Radio Shack TRS-80 III User manual

TRS-SO®
Model ID
Disk System Owners Manual
Mini-Disk Operation
TRSDOS™ Disk Operating System
Disk BASIC Programming Language
Cysr^M MANUFACTURED IN THE USA BY RADIO SHACK MADIVISION OF TANDY CORPORATIO|f

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The FCC Wants You to Know ..
.
This equipment generates and uses radio frequency energy. If not installed and used prop-
erly, that is, in strict accordance with the manufacturer's instructions, it may cause interfer-
ence to radio and television reception.
It has been type tested and found to comply with the limits for aClass Bcomputing
device in accordance with the specifications in Subpart Jof Part 15 of FCC Rules, which are
designed to provide reasonable protection against such interference in aresidential instal-
lation. However, there is no guarantee that interference will not occur in aparticular
installation.
If this equipment does cause interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
•Reorient the receiving antenna
•Relocate the computer with respect to the receiver
•Move the computer away from the receiver
•Plug the computer into adifferent outlet so that computer and receiver are on different
branch circuits.
If necessary, you should consult the dealer or an experienced radio/television technician for
additional suggestions. You may find the following booklet prepared by the Federal Com-
munications Commission helpful: How to Identify and Resolve Radio-TV Interference
Problems.
This booklet is available from the US Government Printing Office, Washington, DC
20402, Stock No. 004-000-00345-4.
Warning
This equipment has been certified to comply with the limits for aClass Bcomputing device,
pursuant to Subpart Jof Part 15 of FCC Rules. Only peripherals (computer input/output
devices, terminals, printers, etc.) certified to comply with the Class Blimits may be attached
to this computer. Operation with non-certified peripherals is likely to result in interference to
radio and TV reception.

Model III
Owner's
Manual
Radio /hack
9A DIVISION OF TANDY CORPORATION
FORT WORTH, TEXAS 76102

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TRS-80 Model III Disk System Owner's Man-
ual: ©1980 Tandy Corporation, Fort Worth,
Texas 76102 U.S.A. AH Rights Reserved.
Reproduction or use, without express written per-
mission from Tandy Corporation or any portion of
this manual is prohibited. While reasonable
efforts have been taken in the preparation of this
manual to assure its accuracy, Tandy Corporation
assumes no liability resulting from any errors or
omissions in this manual or from the use of the
information obtained herein.
Model III TRSDOS® Operating System:
©1980 Tandy Corporation, Fort Worth, Texas
76102 U.S.A. All Rights Reserved.
Model III BASIC Software: ©1980 Tandy Cor-
poration and Microsoft. All Rights Reserved.
The system software in the Model III microcom-
puter is retained in aread-only memory (ROM)
format. All portions of this system software,
whether in the ROM format or other source code
form format, and the ROM circuitry are copy-
righted and are the proprietary and trade secret
information of Tandy Corporation and Microsoft.
Use, reproductions, or publication of any portion
of this material without the prior written authori-
zation by Tandy Corporation is strictly prohibited.
10 987654321

OWNER'S MANUAL
To Our Customers
Congratulations on your purchase of the Model III Disk System. We think it's a
valuable tool which will save you work as well as give you hours of enjoyment
(or maybe both at once). You'll have all the power of the non-disk Model III,
plus the following features:
•Your Computer can now be controlled by trsdosCo]\the powerful trs-80 Disk
Operating System, trsdos is included on adiskette with the Disk System.
•Using trsdos, you can run awide variety of programs, such as the Disk basic
interpreter included on the trsdos diskette.
•Each "system" diskette has approximately 126,720 bytes of storage available
for your own programs and data; each "data" diskette has 178,944 bytes
available.
•You can load and save data at the approximate rate of 250,000 bits per second.
•Your system can continue to grow in power and convenience. When Radio
Shack issues improvements and enhancements to the system programs, you
can "install" them simply by obtaining anew release of the trsdos diskette.
Model III Manuals
Publications related to the use of the Model III Disk System;
1
.
Model 111 Disk System Owner sManual (this manual). We1
11 call it the "Disk
Manual" for short.
2. Model HI Disk System Quick Reference Card.
3. Model III Operation and basic Language Reference Manual, the "Model III
Manual" for short.
4. Model HI basic Quick Reference Card,
For Disk Operation;
This Disk Manual supplements the Model III Manual. Use the Disk Manual as
the primary source of information; we'll tell you when to refer to the non-disk
Model III Manual.
For Non-Disk Operation:
To use the Computer as anon-disk system, all you need is the Model III
Manual.
For Programming Information:
The Model III Manual contains most of the programming information, except
that which pertains to disk input/output. In this manual, we will assume that you

