Homogeneous sys copy: means its a system copy with all the database tables from one system to another system of same kind, like same os/db on both system.
Heterogenous System copy:means copy from one system to another system of a different kind, like different os/db in either of those.

Gap analysis is when we going to implement sap system in somewhere client using some old legacy system how we going to implement sap that environment and how much sap can cover this that system process its should be cover more then 80% then we can implement sap if gap less then 20% otherwise not.

script is client dependent.
labelling is possible in scripts.

smartform is client independent.
less programing in smart form.
multiple page format is possible in smart form.
we can maintain background graphics in smartform
labelling is not possible in smart form

*----------------------------------------------------------------------*
* Tables
*----------------------------------------------------------------------*
TABLES: vbak,vbap.

*----------------------------------------------------------------------*
* Global Variable
*----------------------------------------------------------------------*
data: w_var type i.
*----------------------------------------------------------------------*
* Global Data
*----------------------------------------------------------------------*
DATA:it_fieldcat TYPE slis_t_fieldcat_alv,
     wa_fieldcat TYPE slis_fieldcat_alv,
     it_sortcat TYPE slis_t_sortinfo_alv,
     wa_sortcat  LIKE LINE OF it_sortcat.

*----------------------------------------------------------------------*
* Internal Table
*----------------------------------------------------------------------*
data: BEGIN OF it_salesorder OCCURS 0,

        vbeln LIKE vbak-vbeln,    " Sales Document Number
        posnr like vbap-posnr,    " Sales Doc Item
        netwr like vbap-netwr,    " Net Value

      END OF it_salesorder.

*----------------------------------------------------------------------*
*  SELECT OPTIONS
*----------------------------------------------------------------------*
SELECTION-SCREEN BEGIN OF BLOCK b1 WITH FRAME TITLE text-001.
SELECT-OPTIONS: s_vbeln FOR vbak-vbeln.   " Sales Document Number.
SELECTION-SCREEN END OF BLOCK b1.

*----------------------------------------------------------------------*
*  Initialization
*----------------------------------------------------------------------*
INITIALIZATION.
  PERFORM initialization.
*&---------------------------------------------------------------------*
*&      Form  initialization
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*  -->  p1        text
*  <--  p2        text
*----------------------------------------------------------------------*
form initialization .
  s_vbeln-sign   = 'I'.
  s_vbeln-option = 'BT'.
  s_vbeln-low    = '4969'.
  s_vbeln-high   = '5000'.
  APPEND s_vbeln.
endform.                    " initialization

*----------------------------------------------------------------------*
*  Start Of Selection
*----------------------------------------------------------------------*
START-OF-SELECTION.
  PERFORM field_catalog.   "For Structure Creation
  PERFORM fetch_data.      "Get the Data From DB Table
  PERFORM sorting USING it_sortcat.

*----------------------------------------------------------------------*
* End Of Selection
*----------------------------------------------------------------------*
END-OF-SELECTION.
  perform display_data.

*&---------------------------------------------------------------------*
*&      Form  field_catalog
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*  -->  p1        text
*  <--  p2        text
*----------------------------------------------------------------------*
form field_catalog .

  wa_fieldcat-col_pos       = w_var.          " Column Position Variable
  wa_fieldcat-tabname       = 'IT_SALESORDER'. " Internal Table Name
  wa_fieldcat-fieldname     = 'VBELN'.         " Field Name
  wa_fieldcat-key           = 'X'.             " Blue Color
  wa_fieldcat-ref_tabname   = 'VBAK'.          " Table Name
  wa_fieldcat-ref_fieldname = 'VBELN'.         " Field Name
  wa_fieldcat-seltext_m     = 'Sales Doc No'.  " Display Text In Screen
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.
  ADD 1 TO w_var.

  wa_fieldcat-col_pos       = w_var.          " Column Position Variable
  wa_fieldcat-tabname       = 'IT_SALESORDER'. " Internal Table Name
  wa_fieldcat-fieldname     = 'POSNR'.         " Field Name
  wa_fieldcat-ref_tabname   = 'VBAP'.          " Table Name
  wa_fieldcat-ref_fieldname = 'POSNR'.         " Field Name
  wa_fieldcat-seltext_m     = 'Sales Doc Item'. " Display Text In Screen
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.
  ADD 1 TO w_var.

