Managing file and table size with FILEMGMT

File sizing overview

FILEMGMT calculates Model 204 file size by adding up the sizes of the tables within the file. (For an overview of Model 204 tables, see File architecture overview.)

The sizes of the tables are calculated by evaluating field, record, and procedure definitions.

To calculate the size of...	FILEMGMT uses...
Table A	All the field definitions linked to the file entry.
Table B, Table C, Table D, and Table E	Only field definitions linked to record definitions.

If there are no field and record definitions, Table A, B, C, D, and E sizes are based on the number of records defined for the file in the FILE entry. The value would have originated from a field entry documented in an earlier release of Dictionary/204.

If the value for the number of records is null, default table sizes for A, B, C, and E are used.

To calculate Table D size when the number of records is null, FILEMGMT does the following:

Examines the STORED IN links to the file to find the current number of procedures in the file.
Requests information on the File Definition - Procedure screen about the number of procedures you expect to store in the file. FILEMGMT uses the higher of the two numbers to calculate Table D size.

Sizing a new file

Use the File Size Definition screen to size your files. You must size each file before you can execute a CREATE command to complete the file creation.

Prerequisite: Before specifying the file sizes, read the file table sizing information.

Display the following File Size Definition screen with one of the following methods:

Select the File maintenance Size function (number 6) from the primary screen.
Press the F9 (SIZe) key from any of the FILEMGMT screens that support the SIZe command.

FILEMGMT File Size Definition Screen FILENAME: CLAIMS03 Active FICREATE: 7.5 FILEORG: Entry Order PAGESZ: 6184 ASIZE: 3 ASTRPPG: 400 ATRPG: 1 FVFPG: 1 MVFPG: 1 BSIZE: 5 BRECPPG: 256 BRESERVE: 17 CSIZE: 1 DSIZE: 15 DRESERVE: 15 % DPGSRES: 2 PDSTRPPG: 128 PDSIZE: 3 ESIZE: 0 XSIZE: 0 XRESERVE: 0 XRECPPG: 0 RECRDOPT: 0 PROCS: CUR: 0 EXP: 0 AVPG: 1 RECS: 0 FREESIZE: TOTAL PAGES: 32 DDname Dataset Name ( 1 of 3 ) Device Trks/Blks CLAIMS03 ____________________________________________ ________ __________ ________ ____________________________________________ ________ __________ ________ ____________________________________________ ________ __________ ===> 1=HELp 2=RECords 3=QUIt 4=FIElds 5= 6=COMmands 7= 8=FORward 9=SIZe 10=FILe 11= 12=END

The File Size Definition screen displays the following read-only values:

Field	Value
FILENAME	The name of the file that you entered on the primary screen, and indicates whether the file is Active or Inactive.
FICREATE	`Model 204` version number for the file you are creating. FILEMGMT uses this value to calculate the file size and validate certain `Model 204` features.
FILEORG	The file organization that you entered on the File Definition - Organization screen.
ASIZE	The sum of the `ATRPG`, `FVFPG`, and `MVFPG` parameters. You cannot change this parameter. The default is 3.
RECS	The number of records in the file. For an existing file, FILEMGMT displays the number of records in the file, and you cannot change the value.
CUR	The number of procedures defined in the procedure directory.
FREESIZE	The number of unassigned pages in the file. You cannot change this value. For a file in the process of being created or recreated, FREESIZE is not determined; it is left null. When `CREATE` or `RECREATE` is executed, the value is filled in appropriately.
TOTAL PAGES	The total number of pages used by the file.

For the PAGESZ parameter, specify the page size (physical record length) of the file. For an active file, PAGESZ must correspond to the Model 204 PAGESZ parameter. Valid values are:
3368

3624

6184

7208

The default is 6184.

Enter values for the Table A parameters as shown in the following table.

