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From: tdiaz-a(in_a_circle)-apple2-dotsero-org (Tony Diaz)
Newsgroups: comp.sys.apple2,comp.answers,news.answers
Approved: news-answers-request@MIT.EDU
Followup-To: comp.sys.apple2
Subject: Apple DOS & Commands Frequently Asked Questions (FAQ)

Archive-name: apple2/dos
Posting-Frequency: monthly
Last-modified: August 21 2007
Version: 1.03

FAQtual NOTE: This document contains both reference and contact information. While the reference information is still accurate, due to the passage of time you should assume that contact information is out of date and is only provided for historical reference.


Apple II DOS & Commands FAQ

This document attempts to give a detailed and correct set of Apple II DOS command line commands, covering those found in official releases of DOS 3.3 and ProDOS. It may also get into usage notes, non-command line OSs (GS/OS), etc, eventually.

Copyright (c) 1998-2007 by Tony Diaz (email: tdiaz-a(in_a_circle)-apple2-dotsero-org), all rights reserved. This document can be freely copied so long as 1) it is not sold, 2) any sections reposted elsewhere from it are credited back to this FAQ with the FAQ's copyright info and official WWW location (URL: left in place.

This FAQ may not be sold, bundled on disks or CD-ROMs, reprinted in magazines, books, periodicals, or the like without prior consent from the maintainer, Tony Diaz. Exceptions are explicitly granted for Juiced.GS and _The_Lamp. Email me for permission otherwise.

Big thanks to Nathan Mates, the previous maintainer of this comp.sys.apple2 FAQ, for allowing it to live on after his departure and anyone who took up that mantle before him.

Further, please link to, rather than post a copy elsewhere as this is subject to changes.

Disclaimer: I've tried to make this FAQ as accurate as possible, but there's the chance that it's not perfect. I apologize in advance for any slipups. Until I am confident that all information is 100% accurate, you are advised that you are following all info at your own risk. I will fix any problems found with this FAQ, but will not be held liable for the results of problems.

Last-modified: August 21 2007 Version: 1.03

General Intro to this FAQ and the command line environment

This FAQ attempts to be a reference for the commands supported by DOS 3.x (x=2, 2.1, or 3) and ProDOS at the command line level, as well as general usability issues. It does not cover where to acquire a copy and/or upgrade to any version of any OS; you should visit the comp.sys.apple2 Frequently Asked Questions (FAQ) at section 7.2 and other referenced sections.

Note that ProDOS does not have any command line support in the base OS; all command line functionality is part of the Applesoft BASIC environment provided by launching the 'BASIC.SYSTEM' 'System' file. Without BASIC.SYSTEM, ProDOS only has a Machine Language Interface (MLI) for interfacing with apps; during the rest of this FAQ, I have been lazy in referring to things as 'ProDOS' commands when they are ProDOS's BASIC.SYSTEM commands.

Applesoft BASIC commands are not included in this FAQ; they have a FAQ of their own at

This FAQ has a set of conventions as to items presented. Items presented in square brackets '[' ']' are optional. 'filename' is a legal filename for the OS being used, and for ProDOS, 'dirname' is a legal directory/path name, 'volname' is a ProDOS volume name. I list all commands in uppercase; DOS 3.x is case sensitive and commands must be uppercased. ProDOS is case insensitive, but for consistency, commands are still uppercased.

History and features of DOS 3.x and ProDOS

History of DOS 3.x and ProDOS

Apple's DOS (Disk Operating System) was written to support their Disk ][ drive when it debuted in early 1978. Version numbers for software were not as strict as they are now; the code started at v0.1, and incremented that by 0.1 per revision. When delivered to Apple, it was at version 3.0, and after Apple was done with their last modifications, v3.1 was the first version shipped. As the disk drive was single sided, all support for Apple 5.25" disks has been singlesided only.

With various bugfixes, DOS was at version 3.2.1 by 1979. These early releases supported only 13 sectors/track * 35 tracks for a total of 113.75K per disk side. With technological improvements to the disk interface card, 16 sectors could be fit in, for a total of 140K/side. DOS 3.3 was the revision capable of handling these 140K disks, and was released in 1980.

