Commodore 1570 User manual

COMMODORE
DISK DRIVE
1570/71==
Users's Guide
COMMODORE
DISK DRIVE
1570171
Users's Guide

USERS MANUAL STATEMENT
WARNING: This equipment has been certified to comply with the limits for
a Class B computing device, pursuant to subpart J of Part 15 of the
Federal Communications Commission's rules, which are designed to pro
vide reasonable protection against radio and television interference in a
residential installation. If not installed properly, in strict accordance with
the manufacturer's instructions, it may cause such interference. If you
suspect interference, you can test this equipment by turning it off and on. If
this equipment does cause interference, correct it by doing any of the
following:
• Reorient the receiving antenna or AC plug.
• Change the relative positions of the computer and the receiver.
• Plug the computer into a different outlet so the computer and
receiver are on different circuits.
CAUTION: Only peripherals with shield-grounded cables (computer input-
output devices, terminals, printers, etc.), certified to comply with Class B
limits, can be attached to this computer. Operation with non-certified
peripherals is likely to result in communications interference.
Your house AC wall receptacle must be a three-pronged type (AC
ground). If not, contact an electrician to install the proper receptacle. If a
multi-connector box is used to connect the computer and peripherals to
AC, the ground must be common to all units.
If necessary, consult your Commodore dealer or an experienced radio-
teievision technician for additional suggestions. You may find the following
FCC booklet helpful: "How to Identify and Resolve Radio-TV Interference
Problems." The booklet is available from the U.S. Government Printing
Office, Washington, D.C. 20402, stock no. 004-000-00345-4.
FOR USERS IN UK
WARNING: THIS APPARATUS MUST BE EARTHED !
IMPORTANT. The wires in this mains lead are coloured in accordance with the fol
lowing code:
Green and yellow
Blue
Brown
Earth
Neutral
Live
As the colours of the wires in the mains lead of this apparatus may not correspond
with the coloured marking identifying the terminals in your plug, proceed as follows:
The wire which is coloured green and yellow must be connected to the terminal in
the plug which is marked by the letter E or by the safety earth symbol—or coloured
green or green and yellow.
The wire which is coloured blue must be connected to the terminal which is
marked with the letter N or coloured black.
The wire which is coloured brown must be connected to the terminal which is
marked with the letter L or coloured red.
USER'S MANUAL STATEMENT
WARNING: This equipment has been certified to comply with the limits for
a Class B computing device, pursuant to subpart J of Part 15 of the
Federal Communications Commission's rules, which are designed to pro-
vide reasonable protection against radio and television interference in a
residential installation.
If not installed properly, in strict accordance with
the manufacturer's instructions, it may cause such interference.
If you
suspect interference, you can test this equipment by turning it off and on. If
this equipment does cause interference, correct it by doing any of the
following:
• Reorient the receiving antenna or AC plug.
• Change t
he relative positions of the co mputer and the receiver.
•
Pl ug the co mputer in to a di ff ere nt o ut let so the co mputer and
receiver are on diffe r ent ci rcu its.
CAUTION: Only peripherals with shield-grounded cables (computer input-
output devices,
te rminals, printers, etc.), certified to comply with Class B
limits, can be attached to this computer. Operation wi th non-certified
pe ripherals is likely to result in communications interference.
Your house
AC wall receptacle must be a three-pronged type (AC
ground). If not, contact an electrician to install the proper receptacle. If a
multi-connector box is used to connect the computer and peripherals to
AC, the ground must be common to all units.
If necessary, consult your Commodore dealer or an experienced radio-
television technician for additional suggestions.
You may find the following
FCC booklet h elp ful: "How to Identify and Resolve Radio-TV Interference
Problems." T he booklet is available from the U.S. Gove rn ment Pr inting
Offi ce, Washington, D.C. 20402, stock no. 004-000-00345-4.
FOR USE RS IN UK
WARNI NG : TH IS APPARATUS MUST BE EARTHED!
IMPORTANT . The wires in this mains lead are coloured in accordance with the fol·
lowi
ng code :
Green and yellow Earth
Blue Neutral
Brown live
As the colours of the wires in the mains lead of this apparatus may not correspond
wi
th the coloured marking identifying the terminals in your plug. proceed as follows;
The wire which is coloured green and yellow must be connected 10 the terminal in
the plug which is marked by th e letter E or by the safety earth symbol-or coloured
green or green and yellow.
The wire which is co loured blue must be connected to the terminal which is
marked with the letter N or coloured black.
The wire
which is coloured brown must be connected to the terminal wh ich is
marked with the letter L or co loured red.