Field	Entry
ASIZE	The sum of the ATRPG, FVFPG, and MVFPG parameters. You cannot change this parameter. The default is 3.
ASTRPPG	The number of Table A strings per page. Valid values are 1-4000. `ASTRPPG*ATRPG` cannot exceed 4000. The default is 400.
ATRPG	The number of Table A pages for field names. Valid values are 1-4000. The default is 1.
FVFPG	The number of Table A pages for `CODED` values of `FEW-VALUED` fields. Valid values are 1-65535. The default is 1.
MVFPG	The number of Table A pages for `CODED` values of `MANY-VALUED` fields. Valid values are 1-65535. The default is 1.

Enter values for the Table B parameters as shown in the following table:

Field	Entry
BSIZE	The number of pages in Table B of the file. `BSIZE*BRECPPG` cannot exceed 16777216. Valid values are 1 - 16777216. The default is 5.
BRECPPG	The maximum number of records per Table B pages. Valid values are 1 - 1227. The default is 256.
BRESERVE	The number of bytes reserved for expanding records stored on Table B pages. BRESERVE cannot exceed `PAGESZ-40`. The default is 17. It should usually be the average weighted record length.
BREUSE	If your file is of type Unordered, enter a value for BREUSE. The value is specified as a percentage of space on a page; it determines which pages can hold another record. When used for storing another record, the page must have the following minimum bytes of free space: (usable page size - BRESERVE)*BREUSE + BRESERVE Usable page size is the size of the page minus overhead. The default is 20.

For the Table C parameter, CSIZE, enter the number of pages in Table C of the file. Valid values are 1-16777216. The default is 1.

Enter values for the Table D parameters as shown in the following table:

Field	Entry
DSIZE	The number of pages in Table D of the file. Valid values are 1-16777216. The value should not be less than the value of `DPGSUSED` plus DPGSRES, or you cannot store index records or found sets; it cannot be greater than the current value of FREESIZE. The default is 15.
DRESERVE	The percentage of space in a Table D page reserved for expansion. DRESERVE applies only to inversion pages. Valid values are 0-100. The default is 15.
DPGSRES	The number of pages in Table D held in reserve. The file is marked full when the first of the DPGSRES pages is used, but transaction backout processing is allowed to continue. Valid values are 1-32767. DPGSRES must be less than the value of DSIZE. The default is `DSIZE/50 + 2`; if `DSIZE/50 + 2` is greater than 40, the default is 40.
PDSTRPPG	The maximum number of procedure entries per directory page. Valid values are 1-256. The default is 128.
PDSIZE	The number of contiguous pages in the procedure directory. Valid values are 1-255. `PDSIZE/PDSTRPPG` must be greater than 0 if the number of expected procedures is greater than 0. The default is 3.

Enter values for the Table E parameter.

Prompt Response

ESIZE Specify the number of pages in Table E of the file. Valid values are 0-1,073,741,823. The default value is 0.
Enter values for PROCS, the procedure parameters:

For EXP, specify the number of procedures that you expect to store in the file. Valid values are 0 through the number of pages allowed in Table D, and null. The default is null.
Values for CUR (procedures currently defined in the procedure directory) and AVGP (expected average number of pages of the procedures stored in the file) are displayed once the file has been created.

If your file is of type Sorted, fill in the Sorted parameters:

Prompt	Response
BEXTOVFL	The number of extra overflow areas. The parameter must be greater than 1. The default is null.
BPGPOVFL	The number of Table B pages per overflow area.Valid values are 1-32767. The default is null.
BPGPMSTR	The number of Table B pages per master area. Valid values are 1-32767. The default is null.

Enter the names of the data sets in which the file is stored.
The DDname field displays the names of the currently defined data sets in which the file is stored. The data set names provide links to the physical file; they must be entered in order for FILEMGMT to create the file.

Scroll to the bottom of the list and add new DDnames up to the 100 data sets per file maximum.

A DDname must:
- Have 1-8 characters (letters and/or numbers) and not contain any special characters
- Begin with a letter
- Not begin with the characters SYS, CCA, OUT, or TAPE
  The list of DDnames must contain one DDname that is identical to the actual file name. For new files created through FILEMGMT, this is the first DDname, which is added when the file is created.
Enter the Dataset Name values corresponding to the data sets.
Dataset Name displays the data set name associated with the DDname on the same line. If needed, change a data set name by typing over it. Or scroll to the bottom of the list and add new data set names.