ProDOS was comissioned to be the 'Professional Disk Operating System', abbreviated 'ProDOS', and was first part of the Apple III's 'Sophisticated Operating System' (SOS, for an unfortunate acronym related to the general state of the Apple III). ProDOS was designed to be a replacement for DOS 3.3, and added many features not part of original DOS 3.3 such as support for disks other than the 5.25" drive, as well as directories and timestamping of files. A number of people have continued to use DOS 3.3 for various reasons, though ProDOS and various GS versions of it (ProDOS 16 and GS/OS) have become much more popular among Apple IIGS owners, as well as HD users.

Features of DOS 3.x

DOS 3.x as released from Apple supports only the 113.75 and 140K 5.25" disk formats. It supports up to 105 files per side, no directory support, with very loose rules on filenames. It was initially bundled with Apple's disk ][ drives, so it won a lot of support for being free and usable. Since 1980, DOS 3.3's 140K per 5.25" side has become the reigning standard for the DOS 3.x versions. DOS 3.x 'System Master' disks could boot and run on any machine with at least 16K of memory (though 24-32K was rather recommended)

It did have a number of unsuccessful patches to fix a problem with the APPEND command not properly finding the end of a file before beginning to write; I know of no 100% fixes for that bug.

Due to some double-buffering while reading and decoding files off disks, DOS 3.x was not as fast as it could be. A few companies sold modified versions of DOS 3.3 to avoid the extra copy and thus dramatically speed up disk access; Beagle Bros's ProntoDOS and many others were widespread. DOS 3.3 could also be modified to do other things, such as use a few more tracks on disk for extra space, relocate itself into the top 16K of memory on a 64K machine, but again, these were all third party patches, nothing official from Apple. Some of these patches and features came at the expense of the INIT command.

2.3 Features of ProDOS

ProDOS allowed directories to be created and files stored in them, time/date stamping of files, and support for disks other than the original Disk ][ drive-- up to 32MB per disk volume (partition). It did go with far more restrictive filenames (possibly as an attempt to move 'towards' MS-DOS), and case insensitive filenames at the cost of everything appearing in uppercase.

Apart from the very earliest versions, ProDOS has required a 64K Apple II. When the Apple IIGS came out, the need for a 16-bit OS was apparent, so with a quick wrapper around ProDOS, 'ProDOS 16' was created, turning the existing ProDOS to 'ProDOS 8'. Versions 2.x of ProDOS 8 require an enhanced //e, //c, IIc+ or GS.

ProDOS incorporates most to all of the disk read speedups provided by DOS 3.3 third party enhancements, so it does not need to be patched to sped up.

ProDOS also has the ability to not reside on a disk when first formatted (at obvious disk space savings), but be copied on later and the disk will be bootable if copied correctly to the root directory as well as an application to run at boot. Similar functionality could be gained in DOS 3.x by using certain utility programs, but is not standard.

ProDOS's 'BASIC.SYSTEM' commandline functionality gained a few features over DOS 3.3, such as support for typing commands in lowercase. A few lesser-used commands were removed, most notably the ability to switch to 'Integer Basic', as well as disk formatting.

Commands quick reference

A listing of all commands, one per line, to facilitate finding the appropriate commands. Only the required part of each command is shown here; optional parts are detailed in the sections on DOS 3.x optional params and ProDOS optional params.

Commands common to both DOS 3.x and ProDOS:

Command Action
CATALOG Shows a directory listing. [ProDOS: see also cat]
LOAD filename Loads a Applesoft BASIC program.
SAVE filename Saves a Applesoft BASIC program.
RUN filename Loads and runs a Applesoft BASIC program.
BLOAD filename Loads a binary file.
BSAVE filename,Aaddr,Llen Saves a binary file.
BRUN filename Loads and executes a binary file
OPEN filename Opens a text file. For BASIC programs only.
CLOSE [filename] Closes specified (or all) open text files.
READ filename Reads from a text file. For BASIC programs only.
WRITE filename Writes to a text file. For BASIC programs only.
APPEND filename Appends to a text file. For BASIC programs only.
POSITION filename Sets position in text file. For BASIC programs only.
EXEC filename 'Executes' a text file, as if every line was typed.
DELETE filename Attempts to remove a file from disk
LOCK filenname Quick file protect from change or deletion
UNLOCK filenname Undoes a LOCK
RENAME file1,file2 Renames 'file1' to 'file2'
IN#slotnum Redirects input from the specified slot
PR#slotnum Redirects output to the specified slot
VERIFY filename Checks existence, DOS 3.3 checks if is readable

