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Apple II Csa2 FAQs: DOS & ProDOS, Part 6/25

( Part1 - Part2 - Part3 - Part4 - Part5 - Part6 - Part7 - Part8 - Part9 - Part10 - Part11 - Part12 - Part13 - Part14 - Part15 - Part16 - Part17 - Part18 - Part19 - Part20 - Part21 - Part22 - Part23 - Part24 - Part25 )
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Archive-name: apple2/faq/part6
Posting-Frequency: monthly
Last-modified: 2009/12/01

See reader questions & answers on this topic! - Help others by sharing your knowledge
The comp.sys.apple2 Usenet newsgroup Apple II FAQs originate from
the II Computing Apple II site, 1997-2010. 

Csa2 FAQs file ref: Csa2DOSMM.txt  rev141 December 2009


 001- What is a "DOS"?
 002- What DOS's are available on Apple II computers?
 003- Are there any faster better versions of DOS 3.3?
 004- What commands are available in DOS 3.3?
 005- How do I use DOS commands from the keyboard?  a program?
 006- How do I use variables in a DOS command?
 007- How do I create new DOS 3.3 diskettes?
 008- How much storage space is on a 5.25" diskette?
 009- Can I format a DOS 3.3 diskette for just data storage?
 010- What is the "Volume Table of Contents" or "VTOC"?
 011- Can I assign names to my DOS 3.3 diskettes?
 012- What does it mean to "Boot" a disk?
 013- What file types does DOS 3.3 have
 014- What do the entries in a DOS 3.3 Catalog display mean?
 015- Re. DOS 3.3 file names: How long? What characters are legal?
 016- How can I use DOS 3.3 to read/write sectors from machine code?
 017- How many 'official' versions of DOS 3.3 are there?
 018- How can I find out the address and size of a BLOADed file?
 019- What information is included in the VTOC and Catalog sectors?
 020- How does DOS 3.3 remember which sectors are used?
 021- What are the formats of DOS 3.3's main file types?
 022- How can I run DOS 3.3 programs from 3.5" disks and hard disk?
 023- How can I get DOS 3.3 from the net without an A2 tcom utility?
 024- What is ProDOS?
 025- What are ProDOS's major features?
 026- Which Apple II's can run which versions of ProDOS?
 027- How can I create bootable ProDOS diskettes?
 028- How do I make a ProDOS disk that will boot and start a BASIC program?
 029- What is the maximum size of a ProDOS volume?
 030- How do I LOAD, SAVE, etc. files under ProDOS?
 031- What is a "pathname"?
 032- What is the default volume and folder when ProDOS boots?
 033- How can I set default volume and folder under ProDOS?
 034- How can I discover the volume name of a just booted disk?
 035- How do I create a folder?
 036- How can I access ProDOS routines from machine language?
 037- How can I convert DOS 3.3 wares to run under ProDOS?
 038- How can I modify ProDOS to do BLOADs to Text Page 1?
 039- How can I boot ProDOS on my Franklin computer?
 040- What are some good DOS 3.3 and ProDOS references?
 041- How can a BASIC program tell which DOS it's running under?

From: Rubywand

001- What is a "DOS"?

    "DOS" means "Disk Operating System". A DOS is a collection of machine language routines and data which lets a computer Read and Write information to/from disk. A DOS also includes commands, such as SAVE and LOAD, which you can use to create and access files on disk.

     Apple II DOS, Commodore 64 DOS, and the DOS used on PC's are all called "DOS"; but, they are different systems. Their commands are similar, sometimes identical, because what users want to do with disks is about the same whatever the computer. However, the way each DOS arranges and keeps track of data on disk is very different. You will not, for example, be able to read files from a C-64 diskette on your Apple II running under DOS 3.3.


002- What DOS's are available on Apple II computers?

     DOS 3.3 is the first DOS to be widely used on Apple II computers. Many programs were written to use DOS 3.3 commands and saved on DOS 3.3 diskettes. Apple 'officially' replaced DOS 3.3 with ProDOS back in the early '80's. However, DOS 3.3 continues to be popular with II users. To get DOS 3.3 from the net, see Csa21MAIN4: Get It- Links to popular software packages.

     Another Apple II DOS is the one introduced with Apple Pascal. Compared to DOS 3.3 or ProDOS, the Apple Pascal DOS is a very limited, cumbersome operating system.


003- DOS 3.3 seems kind of slow. Are there any faster
     better versions of DOS 3.3?

     Yes. Today, most "DOS 3.3 users" do not actually use DOS 3.3. Long ago, Beagle Bros introduced patches which resulted in much better speed, freed-up extra disk space, and added a CATALOG command which shows number of Free Sectors. Their Prontodos or some modification of it is, for practical purposes, the "current version" of DOS 3.3.

     ES DOS ][ adds a few mods to Prontodos. CATALOG shows Free Sectors and Number of Tracks and it scrolls the entire Catalog (scrolling stopped by pressing any key) instead of stopping when the screen is full. ES DOS ][ also lets you use the semi-colon as a terminating 'wildcard' character. This DOS includes a CATALOG fix to show correct size of files bigger than 255 sectors.

     Other popular, higher speed versions of DOS 3.3 include David DOS and Diversi-DOS; and, there are several small, special-purpose versions of DOS 3.3. (For example, one game maker used RDOS to save space and to make its diskettes harder to copy.)  Below is a chart which compares speed and features for standard and speeded versions of DOS 3.3.

              BLOAD Time   Does    Large Files   Frees 15  Disp Free  Error
               Test***     INIT    CATALOG fix   Sectors    Sectors    Msg

 Std DOS 3.3**- 8.9 sec     Yes         No          No         No      Yes
 DavidDOS-      2.8 sec      No        Yes          No        Yes      Yes
 DiversiDOS-    2.9 sec     Yes        Yes          No        Yes      err#
 EsDOS-         2.3 sec     Yes        Yes         Yes        Yes      abbr*
 ProntoDOS v1-  3.0 sec     Yes         No         Yes         No      Yes
 ProntoDOS v2-  3.0 sec     Yes         No         Yes        Yes      Yes
  * abbr: shows abbreviated error messages
 ** 1980-1983 versions
*** time to BLOAD MUFFIN from the 1983 DOS 3.3 System Master disk

     You can get standard and high-speed DOS 3.3's from a number of places on the net. See Csa21MAIN4: Get It- Links to popular software packages.


