>'UTIL10
>N1
>f
 
 
                              pclear - utility
                                    - # -
>X
pclear
======
 
 
tHE pclear uTILITY IS A COMPREHENSIVE dISK cLEAN-uP uTILITY.  iT ALLOWS THE USER TO EASILY ERASE UNASSIGNED GRANULES AND DIRECTORY RECORDS.  aLL ldos SUPPORTED DISK DEVICES MAY BE OPERATED ON, INCLUDING sINGLE/dOUBLE dENSITY, sINGLE/dOUBLE sIDED, 5" AND 8" FLOPPIES AND FIXED/REMOVABLE DISK SYSTEMS.  tHE SYNTAX OF THE pclear COMMAND IS:
 
          =====================================================
          !  pclear,:A,d,s,B                                  !
          !  pclear,FILESPEC,B                                !
          !                                                   !
          !          :A  = CLEAR THIS DRIVE (COLON OPTIONAL)  !
          !          d   = CLEAR UNUSED DIRECTORY RECORDS     !
          !          s   = CLEAR UNASSIGNED GRANULES          !
          !          FILESPEC = ANY VALID ldos FILESPEC       !
          !          B   = FILL COMMAND (DEFAULT 00h)         !
          !          FILL = #CC   = NUMERICAL VALUE           !
          !               = "CC"  = ASCII STRING              !
          !                 (NUMBERS AND ASCII CAN BE MIXED)  !
          !                                                   !
          !  ABBR: none                                       !
          =====================================================
 
     aFTER SELECTING THE DESIRED PARAMETERS, ONE OF THE FOLLOWING ROUTINES WILL BE EXECUTED.
 
     iF A disk WAS SPECIFIED TO BE CLEARED:
iF THE s OPTION WAS GIVEN, THE DIRECTORY gat TABLE WILL BE READ INTO MEMORY.  aLL non allocated GRANULES WILL BE WRITTEN TO WITH SECTORS OF THE DEFINED FILL DATA.
iF THE d OPTION WAS GIVEN, THEN ALL DIRECTORY RECORDS THAT DO NOT HAVE BIT 4 SET (INACTIVE RECORD) WILL BE SET TO ALL ZEROES.
 
     iF A file WAS SPECIFIED TO BE CLEARED:
aLL SECTORS ASSIGNED TO THE FILE WILL BE WRITTEN TO WITH ALL THE DEFINED DATA.  tHIS WILL DESTROY ALL DATA BELONGING TO THE FILE.
 
     tHE USER MAY OPTIONALLY DEFINE WHAT DATA IS TO BE WRITTEN INTO THE EMPTY SECTORS.  tHE DEFAULT VALUE IS ZERO (00h).  a SINGLE POUND SIGN (#) FOLLOWED BY A ONE BYTE NUMERICAL VALUE (0-255) TO BE USED AS THE FILL BYTE.  tHE NUMBER MAY BE ENTERED IN bINARY, dECIMAL, hEX, OR oCTAL BY preceding THE NUMBER WITH b, d, h OR o RESPECTIVELY (DEFAULT DECIMAL).  a QUOTATION MARK (") FOLLOWED BY A STRING WILL COPY THIS STRING REPETIVELY INTO THE EMPTY SECTORS.  nUMERICAL VALUES AND STRINGS MAY BE INTERMIXED.
>F
eXAMPLE:
pclear,:0,D,S,#H40
     fILL ALL UNASSIGNED GRANULES WITH SECTORS FILLED WITH THE BYTE 40h, AND CLEAR ALL UNUSED DIRECTORY RECORDS.
pclear,DEADFILE/CMD:3,"MESSAGE"
     fILL ALL SECTORS CURRENTLY ASSIGNED TO FILE "DEADFILE/CMD" WITH THE REPETITIVE STRING "MESSAGE".
pclear,:7,S,#95,"kIM WAS HERE
     fILL ALL UNASSIGNED GRANULES WITH THE STRING "kIM WAS HERE" PRECEDED BY THE CURSOR CHARACTER (ASCII 95 DECIMAL).  tHE TERMINATING QUOTE MAY BE LEFT OUT IF IT IS THE LAST CHARACTER ON THE LINE.
 
     wHEN A FILE IS KILLED WITH ldos, SEVERAL ACTIONS OCCUR.  fIRST THE FIRST BYTE OF ALL PRIMARY AND EXTENDED DIRECTORY RECORDS IS SET TO 00h.  aLL GRANULES ASSIGNED TO THE FILE ARE RELEASED AND MADE AVAILABLE IN THE gat TABLE.  aLL PRIMARY AND EXTENDED DIRECTORY RECORDS HAVE THEIR CORRESPONDING hit BYTES SET TO 0.
     tHIS WILL kill A FILE, AND MAKE IT INACCESSIBLE TO ldos, BUT ALL THE INFORMATION IS STILL THERE.  tHE DIRECTORY RECORD IS STILL IN THE DIRECTORY, BUT IT IS INDICATED AS inactive BY THE SYSTEM.  aLL DATA THAT WAS ASSIGNED TO THE FILE IS ALSO STILL ON THE DISK.  oNLY THE DIRECTORY RECORD HAS BEEN CHANGED, NONE OF THE DATA HAS BEEN TOUCHED.  aT THIS POINT, A COUPLE OF MINOR CHANGES TO THE DIRECTORY CAN REINSATATE THE FILE AND MAKE IT TOTALLY AVAILABLE AGAIN WITH FULL ACCESS TO THE DATA.
     bY RUNNING pclear ON A DRIVE, YOU MAY SAFELY REMOVE ALL TRACES OF BOTH THE FILES DATA, AND IT'S ASSOCIATED DIRECTORY RECORD.  iF YOU HAVE A DISK THAT HAS BEEN USED SEVERAL TIMES, CHANCES ARE THAT SEVERAL "KILLED" FILES ARE STILL ON THE DISK.  iF THIS DISK WAS GIVEN TO A PROGRAMMER, CHANCES ARE THAT THE DATA COULD BE "UNKILLED".  pclear WILL MAKE SURE THAT EVEN THE best programmer CANNOT ACCESS ANY OF THE KILLED FILES ON YOUR DISK, BECAUSE THE INFORMATION HAS BEEN COMPLETEY REMOVED FROM THE DISK.
 
     tHE file OPTION OF pclear IS A VERY POWERFUL FEATURE, BUT COULD BE DISASTROUS IF YOU ARE NOT CAREFUL.  tHIS WILL totally erase all data assigned to the file.  eACH SECTOR WILL CONTAIN THE SPECIFED FILL DATA.  tHIS ROUTINE COULD BE USEFUL TO SET ALL BYTES OF A FILE TO A KNOWN INITIAL VALUE TO BE USED AS A DATA FILE.