DOS 3.x only commands:

INIT filename Formats disk, current BASIC program saved as boot app.
MON [,C][,I][,O] Traces DOS 3.3 commands
NOMON [,C][,I][,O] Cancels tracing of DOS 3.3 commands
MAXFILES n Reserves buffers for disk i/o
FP Switches to Applesoft BASIC, erases program in memory
INT Switches to Integer BASIC, erases program in memory

ProDOS's BASIC.SYSTEM only commands:

CAT 40-column directory listing.
PREFIX [dirname] Displays current directory or changes current dir.
CREATE filename Creates a file with optional type
- filename Executes Applesoft, binary, text, system file
BYE Exits to ProDOS application switcher
FLUSH Writes all buffers to disk
CHAIN filename Runs another Applesoft program, variables intact
FRE Faster Applesoft string garbage collection
STORE filename Writes Applesoft variables to a file
RESTORE filename Reads Applesoft variables from a file
MTR Jumps to monitor (same as 'CALL -151')

In depth explanation of commands, optional params

DOS 3.x file names and types

DOS 3.x filenames can from 1-30 characters in length, and must start with an uppercase letter. They cannot contain commas, colons, but can contain control characters. (Return (control-M) is a pain to type, and thus usually out). DOS 3.x has essentially 8 filetypes, noted by the character in the directory listing: Applesoft Basic (A), Integer Basic (I), Text file (T), Binary (B), 'S' (source? -- rarely used) type files, and 'R' (relocatable-- also rarely used) files, plus a second 'A' and 'B'.

A sample directory listing from a CATALOG is shown below:


*A 006 HELLO



*B 010 BOOT13

The leftmost column contains either a '*' or is empty. A '*' means the file is 'LOCKed' against accidental deletion or overwriting, a blank space means that it can be saved over or deleted at will. The next column is the filetype, as noted above. The third column, of three digit numbers, represents the file size on disk in number of 256-byte sectors used. [If this size is greater than 255, the number is modulo 256]. Finally, the filename is given.

ProDOS file names and types

ProDOS is far more limited in its filenames. Names are up to 15 characters, must start with a letter, and can contain letters, digits [0..9] and the period. Filenames are essentially case insensitive, though they are always displayed as uppercase on disk.

ProDOS also allows directories and volume names; components are separated with the forward slash ('/') used by OSs whose designers weren't being idiotic, like MS-DOS.

ProDOS allows far more types, allowing 256 'major' types, with each major type capable of having up to 65536 subtypes. Unlike MS-DOS, the filetype is not part of the actual filename, nor can two different files with the same name but different types exist. In a BASIC.SYSTEM and similar directory listing, the major type is listed as either a 2-digit hexadecimal value preceede by a $, or for certain other common types, a 3-letter acronym is used. The most common types that are encountered are:

  • 'SYS': System files, such as ProDOS and certain applications
  • 'DIR': Directory
  • 'BIN': Binary file
  • 'BAS': Applesoft BASIC file
  • 'TXT': Text file

Filetypes are not considered part of the filename, so there can only be one file with a given name, regardless of the type. A sample ProDOS directory listing is shown below:

STARTUP BAS 12 20-AUG-96 20-AUG-96 3:14 5645

This is the 80-column version generated by CATALOG; the 40-column version by CAT omits the right 40 columns from the listing. Again, we have the first column being either blank or a '*' for locked files, the filename ('STARTUP' here), then the filetype (BAS), number of 512-byte blocks used, creation and modification dates and time, and finally the filelength of 5645 bytes.

Extended command line parameters for DOS 3.x commands

Certain commands under DOS 3.3 require a you to specify the address and/or length; this is noted with an ',Aadr' or ',Llen' after the filename. The address and length can be either decimal or hexadecimal (proceeded by a '$'), and must range from 0 to 65535 (0..$FFFF hex). See the extended syntax below for which files require which parameters.

