Specifying compression options for segment entries

Use the following procedure to specify a compression technique for the segment registration entry. If you select Shared Table, you must indicate an existing table name. You can also specify an MSL or FPS to help prevent segment splits.

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

  2. If you are adding compression options, the panel shown in Figure 1 is displayed.

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

                         DPICDS Entry ADD - Compression Options                     
                                                                                   
     DPICDS Entry                                                  More:     +      
       IMSID . . . . . . : ****                                    DOWN to continue
       Database  . . . . : HDAMHDOP                                                 
       Segment . . . . . : LA7S09AA                                                 
                                                                                   
     DPICDS Information                                                             
       Record type . . . : Segment Registration      Level : Run                    
                                                                                   
     Type compression information.  Then press Enter.                               
       Technique . . . . . 3 1. SH - Static Huffman      5. HY - Hybrid
                             2. BC - Basic Character     6. CD - Custom HW Dict
                             3. EC - Extended Character  7. ST - Shared Table
                             4. HW - Hardware                                       
        Shared Table . . . ________                                                 
        Custom HW Dict . . ________                                                 
       Min Seg Length  . . 20___  (10-32000)                                        
       Fixed Pad Size  . . ___    (5-512)                                           
                                                                                   
     Commands:  CANCEL   SAVE                                                       
                                                                                   
                                                                                   
     Command ===> _________________________________________________________________

    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)
    • 6 (CD - Custom Hardware Dictionary)
    • 7 (ST - Shared Table)

    If you select 6 (CD), you must also indicate the Custom Hardware Dictionary name in the Custom HW Dict field. The dictionary specified must be an existing dictionary at the RUN level; you must have built the dictionary previously by running the Trial utility.

    If you select 7 (ST), you must also indicate the Shared Table name in the Shared Table field. The table specified must be an existing table at the RUN level; you must have built the table previously by running the Trial utility.

  3. If you are changing a segment entry, the panel shown in Figure 2 is displayed.

    Figure 2. DPICDS Entry CHANGE – Compression Options panel (segment entries)

                        DPICDS Entry CHANGE - Compression Options                   
                                                                                   
     DPICDS Entry                                                  More:     +      
       IMSID . . . . . . : ****                                    DOWN to continue
       Database  . . . . : HDAMHDOP                                                 
       Segment . . . . . : LA7S09AA                                                 
                                                                                   
     DPICDS Information                                                             
       Record type . . . : Segment Registration          Level : Run                
                                                                                   
     Type compression information.  Then press Enter.                               
       Technique . . . . . 3 1. SH - Static Huffman      5. HY - Hybrid
                             2. BC - Basic Character     6. CD - Custom HW Dict
                             3. EC - Extended Character  7. ST - Shared Table
                             4. HW - Hardware            8. CH - Custom Huffman
        Shared Table . . . ________                                                 
        Custom HW Dict . . ________                                                 
       Min Seg Length  . . 20___ (10-32000)                                         
       Fixed Pad Size  . . ___   (5-512)                                            
                                                                                   
     Commands:  CANCEL   SAVE                                                       
                                                                                   
                                                                                   
     Command ===> _________________________________________________________________

    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)
    • 6 (CD - Custom Hardware Dictionary)
    • 7 (ST - Shared Table)
    • 8 (CH - Custom Huffman)

    If you select 6 (CD), you must also indicate the Custom Hardware Dictionary name in the Custom HW Dict field. The dictionary specified must be an existing dictionary at the RUN level; you must have built the dictionary previously by running the Trial utility.

    If you select 7 (ST), you must also indicate the Shared Table name in the Shared Table field. The table specified must be an existing table at the RUN level; you must have built the table previously by running the Trial utility.

    If you select 8 (CH), the Custom Huffman table record must already exist at RUN level.

  4. You can specify a Min Seg Length (MSL) or Fixed Pad Size (FPS) to help prevent segment splits from occurring when the segment is replaced in the database. Both fields appear only on segment entries and are optional. 

    Note

    You can specify an MSL or FPS, but you cannot specify both.

    • The MSL is the minimum number of bytes (key and data) between 10 and 32,000 to which a segment should be compressed. If a segment compresses to a smaller size, it will be padded to the MSL.
    • The FPS is the fixed number of bytes between 5 and 512 which is added to a segment when it is inserted.

    For additional information on these features, see Preventing-segment-splits.

  5. 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 Figure 1.

 

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