Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
FileSize
File Size
Function Call 23H
Searches the disk directory for the first matching entry for a
specified FCB. If
a matching directory entry is found, the rela-
tive record field (offset 21H) is set
to the number of records in
the file, calculated from the total file size in the directory entry
(offset 1CH) and the record size field (offset
0EH) of the FCB.
If the value
of the record size field of the FCB does not match
the actual number
of characters in a record, this function does
not return the correct file size. If the default record size (128) is
not correct, you must set the record size field
to the correct value
before using this function.
Entry Conditions:
AH = 23H
DS:DX = pointer to the file's unopened FCB
Exit Conditions:
If AL = 00H, a directory entry was found.
If
AL = FFH, no directory entry was found.
Macro Definition:
f 1le-51ze macro fcb
mov dx,offsetfcb
mov ah,23H
Int 21 H
endm
__
73

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200