'Random access' text files may have the record specified when accessing them by ',Rn', or the byte within a field specified by ',Bn'. For more information on accessing text files from within Basic, please see the Applesoft Basic FAQ at

Pretty much all DOS 3.x commands that deal with files can have any of 3 extra parameters specified in any order with commas after the filename: [,Dn] [,Sn] or [,Vn]. ',Dn' sets the drive number for this and subsequent DOS commands; DOS 3.x only supports 2 drives per slot.

',Sn' sets the slot number for this and subsequent DOS commands. Specifying a slot/drive combination that does not exist will return an error. Both the slot and drive number 'stick' until changed, even if the disk is physically swapped for another.

The third parameter, ',Vn' sets the "volume number" for DOS 3.3 to 'expect' on a disk when accessed. This volume number is specified when formatted with INIT, defaulting to 254 if not specified. ',V0' will match any disk volume number, which is the default.

Extended command line parameters for ProDOS commands

While ProDOS lost the ',Vn' parameter, the ',Sn' and ',Dn' can be specified for all commands accessing files. In addition, a number of commands (APPEND, BLOAD, BSAVE, CREATE, OPEN) can take a ',Ttype' parameter, specifying the type of file to match against instead of the default of TXT, BIN, BIN, DIR, and TXT respectively.

In addition to the DOS 3.x ',An', ',Llen', 'Bn', and ',Rn' parameters when appropriate, certain commands can also take a few other parameters: ',En' for ending address, ',Fn' for field number, and ',@num' for BASIC line number.

Detailed explanation of commands

Please note that I only list any additional commandline params; for optional (and OS-specific) command line params, please see above.

- filename

[ProDOS only] This command is simply the 'dash' character, followed by a filename. Loads and executes a file of type BIN, BAS, TXT or SYS.

APPEND filename

[Basic programs only, not from command line.] Parallel to the OPEN command, but positions the file for writing to the end. This is not guaranteed to work under DOS 3.3. For more information on accessing text files from within Basic, please see the Applesoft Basic FAQ at

ProDOS extended syntax: 'APPEND filename[,Ttype][,Llen]': allows overriding of the default filetype of TXT, and also specifies where to append from.

BLOAD filename[,Aadr]

Loads a binary file from disk to address and length specified when saved. The optional ',Aadr' parameter allows you to specify a new location for the first byte of the file when loaded. No relocation of program code is performed, however.

ProDOS extended syntax: 'BLOAD filename[,Aadr][,Blen][,Llen][,Elen][,Ttype]'. Allows you override the address, length, filetype, and from where in the file the chunk you want should be loaded.

BSAVE filename,Aadr,Llen

Saves a binary file to disk, writing len bytes from the starting address.

ProDOS extended syntax: 'BSAVE filename[,Aadr][,Blen][,Llen][,Elen][,Ttype]'. The address and length can be omitted; if so, they default to what was last explicitly specified for the file.

BRUN filename

Does a BLOAD on a file, and then does a machine language jump to the starting byte, attempting to execute the file. If the file is not designed to be executed, it may crash or behave oddly.

ProDOS extended syntax: my copy of 'Apple ProDOS-- Advanced features for programmers' notes that all of the extended params for BLOAD are usable, except for the type.


[ProDOS only]. Exits to the currently installed program switcher provided by ProDOS. May not be available on the earliest versions of BASIC.SYSTEM.

CAT [pathname]

[ProDOS only]. 40-column directory listing.


Directory listing. DOS 3.x's directory listing fits in 40 columns wide, while ProDOS's CATALOG is 80 columns wide. See also CAT

CHAIN filename

DOS 3.x integer basic: loads another program, starts executing it with all the variables unchanged from the first. Not really usable with DOS 3.x and Applesoft Basic

ProDOS extended syntax: 'CHAIN filename[,@line]'-- works with Applesoft BASIC programs properly, allows you to specify a starting line number for program execution

CLOSE [filename]

Closes any OPENed text files, flushes any pending changes to disk. If a filename is specified, that file is closed; if no filename is specified, any and all open files are closed.

