Int 50 Fn 0004  - PC Thuis Organizer Shell - Read File                     [l]

   AX = 0004h
   ES:BX -> buffer for data
   CX = number of bytes to read or 0000h for entire file
   DL = file type
       01h setting shell
       02h setting sterm
       03h INT21 file
   DS:SI -> filename

Return: AX = status
       0000h successful
       FFFFh error

Note:  file type numbers are maintained by John Vanderaart; if a new file type
     is needed, a type number should be requested from him through the
     magazine:
       PC Thuis BV
       Spaarne 55
       2011 CE HAARLEM
       The Netherlands

See Also: AX=0003h"Shell"