Disk Drive
User's Guide
1570/1571

Copyright © 1985 by Commodore Electronics Limited
Second Printing. August 1985
All rights reserved
This manual contains copyrighted and proprietary information.
No part of this publication
may be reproduced, stored
in a retrieval system, or transmitted in any form or by any
means, electronic, mechanical, photocopying, recording or otherwise, without the prior
written permission
of Commodore Electronics Limited.

CONTENTS
INTRODUCTION ...................................................... 1
PART ONE: BASIC OPERATING INFORMATION
CHAPTER 1:
HOW TO UNPACK, SET UP AND BEGIN USING THE 1571 .... 3
step-by-step instructions
......................................... 3
operating modes
................................................. 5
troubleshooting guide
............................................ 6
simple maintenance tips
.......................................... 7
inserting a diskette
.............................................. 7
diskette care
................................................... 8
using pre-programmed (software) diskettes
......................... 9
how to
prepare a new diskette ................................... 10
diskette directory .............................................. 11
selective directories ............................................. 12
printing a directory ............................................ 13
pattern matching .............................................. 13
splat files ..................................................... 13
CHAPTER 2: BASIC 2.0 COMMANDS ................................... 14
error checking ................................................. 14
BASIC hints .................................................. 15
save .......................................................... 16
save with replace
............................................... 16
verify ........................................................ 17
scratch ....................................................... 18
more about scratch ............................................. 19
rename ....................................................... 20
renaming
and scratching troublesome files (advanced users) .......... 21
copy ......................................................... 21
validate ....................................................... 23
initialize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
CHAPTER 3: BASIC 7.0 COMMANDS ................................... 25
error checking ................................................. 25
save .......................................................... 25
save with replace ............................................... 26
dverify ....................................................... 27
copy ......................................................... 27
concat. ....................................................... 28
scratch ....................................................... 28
more about scratch ............................................. 29
rename ....................................................... 30
renaming and scratching troublesome files (advanced users) .......... 30
collect ........................................................ 31
initialize ...................................................... 32

CHAPTER 4: DOS SHELL ......•...•......•....•..•..•................ 33
language selection
...•...•...•.........•........................ 33
primary menu screen •...•...................................... 33
disk/printer setup
..•.......................................•..• 33
run a program ••...•........................................... 34
format a disk .••...........................•.....•............. 34
cleanup a disk .....•....•...•............................. ' ..... 34
copy a disk
•....................•.....•..........•............. 35
copy files
..............•...••..........•...................•.. 35
delete files
..............••............................•....... 36
restore files
...........................................•....... 36
rename files
..............................................•.... 37
reorder directory .......•...................................... 37
PART TWO: ADVANCED OPERATION
AND PROGRAMMING
CHAPTER 5: SEQUENTIAL DATA FILES
........•...................... 39
the concept of files
............................................• 39
opening a file ...............•......•........................... 39
adding to a sequential file •...•......•........................... 43
writing file data: using print# ................................... 43
closing a
file ........•....•............•........................ 45
reading file data: using input# ................................... 46
more about input# (advanced users) .............................. 47
numeric data storage on diskette ................................. 48
reading file data: using get# ..................................... 49
demonstration of sequential files .................................. 51
CHAPTER 6: RELATIVE DATA FILES .................................. 53
the value of relative access ....................................... 53
files, records, and fields ......................................... 53
file limits •.................................................... 54
creating a relative
file ........................................... 54
using relative files:
record# command ............................. 55
completing relative file creation .................................. 57
expanding a relative
file .....................................•... 59
writing relative
file data ..............................•.......... 59
designing a relative record
...................................... 59
writing the record
.............................................. 60
reading a relative record ........................................ 64
the value
of index files (advanced users) ........................... 66

