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

$:
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

s~\
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.

OPERATION
^ii^^mm^^
MINI-DISK (REAR VIEW)
Attach the plug so the cable exits
toward the rear of the Computer.
EDGE CARD PLUGS GUIDE PIN GUIDE SLOT
Figure 3. Connection of external disk drives.

TRS-80 MODEL III DISK SYSTEM
Operation
First, take afew minutes to become familiar with the various elements of your
Disk System. Refer to Figures 4and 5, This is very important. If you try to use
the Computer without having alittle background information, you could damage
adiskette.
Figure 4. The Model III Disk System with External Drives (optional/extra).
;Drive 0. The trsdos "system diskette" goes
in this drive.
:Drives 1, 2, and 3. These drives may
contain "data diskettes." Data diskettes are
described briefly in this chapter.
Drive Select led. When adrive is being
accessed, its led lights up.
)Drive Door. To insert or remove adiskette,
open this door. Never remove adiskette
while the led is lit, or while the diskette
contains open files.
CD Reset Button. When you press this button,
the Computer will attempt to load the
operating system software from Drive 0. The
trsdos diskette should be in Drive when
you press this button.
©Power Switch. All drives shouid be empty
when you turn the Computer on or off.
Otherwise, the information on the diskettes
could be destroyed.

Figure 5. ADiskette. (Catalog Number 26-305, 26-405, or 26-406)
©Storage Envelope. While adiskette is not in
use, keep it here.
©Write Protect Notch. When this is covered,
the disk-drives cannot write (change infor-
mation) on the diskette, Do not pinch the tab
into the notch when you apply it. If the tab
becomes indented, the disk drive may not
sense that the disk is write-protected. Leave
the notch uncovered if you want to save or
change information on the diskette.
<D Jacket. The diskette is permanently seated
inside this protective jacket. Do not attempt
to remove it.
©Read/Write Window. The disk drive
accesses the diskette surface through this
window. Don't touch the diskette surface.
CD Label. To write on this label, use only afelt-
tipped pen. Any other writing implement
might damage the diskette.
Diskettes
In general, handle diskettes carefully, using the same precautions you use with
tape cassettes and high-fidelity records. Asmall indentation, dust particle, or
scratch can render all or part of adiskette unreadable—permanently.
•Keep the diskette in its storage envelope whenever it is not in one of the
drives.
•Do not place adiskette in the drive while you are turning the system on or off.
•Keep diskettes away from magnetic fields (transformers, AC motors, magnets,
tvs, radios, etc.). Strong magnetic fields will erase data stored on adiskette.

TRS-80 MODEL III DISK SYSTEM
•Handle diskettes by the jacket only. Do not touch any of the exposed surfaces.
Don't try to wipe or clean the diskette surface; it scratches easily.
•Keep diskettes out of direct sunlight and away from heat.
•Avoid contamination of diskettes with cigarette ashes, dust or other particles.
•Do not write directly on the diskette jacket with ahard point device such as a
ball point pen or lead pencil; use afelt tip pen only.
•Store diskettes in avertical file folder on ashelf where they are protected from
pressure to their sides (just as phono records are stored).
•In very dusty environments, you may need to provide filtered air to the
computer room.
Tips on Labeling Diskettes
Each diskette has apermanent label on its jacket. This label is for "vital
statistics" that will never change. For example, to help keep track of diskettes,
it's agood idea to assign aunique number to each diskette. Write such anumber
on the permanent label. You might also put your name on the diskette, and
record the date when the diskette was first put into use. Remember, use only a
felt tip pen for marking.
This fc 'permanent 1'label is not agood place to record the contents of the diskette
since that will change, and you don't want to be erasing or scratching out
information from this label.
System Start-Up
1
.
Turn all peripherals on.
2. Turn the Computer on. Wait until all disk drive motors stop.
3. Locate the trsdos diskette that was supplied with the Disk System. Insert it
into Drive 0, with the label side facing up and the read/write window
pointing into the drive slot. See Figure 6.
4. When the diskette is fully inserted, close the drive door.
5. Press reset. The Computer should now load trsdos and begin the start-up
dialog described in the next section.
If nothing happens on the Display, or if the message: DISKETTE? or NOT A
SYSTEM DISK is displayed, check the following:
•Are you using atrsdos "system" diskette?
•Is the diskette properly inserted into Drive 0?
•If external drives are present, are they properly connected and turned on?

