Commodore 1541-II - File Limits; Creating a Relative File

desired person out of a thousand in under 15 seconds, a feat no sequential file program
could match.
FILE LIMITS
One of the nicest aspects of relative files is that all this is done for you without your
having to worry at all about exactly where on the diskette's surface a given record will be
stored, or whether it will fit properly within the^current disk sector, or need to be extended
onto the next available sector. DOS takes care of all that for you. All you need to do is
specify how long each record is, in bytes, and how many records you will need. DOS will
do the rest, and organize things in such a way that it can quickly find any record in the file,
as soon as it is given its record number (ordinal position within the file).
The only limit that will concern you, is that each record must be the same size, and
the record length you choose must be between 2 and 254 characters. Naturally the entire
file also has to fit on your diskette too, which means that the more records you need, the
shorter each must be.
CREATING A RELATIVE FILE
When a relative file is to be used for the first time, its Open statement will create the
file; after that, the same Open statement will be used to reopen the file for both reading
and writing.
FORMAT STATEMENT TO OPEN A RELATIVE FILE:
OPEN file #, device #, channel #, "drive #: file name, L," + CHR$ (record
length)
where "file #" is the file number, normally an integer between 1 and 127; "device #" is
the device number to be used, normally 8 on the 1541; "channel #" selects a particular
channel along which communications for this file can take place, normally between 2 and
14; "drive #" is the drive number, always 0 on the 1541; and "file name'* is the file
name, with a maximum length of 16 characters. Pattern matching characters are allowed
in the name when accessing an existing file, but not when creating a new one. The
"record length" is the size of each record within the file in bytes used, including carriage
returns, quotation marks and other special characters.
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