The data set name cannot exceed 44 characters. Valid characters are:

A to Z (0 to 9) + = #

As you move the cursor over the data set names, FILEMGMT changes the number displayed to the right of the Dataset Name heading. The number indicates the relative number of the data set out of the total number of lines in the list. (1 of 2 in the above screen indicates that the cursor is on the first of two lines.)

You can enter FORward or BACkward and the relative data set number to scroll to the corresponding line in the list. You can scroll forward up to 100 lines, which corresponds to FILEMGMT's limit for data sets per file.
Enter one or more device names.
For Device, FILEMGMT displays the device name currently associated with the DDname on this line.

You can change a device name by typing over it. Or scroll to the bottom of the list and add new device names.

The device name can be any of the following:

2311

2314

3330

3340

3350

3370

3375

3380

3390

9335

2305-2
Change the the number of tracks or blocks per data set as needed.
Trks/Blks is the number of tracks or blocks allocated to a data set. FILEMGMT calculates this number if you size the file by pressing the F9 (SIZe) key.
- If your file resides in one data set, leave the Trks/Blks value as is.
- If your file resides in more than one data set, recalculate the Trks/Blks value in order to allocate the tracks/blocks among all the data sets that contain the file. Note that the value FILEMGMT provides refers to total number of pages and not to tracks/blocks.
- You can change the value by typing over it or scroll to the bottom of the list and add new values.
Calculate the size of the Model 204 file by pressing the F9 (SIZe) key. FILEMGMT calculates the parameters and displays them on the File Size Definition screen.

Store the values you entered by pressing any of the following function keys or by typing a command name at the prompt (===>) and pressing Enter.

Key	Command	Meaning
F2	RECords	Completes the sizing operation. Proceeds to the Record Name List screen in `DEFINE` mode. This screen lists the records defined for the file.
F4	FIElds	Completes the sizing operation. Proceeds to the Field Name List screen in `DEFINE` mode. This screen lists the fields defined for the file.
F6	COMmands	Completes the sizing operation. Proceeds to the Execute Commands screen. This screen displays the staged commands that were generated for the file and allows you to select the commands you want to execute.
F10	FILe	Completes the sizing operation. For a new file, proceeds to the File Definition - Organization screen.
F12	END	Completes the sizing operation. Exits from the File Size Definition screen and returns to the previous screen.

Any of the above PF actions completes the sizing operation. If the file was staged with a "sizing required" status (see Execute Commands screen), you can now execute the command for the file on the Execute Commands screen.

Note: The WGTD RECORD LENGTH attribute for the file is set equal to the file's average record length (weighted by number of occurrences in the file) once you complete the file sizing.

Sizing an existing file

Use the File Size Definition screen to (re)size your files.

Prerequisite: Before specifying the file sizes, you should have read the file table sizing information.

Display the File Size Definition screen with one of the following methods:

Select the File maintenance Size function (number 6) from the primary screen.
Press the F9 (SIZe) key from any of the FILEMGMT screens that support the SIZe command.

FILEMGMT File Size Definition Screen FILENAME: VEHICLES Inactive FICREATE: 7.5 FILEORG: Hashed Order PAGESZ: 6184 ASIZE: 3 ASTRPPG: 511 ATRPG: 1 FVFPG: 1 MVFPG: 1 BSIZE: 57 BRECPPG: 233 BRESERVE: 29 CSIZE: 1 DSIZE: 4 DRESERVE: 15 % DPGSRES: 2 PDSTRPPG: 128 PDSIZE: 1 ESIZE: 0 XSIZE: 0 XRESERVE: 0 XRECPPG: 0 RECRDOPT: 0 PROCS: CUR: 0 EXP: 0 AVPG: 1 RECS: 11000 FREESIZE: TOTAL PAGES: 73 DDname Dataset Name ( 1 of 1 ) Device Trks/Blks USER5XXX MMUUSER5.USER5XXX 3390 10 ===> 1=HELp 2=RECords 3=QUIt 4=FIElds 5= 6=COMmands 7= 8=FORward 9=SIZe 10=FILe 11= 12=END

Use the File Size Definition screen to size your files. A CREATE command cannot be executed for a file until the file is sized on this screen.