OPERATION
Figure 6. Inserting aDiskette.
If you can't find the problem, refer to the Troubleshooting and Maintenance
chapter for further suggestions.
TRSDOS Start-Up Dialog
Whenever you reset the Model III Disk System, it loads trsdos and begins the
start-up dialog.
1
.
The trsdos version number and date of creation will be displayed, followed
by the amount of ram (32K or 48K) and the number of drives in the system.
2. trsdos will prompt you to enter the date in the form mm/dd/yy. For example.
07/04/80 for July 4, 1980. Type in the correct date and press (ENTER) ,trsdos
will not continue until you type in the date correctly.
3. trsdos will prompt you to enter the time in 24-hour form hh:MM:SS. For
example, 14:45:00 for 2:45 p.m. Type in the correct time and press [ENTER) .If
you don't wish to set the time, simply press CENTER) at the beginning of the
line, trsdos will set the time to 00:00:00.
4. trsdos will now display the message, TRSDOS READY
Whenever this is displayed, you are in the trsdos ready mode, and you may
type in atrsdos command.

TRS-80 MODEL III DISK SYSTEM
Important Disk Operations
In this section we will describe three very important operations:
1
.
Duplicating the trsdos diskette (backup)
2. Initializing adata diskette (format)
3. Converting files from Model Ito Model III trsdos (convert).
All new customers should complete the trsdos backup procedure now; multi-
drive customers should also complete the format operation for afew diskettes.
Detailed information is provided later in this manual; here we will simply
outline the procedures.
Making aBACKUP (Duplicate) of TRSDOS
Your first operation should be to duplicate the trsdos diskette you received
from Radio Shack. The trsdos diskette contains autility program called
backup to accomplish this.
1
.
Locate the trsdos diskette and anew, blank diskette. The trsdos diskette
will be referred to as the "source," while the blank one will be called the
"destination," during backup.
2. Start trsdos as explained in the previous section. TRSDOS READY should be
displayed.
3. Type: BACKUP (ENTER)
4. trsdos will now load and start backup. It will ask you:
SOURCE DRIVE NUMBER?
Specify the drive which contains the original trsdos diskette by typing:
CENTER)
Next trsdos will ask: DESTINATION DRIVE NUMBER?
Now specify the drive which will be used for making the duplicate trsdos. If
you have two or more drives in your system, type: 1CENTER)
trsdos will ask: SOURCE DISK MASTER PASSWORD?
Type: PASSWORD (ENTER)
(password is the password of the supplied diskette.)
Now'the duplication process will begin.
If the destination diskette is not formatted, backup will format it before
continuing. (Before any diskette can be used, it must be initialized or
"formatted" —the data regions defined and labeled, and atable of contents
or "directory' 1created.)

OPERATION
If you are using asingle-drive system, trsdos will prompt you to swap
source and destination diskettes several times during the formatting/backup
process.
After asingle-drive backup, trsdos will display the message:
INSERT SYSTEM DISKETTE CENTER]
Be sure you have atrsdos diskette in Drive 0, then press [ENTER) .
The duplication process is now complete. We suggest you save the original
trsdos and use the duplicate as your working copy. If anything happens to the
working copy, you can make another one from the original.
Making aData Diskette (FORMAT)
This section applies to multi-drive systems only.
Drive must always contain atrsdos diskette, so the Computer can have
access to the system programs stored there. Much of the storage capacity of this
diskette is taken up by the system programs.
However, the other drives in the system may contain tl data" diskettes which
have no system programs. All of the storage capacity of such diskettes is
available for your programs and data.
The format utility program takes adiskette and initializes or "formats" it.
If the diskette was previously formatted, all prior information can be lost.
The resultant diskette contains no system files and may only be used in
Drive 1, 2or 3.
1
.
In the trsdos ready mode, type: FORMAT CENTER)
2. trsdos will start the formatter program and ask you aseries of questions:
FORMAT WHICH DRIVE?
Insert ablank diskette into Drive 1.Type: i(ENTER)
DISKETTE NAME?
This name will serve as an internal label for the diskette. Type in any
appropriate name of one to eight letters and numbers, starting with aletter.
Press CENTER) at the end of the name.
MASTER PASSWORD?
The password may be from one to eight letters and numbers, starting with a
letter. Press CENTER) at the end of the password.
Use of the password allows backup, prot, and purge access to all non-
system files. Unless special protection is needed, we suggest you use the
password password. Whatever password you select, don't forget it!

