Q21790: Compatibility with AT&T PC 6300: No SCREEN 100 or SCREEN B

Article: Q21790
Product(s): See article
Version(s): 1.00 1.01 1.02 2.00 2.01 3.00 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom | mspl13_basic
Last Modified: 27-DEC-1989

In general, QuickBASIC works very well on the AT&T PC 6300
computer. However, please note that in QuickBASIC Versions 2.x, 3.00,
4.00, 4.00b, and 4.50 you must run QB with the /B option to see the
QuickBASIC editor menus and help screens properly on the AT&T's
monochrome monitor.
   The BASIC that comes with the AT&T PC 6300 has SCREEN B and SCREEN
100 statements that are not supported in any version of QuickBASIC or
IBM BASICA. However, QuickBASIC Version 4.00b has added a new screen
mode, SCREEN 4, which is supported on the following machines:

   Olivetti Personal Computers, models M24, M28, M240, M280, M380
   AT&T 6300 Personal Computer series

   SCREEN 4 is a 640x400 graphics mode that allows you to specify one
of 16 colors (0-15) as the foreground color. Use the SCREEN statement
to select the mode and the COLOR statement to select the foreground
color. The example below shows how to specify this mode with a blue
foreground color:

   SCREEN 4
   COLOR 1

   You must invoke QB with the /B option on the AT&T PC 6300 because
the AT&T has a graphics card and a monochrome monitor installed.
QuickBASIC can detect what graphics card is installed, but you have to
tell it with the /B option that a monochrome monitor is installed.
(Please read about the QB /B option on Page 72 of the "Microsoft
QuickBASIC Compiler" manual for Versions 2.x and 3.00, or Page 49 of
the "QuickBASIC Version 4.00: Learning and Using" manual.)
   The BASIC interpreter provided with the AT&T 6300 gives a cursor on
graphics screens; however, there is no cursor in IBM BASICA or
Microsoft QuickBASIC when working with graphics screens.
   On the AT&T machines, the communications ports ("COM1:" and
"COM2:") produce errors such as "Device not available" in QuickBASIC
Versions 1.00, 1.01, and 1.02. QuickBASIC Versions 2.x and later have
had few reports of problems with communications on the AT&T PC 6300.