CREATE filename[,Ttype]

[ProDOS only] Creates a file on disk with the specified name and type. If the type is omitted, a subdirectory (type='DIR')is created.

DELETE filename

Attempts to delete a file. Files cannot be deleted if the disk is write protected, the file is LOCKed, or an error occurs.

EXEC filename

Takes a text file on disk, and redirects input from it as if all lines had been typed at the command prompt. It continues until all of the file is parsed this way, not stopping for errors if this is not a valid set of commands.

ProDOS extended syntax: 'EXEC filename[,Fnum][,Rnum]'-- allows you to specify the number of the first line in the file executed


[ProDOS only] Writes any pending (i.e. cached) disk writes to their physical media.


[DOS 3.x only] Switches to 'Floating Point' (i.e. Applesoft BASIC), if that is available, also dumps any Basic programs out of memory, even if Applesoft was active to start with.


[ProDOS only] Faster string garbage collection than that provided by Applesoft Basic in ROM. Useful mainly from within Basic programs.


Redirects input to come from the specified slot, or use slot 0 for the keyboard. This parallels the Basic command of the same name, since both DOS 3.x and ProDOS hook themselves into the i/o vectors, and need to stay attached, even with input coming from elsewhere. Like all OS commands, within an Applesoft Basic program, this command should be preceeded by the control-D character.

INIT filename

[DOS 3.x only] Formats a disk, and saves the currently loaded Basic program in memory as the program run on boot of that disk with the specified name.


[DOS 3.x only] Switches to Integer Basic, if available, dumps any Basic programs from memory.

LOAD filename

Loads a Basic program from disk. Under DOS 3.x, if you load a program with the 'wrong' Basic from what is currently loaded, the Basic is switched, if available.

Note that Basic on machines with cassette ports (][, ][+, //e) has a 'LOAD' command of its own, where it tries to load from the cassette port. If a filename is specified, then DOS handles it, otherwise it passes it to Basic.

LOCK filename

Sets a flag on the file so that it cannot be accidentally overwritten or deleted. Does not protect from disk initialization, and is easy to undo with an UNLOCK


[DOS 3.x only] Allocates memory space for the specified number of files to be open at once. The default is 3. BASIC.SYSTEM moves memory around as needed, so this command does not exist under ProDOS.

MON [,C][,I][,O]

[DOS 3.x only] Provides a running trace of DOS 3.x commands for 'Commands', 'Input' and 'Output'.


[ProDOS only, and also only available with BASIC.SYSTEM v1.4 or higher, I believe]. Goes to the builtin monitor ('*' prompt), just like typing 'CALL-151'.

NOMON [,C][,I][,O]

Cancels any pending traces of things by MON. ProDOS accepts by ignores this command, as there is no builtin MON.

OPEN filename[,Llen]

[Basic programs only, not from command line.] Opens a text file from within a program. It can be read from or written to with the appropriate subsequent commands. The optional length parameter is used to specify that a text file is to be opened in 'random access' mode. For more information on accessing text files from within Basic, please see the Applesoft Basic FAQ at

POSITION filename[,Rn]

[Basic programs only, not from command line.] Moves the disk file pointer for the specified file the specified number of fields forward from its current position. If the file is not open, it is OPENed first. If the ',Rn' parameter is omitted, the file pointer is not changed. For more information on accessing text files from within Basic, please see the Applesoft Basic FAQ at

ProDOS extended syntax: the ',Fn' parameter may be used to the same effect.


Sends subsequent output to the specified slot, or the 40-column screen if '0' is given for the slotnum. If output is sent to a slot containing a disk controller, the system attempts to boot from drive 1 of that slot. Like all OS commands, within an Applesoft Basic program, this command should be preceeded by the control-D character.

PREFIX [pathname]

[ProDOS only] Gets or sets the current pathname prefix. If a prefix or slot/drive location is specified, it is used as the new prefix; use a leading slash on a pathname to specify an absolute path, or omit it for a path relative to the current. There is no '..' "backup" operator provided. If no pathname or drive/slot location is specified, the current prefix is returned.