TRS-80 MODEL III DISK SYSTEM
If the diskette contains data, trsdos will warn you:
DISKETTE CONTAINS DATA »USE DISK OR NOT?
The warning is needed since format erases all previous information from the
diskette. Type NCENTER) to cancel format; type YCENTER] or UCENTER] to
continue it.
3. trsdos will now format and verify the diskette. The data diskette will then
be ready for use in Drive 1,2, or 3.
Model I/III Conversion (CONVERT)
In general, Model Itrsdos diskettes cannot be used in aModel III Disk
System. However, Model III trsdos includes aspecial program, convert, to
read aModel Itrsdos diskette and copy its non-system files onto aModel III
trsdos diskette.
In two-drive systems, the files must be copied onto aModel III system diskette;
in three- or four-drive systems, the files may be copied onto adata diskette.
Here are abbreviated instructions for using this program. For further details, see
convert.
1
.
Using aModel IDisk System, remove all passwords from the diskette to be
converted. You can do this with the prot command, described in the Model I
TRSDOSlDisk basic Owner's Manual.
2. Start Model III trsdos.
3. Place the Model Idiskette in Drive I, 2or 3. (In two-drive systems, use
Drive 1; in three- or four-drive systems, Drive 2.)
4. In three- or four-drive systems, place aModel III data diskette in Drive 1
.
5. Type: CONCERT CENTER)
4. The conversion program will start by asking for the source drive number.
Type in the number of the drive containing the Model Idiskette, then press
CENTER] .
5. Next, the conversion program will ask for the destination drive number. Type
in the number of the drive containing the Model III diskette, then press
(ENTER) .(In two-drive systems, use Drive 0; in three- or four-drive systems,
Drive 1.)
6. Now all the non-system files will be converted and copied onto the
destination diskette. As each file is copied, its name will be displayed.
7. When the process is completed, you may remove the Model Idiskette. It is
unchanged by the convert program. The destination diskette contains the
converted files.
8. To restore password protection to the converted files, you may use the prot
or attrib command.
10

OPERATION
Disk BASIC
Quick Instructions for Using Disk BASIC
In this section we'll "walk you" through the following procedures:
1. Starting Disk basic
2. Running asimple program
3. Saving aprogram in adisk file
4. Loading aprogram from adisk file
For programming information, see the Disk basic section of this manual.
Here we are showing procedures only.
Starting Disk BASIC
Under trsdos ready, type: BASIC (ENTER)
The Computer will load and start basic. First, it will ask two questions.
Press (ENTER) in response to each of them.
HOW MANY FILES? CENTER)
MEMORY SIZE? (ENTER)
Aheading will be displayed, followed by:
READY
You may now begin using Disk basic.
Saving aProgram
You should have aprogram in memory, and be in Basic's ready mode. Type:
SAVE "PROGRAM" (ENTER)
basic should now save the program in adisk file we arbitrarily named
"program." Any other suitable file name would do.
Loading aProgram
For this sample session, we will load the program just saved.
First type: NEN (ENTER) to erase it from memory. (This is to prove that it can be
retrieved from the disk file.)
11

*K TRS-80 MODEL III DISK SYSTEM
Now type: LOAD "PROGRAM" (ENTER) and basic will load the specified
program.
You may now list it and run it.
For further information on using Disk basic, see Section 3of this manual.
Setting the Cassette Baud Rate under Disk
BASIC
trsdos sets the cassette baud rate to High, If you would like to change this, use
the following trsdos command;
PATCH BASIC/CMD <ADD =5202 ,FIND =02) ,CHG=FF )CENTER)
Consequently, you will be prompted with: CASS? whenever you start Disk
BASIC.
You may then type either H(High) or L (Low) to choose the rate you need.
To change the system diskette back to its original state (i.e., no CASS?), simply
use the trsdos patch command again but reverse the find and chg values.
12