  wa_fieldcat-col_pos       = w_var.          " Column Position Variable
  wa_fieldcat-tabname       = 'IT_SALESORDER'. " Internal Table Name
  wa_fieldcat-fieldname     = 'NETWR'.         " Field Name
  wa_fieldcat-ref_tabname   = 'VBAP'.          " Table Name
  wa_fieldcat-ref_fieldname = 'NETWR'.         " Field Name
  wa_fieldcat-do_sum        = 'X'.             " Sum
  wa_fieldcat-seltext_m     = 'Net Value'.  " Display Text In Screen
  APPEND wa_fieldcat TO it_fieldcat.
  CLEAR wa_fieldcat.
  ADD 1 TO w_var.
endform.                    " field_catalog
*&---------------------------------------------------------------------*
*&      Form  sorting
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*      -->P_IT_SORTCAT  text
*----------------------------------------------------------------------*
form sorting using p_it_sortcat TYPE slis_t_sortinfo_alv.
  wa_sortcat-fieldname = 'VBELN'.
  wa_sortcat-up        ='X'.
  wa_sortcat-subtot    = 'X'.
  APPEND wa_sortcat TO p_it_sortcat.
endform.                    " sorting
*&---------------------------------------------------------------------*
*&      Form  display_data
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*  -->  p1        text
*  <--  p2        text
*----------------------------------------------------------------------*
form display_data .
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
 EXPORTING
*   I_INTERFACE_CHECK                 = ' '
*   I_BYPASSING_BUFFER                = ' '
*   I_BUFFER_ACTIVE                   = ' '
    I_CALLBACK_PROGRAM                = SY-REPID
*   I_CALLBACK_PF_STATUS_SET          = ' '
*   I_CALLBACK_USER_COMMAND           = ' '
*   I_CALLBACK_TOP_OF_PAGE            = ' '
*   I_CALLBACK_HTML_TOP_OF_PAGE       = ' '
*   I_CALLBACK_HTML_END_OF_LIST       = ' '
*   I_STRUCTURE_NAME                  =
*   I_BACKGROUND_ID                   = ' '
*   I_GRID_TITLE                      =
*   I_GRID_SETTINGS                   =
*   IS_LAYOUT                         =
    IT_FIELDCAT                       = it_fieldcat
*   IT_EXCLUDING                      =
*   IT_SPECIAL_GROUPS                 =
    IT_SORT                           = it_sortcat
*   IT_FILTER                         =
*   IS_SEL_HIDE                       =
*   I_DEFAULT                         = 'X'
*   I_SAVE                            = ' '
*   IS_VARIANT                        =
*   IT_EVENTS                         =
*   IT_EVENT_EXIT                     =
*   IS_PRINT                          =
*   IS_REPREP_ID                      =
*   I_SCREEN_START_COLUMN             = 0
*   I_SCREEN_START_LINE               = 0
*   I_SCREEN_END_COLUMN               = 0
*   I_SCREEN_END_LINE                 = 0
*   IT_ALV_GRAPHICS                   =
*   IT_HYPERLINK                      =
*   IT_ADD_FIELDCAT                   =
*   IT_EXCEPT_QINFO                   =
*   I_HTML_HEIGHT_TOP                 =
*   I_HTML_HEIGHT_END                 =
* IMPORTING
*   E_EXIT_CAUSED_BY_CALLER           =
*   ES_EXIT_CAUSED_BY_USER            =
  TABLES
    t_outtab                          = it_salesorder
 EXCEPTIONS
   PROGRAM_ERROR                     = 1
   OTHERS                            = 2
          .
IF sy-subrc <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.

endform.                    " display_data
*&---------------------------------------------------------------------*
*&      Form  fetch_data
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*  -->  p1        text
*  <--  p2        text
*----------------------------------------------------------------------*
form fetch_data .
select a~vbeln
       posnr
       b~netwr
  from vbak as a
 inner join vbap as b on  a~vbeln = b~vbeln
  into table it_salesorder
  where a~vbeln in s_vbeln.

endform.                    " fetch_data.

SM37 displays the background jobs running in the system.SM37 is nothing but its a transaction used for 
  monitoring back ground "btc jobs".Similarly FYI sm36 is use to schedual btc jobs or the house keeping jobs.
SM31 To maintain table Table T000.
SM30 To maintain table RSCRMEXTERN for CRM purpose.
Sm30 and Sm31 are used for table maintainance also.