CHAPTER 7: DIRECT ACCESS COMMANDS ............•.............•. 67
a tool for advanced users ......................................•. 67
opening a data channel for direct access ........................... 67
block-read .................................................... 68
block-write ..........•....••..••..•...•............•.....•..... 69
the original block-read and block-write commands (expert users) ...... 70
the buffer pointer .............................................. 71
allocating blocks ...................•..•..................•..•.. 72
freeing blocks .....•...•..........•.........•............•..... 73
using random files (advanced users) ............................... 73
CHAPTER 8: INTERNAL DISK COMMANDS ............................ 74
memory-read ....•.......•...•.............•................... 75
memory-write ................................................. 76
memory-execute
..•...•••.........••..•..................••.... 77
block-execute .................................................. 78
user commands .•...•.............•...•...•...............•..•. 79
utility loader .................................................. 80
CHAPTER 9: MACHINE LANGUAGE PROGRAMS
....................... 81
disk-related kernal subroutines .................................. 81
CHAPTER 10: BURST COMMANDS .•......•..•........................ 82
read ......................................................... 82
write
.•...•..................•...............•................ 83
inquire disk
.....•............•...•............................ 83
format MFM ................................................•. 84
format
GCR (no directory) ...................................... 85
sector interleave
.................................•............. 85
query disk format ....................................•......... 86
inquire status ..................................•........•...... 86
chgutl utility
.................................................. 87
fastload utility ................................................. 87
status byte breakdown .......................................... 88
burst transfer protocol. .........•..•..........................•. 89
explanation of procedures ...•...•..•..••......................•. 90
example burst routines ..............•.........................•. 91
APPENDICES:
A: changing the device number .................................. 98
B: dos error messages .............•...............•............ 99
C: diskette formats: GCRfMFM .....•..••.................... ' ... 103
D: disk command quick reference chart .................•.......• 112
E: specifications of the
1571 disk drive ...•...•................... 114
F: serial interface information
..•............................... 116
G: disk operating systems: Commodore and CP/M
............•.... 118
USER'S MANUAL STATEMENT
........................... inside back cover

INTRODUCTION
MAIN OPERATING FEATURES
The 1571 is a versatile disk drive that handles multiple disk formats and data transfer
rates. Disk formats range from single-sided, single-density
to double-sided, double-
density. The
1571 can be used with a variety of computers, including the Commodore
128, the Commodore 64, the Plus 4, C16, and
VIC 20.
When used with the Commodore
128 Personal Computer, the 1571 offers the
following features:
• Standard andfast serial data transfer rates- The 1571 automatically selects the
proper data transfer rate (fast or slow) to match the three operating modes
available on the Commodore
128 computer (C128 mode, C64 mode, and CP/M
mode).
• Ability to read and write in double-density MFM format- This allows access to
the CP/M software libraries of other personal computers.
• Double-sided, double-density data recording-Provides up to 339K storage ca-
pacity per disk (l69K per side).
• Special high-speed burst commands- These commands, used for machine lan-
guage programs, transfer data several times faster than the standard or fast serial
rates.
When used with the Commodore 64 computer, the
1571 disk drive supports the
standard single-density GCR format disks used with the Commodore
1541,1551,4040,
and 2031 disk drives.
NOTE
CP/M disks are included in Commodore 128
carton; CP/M operating information is pre-
sented
in the Commodore 128 user manuals.
HOW THIS GUIDE IS ORGANIZED
This guide is divided into two main parts and seven appendices, as described below:
PART ONE: BASIC OPERATING INFORMATION-includes all the information
needed by novices and advanced users
to set up and begin using the Commodore
1571 disk drive. PART ONE is subdivided into four chapters:
• Chapter I tells you how
to use disk software programs that you buy, like Perfect
Writer® and Jane®. These pre-written programs help you perform a variety of
activities in fields such
as business, education, finance, science, and recreation. If
you're interested only in loading ard running pre-packaged disk programs, you
need read no further than this chapter. If you are also interested in saving, loading,
and running your own programs, you will want
to read the remainder of the guide.
• Chapter 2 describes
the use of the BASIC 2.0 disk commands with the Commo-
dore 64 and Commodore
128 computers.

