AST RESEARCH TECHNICAL BULLETIN TB-0028                   7-13-84

              BASIC'S AVAILABLE MEMORY DISCREPANCY


When using the IBM PC BASIC Interpreter,  at  initialization,  it 
displays  the version,  release,  and copyright information.   In 
addition  it displays the amount of memory available to the  user 
and their program.   It is displayed as 'xxxxx Bytes free', where 
xxxxx  is a decimal value from 0 to 65536.   BASIC is limited  to 
64kb regardless of total memory in system.

After   installing  an  AST  board  with  one  or   more   serial 
(asynchronous) port(s),  one may notice that available memory has 
changed.   The  reason being that when invoking Disk or  Advanced 
BASIC,  BASIC determines if there are serial ports in the system; 
and  if so keeps an internal driver resident for each port found.  
This means less available memory to the user.  This driver is 436 
bytes in length. 

This data was gathered from tests using Disk and Advanced  BASIC, 
of releases 1.10, 2.00, 2.10. Be aware that the Disk BASIC is the 
BASIC.COM and Advanced BASIC is the BASICA.COM on your DOS disk.