Tandy 1000 Programmer's Reference Guide

Chauter 1 I System Calls
Treatment Of Registers
When MS-DOS takes control, it switches to an internal
stack. All registers are saved except
AX and those regis-
ters used
to return information, The calling program’s
stack must be large enough
to accommodate the interrupt
system. It should be at least 80H bytes, in addition to
the program’s needs.
MS-DOS Function Calls in Numeric Order
Function
Number
OOH
01H
02H
03H
04H
05H
06H
07H
08H
09H
OAH
0BH
OCH
ODH
OEH
0FH
10H
11H
12H
13H
14H
15H
16H
17H
19H
1AH
21H
22H
23H
24H
Function Name
Terminate Program
Read Keyboard and Echo
Display Character
Auxiliary Input
Auxiliary Output
Print Character
Direct Console
110
Direct Console Input
Read Keyboard
Display String
Buffered Keyboard Input
Check Keyboard Status
Flush Buffer, Read Keyboard
Reset Disk
Select Disk
Open File
Close File
Search
for First Entry
Search
for Next Entry
Delete File
Sequential Read
Sequential Write
Create File
Rename File
Current Disk
Set Disk Transfer Address
Random Read
Random Write
File Size
Set Relative Record
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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