READ filename[,Rnum]

[Basic programs only, not from command line.] Specifies that subsequent input should come from an already OPENed file. If specified from a random access file, the ',Rnum' jumps to the specified record number. For more information on accessing text files from within Basic, please see the Applesoft Basic FAQ at

ProDOS extended syntax: the ',Fnum' lets you go to the specified line number, and/or ',Bnum' to go to the specified byte position from the current. If multiple params are specified, the record number is jumped to first, then field, then byte.

RENAME oldfilename,newfilename

Renames the first specified file to the new name. This is one of the few cases where two filenames are required, separated by a comma.

RESTORE filename

[ProDOS only] Loads a file of Applesoft Basic variable declarations saved with a STORE. Applesoft implements its own RESTORE command for a rather different purpose; the filename is used to flag that this is a DOS command.

RUN filename

Loads the specified Basic file, and runs it. [Clears all variables, starts execution at lowest numbered line.]

ProDOS extended syntax: 'RUN filename[,@line]' -- optional paramter for starting at a line other than the first line. See also CHAIN

SAVE filename

Writes the current Basic program (no variable declarations) to disk.

Note that Basic on machines with cassette ports (][, ][+, //e) has a 'SAVE' command of its own, where it tries to save to the cassette port. If a filename is specified, then DOS handles it, otherwise it passes it to Basic.

STORE filename

[ProDOS only] Stores all current variable declarations (simple and arrays), but not function declarations to disk. Can be loaded back later with a RESTORE.

Note that Basic on machines with cassette ports (][, ][+, //e) has a 'STORE' command of its own, where it tries to save to the cassette port. If a filename is specified, then DOS handles it, otherwise it passes it to Basic.

UNLOCK filename

Undoes a LOCK, allowing overwriting or deleting of a file.

VERIFY filename

DOS 3.x reads every sector of the file to make sure that the file is readable. ProDOS merely checks to see if the file exists or not; does not perform a read test.

ProDOS extended syntax: 'VERIFY' with no filename displays a copyright notice.

WRITE filename[,Rnum]

[Basic programs only, not from command line.] Specifies that subsequent output shoud go to an already OPENed or APPENDed file. If specified from a random access file, the ',Rnum' jumps to the specified record number. For more information on accessing text files from within Basic, please see the Applesoft Basic FAQ at

ProDOS extended syntax: the ',Fnum' lets you go to the specified line number, and/or ',Bnum' to go to the specified byte position from the current. If multiple params are specified, the record number is jumped to first, then field, then byte.

Miscellaneous questions and answers

Which OS am I in?

The best method of checking is to use a command not found in both DOS 3.x and ProDOS, such as 'CAT'. If that command works, you're in ProDOS. If not, try 'CATALOG'-- if the 'CATALOG' fails, you have neither standard DOS 3.3 nor standard ProDOS loaded.

How do I format a disk?

Under DOS 3.x, use the INIT command to format a disk, write the current memory image of DOS 3.x to the disk, and the current Basic program as the startup program. If the INIT command is not recognized, you are either in ProDOS or you are using a nonstandard patchset to DOS 3.x that removed the INIT command.

ProDOS has no builtin disk formatting code; it was removed to make space. You will need to use an application capable of doing the formatting-- common ones are those found on the ProDOS 8 system utilities disk provided by Apple, Copy ][+, Shrinkit, Appleworks, or several other programs. After formatting a ProDOS disk, you will need to copy the 'PRODOS' file and at least one 'SYS' file with name ending in '.SYSTEM' (e.g. BASIC.SYSTEM) to make it bootable, or you'll get an 'UNABLE TO LOAD PRODOS' error on trying to boot that disk.

How do I copy/move files/disks?

This functionality is not built in to either DOS 3.x or ProDOS from the commandline; you will need to run an application to do so. ProSEL 8 published by Charlie's Appleseeds can do a good job at that. Copy ][+ does not follow the rules, and is NOT safe to use on hard drives with ProDOS-- it tends to corrupt the disk if any GS/OS 'extended' files are present.

In a pinch, if you only need to copy files, you can manually LOAD/SAVE or BLOAD/BSAVE to load and then save files from one disk to another, but this is extremely tedious, does not tend to work (unless uses extra params under ProDOS) on large (>35K) files or non-basic/binary files, and errprone.