004- What commands are available in DOS 3.3?

     To get very far with "DOS 3.3" you will need the DOS Manual. This is especially true when it comes to using TEXT files. Other good sources of DOS 3.3 info include _Beneath Apple DOS_ and _Apple II User's Guide_. For now, the following is a quickie guide to most Apple II DOS 3.3 commands:

LOAD NARF- loads a BASIC file named NARF.

SAVE NARF- saves current BASIC program in memory as file named NARF.

DELETE NARF - deletes file named NARF

CATALOG - lists contents of diskette to screen


RUN NARF- loads and starts a BASIC file named NARF.

BLOAD NARF.PICTURE, A$2000 - loads in a binary file named NARF.PICTURE starting at address $2000.

note: $2000 is a hexadecimal number ($2000 = 8192 in decimal). DOS commands can use hex or decimal numbers.

BSAVE NARF, A$300, L$7F - saves $7F bytes of memory starting at address $300 as a binary file named NARF. (BSAVE NARF, A768, L127 uses decimal numbers to do the same thing.)

note: The above command statement illustrates typical DOS syntax ...

 BSAVE--  the DOS command

 NARF-- the file name (the space between the command and file name
 is not a requirement; BSAVENARF is okay)

 ,-- a comma to separate file name from parms which follow

 A-- means an Address follows

 $300-- the address from which you want to start saving bytes (the $
 indicates a hex value; $300= 768). Again, spaces do not matter;
 A768, A 768, A $ 300 are all okay

 ,-- a comma to separate one parm from another

 L-- means a Length follows

 $7F-- the length in hex (= 127); this is the number of bytes to be saved

 The command statement says Save $7F bytes, starting at address $300, to a file named "NARF". NARF will have the bytes found at addresses $300 through $37E.

note: The order of parms following a file name does not matter.

BRUN NARF.DISP, A$1000 - loads in a binary file named NARF.DISP starting at address $1000 and starts executing machine instructions at address $1000

LOCK NARF- locks file NARF (indicated by * in a CATALOG). LOCKed files cannot be deleted, over-written, etc.

UNLOCK NARF - cancels LOCKed status of NARF.

VERIFY NARF - uses checksums to verify that NARF is not a damaged file

MON C, I, O - tells DOS to display Commands, Inputs from disk, Outputs to disk. You can specify one, two, or all three (e.g. MON C, O  etc.).

NOMON C, I, O - cancels all MON requests. NOMON I cancels just the "I" request.

MAXFILES 7 - sets the number of file buffers to 7. (Upon booting DOS, the default for the MAXFILES value is 3.)

PR#1 - sets the destination for Apple outputs to the device in Slot 1 (usually a printer).  PR# 3 sets it to Slot 3, etc..  PR# 0 sets the destination back to the display screen.

PR#6 - normally, boots the diskette in Drive 1, Slot 6.

IN# 6 - sets the source for Apple inputs to the device in Slot 6.

IN# 0 - sets the source for Apple inputs to the keyboard (default).

INT - (integer) puts system into Integer BASIC if it is present.

FP - (floating point) puts system into standard Applesoft BASIC.

OPEN NARFOO - prepares to read or write a TEXT file named NARFOO.

READ NARFOO - tells DOS that INPUT and GET statements will obtain characters from a TEXT file named NARFOO.

WRITE NARFOO - tells DOS that PRINTed characters will go to a TEXT file named NARFOO.

CLOSE NARFOO - used to terminate access to a TEXT file named NARFOO. Just CLOSE terminates access to all OPENed TEXT files.

EXEC NARFGO - tells DOS to execute the BASIC and DOS commands found in a TEXT file named NARFGO

The above TEXT file commands handle 'normal' sequential TEXT files. DOS can also OPEN, READ, WRITE, ... random access TEXT files. (See DOS manual.)

Most DOS commands also let you specify Drive and/or Slot. For example CATALOG, D2  lists the contents of the diskette in Drive 2 to screen. SAVE NARF,S5,D2 saves NARF to Drive 2 in Slot 5.

NOTE --> Using Drive or Slot parms in a DOS command sets the default Drive or Slot. So, after CATALOG, D2, a plain LOAD or SAVE will access Drive 2.


005- How do I use DOS commands from the keyboard? ... from a program?

     To use a DOS command from the keyboard, type it in. (A few commands can be issued only from a program.)  To use a DOS command in a program enclose it in quotes preceded by PRINT CHR$(4). For example:

100 PRINT CHR$(4) "BLOAD NARF, A$2000"


006- How do I use variables, say for file length, in a DOS command?

     Use variables in a command this way:

120 PRINT CHR$(4) "BSAVE NARF, A$2000, L"; NB

Line 120 says that the Length of NARF is the value of variable NB. NB is used here to represent the number of bytes (in decimal) to be saved.


007- How do I create new DOS 3.3 diskettes?

     One of the best features of DOS 3.3 is that any bootable DOS diskette can create other bootable diskettes.

INIT HELLO - formats one side of the diskette in the currently active drive, adds DOS, and saves the current program as HELLO.

     The program that's automatically placed on the new diskette is the one in memory when INIT is executed.  It is called the "greeting program" or "hello program" because it is the program which will be run when the diskette is booted. Usually, the program is named HELLO; but, you can INIT HOWDY, or any name you like. The hello program can be very simple, such as ...

110 END

You are free to load in and change the hello program or even delete it, just like any other. The one restriction is that once a diskette is INITed, the name of the hello program is fixed for that diskette unless you use a utility (like Copy II+) to make a change. This is why it's a good idea to stick with the name HELLO. You will always know what the hello program's name is.

     Once a diskette is INITed it can be used to store your programs and data files.


008- How much storage space is on a newly INITialized 5.25" diskette?

     A standard DOS 3.3 diskette has 35 Tracks. Each Track contains 16 256- byte Sectors. This gives 35 x 16 x 256 = 143360 bytes per side.  Current versions of DOS 3.3-- e.g. Prontodos, etc.--  use Track 0 and Track 1 plus a sector on Track 2 for DOS; and, Track 17 is used for holding the Catalog of files and other disk information. This leaves roughly 130k bytes per side free for your HELLO program and other files.

     By the way, when it comes to the way it is stored on-disk, DOS 3.3 is not like the PC's MSDOS or Apple's ProDOS. DOS 3.3 is 'hidden' on reserved tracks, mainly Tracks 0 and 1. There is no "DOS 3.3" file which will show up on a CATALOG.


