Specifying compression options for database entries

To specify a compression technique for the database registration entry, complete the following steps. You can also specify an FSS for as many an ten data set groups.

  1. The Compression Options panel shown in Figure 1 is displayed when you indicate the following information on the DPICDS Administration panel (see Specifying-selection-criteria-and-process): an asterisk (*) for IMSID and segment and a valid name for database to select a database registration entry; Y to select compression options.The panel is displayed for Add and Change; the function you are performing is indicated in the panel title.

    Figure 1. DPICDS Entry ADD – Compression Options panel (database entries)

                         DPICDS Entry ADD - Compression Options                     
                                                                                   
     DPICDS Entry                                                  More:     +      
       IMSID . . . . . . : ****                                    DOWN to continue
       Database  . . . . : HDAMHDOP   Segment : ********                            
                                                                                   
     DPICDS Information                                                             
       Record type . . . : Database Registration         Level : Run                
                                                                                   
     Type compression information.  Then press Enter.                               
                                                                                   
       Technique . . . . . 3 1. SH - Static Huffman                                 
                             2. BC - Basic Character                                
                             3. EC - Extended Character                             
                             4. HW - Hardware
                             5. HY - Hybrid
                                                                                   
       Freespace Segment Size (FSS) in DSG order:      (4-32760)                    
                   DSG  1  _____   2  _____   3  _____   4  _____   5  _____        
                        6  _____   7  _____   8  _____   9  _____  10  _____        
                                                                                   
     Commands:  CANCEL   SAVE                                                       
                                                                                   
                                                                                   
     Command ===> _________________________________________________________________
  2. You can specify a compression technique. Type the number which corresponds to the technique you want to select:
    • 1 (SH - Static Huffman)
    • 2 (BC - Basic Character)
    • 3 (EC - Extended Character)
    • 4 (HW - Hardware)
    • 5 (HY - Hybrid)

  3. You can also specify a Freespace Segment Size (FSS) for as many as ten data set groups, which is the IMS limitation. This field is optional and appears only for database entries . If you have a partitioned database, you only specify one FSS value on the database entry panel.The values specified must be entered in data set group order. The value is the number of bytes that IMS will use to set the free space bitmaps for the data set groups.

    The FSS is valid only for HDAM and HIDAM databases. The minimum value is 4; the maximum value is 32,760. There is no default. Refer to Specifying-a-Free-Space-Segment-Size for more information on implementing FSS.

    Note

    If both FSS and the LOAD PLUS UCBITMAP parameters are used, FSS takes precedence.

  4. If you specified Y for output options, press the SCROLL DOWN function key (usually F8). Pressing this key validates the data entered and displays the next panel for specifying message options. See Specifying-message-options.If you do not want to display the next panel or if you specified N for output options, then type the SAVE command and press Enter to record the data for this entry. You are returned to the DPICDS Administration panel. See Specifying-selection-criteria-and-process.

 

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