Int 13 Fn 1A  - Esdi Fixed Disk - Format Unit (ps)                         [d]

   AH = 1Ah
   AL = defect table count
   CL = format modifiers (see below)
   DL = drive
   ES:BX -> defect table

Return: CF set on error
   AH = status (see AH=01h)

Note:  if periodic interrupt selected, INT 15/AH=0Fh is called after each
     cylinder is formatted

See Also: AH=07h,INT 15/AH=0Fh

Bitfields for format modifiers:
 bit 4 generate periodic interrupt
 bit 3 perform surface analysis
 bit 2 update secondary defect map
 bit 1 ignore secondary defect map
 bit 0 ignore primary defect map