Can I put DOS 3.x on my hard disk?

Not by any publically available methods to my knowledge. DOS 3.x was designed for only 5.25" disks, though it is possible to put up to 400K on a DOS 3.x volume. With 254 volume types available, you could creake up to about 98MB on a HD. DOS 3.x also does not have any builtin support for any drives other than the 5.25" drive-- you'd have to manually hack the OS to talk to a different drive. In any case, you're still limited by a lot of 400K volumes, lack of subdirectories, and having to rewrite the OS yourself.

ProDOS is much more HD friendly, in terms of being able to talk to volumes up to 32MB in size, subdirectory support, and the like.

A somewhat workable solution is to use DOS 3.3 Launcher. It lets you copy unprotected DOS 3.3 140K disks to your hard drive, and run DOS 3.3 under ProDOS. Such functionality does have some requirements, though: programs must only use 48K of RAM (the upper 16K is reserved for ProDOS, which is running at the same time), not do any copy protection or disk hackery, and generally behave themselves. DOS 3.3 Launcher is available from the normal Apple II ftp sites:

Can I speed up DOS 3.3 or ProDOS?

Due to some double-buffering while reading and decoding files off disks, DOS 3.x was not as fast as it could be. A few companies sold modified versions of DOS 3.3 to avoid the extra copy and thus dramatically speed up disk access; Beagle Bros's ProntoDOS and many others were widespread. Sorry, I do not know where any copies of these speedups can be found legally online. [And I'm not going to help anyone break the law.] ProDOS incorporates most to all of the disk read speedups provided by DOS 3.3 third party enhancements, so it does not need to be patched to sped up.

What about file/disk undeletion?

File undeletion capabilities are available for DOS 3.x via various programs (sorry, no idea if any are available legally online). ProDOS prior to version 1.4 (or maybe 1.2) scrambled filetables on deletion, so it is much harder to recover data if deleted under that. ProSEL and other commercially available programs can undelete ProDOS files.

There is no disk undelete functionality available-- if a disk is fully reformatted (all sectors/blocks overwritten), all previous data is obliterated. If only the directory track(s) are erased, it might be possible with a lot of work-- ProSEL 8 published by Charlie's Appleseeds has a number of tools for dealing with ProDOS disks.

How do I view a text file?

Along with copying files/disks, this is another area not directly supported by either DOS 3.3 or ProDOS without addon programs. Under ProDOS, 'Sneeze' is reported to be a good file viewer:

What does "UNABLE TO LOAD PRODOS" mean when I boot a disk?

As noted above, ProDOS is not automatically installed on every disk formatted under ProDOS. All that is writted to disk is a very short boot program that looks for a system (type 'SYS') file in the root directory called 'PRODOS'. If that file is present, it is loaded, and ProDOS installs itself. If there is no PRODOS file found, the error message of "UNABLE TO LOAD PRODOS" is displayed on the screen.

To make such a disk bootable, all you need to do is copy the file 'PRODOS' from a working ProDOS boot disk to the root directory of the disk you want to be able to boot from, assuming there is enough free space to copy that file.

You will also want to copy at least one other system (type='SYS') to the root directory of any disk you want to boot, as ProDOS scans the root directory for the first SYS file with name ending in ".SYSTEM" to execute, or it'll be unhappy. A good candidate for such a file is Apple's "BASIC.SYSTEM", providing the Basic interpreter and command line interface to ProDOS.

If you choose to use Macs and Disk Copy to download System 6.x, make sure to use Double Sided/Double Density (DSDD - 720K or 800K) disks-- 1.44MB (HD) disks will be written to as 1.44MB disks, which most GS drives cannot deal with. Also, if your GS is refusing to boot off the install disk (with an 'UNABLE TO LOAD PRODOS' message), and you have a Quadra or Powermac, you may be a victim of Apple's costcutting in 3.5" drives-- those drives may report disks as successfully written, but GSs will be unable to read them. Switch to an older Mac with a usable drive, or use a null modem program to transfer the files.

How do I switch drives/disks?