009- On my PC I can FORMAT diskettes with or without adding the
     operating system. Can I format a DOS 3.3 diskette for just
     data storage? -- i.e. without adding DOS or a HELLO program?

     Yes. DOS 3.3 does not have a plain "FORMAT" command; but, you can use utilities such as Copy II+ to easily format a diskette without adding DOS or a HELLO program.

     A format will create 35 Tracks of 16 256-byte sectors each and verify that each Track is good. Then, it will allocate the Catalog track and create a disk info record called the "Volume Table of Contents" or "VTOC".


010- What is the "Volume Table of Contents" or "VTOC"?

     The VTOC is a Sector which stores such basic information as Number of Tracks, Sectors per Track, DOS version, ..., and the 'map' of used/un-used Sectors. DOS 3.3 writes the VTOC at Track 17, Sector 0. (For more details on VTOC content see Question 019.)


011- Can I assign names to my DOS 3.3 diskettes?

     DOS 3.3 has no way to name a diskette "NARF", "DISK 100", "DATA DISK ", etc. which DOS will recognize. You can, however, 'name' a diskette by giving it a Volume  Number in the range 1-255.

     Volume Number is set at the time a diskette is initialized. For example ...


INITs a diskette as Volume 19. If no number is specified, the default Volume Number used by INIT is 254.

     Several DOS commands can specify a Volume Number in order to decide whether a diskette is the right one for some application.

LOAD NARF, D2, V5    ... for example, will not load NARF from Drive 2 unless the diskette's Volume Number is 5.

     A few early pieces of commercial software used Volume numbering; and, new users often like to Volume number their diskettes. In practice, this turns out to be a bad idea. A diskette with any Volume Number except the default (254) is often difficult to work with via standard utilities. Also, once a diskette is INITed for a certain Volume Number, changing the number is difficult because Volume Number is embedded in each Sector. (i.e. You'll end up having to copy every file to another diskette and, then,
 re-INITing the source diskette to the new Volume Number.)

     Besides, there's an easy way to give descriptive names to your DOS 3.3 diskettes which will not interfer with normal access. Just write the name ("GAMES DISK ONE", or whatever) to a Text file named, say, "DISK.ID".

     DOS 3.3 will not know about the name or show it in a CATALOG. However, your programs will be able to find out the name by just reading DISK.ID.


012- What does it mean to "Boot" a disk?

     BOOT comes from the idea of 'pulling yourself up by your bootstraps'. The Apple II disk controller ROM has just enough smarts to load-in DOS's Bootstrap Loader from Track 0, Sector 0 (it comes in at address $800 ...).

     The Loader loads in a still smarter, bigger routine from several sectors of Track 0. This routine is the one which loads in the rest of DOS, moves it to the proper place in memory, and ends up going to DOS's Cold Start routine. Finally, the hello program is loaded and executed.


013- What file types does DOS 3.3 have and how is file
     type information saved in the Catalog?

     In a DOS 3.3 Catalog sector, the third byte in each file's entry tells the type of the file:

Byte Value*     File Type
    00           Text
    01           Integer BASIC
    02           AppleSoft BASIC
    04           Binary
    08           S type
    10           R: Relocatable object module
    20           new A type
    40           new B type

*DOS 3.3 sets bit 7 of the byte if the file is locked. (e.g. 84 --> a locked Binary file)

    Type R files show up in just a few applications. An R file begins with 6 bytes which a "loader" routine can use to tell the Target location of file contents, How many bytes to move, and Source location to move from.

    Although S, new A, and new B are included, no official application was defined for them and no DOS commands were created to make any special use of these files.


from David Empson

    There was an "R" type relocating loader included with the toolkit for use with BASIC programs and relocatable routines being loaded into upper memory.

   "S" was used by some programs for a generic image file, or something that was not likely to be touchable with normal code.

    The LISA assembler used the second "B" type for its source files.  It had a patched version of DOS that changed the file type list to read "LARSBAIT", so the source files appeared in the catalog as "L" if you booted LISA, or "B" if you booted a normal disk.

    The "B", "A", "R" and "S" special file types cannot be accessed by BASIC programs (unless you patch DOS) - commands are only provided for dealing with "B", "A", "I" and "T" files.

    The four special types can only be accessed using direct calls to the File Manager.


From: Dave Althoff, Jr.

014- What do the entries in a DOS 3.3 Catalog display mean?

A standard DOS 3.3 Catalog display looks something like this:

 *A 002 HELLO
 ^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 || ||| ||||||||||||||||||||||||||||||
 || ||| |___________________________________Filename
 || |_______________________________________File length (in Sectors)
 ||_________________________________________File type
 |________________________________________* means the file is locked


015- How long can a DOS 3.3 file name be and what characters
     can it include?

     DOS 3.3 filenames may be up to 30 characters long, and must conform to the following restrictions:

a.  The first character must have an ASCII code value greater than 63. This excludes numerals, SPACE, and most punctuation. The "@" character is allowed as well as letters, and some special chars such as "]", "~", "_", and a few others.

b.  Commas and colons may not be used at all. Apart from these restrictions, anything goes. All kinds of characters, including uppercase, lowercase, numbers, symbols, and CONTROL characters can be used after the first character.


From:  Andy McFadden

016- How can I use DOS 3.3 to read and write sectors from machine code?

     DOS 3.3 works like this:

     JSR  $3E3      ;get address of RWTS IOB (low in Y, high in A)

    (you can either change the stuff that Y/A point to, or set up
     your own IOB and skip the call to $3E3)

     JSR  $3D9      ;call RWTS (with IOB address in Y/A)

     The IOB (Input/Output Block) is small but non-trivial. Here's what Beneath Apple DOS says:

$00     table type (always $01)
$01     slot *16
$02     drive (1 or 2)
$03     volume expected ($00 for any)
$04     track ($0-$22)
$05     sector ($0-$0f)
$06-07  address (lo/hi) of the Device Characteristics Table
$08-09  address (lo/hi) of the 256 byte buffer for read/write
$0A     not used
$0B     byte count for partial sector ($00 for 256 bytes)
$0C     command code (0=seek, 1=read, 2=write, 4=format)
$0D     return code (carry set on error):

       $00 = no errors
       $08 = error during initialization
       $10 = write protect error
       $20 = volume mismatch error
       $40 = drive error
       $80 = read error (obsolete)

$0E  volume number of last access (must be initialized)
$0F  slot number of last access *16 (must be initialized)
$10  drive number of last access (must be initialized)

Device characteristics table:

$00     device type (should be $00 for DiskII)
$01     phases per track (should be $01 for DiskII)
$02-03  motor on time count (should be $EFD8 for DiskII)

NOTE: RWTS uses zero-page location $48, which is also used by the Apple monitor to hold the P-register value.  Location $48 should be set to zero after each call to RWTS.


