TOPIC :  CHEK15 (CYCLIC REDUNCANCY FILE-CHECK PROGRAM)

FROM  :  IRV HOFF W6FFC

DATE  :  11 APR 83



     CHEK is a file-checking program that calculates and prints (or puts
on disk) a CRC (Cyclic Reduncancy Check) value.  It can be valuable for
quickly checking the accuracy of a file transfer or to see if one file
is identical to another.

     It is similar to another program named CRCK but uses a more common
algorithm which gives a different mathematical result.  After talking
with the original author of CRCK (Keith Petersen W8SDZ), a new name was
selected, to avoid confusion when checking results.

     The algorithm used is the same one standardized with such programs
as the COMM7, DISK7, MDM7, MODEM2, MODEM7 and XMODEM7 series.  Packet
radio and other SDLC networking programs use the same algorithm.  

        NOTE:  Keep one file of CHEK15.COM on hand, to pass along
               to others or to check your library to see what ver-
               sion you have.   Then consider renaming it CHEK.COM
               on your normal disk.  This saves having to remember
               the version number and typing the extra characters
               each time it is used.


      SYSOPS:  If 0103H is 0, no disk file will be made, regardless
               of request.  If a disk file is attempted a reminder is
               displayed that the disk file has been disabled.  If 0104H
               is 0, no system files will be displayed or checked or put
               on disk.

               You may wish to put this on your A0: drive simply as
               CHECK.COM so the user does not need to remember a ver-
               sion number.  (It is displayed in any case each time
               the program is used).		


     A small menu comes up if you merely type the name of the program,
and do not ask for any files to check:


A>CHEK <RET>


     ++ No file name specified ++
 
 
     COMMANDS:  CHEK [drive:]<filename.filetype> FILE


     Examples:  CHEK B:HELLO.ASM     check only HELLO.ASM
		CHEK *.ASM	     check only .ASM files
		CHEK *.*             check all files, check disk quality
                CHEK *.* F           makes disk file named CHEKLIST.CRC
                CHEK *.* FF          makes disk file named FF.CRC
                CHEK *.* FILE        makes disk file named FILE.CRC
                CHEK *.* HELLO.ABC   makes disk file named HELLO.ABC


     NOTE: If byte 0103H is 0, no disk file is made regardless of request.

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