The screen displays the values of file size parameters that have been specified on previous screens or calculated by FILEMGMT. Some of these parameters can be changed for both new and existing files. Some can be changed only for new files. Others can be viewed but not changed.

The screen provides PF key support to facilitate the sizing operation:

To calculate the size of the Model 204 file or to recalculate the size if you change file size parameters, press the F9 (SIZe) key. FILEMGMT calculates the parameters and displays them on the File Size Definition screen.
If you change a resettable parameter (for example, BRESERVE) for an existing file, FILEMGMT stages the file for RESET, provided that the file is not already staged for any other command and does not need to be increased, decreased, or recreated.
If you change a non-resettable parameter (for example, ASIZE) for an existing file, FILEMGMT asks if you want to stage the file for RECREATE.
To compare the values of parameters whose values have changed as a result of a F9 sizing operation, press the F11 (PARameters) key. The action displays the new and previous values on the File Size Parameters screen. You can return to the File Size Definition screen and restore a previous value if you do not want the new value for the file.
To store the values specified on this screen, press any of the following function keys:

PF key Command

F2 RECord

F4 FIElds

F6 COMmands

F10 FILe

F12 END

Any of the above PF actions completes the sizing operation. If the file was staged with a "sizing required" status, you can now execute the command for the file on the Execute Commands screen.

You can use the File Size Definition screen to view information about the data sets in which the file is stored, and to add or change data sets. The data set names provide links to the physical file; they must be entered in order for FILEMGMT to create the file. FILEMGMT displays the data sets in a scrollable list.

Note: The WGTD RECORD LENGTH attribute for the file is set equal to the file's average record length (weighted by number of occurrences in the file) once you complete the file sizing.

Steps

Change the PAGESZ parameter as needed.

Change the editable Table B parameters as needed:

Parameter Description

BSIZE

The number of pages in Table B of the file. For an existing file, BSIZE cannot be changed if the file is hashed.

BSIZE*BRECPPG cannot exceed 16777216. Valid values are 1 - 16777216. The default is 5.

BRESERVE

Specify the number of bytes reserved for expanding records stored on Table B pages.

BRESERVE cannot exceed PAGESZ-40. The default is 17. It should usually be the average weighted record length.

BREUSE

For an unordered file only. Specified as a percentage of space on a page; it determines which pages can hold another record.

When used for storing another record, the page must have the following minimum bytes of free space:

(usable page size - BRESERVE)*BREUSE + BRESERVE

Usable page size is the size of the page minus overhead. The default is 20.

Change the editable Table D parameters as needed:

Parameter	Description
DSIZE	Specify the number of pages in Table D of the file. Valid values are 1-16777216; for pre-8.1 files, 1-65536. The value should not be less than the value of DPGSUSED plus DPGSRES or you cannot store index records or found sets; it cannot be greater than the current value of FREESIZE. The default is 15.
DRESERVE	Specify the percentage of space in a Table D page reserved for expansion. DRESERVE applies only to inversion pages. Valid values are 0-100. The default is 15.
DPGSRES	The number of pages in Table D held in reserve. The file is marked full when the first of the DPGSRES pages is used, but transaction backout processing is allowed to continue. For an existing file, you can change this parameter on the File Parameter Reset screen. Valid values are 1-32767. DPGSRES must be less than the value of DSIZE. The default is `DSIZE/50 + 2`; if `DSIZE/50 + 2` is greater than 40, the default is 40.

Change the editable Table E parameters as needed:

Parameter	Description
ESIZE	Specify the number of pages in Table E of the file. Valid values are 0-1,073,741,823. The default value is 0.
EHIGHPG	This is the highest page in Table E currently in use.