From: Edhel Iaur, Esq.

017- How many 'official' versions of DOS 3.3 are there
     and how can I tell which is running?

     According to The Dostalk Scrapbook, there are 3 official (as in Apple made 'em, I think) versions of DOS 3.3.  PEEK (46725) supposedly tells you which is running:

  165: oldest  (1980)
  186: better  (January 1, 1983)
  182: latest  (?)

I remember one had something to do with the way text files are handled.


From: Dave Althoff

     The second version would be the IIe release ("DOS 3.3e") which contains yet another APPEND patch, and an additional bit of code which shuts off the 80- column firmware during boot. That version comes on a new System Master which uses the LOADER.OBJ0 program to fast-load INTBASIC (or FPBASIC), and a revised "HELLO" program which displays the "BE SURE CAPS LOCK IS DOWN" reminder on a IIe.


From: Rubywand and Olcott

     One big problem with DOS 3.3e (and, probably, any later versions) is that it uses some memory in the DOS area which the 1980 release leaves alone. This means it can not be safely patched with Beagle's "Prontodos" speed-up mods.

     With DOS 3.3e, you get an APPEND patch (which turns out to introduce a new APPEND bug),  a IIe display frill, and a DOS which is _much_ slower than the 1980 DOS 3.3 patched for Prontodos.


From: David Empson

018- How can I find out the address and size of a BLOADed
     DOS 3.3 file?

     After you BLOAD a file, you can use the following command to find out the exact length of the file you just BLOADed:

PRINT PEEK(43616) + 256 * PEEK(43617)

Use another PEEK to find out where it was loaded:

PRINT PEEK(43634) + 256 * PEEK(43635)

The value displayed is the load address of the binary file.


From: Neil Parker and Rubywand

019- What information is included in the DOS 3.3 VTOC and
     catalog sectors?


     The Volume Table of Contents (VTOC) is Sector $00 (0) on Track $11 (17). This is the key sector from which all searches start out.

Example: A typical DOS 3.3 Disk's VTOC sector

Byte  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E

0000- 04 11 0F 03 00 00 FE 00 00 00 00 00 00 00 00
0010- 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0020- 00 00 00 00 00 00 00 7A 00 00 00 00 00 00 00
0030- 15 01 00 00 23 10 00 01 00 00 00 00 00 00 00
0080- 3F 7F 00 00 00 00 00 00 00 00 00 00 00 00 00
00F0- 00 00 00 00 00 00 00 7A 00 00 00 00 00 00 00

Byte   Meaning
----   -------
$00    Unused (always $04 on my disks)
$01-02 Track/Sector location of first catalog sector-- the standard
       location is Track $11/Sector $0F (17/15)
       Note: The location of first catalog sector may be different on some
       disks. DOS 3.3 can adjust; but, some utilities (e.g. Copy II Plus)
       assume T/S $11/$0F and will not be able to find the catalog.
$03    DOS version number ($03 for DOS 3.3)
$04-05 Unused
$06    Volume Number-- $01-$FE (1-254) is the standard range;
       $FE (254) is the standard default VN
       Note: This entry merely records the VN for handy reference.
       VN is set when a disk is INITed and it is embedded in the
       Address header of each sector.
$07-26 Unused
$27    Max number of Track/Sector pairs in each sector of
       a file's Track/Sector list-- normally $7A (122)
$28-2F Unused
$30    Last track where sectors were allocated-- in the example
       it is Track $15 (21)
$31    Direction of allocation-- $01 (+1)=inward; $FF (-1)=outward
$32-33 Unused
$34    Number of tracks per disk-- normally $23 (35)
$35    Number of sectors per track-- normally $10 (16)
$36-37 Number of bytes per sector-- normally $0100 (256)
$38-3B Bit map for Track $00-- four bytes per entry (only two bytes are
       used); each bit in the two-byte entry indicates whether a sector
       is in use (0) or free for use (1). See example just below.
$3C-3F Bit map for Track $01
$80-81 Bit map for Track $12 (18)
       Example: The entry shown is 3F 7F 00 00. Only the first two
       bytes (3F 7F) are used:

       Sector-  F E D C  B A 9 8   7 6 5 4  3 2 1 0
       Bit-     0 0 1 1  1 1 1 1   0 1 1 1  1 1 1 1
       Hex-        3        F         7        F

       This shows that on Track $12 only sectors $F, $E, and $7 (15, 14,
       and 7) are used. The other sectors on the track are free for use.
$C0-C3 Bit map for Track $22 (34)-- usually the last track
$C4-FF Unused on normal disks (may contain extra bit maps on disks with
       more than 35 tracks)


     Starting at Track $11/Sector $0F (17/15 in decimal) and working downward in the track (e.g. Sector $0E, $0D, ...), each catalog sector contains a pointer to the next catalog sector, and seven file entries:

Byte   Meaning
----   -------
$00    Unused
$01    Track number of next catalog sector ($00 if no more)
$02    Sector number of next catalog sector
$03-0A Unused
$0B-2D First file entry
$2E-50 Second file entry
$51-73 Third file entry
$74-96 Fourth file entry
$97-B9 Fifth file entry
$BA-DC Sixth file entry
$DD-FF Seventh file entry

     Each file entry looks like this:

Byte   Meaning
----   -------
$00    Track number of this file's first track/sector list
$01    Sector number of this file's first track/sector list
$02    File type:
       Bit   Meaning
       ---   -------
       7     0=unlocked, 1=locked
       6-0   File type ($00=Text, $01=Integer, $02=Applesoft,
            $04=Binary, $08=S, $10=Relocatable, $20=A, $40=B)
$03-20 File name (high bits set; padded with blanks on right)
$21-22 Number of sectors allocated to this file


020- How does DOS 3.3 remember which sectors are used to store a file?