• Chapter 3 describes the use of the BASIC 7.0 disk commands with the Commo-
dore 128.
• Chapter 4 describes the use
of the DOS Shell program, which provides you with a
convenient alternative way to execute disk drive commands. The DOS Shell
is
included on the 1571 test/demo diskette supplied with your disk drive.
PART TWO: ADVANCED OPERATION AND
PROGRAMMING-is primarily
intended for users familiar with computer programming.
PART TWO is subdivided
into six chapters:
• Chapter 5 discusses the concept
of data files, defines sequential data files, and
describes how sequential data files are created and used on disk.
• Chapter 6 defines the differences between sequential and relative data files, and
describes how relative data files
are created and used on disk.
• Chapter 7 describes direct access disk commands
as a tool for advanced users and
illustrates their use.
• Chapter 8 centers on internal disk commands. Before using these advanced
commands, you should know how to program a 6502 chip
in machine language
and have access to a good memory map of the 1571.
• Chapter 9 provides a list
of disk-related kernal ROM subroutines and gives a
practical example
of their use in a program.
• Chapter
10 gives information on high-speed burst commands.
APPENDICES A THROUGH
G-provide various reference information; for example,
Appendix A tells you how to set the device number through use
of two switches on the
back
of the drive.
2

PART ONE:
BASIC OPERATING INFORMATION
CHAPTER 1
HOW TO UNPACK, SET UP AND BEGIN USING THE 1571
STEP-BY-STEP INSTRUCTIONS
I. Inspect the shipping carton for damage.
If you find any damage to the shipping carton and suspect that the disk drive may have
been affected, contact your dealer.
2. Check the contents
of the shipping carton.
Packed with the
1571 and this book, you should find the following: 3-prong electrical
power cord, interface cable, Test/Demo diskette, and a warranty card to be filled out
and returned to Commodore.
3. Remove the cardboard shipping spacer from the disk drive.
The spacer is there
to protect the inside of the drive during shipping. To remove it,
rotate the lever on the front
of the drive counter-clockwise (see Figure I) and pull out
the spacer.
Figure L Front of 1571 Disk Drive
POWER DRIVE
LEVERFOR CLOSING DRIVE.
3

4. Connect the power cord.
Check the ON/OFF switch on the back
of the drive (see Figure 2) and make sure it's
OFF. Connect the cord where indicated in Figure
2. Plug the other end into a grounded
(3-prong) outlet. Don't tum the power
on yet.
Figure 2. Connection of Power Cord and Interface Cables to 1571
POWER CORD
SOCKET
GROUNDED
POWER
OUTLET
SERIAL PORT
CONNECTORS
FOR
INTERFACE
CABLES
4
ON/OFF
SWITCH
DIP SWITCHES
FOR CHANGING
DEVICE
NUMBER

5. Connect the interface cable.
Make sure your computer and any other peripherals are OFF. Plug either end
of the
interface cable into either serial port on the back of the drive (see Figure 2). Plug the
other end
of the cable into the back of the computer. If you have another peripheral
(printer or extra drive), plug its interface cable into the remaining serial port on the
drive.
6. Turn ON the power.
With everything hooked up and the drive empty, you can turn on the power to the
peripherals
in any order, but turn on the power to the computer last. When everything
is on, the drive goes through a selftest. Ifall is well, the green light will flash once and
the red power-on light will glow continuously.
If the green light continues to flash,
there may be a problem. Refer
to the Troubleshooting Guide.
OPERATING MODES
To achieve maximum compatability between the 1571 and other disk drives, the
1571 has two modes of operation that allow it to be used in a variety of situations.
1541 Mode
When you first turn on the 1571, it powers up in 1541 mode. That is, it works almost
exactly as a
1541 disk drive, which helps maintain compatability with certain special
programs and copy-protected diskettes. Also, many loading routines are dependent upon
the 1541-speed internal timing. However, when the drive
is in this mode, it can't take
advantage
of the special 1571 features.
1571 Mode
In 1571 mode, the drive can take advantage of such features as double-sided
diskettes, MFM-format diskettes, fast data transfer rates, and burst transfer protocol. The
1571 can determine whether or not the host computer can receive fast data transfer and
transmits accordingly.
Mode Selection
As mentioned above, the 1571 powers up in 1541 mode. However, it automatically
shifts to
1571 mode upon the first of a fast serial transfer initiated by the host (the
Commodore 128). The Commodore 64 and Plus 4 can't perform fast serial transfers on the
serial bus, but you can shift from
1541 to 1571 mode by sending the following BASIC
command: OPEN
1,8,15,"U0>Ml". Although these computers can't directly take
advantage
of the drive's faster transfer speeds, they can have twice the normal storage.
If you are using a Commodore 128 and want the 1571 to remain in 1541 mode, you
can send the following BASIC command: OPEN 1,8,15, "U0>M0". The drive will
then remain in
1541 mode until the next power up or system reset.
The possible combinations
of modes with the Commodore 128 and 1571 are shown
below:
C1281l571
modes-Turn on the drive, then turn on or reset the computer.
5

