The Screen Resolution-The Smallest Discernible Item On The Display; The Basic Interpreter - AMSTRAD cpc 6128 User Instruction

The generally accepted reference points for personal computers are now:
1. The screen resolution - the smallest discernible item on the
display.
This is a combination offactors, including the number of different colours available to
the programmer, the number of distinctly different areas that can be resolved on the
display (i.e. the pixels), and the number of text characters that can be displayed on a
single screen area.
You will find that your 6128 compares very favourably with any similarly priced
machine in each of these respects.
2. The BASIC interpreter
Virtually every home computer includes with it a BASIC interpreter that allows the
user to start creating programs to use the hardware features. The built in
programming language (BASIC) that comes supplied with your machine is itself a
program - an immensely complicated and intricate program that has been evolved
over a million man-years of experience since BASIC was 'invented' in the USA. The
'Beginners' All-purpose Symbolic Instruction Code' is easily the most widely used
computer language in the world, and like any language, it comes in a variety oflocal
'dialects'.
The version in the 6128 is one of the most widely compatible dialects ufBASIC, arid
will also run programs written for operation under the CP IM disc operating system. It
is a very fast implementation of BASIC - in other words it performs its calculations
quickly - and whilst you may not be too concerned that one computer may take 0.05 of
a second to multiply 3 by 5 and display the answer, whereas another may take 0.075
second to do the same - where a program that draws graphics patterns on the screen
may call for many thousands of simple repetitive calculations, the difference between
0.05 and 0.075 of a second adds up to a considerable difference in performance.
You will frequently hear the term 'machine code' being used. Machine code is the raw
form ofinstruction code that can be passed to the processor. It takes less time to work
out what it's been asked to, and gets on with producing the result some 5 to 15 times
faster than an equivalent operation being passed along through the BASIC
interpreter. On the other hand, it can take 5 to 50 times longer to write an equivalent
program in machine code when compared to performing the same overall task using
BASIC.
Chapter 9 Page 2 At your leisure ....