TRS-80 MODEL III DISK SYSTEM
are familiar with the basic programming definitions and details given in the
Model III Manual.
About This Manual
The Model III Disk System is intended for use by novices as well as
experienced computer operators and programmers. In designing and writing this
Disk Manual, we've tried to define and satisfy the needs of both groups:
Novices who might prefer asequential presentation which emphasizes
procedures and explains the purpose of various features.
•Experienced users who might prefer amore analytical presentation which
makes it easy to find specific information.
In this manual, you'll find information that should satisfy your needs, whichever
group you might belong to.
The ''Sample Sessions" are especially geared for novices, while the Technical
Information chapters are for the more experienced users.
Keep in mind, however, that it isn't necessary to read the entire manual to
operate the Disk System. If you are only interested in Disk basic, for example,
read the Operation section of this book and then turn directly to the Disk basic
section. You can then go back to the trsdos section when you need to.
Special Terms
Even in the non-technical sections of this manual, we've had to use numerous
special terms. Rather than scattering and repeating definitions throughout the
book, we have used the following convention which we hope you'll find
helpful.
Special terms which are fully defined in another part of the manual are printed in
boldface. Look up the word or phrase in the Index; this will tell you where the
word is fully defined.

OWNER'S MANUAL
Contents
Operation
Installation :1
Operation 4
Diskettes 5
Description Care
System Start-Up 6
Important Disk Operations 8
backup format Model 1/ III Conversion
Disk basic 11
Quick Instructions Start-Up Loading Baud Rate
TVoubleshooting and Maintenance 13
Notation and Abbreviations 14
Specifications 15
TRSDOS
Description of trsdos 17
Roles basic ram Use Memory Map
Using trsdos 20
Commands 20
Entering Syntax Forms
File Specification 22
File Name 23
Drive Specification 23
Password 24
AFew Important Definitions 24
Library Commands 26
Utility Commands 67
Technical Information 74
Disk Organization File Structure Systems Routines (I/O)
trsdos Error Codes/Messages .90

TRS-80 MODEL III DISK SYSTEM
Disk BASIC
Introduction 91
Enhancements to Model III Disk basic 93
Abbreviations Commands
Disk-Related Features ,116
QFile Manipulation QFile Access
Methods of File Access 145
QSequential QRandom
Disk basic Error Codes/Messages 155
Index 157
Customer Information 160
Warranty Back Cover
IV

OPERATION
Installation
First set up the Computer according to the instructions in the Model III Manual.
If you have aone- or two-drive system, installation is now complete. The built-
in drives should be ready for use.
If you have athree- or four-drive system, you need to connect the external
drives.
External Disk Drives
The two external drives are not interchangeable. They have different Radio
Shack Catalog Numbers and afew internal differences.
First External Drive Purchased
(Includes Cable)
Second External Drive Purchased
System
Name
"Drive 2/3'
"Drive 2"
Catalog
Number
26-1164
26-1161
The 26- 1164 drive may be used as Drive 2or 3, depending on the number of
drives in the system, In athree-drive system, it is always Drive 2(the last
drive). In afour-drive system, it is always Drive 3(again, the last drive).
The 26-1 161 drive may only be used in afour-drive system, in which it must be
Drive 2.
1
.
Locate the flat "ribbon" cable that was included with the 26-1 164 drive.
Notice that it has asingle plug on one end, and two plugs clustered at the
other end. See Figure 1for plug labels.
2. Connect the solitary "Computer" plug to the Disk Expansion Jack on the
bottom rear of the Computer. See Figure 2,
3. Now refer to Figure 3. Connect the external drive(s) to the other end of the
cable, as follows:
3-A. If you have one external drive (26-1 164);
Connect it to the "Drive 2" plug near the middle of the ribbon cable.
3-B. If you have two external drives (26-1 164 and 26-1 161):
Connect the 26-1 164 to the "Drive 3" plug on the end of the cable.
Connect the 26-1 161 to the "Drive 2" plug near the middle of the cable.
4. Plug the external drive(s) into an appropriate source of ac power. Power
requirements are specified on the unit and in the specifications given in this
manual.
You are now ready to start the Disk System.

TRS-80 MODEL III DISK SYSTEM
Computer Plug
Drive 3Plug
Figure 1. External Disk Cable with Plugs Labeled.
Figure 2. Connection of the External Disk Cable to the Model III.