Texas Instruments TI-99/4A - Page 141

OPEN
• open-mode - This entry instructs the computer to process the file
in the INPUT. OUTPUT. UPDATE or APPEND mode. If vou
omit this clause, the computer will assume the UPDATE mode.
-
INPUT files may be read only.
-
OUTPUT files may be written only. The new file created
will have all the characteristics given by the OPEN
statement specifications and any standard defaults.
-
UPDATE files may be both read and written, The usual
processing is to read a record, change it in some way,
~mrl thpn write the altered record back out on the file.
-
APPEND mode allows data to be added at the end of the
existing file. The records already on the file cannot be
accessed in this muue.
• record·type - This entry specifies whether the records on the file
are all the same length (FIX EO) or vary in length (VARIABLE).
The keyword FIXED or VARIABLE may be followed by a
numeric expression specifying the maximum length of a record.
Each accessory device has its own maximum rpf:orrllength. so be
sure to check the manuals which accompany them. If you omit
the record-length specification, the computer will assume a
record length depending upon the device userl
If you define a file as RELATIVE, you must use FIXED-length
records. If this entry is omitted for RELATIVE files, FIXED·
length records are assumed, with the length dependent on the
device.
SEQUENTIAL files may have FIXED or VARIADLE length
records. If this entry is omitted for SEQUENTIAL files,
VARIABLE-length records are assumed.
If records are FIXED. the computer will pad each record on the
right to ensure that it is the specified length. If the data is
recorded in DISPLAY format, the COlllplltpr will pad the record
with
spaces. If the INTERNAL format is used, the FIXED·
length record will be padded with binary zeroes.
• f7.le-life - Files you create with your TI Computer are
considered PERMANENT, not temporary. You may omit this
entry entirely. since the computer will assume a PERMANENT
riJe-life.
User's Reference Guide
Examples:
>100 OPEN #53:NAME$,FIXED,INT
ERNAL .. RELATIVE
(computer o~~umeo UPPAT~)
>100 OPEN #ll:NAME$,INPUT,INT
ERNAL,SEQUENTIAL,VARIABLE 10
o
>100 OPEN 1175:"CS1",OUTPUT,FI
XED
(computer assumes SEQUENTIAL,
DISPLAY,FIXED
Length of 64
positions)
II-I2l