• Open all files at the begining of the code
• Carry a structure that has Chandra's Status. Created functions to update the status, write the status to the .dat files and to write out to the Load Review file.
• Carry an array of commands that we are concerned with to prevent a looping of all possible commands in the backstop file.
• Place all errors into an array that can be read out at the end of the script instead of carrying several flags that must be tested at the end of the code.
• Changing variable names (example flag0000) to something reflecting the actual value stored (flag_window_block)

while (  ) 
{

    Process_Next_Record($_);
    push (@timecont,$dec_day);
    
    #----------------------------------------
    #Confirm that this is a command we care about
    #----------------------------------------
    if ($Rec_Event eq "ACISPKT" ||
        $command_list{($Rec_Eventdata{TLMSID})} ||
        $command_list{($Rec_Eventdata{TYPE})}  ||
        $command_list{($Rec_Event)}  ||
        $Rec_Eventdata{TLMSID} =~ /CSELFMT/){
        #----------------------------------------
        # We care. Handle each set of commands
        #----------------------------------------
        SWITCH: {
            #Comms:
            if($Rec_Eventdata{TLMSID} =~ /CTX/){
                process_comm();
                last SWITCH;
            }
            #Gratings:
            if($Rec_Eventdata{TLMSID} =~ /ETG/){
                process_TG(\%chandra_status);
                last SWITCH;
            }
            #Dither:
            if($Rec_Eventdata{TLMSID} =~ /DITH/){
                process_dither(\%chandra_status);
                last SWITCH;
            }
            #Radiation Monitor
            if($Rec_Eventdata{TLMSID} =~ /OORMP/){
                process_radmon(\%chandra_status);
                last SWITCH;
            }
            #Format Change
            if($Rec_Eventdata{TLMSID} =~ /CSELFMT/){
                process_format(\%chandra_status);
                last SWITCH;
            }
            #RadZone Entry and Exit
            if($Rec_Event =~ /ORBPOINT/){
                process_radzone();
                last SWITCH;
            }
            #SIM FOCUS and Translations
            if($Rec_Event =~ /^SIM/){
                process_sim(\%chandra_status);
                last SWITCH;
            }
            #Obsid Changes
            if ($Rec_Event =~ /MP_OBSID/) {
                obsid_change(\%chandra_status);
                last SWITCH;
            }
            #Stop Sciences
            if ($Rec_Eventdata{TLMSID} =~ /AA00000000/){
                process_stop_science();
                last SWITCH;
            }
            #Start Sciences
            if ($Rec_Eventdata{TLMSID} =~ /XTZ0000005/ || 
                $Rec_Eventdata{TLMSID} =~ /XCZ0000005/) {
                check_acistime();
                process_start_science();
                last SWITCH;
            }
            #Load Parameter blocks
            if ($Rec_Eventdata{TLMSID} =~ /WT0*/  ||
                $Rec_Eventdata{TLMSID} =~ /WC0*/ )  {
                check_acistime();
                load_pblock(\%chandra_status);
                last SWITCH;
            }
            #Load Window Blocks
            if ($Rec_Eventdata{TLMSID} =~ /W100*/ ||
                $Rec_Eventdata{TLMSID} =~ /W200*/) { 
                check_acistime();
                load_windowblock(\%chandra_status);
                last SWITCH;
            }
            #all other ACIS commands:
            else{
                check_acistime();
                process_acispkt();
            }
        }#end SWTICH   
      }#end lines we care about
    } #end processing backstop file

end_load(\%chandra_status);
check_errors();
#cleanup