DOS & ProDOS. .
..
...
DOS
& ProDOS. ......
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 name of the current
default volume?
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?
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.
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 Big Files Frees 15 Disp Free
Error
Test*** INIT CAT 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 find plain DOS 3.3 as well as several
high-speed variants on
GS WorldView's archive (on Archive
page, click "System").
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
RENAME NARF, NEWNARF - renames file NARF to NEWNARF
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.)
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 in hex from which you want to start saving
bytes (= 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$2000, L"; NB
Line 120 says that the Length of NARF is the value of variable NB. NB
is used
here to represent the number of bytes (in decimal) to be saved.
007- How do I create new DOS 3.3 diskettes?
One of the best features of DOS 3.3 is that
any bootable DOS diskette can
create other bootable diskettes.
INIT HELLO - formats one side of the diskette in the currently active
drive,
adds DOS, and saves the current program as HELLO.
The program that's automatically placed on
the new diskette is the one in
memory when INIT is executed. It is called the "greeting program"
or "hello
program" because it is the program which will be run when the diskette
is
booted. Usually, the program is named HELLO; but, you can INIT HOWDY,
or any
name you like. The hello program can be very simple, such as ...
100 PRINT CHR$(4) "CATALOG"
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 Q&A 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
...
INIT HELLO, V19
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.
014- What do the entries in a DOS 3.3 Catalog display mean?
A standard DOS 3.3 Catalog display looks something like this:
DISK VOLUME 254
*A 002 HELLO
B 033 TETRA/SOFT LOGO.BIN
T 142 DAVE'S LIST OF DOS COMMANDS
I 002 INTEGER BASIC PROGRAM
^^ ^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|| ||| ||||||||||||||||||||||||||||||
|| ||| |___________________________________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.
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.
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 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 the newer DOS, you get an APPEND
patch (which turns out to introduce a new
APPEND bug), a few IIe display frills, and a DOS which is _much_
slower than the 1980
DOS 3.3 patched for Prontodos.
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?
VTOC
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)
Catalog
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
dictionary)
$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.
______________________________
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.
You can find ...
AmDOS at ftp://apple2.tffenterprises.com/pub/apple2/8bit/utils/
http://apple2.org.za/gswv/a2zine/System/
OzDOS at http://apple2.org.za/gswv/a2zine/System/
DOS3.3.Launcher at http://apple2.org.za/gswv/a2zine/System/
ProSel 8 at http://apple2.org.za/gswv/a2zine/Utils/
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 a companion
Text directions file as
dos33dmp.zip on ...
Ground
Asimov
GS WorldView; click
"Getting DOS 3.3"
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.
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.
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 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.
____________________________
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 disk.
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 ...
10 TEXT: HOME
20 PRINT CHR$(4)"CAT"
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 from diskette on a IIgs is SpeedGS. It displays name
of the
Boot Volume, Date/Time, and current Speed plus program names you've
entered.
The download file unShrinks to the Startup program and a Readme directions
file:
SpeedGS.zip
on GSWV
speedgs.shk
on Ground
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).
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
BLOAD /NARF/PICS/GAME3.PIC,A$2000
or, in BASIC
100 PRINT CHR$(4)"BLOAD /NARF/PICS/GAME3.PIC,A$2000"
So, in ProDOS, you can access a disk (or volume) by name ...
RUN /GAMES/CHINA.SEA
will find the disk (volume) named "GAMES", then, find, load, and run CHINA.SEA.
You can, also, refer to a disk by its location ...
CAT,S6,D1
will do a short-form catalog of the main directory of the diskette in
DRIVE 1
connected to SLOT 6.
Suppose the file BARDS2.PIC is in the
folder PICS on the diskette
(volume) named "NARF". Then ...
/NARF/PICS/BARDS2.PIC is BARDS2.PIC's complete "pathname".
/NARF/PICS/ is a "pathname prefix" for all
files in the PICS directory on
the volume named "NARF".
A leading "/" indicates a volume name (/NARF).
The "main directory" or "root directory" is
the one in which the files
PRODOS and BASIC.SYSTEM (along with any other files the user wants
there) are
usually located on a ProDOS diskette. NARF's main directory pathname
prefix is
just /NARF/.
From: Rubywand and David Empson
032- What is the default volume and folder when ProDOS boots?
When ProDOS boots, it will assume that LOADs,
SAVEs, etc. refer to the main
directory of whatever volume is in the boot Slot and Drive. It does
not automatically
establish a default volume or folder by name.
So long as no default volume name is set, references
to disks by Slot and/or Drive
(e.g. CAT,S6,D2) will set the default device (by Slot and Drive) much
as happens
with similar commands entered from the keyboard under DOS 3.3.
033- How can I set default volume and folder (directory) under ProDOS?
The ProDOS PREFIX command followed by a pathname
lets you set the default
volume and folder (or directory) by name-- i.e. you set the default
pathname prefix.
For example,
PREFIX /NARF
or, in a BASIC program
100 PRINT CHR$(4)"PREFIX /NARF"
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 CAT 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,
PREFIX /NARF/EAMON/
or, in a BASIC program
100 PRINT CHR$(4)"PREFIX /NARF/EAMON/"
sets the volume (/NARF/) plus folder (EAMON/) as the new default prefix.
A program running in that folder can BLOAD picture, etc. files and
RUN games
in that folder without worrying about the names of the volume and folder
in which
your Eamon stuff is located.
If you know that the EAMON folder is in the
currently active directory,
you can use
PREFIX EAMON/
or, in a BASIC program
100 PRINT CHR$(4)"PREFIX EAMON/"
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
CAT /PICS/BOXES/
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 "/")
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:
PREFIX
This command, when used alone, 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:
100 PRINT CHR$(4)"PREFIX": INPUT"";P$
The volume name of the just booted disk will be saved in P$.
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
CREATE GIFPICS
would create a folder named "GIFPICS" in the current default directory.
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
50 03 DW
PARAM_LIST_LOCATION
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 MLI functions
including command codes and parameters,
see a ProDOS manual or one of the other references mentioned in Q&A
040 below.
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".
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 series
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 Franklin 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.
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.