     Every file has a set of one or more Track/Sector List sectors. A Track/Sector List (T/S List) lists sectors (by Track and Sector number) which make up the file.  Each T/S List sector points to up to 122 data sectors If the file is too long for one T/S List sector, a second one is allocated, and a pointer to it is stored in the first one, and so on.

     Note that DOS 3.3 supports "sparse" files...there may 0/0 pairs in the T/S List indicating parts of the file that were never written. When DOS 3.3 is reading a file and encounters a 0/0 pair in the T/S List, it passes a buffer full of binary zeros back to the calling program.

     A Track/Sector List sector looks like this:

Byte   Meaning
----   -------
$00    Unused
$01-02 Track/Sector location of next T/S List sector (00 for Track means
       the list uses no more sectors since Track 0 can not be used)
$03-04 Unused
$05-06 Sector number in file (offset) of first sector represented in this
       T/S List sector (starting at byte $0C below).
       Ex: 00 00 = file sector #0 (i.e. the sector specified is the first
       sector in the file).  In a second T/S list sector, if required,
       the first sector listed would be file sector #122 (i.e. the 123rd
       sector) indicated by 7A 00-- hexadecimal $007A = 122 in decimal.
$07-0B Unused

The rest of the T/S List sector lists sectors in which the file is stored ...

$0C-0D Track/Sector location of first sector (in this T/S List sector)

$0E-0F Track/Sector location of second sector (in this T/S List sector)

 ... etc.


021- What are the formats of DOS 3.3's main file types?

     A machine-language program is free to store whatever it wants in any file, but most programs (including DOS 3.3's own command interpreter) expect the data in each type of file to conform to certain formats:

     A sequential text file consists of lines of ASCII text separated by carriage returns, and ending with a $00 byte.  The high bit of each character (except the $00 at the end) is set.

     A random-access file may be thought of as a set of mini sequential access files separated by strings of $00 bytes.  Each "mini-file" begins at a file position which is a multiple of the random-access record length. (Note that sequential and random-access text files share the same file type. It is up to individual programs to know whether their data files are sequential or random-access.)

Applesoft and Integer BASIC files have the following format:

Byte    Meaning
----    -------
$00-01  Length of tokenized BASIC program
$02-end Tokenized BASIC program

Binary files have the following format:

Byte    Meaning
----    -------
$00-01  Load address
$02-03  Length of binary image (i.e. file contents)
$04-end binary image

A Relocatable file contains the image of a program, followed by a relocation dictionary containing the information necessary to relocate the program to an arbitrary memory location. The file format is as follows:

Byte   Meaning
----   -------
$00-01 Original program load address
$02-03 File length (program image + relocation dictionary)
$04-05 Length of program image alone (not including relocation
$06-xx Program image
$xx-yy Relocation dictionary

(The format of the relocation dictionary is a bit too complex to describe
here. I can provide details if anybody's interested.)

     The other three file types (S, A, and B) have never been consistantly defined by anybody.  Several programs use these file types (especially type S) to store their private data files, but there doesn't seem to be any agreement on their internal format.

     For further information I recommend the book "Beneath Apple DOS" by Don Worth and Pieter Lechner.

P.S.  By the way, all two-byte fields in the above are stored in normal Apple II byte order, low byte first.


From: Rubywand

022- How can I run DOS 3.3 programs from 3.5" disks and hard disk?

     You can run quite a few DOS 3.3 programs from 3.5" disk, a large RAM disk, or hard disk. However, there are numerous DOS 3.3 programs which will not run this way and which could even damage files and directories on the larger media.

     Problems are especially likely when a program modifies and CALLs machine code routines such as Read/Write Track-Sector (RWTS) and/or makes assumptions about the physical locations on disk of important DOS 3.3 areas such as the Volume Table of Contents, CATALOG track, and DOS itself. Using a special routine to save "High Scores" to a specific Track/Sector is just one of many ways a DOS 3.3 program might create havoc on a hard disk.

     On the other hand, you have programs which stick to using standard DOS commands from BASIC such as, probably, most of your own DOS 3.3 programs and most 'type-in' software from publications like SoftSide. Programs like these should run fine using one of the techniques for accessing DOS 3.3 software from 3.5" diskette or hard disk.

     There are two fairly popular approaches to running DOS 3.3 software from 3.5" diskette on an Apple II. One is to copy it to a specially formatted 3.5" diskette which boots a modified "DOS 3.3" such as AmDOS or OzDOS. Typically, you get two "400k disks" on each 3.5" diskette.

     A very different approach is used by DOS 3.3 Launcher. It offers two options:

1- You can save some DOS 3.3 programs to ProDOS disk (including 3.5" disk or hard disk).  These must be single-file programs that do not access the disk once they are loaded into memory. DOS 3.3 Launcher's Copier is used to set launch options.

2- Using the DOS 3.3 Launcher Copier, you can save an entire DOS 3.3 disk as a disk image to a ProDOS 3.5" diskette, hard disk, etc.. According to 'Launcher's docs:

>> Any disk that uses a standard RWTS (Read/Write Track/Sector) routine can be copied in this manner. This includes not only DOS 3.3 disks, but also many old games which use a standard RWTS, but are not actually DOS 3.3. They can then be launched by DOS 3.3 Launcher, which "boots" the large file directly from your hard disk. <<

     To run a program from ProDOS-8, you start DOS 3.3 Launcher from a program selector such as ProSel-8 which supports the ProDOS 8 startup protocol- - i.e. it can make applications automatically open a data file. (The DOS 3.3 Launcher docs tell how to setup a ProSel entry for a program.)

     Running a program from the IIgs System Finder is much easier.

>> If you have properly installed DOS 3.3 Launcher, your DOS 3.3 programs should appear with DOS 3.3 icons when viewed through the Finder. To launch them, you simply double click on them, which launches them via ProDOS 8. <<

     Of the two basic approaches (a special 3.5" DOS 3.3 or DOS 3.3 Launcher), DOS 3.3 Launcher seems to be the better way to go:

First, it is easy to set up the contents of a DOS 3.3 disk prior to converting it to disk image form-- you can use any of the popular disk management utilities such as Copy II Plus. Moving DOS 3.3 files onto an AmDOS or OzDOS disk with the crude FID-type copiers available is a hassle.

Second, DOS 3.3 Launcher turns out to create and use standard 143,360-byte ProDOS order (.po) disk images, except, at least on the IIgs, the 'Launcher requires a special filetype-- e.g. $F1 to run at 1MHz, $F2 to run at "Fast" speed. These filetypes make it possible for the DOS 3.3 Launcher icons (included) to link images to the program for easy launching under the Finder-- you just double-click on the image's icon.