C128/1541 modes-Tum on or reset the computer, and when the cursor appears,
tum on the drive. In this case, the first disk access will switch
the drive
to 1571 mode, so send the BASIC command given on
the previous page
to lock the drive into 1541 mode.
C64!1571 modes
-Tum on the drive, then tum on or reset the computer and type:
GO 64
C64!1541 modes
-Tum on the drive, then hold down the COMMODORE key
while you tum on or reset
the computer.
TROUBLESHOOTING GUIDE
Problem
Red power-on
indicator not
lit
Green drive light flashing
Programs won't load and the
computer says
"DEVICE
NOT PRESENT ERROR"
Programs won't load, but
the computer and disk drive
give no error message
Possible Cause
Power not
ON
Power cable not
plugged
in
Power off to wall outlet
Drive failing its self test
Interface cable not well
connected or drive not ON
Switches on back
of drive
may not
be set for correct
device number
Another part
of the system
may
be interfering
6
Solution
Make sure ON/OFF switch
is ON
Check both ends
of power
cable to be sure they are
fully inserted
Replace fuse or reset circuit
breaker
in house
Turn the system off for a
moment then try again. If
the light still flashes. turn
the drive off and on again
with the interface cable
disconnected.
If the problem
persists. contact your dealer.
If unplugging the interface
cable made a difference.
make sure the cable is
properly connected. If that
doesn't work, the problem
is
probably in the cable itself
or somewhere else
in the
system
Be sure the cable
is properly
connected and the drive
is ON
Check Appendix A for
correct setting
to match
LOAD command
Unplug
all other machines
on the computer. If that
cures it, plug them
in one at
a time. The one just added
when the trouble repeats
is
most likely the problem
Trying
to load a machine
language program into
BASIC space will cause this
problem

TROUBLESHOOTING GUIDE (continued)
Problem
Programs
won't load and
green dri
ve light flashes
Possible Cause
Disk error
Solution
Check the error channel to
determine the error, then
follow the advice
in
Appendix B to correct it.
The error channel is
explained in Chapters 2 and 3
(Be sure to spell program names correctly and include the exact punctuation when loading the
programs)
Your programs load OK, but
commercial programs and
those from other 1571s don't
Your programs that used
to
load, won't anymore, but
programs saved on newly-
formatted diskettes will
Either the diskette
is faulty,
or your disk drive
is
misaligned
Older diskettes have
been damaged
The disk drive has gone out
of alignment
SIMPLE MAINTENANCE TIPS
1. Keep the drive well ventilated.
Try another copy of the
program.
[f several
programs from several
sources
fail to load, have
your dealer align your disk
drive
See the safety tips for
diskettes in the next section.
Recopy from backups
Have your dealer align
your disk dri
ve
A couple of inches of space to allow air circulation on all sides will prevent heat from
building up inside the drive.
2. Use Commodore diskettes.
Badly-made diskettes can cause increased wear on the drive's read/write head. If
you're using a diskette that is unusually noisy, it could be causing added wear and
should be replaced.
3. The
1571 should be cleaned once a year in normal use.
Several items are likely
to need attention: the two read/write heads may need cleaning
(with
91 % isopropyl alcohol on a cotton swab). The rails along which the head moves
may need lubrication (with a special molybdenum lubricant, not oil), and the write
protect sensor may need
to be dusted. Since these chores require special materials or
parts, it is best
to leave the work to an authorized Commodore service center. If you
want to do the work yourself, ask your dealer for the appropriate materials. IMPOR-
TANT: Home repair
of the 1571 will void your warranty.
INSERTING A DISKETTE
To insert a diskette, first open the drive door by rotating the door lever counter-
clockwise one quarter
tum until it stops, with the lever parallel to the horizontal slot in the
front
of the drive.
Grasp the diskette by the side opposite the large oval access slot, and hold it with the
label up and the write-protect notch to the left (See Figure 3). Now insert the diskette
by
pushing it straight into the slot, the access slot going in first and the label last. Be sure the
diskette goes in until it stops naturally. You shouldn't have
toforce or bend it to get it in.
7