DOS 3.3 and also ProDOS allow you to specify which disk you want to use by specifying its physical location when accessing it. This is done with the slot-changing ',Sx' (1<=x<=7) and/or drive-changing ',Dy' (y=1 or y=2) parameters at the end of a command. Each slot may have up to 2 drives connected to it. Slot 6 is normally used for 5.25" drives, and slot 5 for 3.5" [or to a lesser degree, Slot 3 Drive 2 if /RAM5 is used] disks, but system configurations may vary.

The slot/drive selections are 'sticky'-- they'll remain in effect until you select another slot/drive to use.

Under ProDOS, you can also use the PREFIX command to change to a slot/drive combination [PREFIX[,Sx][,Dy]] or to a volume by volume name [PREFIX /volname].

I don't have an OS for my Apple II or want an update. Where do I get it from?

[Copied from the comp.sys.apple2 FAQ section 7.2 at . Consult that FAQ for help on downloading, etc.]

First, consult the following chart to help determine what you should be looking to run on your Apple II-- there's a lot of possible OSs. Downloads usually require you to have comm programs up and running on your Apple II and/or Mac with a 3.5" disk that fully supports 800K disks (a lot of Powermacs are flakey in that area). Without such an ability, see below for places to purchase/copy it from. See csa2 FAQ Section 2.* on the Apple II models or csa2 FAQ section 7.7 on determing RAM to determine what your Apple II has if the limitations in the following are confusing.

  • Any Apple II, 5.25" drive, 32K or more RAM: DOS 3.3. This is not legally available online to the best of my knowledge, as Apple still holds the copyright and distribution restrictions on it. However, Diversi-DOS, a Shareware enhanced version (may require 48K or 64K RAM) of it with many speedups is available online:

  • Apple II+ or better, 5.25", 3.5", or HD, 64K RAM: ProDOS 8 v1.0-1.9. [Avoid v1.3 if using a ][+ or unenhanced //e]. [Note: have not verified that this is ProDOS 1.9]

  • Apple //c or IIc+, Enhanced //e, GS, 5.25", 3.5", or HD: ProDOS 8 v2.x. A shrunk 800K 3.5" disk with this version is at bsc [Not available in 5.25" format online]

  • Apple IIGS, 3.5" disk or HD, 512K or more RAM: ProDOS 16. Very old and slow. Not available anywhere online legally to my knowledge.
  • Apple IIGS (ROM version 01 or 3), 3.5" disk or HD, 768K or more RAM: GS/OS version 5.0.4. Get the .bsc files from

  • Apple IIGS (ROM version 01 or 3), 3.5" disk or HD (HD highly recommended), 1MB or more RAM: GS/OS version 6.0.1.

Download from or a Mac 'Disk Copy' format at See the csa2 FAQ's Section 9 (System 6.0 Mini-FAQ) for more info on bugfixes, updates, problems with this version.

All of the above were always distributed as full versions of the system software; there is no need to 'upgrade' thru system 4 or 5 to get to 6. Consequently, don't look for any patches to save download time; those never existed.

[Note: there are some other versions of the System Disks not listed above; the ones listed are the latest versions, which you should be running to get as many features and as few bugs as possible. Most of the older (and especially the very buggy) versions are not available online for that reason.]

Without an operating system, you can't run a comm program to download the operating system, so you're in a bit of a quandry. One method is to call 1-800-SOS-APPL and try and find an Apple II user group in your area. They should be able copy things for you.

If you are unable to find a local user group, one of the next best options is to contact Steve Cavanaugh (section 10.2), who is licensed to copy ProDOS 8 [runs on pretty much all Apple IIs with at least 64K of RAM], along with a 5.25" disk full of comm programs, etc. The comm program disk costs only $3, which is a great deal. Ask him for more details if interested.

Alltech Electronics (see csa2 FAQ section 10.2) is licensed to sell many of the above, such as GS System Software 5.0.4 and 6.0.1, Apple // System Disk 4.02, and ProDOS 1.1.1. Contact them for details on pricing, etc.

There are a lot more questions with answers not included directly in this FAQ; please see for more of them.

Copyright 1998-2007 by Tony Diaz

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