     So, you should be able to download any .dsk disk image on your PC, use an emulator to transfer the contents to a .po disk image, and transfer the .po file via NULL modem to your Apple II. Here you just need to adjust the filetype for use under DOS 3.3 Launcher. Or you can convert 5.25" .sdk (shrinked disk) files to .po disk image form and transfer these via NULL modem.

     To download AmDOS, OzDOS, DOS3.3.Launcher, and ProSel, see Csa21MAIN4: Get It- Links to popular software packages.


023- How can I get DOS 3.3 from the net without an Apple II
     telecom utility?

     DOS 3.3 Dump is DOS 3.3 in an Apple II Text file. The purpose of the the dump file (dos33.dmp)is to make it possible for users without DOS 3.3 and without any Apple II telecom program to obtain DOS 3.3 from the net.

     Once you have DOS 3.3, you can obtain ADT and have a way to transfer 5.25" .dsk disk image files from your net computer to your Apple II. (And once you can transfer disk images, you can get a good Apple II telecom utility and have a way to transfer all kinds of files!)

     You can find DOS 3.3 Dump along with directions on several net sites. See Csa21MAIN4: Get It- Links to popular software packages.


024- What is ProDOS?


     ProDOS is the official Apple II DOS which came after DOS 3.3. Do not confuse "ProDOS" and "Prontodos". Prontodos is a slightly modified DOS 3.3 which provides much faster disk I/O than standard DOS 3.3. ProDOS is a whole new disk operating system. To get ProDOS from the net, see Csa21MAIN4: Get It- Links to popular software packages.


025- What are ProDOS's major features?

     ProDOS has lots of nice features-- mainly, you can create sub- directories, diskettes ("volumes") can be named, and ProDOS works well on hard disks. The GS System 6 Finder can handle ProDOS files and launch programs from ProDOS diskettes. ProDOS's BASIC command interpreter shares many commands with DOS 3.3, too; so, it is not difficult for DOS 3.3 users to get started with the newer operating system.


From: David Empson

026- Which Apple II's can run which versions of ProDOS?

     Apple II's from an Apple II+ with 64k RAM through the IIgs can run versions of ProDOS up through version 1.9 and run Applesoft BASIC programs under these versions.

     An older Apple II (with Integer BASIC in ROM) or any Apple II with less than 64k RAM can run ProDOS 1.0 or 1.0.1 but can not use the ProDOS BASIC interpreter (BASIC.SYSTEM).  This is not a very useful setup as there are few applications that will work in this environment.

     Versions 2.x.x of ProDOS require an Apple II equipped with a 65C02, 65C802, or 65C816 such as an Apple IIe-enhanced, //c, IIc+, or IIgs. The current ProDOS is version 2.0.3.


From: Rubywand

027- How can I create bootable ProDOS diskettes?

     Creating bootable ProDOS diskettes is more bother than creating bootable DOS 3.3 diskettes because ProDOS does not have any way to duplicate itself from memory-- i.e., it has no INIT command.

     One way to make a new bootable ProDOS diskette is to first use Apple's ProDOS FILER utility or a ProDOS version of Copy II+ to FORMAT a diskette for ProDOS. This creates tracks filled with blank blocks so that the diskette can be used to hold ProDOS files. It also writes boot startup code in Blocks 0 and 1 on Track 0.

     ProDOS is in a file on a bootable ProDOS disk and so, usually, is the ProDOS 'connection' to BASIC, named "BASIC.SYSTEM". To finish the job you copy BASIC.SYSTEM and PRODOS from some bootable ProDOS disk to the new diskette.

     Another way is to use Disk Muncher or some other whole-disk copier to copy some bootable ProDOS diskette which includes BASIC.SYSTEM. You can delete any files you don't want from the copy.

     Things are a bit easier on a IIgs running GS System. In the Finder (the usual GS main 'desktop'), you can insert a blank diskette and let Finder "Initialize" it for ProDOS. Then you can mouse 'drag and drop' PRODOS and BASIC.SYSTEM from a bootable ProDOS disk to your new disk. (Or, even easier, if you have a 'stock' blank bootable ProDOS diskette the same size as your new disk, you can just drag and drop the bootable disk onto your new disk.)

Note: If you want to copy the ProDOS used by GS/OS, copy the file P8 from the SYSTEM/ folder and rename it to "PRODOS" on your diskette.


028- How do I make a ProDOS disk that will boot and start a BASIC program?

     If you want ProDOS to boot and start a BASIC program, then both PRODOS and BASIC.SYSTEM must be present. (BASIC.SYSTEM should be the first .SYSTEM file on the diskette.) The "hello" program on a ProDOS diskette is named "STARTUP". This is the program which will be run upon booting the diskette. (If there is no "STARTUP" program, you will end up at the usual BASIC prompt after booting.)

     A simple STARTUP program you can type in and save to your new ProDOS diskette is ...

30 END

     After typing in the program, just enter SAVE STARTUP. Next time you boot the diskette, the above program will run and the diskette's CATALOG will be displayed.

     A good ready-made STARTUP program and program selector for launching ProDOS 8 programs on a IIgs is available as speedgs.shk. The file unShrinks to the Startup program and a Readme directions file. To get speedgs.shk from the net, see Csa21MAIN4: Get It- Links to popular software packages.


From: David Empson

029- What is the maximum size of a ProDOS volume?

     When a diskette is formatted for ProDOS it is given a name by the user. A ProDOS diskette is also called a "volume". A ProDOS hard disk will, usually, be partitioned into two or more named volumes. The maximum size of a ProDOS volume is 32767.5 kilobytes (65535 blocks).


From: Rubywand

030- How do I LOAD, SAVE, etc. files under ProDOS?

     LOAD (SAVE, RENAME, etc.) work very much as in DOS 3.3.; so, you can use Slot and Drive parms to specify the target volume. However, to get the most from ProDOS you will usually be working with volume names and folders. (or, "directories").

     If GAME3.PIC is a binary file in a directory named "PICS" on a volume named "NARF", you could load it into memory starting at address $2000 via


 or, in BASIC


     So, in ProDOS, you can access a disk (or volume) by name ...


will find the disk (volume) named "GAMES", then, find, load, and run CHINA.SEA.

