DM>          if TX_free>0 then doswrite(Fport,fchar,1,ret);

 PF> Calling DosWrite/Read for each byte is __very__ 
 PF> expensive.  You should
 PF> try and combine your ReadChar and ReadBlock (and 
 PF> WriteChar/WriteBlock)
 PF> so they use the same buffer (which is emptied by another thread
 PF> perhaps). 

 DM>     The Basic functions included in that unit were originally made to 
 DM> duplicate an existing "DOS" unit (for easy porting).

There is no reason why your class (unit) can't have a "write one
byte" routine;  what I am saying is that under the covers,  this
should not translate to a DosWrite() for 1 byte (calling the device driver,
in ring 0,  is what is expensive).


--- Maximus/2 2.02p1