Change the XSIZE parameter as needed.
For more information about specifying the XSIZE parameter, see Sizing Tables B and X.

In the PROCS section, change the editable procedure parameters as needed:

Parameter	Description
EXP (Expected)	The number of procedures that you expect to store in the file. Valid values are 0 through the number of pages allowed in Table D, and null. The default is null.
AVPG (Avg Pag)	The expected average number of pages of the procedures stored in the file. The default is 1.

Change the editable dataset parameters as needed:

Parameter Description

Dataset Name

The data set name associated with the DDname on this line.

You can change a data set name by typing over it. The data set name cannot exceed 44 characters. Valid characters are:

A to Z (0 to 9) + = #

As you move the cursor over the data set names, FILEMGMT changes the number displayed to the right of the Dataset Name heading. The number indicates the relative number of the data set out of the total number of lines in the list. (1 of 2 in the above screen indicates that the cursor is on the first of two lines.)

You can enter FORward or BACkward and the relative data set number to scroll to the corresponding line in the list. You can scroll forward up to 100 lines, which corresponds to FILEMGMT's limit for data sets per file.

Device

FILEMGMT displays the device name currently associated with the DDname on this line.

You can change a device name by typing over it. The device name can be any of the following:

2311

2314

3330

3340

3350

3370

3375

3380

3390

9335

2305-2

Trks/Blks

FILEMGMT calculates the number of tracks or blocks allocated to a data set if you size the file by pressing the F9 (SIZe) key. The number is valid for Model 204 files that reside in one data set.

If your file resides in more than one data set:

Recalculate the Trks/Blks value in order to allocate the tracks/blocks among all the data sets that contain the file.
Note that the value FILEMGMT provides refers to total number of pages, and not to tracks/blocks.
You can change the value by typing over it. You can scroll to the bottom of the list and add new values.

Store the values you entered by pressing any of the following function keys or typing a command name at the prompt (===>) and pressing Enter.

Key	Command	Meaning
F2	RECords	Completes the sizing operation. Proceeds to the Record Name List screen in `DEFINE` mode. This screen lists the records defined for the file.
F4	FIElds	Completes the sizing operation. Proceeds to the Field Name List screen in `DEFINE` mode. This screen lists the fields defined for the file.
F5	RCReate	If present, stages an existing file for the `RECREATE` command. Stages its fields, records, and field groups for the `DEFINE` command. Incorporates existing `RENAME` and `DELETE` commands in the recreated version. The staged file has the values entered on the File Size Definition screen; you can change the values and restage the file if you choose.
F6	COMmands	Completes the sizing operation. Proceeds to the Execute Commands screen. This screen displays the staged commands that were generated for the file and allows you to select the commands you want to execute.
F9	SIZe	Calculates the file size, based on the parameter values for the file and its fields and records. The values are displayed on the File Size Definition screen.
F10	FILe	Completes the sizing operation. Proceeds to the first of the File Parameter Reset screens.
F11	PARameters	If present, proceeds to the File Size Parameters screen (see below). This screen displays the file size parameters that were changed for an existing file as a result of pressing F9.
F12	END	Completes the sizing operation. Exits from the File Size Definition screen and returns to the previous screen.

Any of the above PF actions completes the sizing operation. If the file was staged with a "sizing required" status, you can now execute the command for the file on the Execute Commands screen.

To issue a command, press a PF key or type a command name at the prompt (===>) and press Enter.

After you have left the File Size Definition screen with F2, F4, F6, F10, F12, or their corresponding commands, an existing file is staged for the RESET command if all of the following are true:

One or more parameter values have changed.
File is not already staged for a file command (for example, INCREASE or SECURE).

Viewing changes to file size parameters

To compare the values of parameters whose values have changed as a result of a F9 sizing operation, press the F11 (PARameters) key. The action displays the new and previous values on the File Size Parameters screen. You can return to the File Size Definition screen and restore a previous value if you do not want the new value for the file.