     You can, also, refer to a disk by its location ...


will do a short-form catalog of the main directory of the diskette in DRIVE 1 connected to SLOT 6.


031- What is a "pathname"?

      Suppose the file BARDS2.PIC is in the folder PICS on the diskette (volume) named "NARF". Then ...

     /NARF/PICS/BARDS2.PIC is BARDS2.PIC's complete "pathname".

     /NARF/PICS/ is a "pathname prefix" for all files in the PICS directory on the volume named "NARF".

     A leading "/" indicates a volume name (/NARF).

     The "main directory" or "root directory" is the one in which the files PRODOS and BASIC.SYSTEM (along with any other files the user wants there) are usually located on a ProDOS diskette. NARF's main directory pathname prefix is just /NARF/.


From: Rubywand and David Empson

032- What is the default volume and folder (directory) when ProDOS boots?

     When ProDOS boots, it will assume that LOADs, SAVEs, etc. refer to the main directory of whatever volume is in the boot Slot and Drive. It does not automatically establish a default volume or folder by name.

     So long as no default volume name is set, references to disks by Slot and/or Drive (e.g. CAT,S6,D2) will set the default device (by Slot and Drive) much as happens with similar commands entered from the keyboard under DOS 3.3.


033- How can I set default volume and folder (directory) under ProDOS?

     The ProDOS PREFIX command followed by a pathname lets you set the default volume and folder (or directory) by name-- i.e. you set the default pathname prefix.  For example,


or, in a BASIC program


tells your computer to find the ProDOS volume (e.g. disk, hard disk partition, etc.) named "NARF" and, once it is found, set the current default directory to /NARF/-- i.e. the main or "root" directory of the volume named "NARF". From then on, commands like CAT, RUN GRAFIX, BLOAD STARTPIC, etc. automatically reference /NARF's main directory.

     If you enter CAT PAINTERS/, ProDOS will go to the PAINTERS/ folder on /NARF and display a CATALOG of the folder's contents.

     If you move your /NARF diskette to a different drive and do a CAT, ProDOS will scan your drives to find /NARF and do the CAT. If you remove /NARF completely and do a CAT, ProDOS will say there is a "PATH NOT FOUND" error.

     Naturally, you can set the default prefix to a specific folder. For example,


or, in a BASIC program


sets the volume (/NARF/) plus folder (EAMON/) as the new default prefix. A program running in that folder can BLOAD picture, etc. files and RUN games in that folder without worrying about the names of the volume and folder in which your Eamon stuff is located.

     If you know that the EAMON folder is in the currently active directory, you can use


or, in a BASIC program


to set the folder as the default location without having to specify volume name. If the current default is /NARF/, the command will result in the new default being /NARF/EAMON/. If the current default is /NARF/GAMES/, the new default will be /NARF/GAMES/EAMON/.

If there is no default path at the time the command is executed, ProDOS will read the volume name, check for the EAMON/ folder, and add "EAMON/" to create the complete default pathname prefix.

     Setting a default pathname prefix does not prevent using commands which specify other locations. For instance


will look for the BOXES/ folder on the volume /PICS/ and do a CAT.

     To clear (eliminate) the default pathname prefix, use

PREFIX/  ("PREFIX" followed by a "/")


From: Rubywand

034- How can I discover the volume name of a just booted disk?

     You can discover the name of a ProDOS volume in a drive by doing a CAT. The volume name will be shown at the top of the screen listing (e.g. "/NARF/").

     Another way-- one which works in programs as well as from the keyboard-- is to use the PREFIX command:


This command will normally return one of two results:

o- If there is an established default prefix, then, the result will be the current default prefix.

o- If there is no established default prefix, then, ProDOS will read the volume name of the volume in the default Slot and Drive.

Note: PREFIX used in this way does not establish or change a pathname prefix.

Booting clears any default prefix and sets default Slot/Drive to the boot drive. For your STARTUP program to discover the name of the volume on which it resides, it could execute the following:


The volume name of the just booted disk (e.g. "/NARF/") will be saved in P$.


From: David Wilson

035- How do I create a folder?

     Creating folders (or directories) is the one time you do not need to provide a type parameter (e.g. TDIR) for the CREATE command. Hence


would create a folder named "GIFPICS" in the current default directory.


From: Neil Parker

036- How do I access ProDOS routines from machine language?

     You use the ProDOS Machine Language Interface (MLI).  The MLI is responsible for carrying out nearly all of the functions (Read Block, Write Block, and 24 others) which ProDOS can perform.

     Machine language programs call ProDOS by doing a JSR to the MLI at $BF00. To determine which function to perform, ProDOS examines the "command" byte immediately following the JSR instruction.  Immediately after the command byte come two more bytes that point to the command's parameter list.  When the call completes, it returns to the code immediately following the parameter list pointer. A ProDOS MLI call looks something like this:

20 00 BF  JSR     MLI
80        DB      COMMAND_CODE
B0 __     BCS     ERROR

In the above, the command code ($80) says "Read a block" and the parameter list is located at $0350. The MLI call returns with the carry flag set and an error code in the accumulator if an error occurred; so, a simple error check (the Branch if Carry Set instruction) is often the next instruction which is executed.

     For a detailed description of functions including command codes and parameters, see a ProDOS manual or one of the other references mentioned in Q&A 040 below.


From: Rubywand

037- How can I convert DOS 3.3 wares to run under ProDOS?

     Quite a few DOS 3.3 programs will run fine under ProDOS with no change at all. Unless you have some reason to believe a DOS 3.3 program will not run under ProDOS, it's worthwhile to just copy it to a ProDOS diskette and give it a try.

Note: A few 'DOS 3.3' programs, mainly old commercial games, include routines which do direct writes to one or more sectors. This could overwrite parts of a file or a ProDOS directory. It's a good idea to copy risky-looking software to a ProDOS disk you can afford to lose (e.g. a bootable disk with no favorite programs, etc. on it).  Boot this disk and try out the program.

     The main barriers to running DOS 3.3 programs under ProDOS are ...

1. Size: DOS 3.3 leaves more space for programs than ProDOS + BASIC.SYSTEM. Some DOS 3.3 programs are too large for ProDOS. To use them you will need to find ways to reduce program size.

