Atari 400 User Manual

Introduction to Atari BASIC 39
No two line numbers can be the same. If the same line number is
used more than once in a program, the line most recently
entered will replace the original. Line numbers can range from 0
to 32767.
The execution sequence of a BASIC program is determined by
the value of its line number. The lowest line numbers will be
executed first, followed by program lines with higher line
numbers. Even if program lines are not arranged in sequential
order, the Atari interpreter will place the lines in the correct
order.
Adding program lines to a program stored in the Atari's RAM is
very easy. Just type in the line number followed by the program
line. The line will be inserted in the program in the position
indicated by its line number. For example, by adding the
following line,
35 PRINT "216-777-5579"
to the program in Illustration 3-1 , the phone number for Jim
Smith
will be displayed on the line following his city, state, and
zip.
Program lines can be deleted by typing the line number to be
deleted followed by Return. For example, the following entry,
30 ,
would result in line 30 being deleted.
Program lines can be changed by merely retyping the new line.
The existing line in the Atari's memory will be replaced with the
new line . For example, the following entry ,
10 PRINT "Thomas Hill"
would result in "Thomas Hill" being output rather than "Jim
Smith" in the program in Illustration 3-1 .
Program lines also can be changed by displaying them on the

Atari 400 Specifications

General

Manufacturer	Atari
Model	400
Type	Home Computer
Release Year	1979
CPU	MOS Technology 6502
CPU Speed	1.79 MHz
ROM	10 KB
Operating System	Atari OS
Keyboard	Membrane keyboard
RAM	8 KB (expandable to 48 KB)
Graphics	ANTIC and GTIA chips
Sound	4 channels
Display	RF output for connection to TV
Storage	Optional cassette tape drive or floppy disk drive
Ports	Cartridge
Display Resolution	320x192 (16 colors)