Commodore RF512C - CHAPTER 5 Sequential File

C HAP TE R 5
FILE AND DIRECT PROGRAMMING
IN TRO DUCTION
30
There have !WO lypes of da ta file structure, s equent ial file and
random access file in th is disk operating sy stem.
Where sequential file are working with continuous steam of data
and it must readfwrite file from the beginning to end. But random
access file can be ab le to access certain record wi th out waiting
for entire file read/write.
Se qu ential file
Here is the flow cha rt of how to create and manipulate a
sequential f ile.
I OPEN S EQ FILE l
I
I
I
I
APPEND TO
Write to
Re ad from
I
S EQ FILE
SEQ FIL E
SE Q F IL E
I
I
I
I
I CLO SE S EQ FILE
Opening a file is the very beginning of file programming;
otherwise, data loss, occurance of error or even demage
another file will be happened . After a read , write or append
action is finished, closing the file to co mplete such o perat ion
is a must.
Other then read , write and append function; in C-128 's BASI C
7.0, the CONC AT command can co nc atenate !W O data files
t oge t her. Th is provide a way to get rid of large data-base
over hard processi ng time. •