Function  28h  Random Block Write to File Specified in Struct -FCB
     Similar to 27h (Random Write) except allows multiple files to be read. 
entry   AH      28h 
	CX      number of records to write 
	DS:DX	address of an opened Struct -FCB
return  AL      00h     successful write 
		01h     disk full, no data written 
		02h     DTA too small for record size specified (write canceled) 
	CX      number of records written 
note 1) The record size is specified in the Struct -FCB.
     2) This service allocates disk clusters as required. 
     3) This function assumes that the Struct -FCB Record Size field (offset
	0Eh) is correctly set. If not set by the user, the default is 128
	bytes.
     4) The record size is specified in the Struct -FCB. The service updates
	the Current Block (offset 0Ch) and Current Record (offset 20h) fields
	to the next record not read.
     5) The record is written to disk at the current DTA address as specified
	by the most recent call to function 1Ah. If the size of the record and
	location of the DTA are such that a segment overflow or wraparound
	would occur, the error return is set to AL=02h
     6) If called with CX=0, no records are written, but the FCB's File Size
	entry (offset 1Ch) is set to the size specified by the FCB's Relative
	Record field (offset 21h).