Tandy 1000 Programmer's Reference Guide

Chapter 1 I System Calls
Open
Open a File
Function Call
3DH
Opens a file. The following values are allowed for the ac-
cess code:
0
- The file is opened for reading.
1 - The file is opened for writing.
2
- The
file
is opened for both reading and writing.
The readiwrite pointer
is set at the first byte of the file
and the record size of the file
is 1 byte. The returned
file handle
must be used for subsequent
IiO to the file.
Entry Conditions:
AH = 3DH
DS:DX
= pointer to ASCIIZ pathname for file to open
AL = access code (0 = read, 1 = write, 2 = read and
Exit Conditions:
Carry set:
Carry not set:
Error Returns:
AX = 12
write)
AX = error code
AX = file handle number
Invalid access. The access specified in AL was not in
the range 0-2.
File not found. The path specified was invalid or not
found.
Access denied. The user attempted to open
a directory
or volume
ID, or open a read-only file for writing.
Too many open files. There were no free handles
available in the current process
or the internal sys-
tem tables were full.
AX
= 2
AX
= 5
AX = 4
108

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