NOTE: When the write/protect notch is covered by tape, the contents of the
diskette cannot be altered or added to. That prevents accidental erasing
of informa-
tion you want to preserve.
If a diskette comes without a write/protect notch, the
contents of that diskette were not meant
to be altered.
Blank diskettes may not have a label on them when you purchase them.
With the diskette
in position, seat it properly for use by twisting the door lever
clockwise one-quarter turn until it stops vertically over the slot. Warning: If
it doesn't
move easily, stop. You may have put the diskette
in the wrong way, or incompletely. If
that happens, reposition the diskette until the door lever closes easily.
=
=
c:::::::::J
OVAL ACCESS
SLOT
WRITE PROTECT
NOTCH
SOMETIMES COVERED WITH TAPE
Figure 3. Inserting a Diskette
DISKETTE CARE
I. Don't touch the exposed parts of a diskette.
That includes the access slot and the center hub (the hole
in the middle).
2. Don't bend a diskette.
They're called floppy diskettes, but they're not supposed to
be flopped.
3. Keep the diskettes (and disk drive) away from magnets.
That includes the electromagnets
in telephones, televisions, desk lamps, and calculator
cords. Keep smoke, moisture, dust, and food off the diskettes. Store diskettes upright
in their paper jackets.
4. Buy diskettes with reinforced hubs.
Although the drive usually centers a diskette correctly,
it would be difficult to rescue
data from a diskette recorded with
its hub off-center. Reinforced hubs make it easier
for the drive to center a diskette.
5. Remove a diskette before turning the drive off.
If you don't, you might lose part or
all the data on the diskette.
6. Don't remove a diskette from the drive while the green light
is glowing.
That light glows when the drive
is in use. If you remove the diskette then, you might
lose the information currently being written to the diskette.
8

USING PRE-PROGRAMMED (SOFTWARE) DISKETTES
Your software user's guide should list the procedure for loading the program into
your computer. Nevertheless, we've included the following procedure
as a general guide.
You'll also use this procedure to load programs or files from your own diskettes. For
purposes
of demonstration, use the Test/Demo diskette included with the disk drive.
1. Tum on system.
2. Insert diskette.
3.
If you are using a VIC 20, Commodore 64, or a Commodore 128 computer in C64
mode, type: LOAD
"HOW TO USE" ,8
If you are using a Plus/4 or Commodore 128 in C128 mode, type: DLOAD "HOW TO
USE"
4. Press the RETURN key.
5. The following will then appear on the screen:
SEARCHING FOR 0:HOW TO USE
LOADING
READY
•
6. Type: RUN
7. Press the RETURN key.
To load a different program or file, simply substitute its name
in place of HOW TO
USE inside the quotation marks. NOTE: The HOW TO USE program is the key to the
Test/Demo diskette. When you LOAD and RUN it, it provides instructions for using the
rest
of the programs on the diskette. To find out what programs are on your Test/Demo
diskette, refer
to the section entitled "DIRECTORIES" later in this chapter.
If a program doesn't load or run properly using the above method, it may
be that it is
a machine language program. But unless you'll be doing advanced programming, you
need not know anything about machine language. A program's user's guide should tell
you if it is written in machine language. If it is, or if you are having trouble loading a
particular program, simply add a
,1 (comma and number 1) at the end of the command.
L 9

.-----------------------------------------------------------------------------
, IMPORTANT
NOTE
Throughout this manual, when the format for a command is given, it will
follow a particular style. Anything that
is capitalized must bc typcd in exactly as it
is shown (these commands are listed in capital letters for style purposes, DO NOT
use the SHIFT key when entering these commands). Anything
in lower case is
more or less a definition of what belongs there. Anything in brackets is optional.
For instance,
in the format for the HEADER command given on the following
page, the word HEADER, the capital I
in lid, the capital 0 in Ddrive#, and the
capital U
in Udevice# must all be typed in as is (Ddrive# and Udevice# are
optional).
On the other hand, diskette name tells you that you must enter a name for the
diskette, but it
is up to you to decide what that name will be. Also, the id in lid is
left to your discretion, as is the device# in Udevice#. Thc drive# in Ddrive# is
always 0 on the 1571, but could be 0 or I on a dual disk drive. Be aware, however,
that there are certain limits placed on what you can use.
In each casc, those limits
are explained immediately following the format (for instance, the diskette name
cannot be more than sixteen characters and the device#
is usually 8).
Also be sure to type
in all punctuation exactly where and how it is shown in
the format.
Finally, press the RETURN key at the
end of each command.
HOW TO PREPARE A NEW DISKETTE
A diskette needs a pattern of magnetic grooves in order for the drive's read/write
head to
find things on it. This pattern is not on your diskettes when you buy them, but you
can use the HEADER command or the NEW command
to add it to a diskette. That is
known as formatting the disk. This is the command to use with the C 128 in CI 28 mode or
Plus/4:
HEADER "diskette
name" ,lid,Ddri ve# [,Udevice#J
Where:
"diskette
name" is any desired name for the diskette, up to 16 characters long (including
spaces).
"id" can be any two characters as long as they don't form a BASIC keyword
(such
as IF or ON) either on their own or with the capital I bcfore them. "drive#" is 0 .
"device#" is 8, unless you have changed it as per instructions in Appendix A (the 1571
assumes 8 even if you don't type it in).
The command for the C64, VIC 20, or CI28
in C64 mode is this:
OPEN 15,device#,
15, "NEWdrive#:diskette name,id"
CLOSE
15
The device#, drive#, diskette name, and id are the same as described above.
The OPEN command
is explained in the next chapter. For now, just copy it as is.
10

