Web site. For example, if a user specifies the URL for the IBM Web site (http://www.ibm.com), the Web page that is returned is the IBM home page. Essentially, the home page is the entry point for accessing the contents of the Web site. The home page may sometimes be called the welcome page or the front page.

homogeneous collection
A collection in which not all elements contain an embedded file address or persistent identifier (PID) or the displacements are different; that is, not all elements can be recouped in the same way.

hop
A link crossed on a path from 1 host or NCP subarea to another.

hop count
The number of links crossed on a path from 1 subarea to another.

horizontal allocation
When allocating record space on DASD, logically adjacent records are allocated to different physical devices. Contrast with vertical allocation.

host application
An application on a TPF host processor that is used to establish a Common Link Access to Workstation (CLAW) connection with an application on a CLAW workstation.

host byte order
The order in which the bytes of all binary integers are stored in a particular machine. In the TPF system, the host byte order used for integers being sent across a TCP/IP network is the same as the network byte order. See also network byte order.

host name
A name assigned to a TPF host processor used in a TCP/IP network to identify that TPF host processor.

host node
An SNA term indicating a combination of a CPU and an associated channel attachment that hosts functions for other processors.

host node LU
An SNA logical unit (application) residing in a host processor as contrasted with a peripheral logical unit that resides in a cluster controller or network control program.

hotcon
Hot conversation or hot connection, depending on the communication protocol used.

In LU 6.2, a TPF Advanced Program-to-Program Communications (TPF/APPC) conversation that remains allocated and active past the completion of the transaction. The TPF/APPC conversation parameters between TPF Application Requester (TPFAR) and the DB2 system are saved in an entry in the hotcon table (HCT). When another entry control block (ECB) requests a conversation with the same remote application server, TPFAR reuses the active conversation.

In Transmission Control Protocol/Internet Protocol (TCP/IP), a TCP/IP connection that remains active past the completion of the transaction. The socket descriptors are saved in an entry in the hotcon table (HCT). When another entry control block (ECB) requests a connection with the same remote application server, TPF Application Requester (TPFAR) reuses the active connection.

HPO
High Performance Option.

HPRMT
High-performance routing message table.

HPRSAT
High-performance routing session address table.

HPR support
High-performance routing support.