The ID (Initialize Data Comm) command is used for the following purposes:

If security administrator status is authorized for the system, a security administrator usercode is required to execute the form of this command that alters the data comm prefix. If security administrator status is not authorized for the system, any operator, SYSTEMUSER, or privileged user can execute the command.

Syntax

── ID ─┬─────────────────────────────────────┬──────────────────────────►
       ├── + ────────────────────────────────┤
       └┬─ - ────────────────────────────────┤
        └─ <FILE NAME> ─┬────────────────────┤
                        └─ ON <FAMILY NAME> ─┘
►─┬────────────────────────────────────────────────────────────────┬───┤
  │     ┌◄─────────────────────────┬─────┬───────────────────────┐ │ 
  │     │                          └─ , ─┘                       │ │
  └─ : ─┴─┬─ /1\ ─ QUIT ───────────────────────────────────────┬─┴─┘
          └─ /1\ ─ MAXPSEUDO ─┬────────────────────────────────┤
                              ├─────┬─ <NUMBER> ─┬─────────────┤
                              └─ = ─┘            └─ UNLIMITED ─┘

Explanation

ID

Displays the current DATACOMINFO prefix, the next prefix (if any), total number of pseudostations used, and any options that are set.

ID +

Initializes the data comm information tables if they are not already initialized.

Other events that cause the data comm information tables to be initialized, if AUTODC is TRUE, are the following:

ID −

Sets the DATACOMINFO prefix to SYSTEM, the default value. Be aware, however, that your DATACOMINFO file might be removed if someone enters the command syntax REMOVE SYSTEM/= on the system software release medium (such as tape) that contains SYSTEM/DATACOMINFO.

ID <file name>

Specifies the prefix for the DATACOMINFO file to be used by the system. If the file name exceeds 24 characters when it is converted to standard form the system responds with the following message:

NAME TOO LONG

The system verifies the presence of the constructed file by using the specified prefix, that is, <file name>/DATACOMINFO. If the file is not present or if a corresponding NIF file is not present (<file name>/NIF), the system responds with the following message:

NO FILES WITH SPECIFIED NIF PREFIX FOUND

The first node of the filename cannot start with a number, and cannot be enclosed in quotation marks.

After an ID <file name> command is issued, the new DATACOMINFO file (whether it is of the same name or not) cannot be used until data comm is brought down through an ID :QUIT command or a halt/load.

ID <file name> ON <family name>

Designates the family name on which the specified DATACOMINFO file resides. If the sequence <file name> ON <family name> exceeds 24 characters, the system responds with the following message:

NAME TOO LONG

The system verifies the presence of the constructed file by using the specified prefix, that is, <file name>/DATACOMINFO. If the file is not present or if a corresponding NIF file is not present (<filename>/NIF), the system responds with the following message:

NO FILES WITH SPECIFIED NIF PREFIX FOUND

ID :QUIT

Causes all remote files to be closed. Any active MCS loses its MCS status. All pseudostations become disabled. The system discards the data comm information tables.

A pending change to a new DATACOMINFOFILE now becomes effective. The existence of a pending change is identified by the NIF TO BE value response returned in response to an ID command. Any subsequent system initialization uses the new DATACOMINFOFILE.

ID :MAXPSEUDO

ID :MAXPSEUDO = <number>

ID :MAXPSEUDO = <number> UNLIMITED

The total number of pseudostations that may be allocated is bounded by the maximum number of stations supported by the system; the system can support a maximum of 32,767 stations. The system provides two classes of pseudostations, which are described in the DCALGOL Programming Reference Manual. The number of pseudostations the system can allocate is 32,755 minus the number of declared stations. The class of pseudostations in the range above 16,384 is not controlled with the MaxPseudo command variant.

If you do not specify a number for MAXPSEUDO, the system displays the maximum number of pseudostations that it can currently allocate.

The recommended setting for MAXPSEUDO is ID:MAXPSEUDO 0 UNLIMITED.

If you specify a number, it is assigned as the pending MAXPSEUDO value. The value you enter in the MAXPSEUDO clause is used by the data comm subsystem to allocate entries in certain tables built at data comm initialization time. Note that you can enter a change to the MAXPSEUDO value at any time, but the pending change does not take effect until the next time that the system initializes the data comm subsystem. Note that other system functions might be suspended while the pseudostations are allocated during initialization of the data comm subsystem, so an initial value should be chosen judiciously.

The MAXPSEUDO variant of the ID command controls only pseudostations associated with the DATACOMINFO file, that is, those stations whose Logical Station Number (LSN) is numbered from 2 through 16383. Stations defined in the DATACOMINFO file and CANDE Schedule Stations are assigned numbers within this range. As ten (10) Schedule Stations are always provided, the maximum number value that may be specified is 16372. The actual number that is allocated is further reduced by the number of stations defined in the DATACOMINFO file.

Although the special value of 0 (zero) can still be used to indicate that there is no limit on the maximum number of pseudostations, the process used to adjust the number of pseudostations based on actual usage is not very efficient and might require you to initialize the data comm subsystem several times. It is recommended that you use the UNLIMITED option to enable the system to incrementally allocate additional pseudostations (in blocks of 100) beyond the specified initial value, when they are needed. Note that other system functions might be suspended until the additional pseudostations are allocated, so you should still specify a sufficiently large initial value.

If you specify the special value of 0 (zero), the system allocates a minimum of 100 pseudostations during data comm initialization. If more pseudostations than this number exist in the DATACOMINFO file, they remain allocated. The next time that the system initializes the data comm subsystem, the number of pseudostations is changed only by a maximum of 100, so you might need to initialize the data comm subsystem several times before reaching an appropriate number of pseudostations. The system incrementally allocates additional pseudostations (in blocks of 100) as needed to supply requests from MCSs.

Pseudostations are assigned (given ownership rights) to MCSs with a variant of the STATION ATTACH DCWRITE request. A pseudostation allocation request is denied if the number of pseudostations already allocated equals the value specified in the MAXPSEUDO clause, unless the value specified was zero or the UNLIMITED option was specified.

While the Interactive Datacomm Configurator (IDC) utility is running against the current DATACOMINFO file, the system rejects any new attempts to allocate pseudostations.

Examples

Example 1

This example displays the DATACOMINFO prefix as well as the setting for MAXPSEUDO:

ID

     NIF: SYSTEM/591L
     MAXPSEUDO: 0 UNLIMITED
     NEXT MAXPSEUDO: 0 UNLIMITED
     NUMBER OF PSEUDOS IN-USE: 16372 

Example 2

This example initializes data comm services on the system. The system responds by initiating the DATACOMSUPPORT library and building the data comm tables. A message of the form “* DC - 16372 Pseudostations Available” is posted.

ID +

Example 3

This example changes the DATACOMINFO prefix from SYSTEST to the default value SYSTEM.

ID –

     NIF PREFIX WILL BE CHANGED TO SYSTEM

Example 4

This example terminates data comm services on the system. The system responds by terminating the DATACOMSUPPORT library and terminating all active MCS processes.

ID:QUIT