2. Areas of memory used: ProDOS reserves parts of memory, such as Text Page 1 ($0400-$07FF), for various pointers. Some DOS 3.3 programs LOAD or BLOAD into one or more of these areas. For example, some games BLOAD a lo-res pic or Text for you to look at while the rest of the game loads. Normally, ProDOS will refuse to do such loads and the result will be a BUFFERS NOT AVAILABLE error message. To run these programs you will need to unmark the reserved areas which get in the way (see next Q&A) and/or change 
the location(s) of the program's troublesome LOADs and BLOADs.

When ProDOS loads it uses most of the memory in the "language card" areas. Some DOS 3.3 programs also use this memory. If a DOS 3.3 program uses the "language card" it will probably have to be modified in order to run under ProDOS.

ProDOS handles buffer allocation differently than DOS. If a DOS 3.3 program lowers HIMEM in order to create space for BLOADing code or data, it may need to be modified to guarantee that the code/area is safe. (See page 237 of Exploring Apple GS/OS and ProDOS 8 or page 7-4 of Beneath Apple ProDOS.)

3. Names: DOS 3.3 file names can be longer and have more kinds of characters than ProDOS names. If a DOS 3.3. program BLOADs, WRITEs, etc. to any files, you will need to be sure that the file names used are compatible with ProDOS.

4. DOS/ProDOS Commands and Syntax: There are, really, very few DOS 3.3 command and syntax differences likely to cause problems under ProDOS. Still, there are some and you will need to check for these and make any indicated mods.

5. Integer BASIC: Int BASIC programs can be transferred to a ProDOS diskette; but, you can not run them directly under ProDOS. If you are willing to move an Int BASIC program to a Text editor, convert the syntax to Applesoft BASIC, and EXEC the resulting Text file, you can obtain an Applesoft BASIC program which you can modify as necessary for ProDOS.

6. It's not DOS 3.3: Very old software, old commercial copy-protected software, and deprotected copies of old software may not be on DOS 3.3 disks. Your first challenge with such software is getting it into a form which will permit transferring files to a ProDOS diskette.

     When checking and modifying a DOS 3.3 program for ProDOS a good program editor is essential. You will save untold hours of work when you invest in Beagle's tried and true "Program Writer".


From: Jeff Blakeney

038- How can I modify ProDOS to do BLOADs in the input buffer
     and Text Page 1 areas?

     You can use a POKE 48984,192 to modify the bit map. This protects pages $00 and $01, and unprotects pages $02-$07.

Note: Because the firmware and I/O cards make use of the "screen hole" bytes in the $0400-$7FF area, BLOADing over these can interfere with some devices.

For this reason, it is best to have special DOS wares on a separate ProDOS diskette with a STARTUP program which does the POKE 48984,192. This way you will know that the system has been changed to run the DOS wares and not inadvertently try to run a program like Appleworks, etc.. under the modified ProDOS.


From: David Empson

A safer method is to BLOAD the file elsewhere, and copy data onto the text screen in a loop, copying 120 bytes and skipping 8 bytes, repeated 8 times.


From: Supertimer, Rubywand, David Wilson, Steve Jensen

039- How can I boot ProDOS on my Franklin computer?

     In an old Apple Clinic note, Stephen Craft listed specific locations to change after your Franklin freezes. You could then restart via a 2000G from the monitor. Here is an updated listing showing the locations to change for several versions of ProDOS:

v1.1.1    $269E: EA EA
v1.4      $282B: EA EA
V1.6      $282B: EA EA
v1.7      $282B: EA EA
v1.8      $2836: EA EA
v1.9      $2865: EA EA
v2.0.3    $2836: EA EA

     It turns out that the bytes Stephen was diddling are D0 03 in the sequence 69 0B D0 03 A5 0C 60.  The sequence is near the end of a routine that checks for the "APPLE ][" string found in all genuine Apple II ROMs but not in most Apple II clone ROMs.

     To fix the booting problem, do this:

 Start Copy II+ and select "Sector Editor"

 Swap-in the ProDOS diskette

 READ Track 0, Sector 0

 Search for (Hex bytes): 69 0B D0 03 A5 0C 60

 When you find the above, change the D0 03 to EA EA
 and write the changed sector back to diskette.

     The patch eliminates the checksum test/branch and allows ProDOS to boot on Apple II clones which would normally fail the check. This patch has no effect on ProDOS functioning on regular Apple II's.

     The above patch is absolutely necessary to get a bootable ProDOS working for many Apple II clones. Jim Sather (inCider, March 1986) recommends a second patch which is optional. It prevents ProDOS from erroneously reporting that a //e-style 64K 80-column card is present when running on a Franklin.

Note: This patch should not be applied except by Franklin 1000 and, possibly, some other clone users. On a //e, //c or IIgs it causes ProDOS to not see an 80-column card or some extra memory.

The patch is not needed for Franlin 2000 series machines (the ones that emulate a IIe and IIc) or any of the Laser 128 series. You would not want to apply the patch to these units because they have emulated 80 column cards and 128k (expandable to 1MB on Lasers).

     To do the patch, procede as described for the main patch and also do this ...

 READ Track 0, Sector 0

 Search for (Hex bytes): AE B3 FB E0 38

 When you find the above, change it to A2 EA EA E0 38
 and write the changed sector back to diskette.


From: Rubywand

040- What are some good DOS 3.3 and ProDOS references?

DOS Books

 The DOS Manual  from Apple
 Beneath Apple DOS  by Worth & Lechner
 Apple II User's Guide  by Poole, Martin, and Cook

ProDOS Books

 ProDOS Technical Reference Manual  from Apple (Addison-Wesley)
 Beneath Apple ProDOS  by Worth & Lechner
 Exploring Apple GS/OS and ProDOS 8  by Little
 ProDOS Inside and Out  by Doms and Weishaar


From: Dennis Jenkins, Rubywand, Dave Althoff
041- How can a BASIC program tell which DOS it's running under?

     A pretty good way is to check the three-byte JMP command starting at $03D0. If it's 4C 00 BE, you're running ProDOS; if it's 4C BF 9D, you're running DOS 3.3 or a compatible variant (such as Prontodos).

     Two (moderately rare) factors may change the DOS 3.3 JMP:  1- On old "slave disks" created on sub-48k Apple II's, DOS loads in at a lower address; 2- DOS 3.3 is sometimes moved up into the Language Card. So, your best procedure is probably to check for ProDOS and, if it isn't ProDOS, just presume that it's DOS 3.3.
eck for ProDOS and, if it isn't ProDOS, just presume that it's DOS 3.3.
 DOS 3.3.

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