NOTE TO ADVANCED USERS
If you want to use variables for the diskette name or id, the format is as follows:
C128, Plus/4: HEADER (A$),J(B$),DO
C64: OPEN
J5,8,15:PRINT#15,"NO:"+A$+B$:CLOSEI5
Where:
A$ contains the diskette name (16 character limit)
B$ contains the
id (2 characters long)
After you format a particular diskette, you can reformat
it at any time. You can
change
its name and erase its files faster by omitting the id number in the HEADER
command.
DISKETTE DIRECTORY
A directory is a list of the files on a diskette. To load the directory on the C 128 or
Plus/4, type the word DIRECTORY on a blank line and press the RETURN key or simply
press the
F3 key on the C128. That doesn't erase anything in memory, so you can call up a
directory anytime--even from within a program. The C64 directory command, LOAD
"$",8 (press RETURN) LIST (press RETURN), does erase what's in memory.
If a directory doesn't all fit on the screen, it will scroll up until it reaches the last line.
If you want to pause, stop, or slow down the scrolling, refer to your particular computer's
user's manual for instructions
as to which keys to use.
To get an idea
of what a directory looks like, load the directory from the Test/Demo
diskette.
The 0 on the left-hand side
of the top line is the drive number of the 1571 (on a dual
disk drive it could be 0 or 1). The diskette name
is next, followed by the diskette id-both
of which are determined when the diskette is formatted.
The
2A at the end of the top line means the 1571 uses Version 2A of Commodore's
disk operating system (DOS).
Each ofthe remaining lines provides three pieces
of information about the files on the
diskette. At the left end
of each line is the size of the file in blocks of 254 characters. Four
blocks are equivalent to almost IK of memory inside the computer. The middle
of the line
contains the name
of the file enclosed in quotation marks. All characters within the
quotation marks are part
of the filename. The right side of each line contains a three-letter
abbreviation
of the file type. The types of files are described in later chapters.
11

TYPES OF FILES
PRG-Program
SEQ-Sequential
REL-Relative
USR-User
DEL-Deleted (you won't see this type)
Note: Direct Access files, also called Random files, do not automatically appear in
the directory. They are covered in Chapter 7.
The bottom line
of a directory shows how many blocks are available for use. This
number ranges from 664 (in
1541 mode) and 1328 (in 1571 mode) on a newly formatted
diskette
to 0 on one that is completely full.
SELECTIVE DIRECTORIES
By altering the directory LOAD command, you can create a kind of "sub-directory"
that lists a single selected type
of file. For example, you could request a list of all
sequential data files (Chapter 5), or one
of all the relative data files (Chapter 6). The
format for this command is:
LOAD"$0:pattern= filetype",8 (for the C64)
where pattern specifies a particular group
of files, and filetype is the one-letter abbrevia-
tion for the types
of files listed below:
P = Program
S = Sequential
R = Relative
U = User
The command for the C128 and Plus/4
is this: DIRECTORY" pattern = filetype"
Some examples:
LOAD"$0:* =
R",8 and DIRECTORY"* = R" display all relative files.
LOAD"$0:Z* =
R",8 and DIRECTORY"Z* = R" display a sub-directory consist-
ing
of all relative files that start with the letter Z (the asterisk (*) is explained in the
section entitled "Pattern Matching. "
12