Press the F11 (PARameters) key from the File Size Definition screen to display the File Size Parameters screen.

FILEMGMT File Size Parameters Filename: ABC Inactive Parameter New Size Value Original Value BSIZE 1 2 ===> 1=HELp 2= 3=QUIt 4= 5= 6= 7= 8= 9= 10= 11= 12=

The File Size Parameters screen compares the new values of file size parameters with their original values.

A file size parameter is displayed on this screen if:

You requested that an existing file be sized by pressing F9 on the File Size Definition screen.
FILEMGMT calculated a different value for the parameter as a result of changes you made to file size parameters. The new value is the value produced by the calculation; the original value is the value of the parameter before the calculation.

If the new value of a non-resettable file parameter is larger than the original value, FILEMGMT advises you to press F5 to stage the file for a RECREATE.

FILEMGMT displays the following information.

Field	Meaning
Filename	Name of the file that you entered on the primary screen. Also indicates whether the file is Active or Inactive.
Parameter	Names of `Model 204` file size parameters that were changed on the File Size Definition screen.
New Size Value	New value of the parameter shown on this line, as calculated on the File Size Definition screen.
Original Value	Original value of the parameter shown on this line, before any changes were made on the File Size Definition screen.

Resizing files

You use the File Increase/Decrease screen to change the values of the Model 204 parameters that determine the sizes of Table B, Table D, Table E, and Table X. Based on the values you enter on this screen, FILEMGMT stages the file for the INCREASE or DECREASE command. If you add data set names, FILEMGMT stages the file for the INC DSN (increase data set name) command.

The Increase/Decrease function calculates table sizes for existing files. The Size function calculates table sizes for new files.

You can use the File Increase/Decrease screen to view information about the data sets that contain the file and to add or change data sets. Data set names provide links to the physical file and are required in order to create the file. FILEMGMT displays the data sets in a scrollable list.

The cursor is initially positioned at the first input prompt. For private and semipublic files, the first prompt is Password. For public files, the first prompt is BSIZE.

Tables A and C

After a file has been created, you cannot change the sizes of Tables A and/or C without recreating the file and reloading all the data. For this reason, the default size of ATRPG, CSIZE, FVFPG, and MVFPG is generous to allow for growth.

Increasing Tables B, D, E, and X

When you want to increase the size of Tables B, D, E, and X, the space comes from pages in the free space, which is determined by the FREESIZE parameter. Free space is made available when you:

Create the file.
Tables B, D, and X can be increased in size automatically using the Automatic Increase feature (BAUTOINC, DAUTOINC, and XAUTOINC).
Put released space back into free space.
The size of Table B (except for hash key files), D, E, or X can be changed easily with the INCREASE and DECREASE commands.

Increasing and decreasing file size

On the primary FILEMGMT screen, enter the name of an existing file beside the Filename prompt at the top of the screen.
Tab to the File section, and enter a number next to the File field:
- 7 for INCREASE
- 8 for DECREASE

Press Enter.

The File Increase/Decrease screen appears:

FILEMGMT File Increase/Decrease Filename: VEHICLES Inactive Fileorg: Hashed Order TOTAL SPACE Pages: 73 New Sizes New Sizes BSIZE: 57 57 DSIZE: 4 4 BHIGHPG: DPGSUSED: ESIZE: 0 0 XSIZE: EHIGHPG: XHIGHPG: FREESIZE: 5 5 DDname Dataset Name ( 1 OF 5 ) Device Trks/Blks VEHICLES PSEDMNT.VEHICLES______________________ ________ _________ ________ ______________________________________ ________ _________ ________ ______________________________________ ________ _________ ________ ______________________________________ ________ _________ ________ ______________________________________ ________ _________ ===> 1=HELp 2= 3=QUIt 4= 5= 6=COMmands 7= 8=FORward 9= 10= 11= 12=END

Enter the following information:

Prompt	Response
Filename	FILEMGMT displays the name of the file that you entered on the primary screen, and indicates whether the file is Active or Inactive.
Password	For active files, FILEMGMT displays this prompt if the file requires a password. Type a valid password for the file (1-10 characters containing no spaces, commas, or colons).
TOTAL SPACE	FILEMGMT displays the total number of pages used by the file. The number is based on the values of the parameters shown on the screen.
BSIZE	FILEMGMT displays the number of pages in Table B of the file. You can change the number by typing a new value between 1 and the maximum valid value. You cannot change the current value for hashed files. The maximum valid value is the current value of BSIZE plus the current value of FREESIZE. BSIZE cannot exceed 16777216 (or 98304 for `RDFS` files). You cannot specify a value less than BHIGHPG for entry order or sorted files.
BHIGHPG	For active files, FILEMGMT displays the number of the highest active Table B page (for entry order and sorted files) or the number of full Table B pages (for hashed files). You cannot change this value.
DSIZE	FILEMGMT displays the number of pages in Table D of the file. You can change the number by typing a new value between 3 and the maximum valid value. The minimum value must be greater than the value of DPGSUSED plus DPGSRES. The maximum valid value is the current value of DSIZE plus the current value of FREESIZE. DSIZE cannot exceed 16777216. Note: If you are increasing the file size without adding a new data set (DDname) to the file, the new value of (BSIZE or DSIZE) minus the old value of (BSIZE or DSIZE) must be equal to or less than FREESIZE.
DPGSUSED	For active files, FILEMGMT displays the number of Table D pages in use. You cannot change this value.
ESIZE	FILEMGMT displays the number of pages in Table E for the file. You can enter a new value between 0 and 1,073,741,823. The minimum value must be greater than the value of EHIGHPG. If ESIZE is non-zero, indicating that Large Object fields may be defined, ESIZE cannot be less than 20.
EHIGHPG	For active files, FILEMGMT displays the highest Table E page. You cannot change this value.
FREESIZE	FILEMGMT displays the number of unassigned pages in the file. You cannot change this value.
DDname	FILEMGMT displays the DDnames of the currently displayed data sets. You can scroll to the bottom of the list and add new DDnames. You cannot delete DDnames in an existing file. The DDname must: Have 1-8 characters (letters and/or numbers) and not contain any special characters. Begin with a letter. Not begin with the characters `SYS`, `CCA`, `OUT`, or `TAPE`. The first DDname for the file must be identical to the actual file name.
Dataset Name	FILEMGMT displays the data set name associated with the DDname on this line. You can change a data set name by typing over it. You can scroll to the bottom of the list and add new data set names. You cannot delete data set names in an existing file. The data set name cannot exceed 44 characters. Valid characters are: A - Z (0 - 9) + = # As you move the cursor over the data set names, FILEMGMT changes the number displayed to the right of the Dataset Name heading. The number indicates the relative number of the data set out of the total number of lines in the list. (`1 of 5` in the above screen indicates that the cursor is on the first of five lines.) You can enter `FORward` or `BACkward` and the relative data set number at the prompt to scroll to the corresponding line in the list. You can scroll forward up to 100 lines, which corresponds to FILEMGMT's limit for data sets per file.
Device	FILEMGMT displays the device name currently associated with the DDname on this line. You can change a device name by typing over it. You can scroll to the bottom of the list and add new device names. You cannot delete device names in an existing file. The device name can be any of the following: 2311 2314 3330 3340 3350 3370 3375 3380 3390 9335 2305-2
Tracks/Blocks	FILEMGMT displays the number of tracks or blocks allocated for the data set. FILEMGMT calculates the value on the File Size Definition screen. You can change the value by typing over it. You can scroll to the bottom of the list and add new values.

Stage the file by issuing one of the following commands:

Press F6 or enter COM at the prompt to stage the file for INCREASE, DECREASE, or INC DSN and proceed to the Execute Commands screen. This screen displays the staged commands that were generated for the file and allows you to select the commands you want to execute.
Press F12 or enter END at the prompt to stage the file for INCREASE, DECREASE, or INC DSN and return to the FILEMGMT primary screen.