001- What programming languages are available for the Apple II?
002- Where can I find out about Apple II programming?
003- Where can I get Apple II languages and programming software?
004- Where can I find PEEKs & POKEs and monitor routine info?
005- How can I see and edit what's in a Text file?
006- How do I save a BASIC program in ASCII text form?
007- Where and how do I get System 6.0.1?
008- Where can I get Applesoft shape table info and programs?
009- What Operating System environments does the GS support?
010- How do I write programs for the Apple Graphics Tablet?
011- How do I read the joystick on a GS in native mode?
012- How do I write programs which use the mouse?
013- Where can I find manuals and other resources for the CP/M OS?
014- How can I view and enter code using the "monitor"?
015- What memory areas should a user be careful about modifying?
016- Can I do multi-tasking on a IIgs? or What is GNO/ME?
Csa2 Programmer FAQs
Feel free to email comments, suggestions, and materials.
Jeff Hurlburt
rubywand@swbell.net
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001- What programming languages are available for the Apple II?
Quite a few. Apple Integer BASIC (in-ROM on the first Apple II's), can be loaded into II+ and later models. Applesoft, a floating point BASIC, is in-ROM on all models starting with the II+. Older Apple II's can load-in Applesoft or, via a plug-in board, access it from ROM.
Then, there is MD BASIC, the BASIC-like MacroSoft from MicroSparc, a beta version of Apple's GS BASIC, and the new (1998) Byte Works GS BASIC! Users who want to speed up their AppleSoft programs can use a BASIC compiler such as TASC or Einstein.
Other Apple II languages are Apple Fortran, UCSD Pascal, Orca (ByteWorks) Pascal, Kyan Pascal, Terrapin Logo, Apple Logo, two Logos from ByteWorks, Isys Forth, Master Forth, (and many other Forths), Modula2, Aztec C, Orca/C, ... . Hyperstudio and HyperCard let you create stacks.
To the above you can add several assemblers including Merlin, Orca/M, an assembler from Ninja Force, and the MicroSparc Assembler.
You can find a comprehensive listing in Larry Virden's "Apple II Programmer's Catalog of Languages and Toolkits" at http://www.purl.org/net/lvirden/Misc/apple2-languages.txt .
For Orca manuals and to order the Orca languages see Byte Works products at Syndicomm ( http://www.syndicomm.com/products/ ).
--Rubywand, Jeffrey Iverson, Andrew Roughan
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002- Where can I find out about Apple II programming?
All Apple II's come with some version of BASIC installed in-ROM on the motherboard. The original Apple II's have Integer BASIC. Starting with the II+ model, all Apple II's have floating-point Applesoft in-ROM. Owners of early Apple II's can load in Applesoft or plug in a card with Applesoft ROMs.
All Apple II's include a "monitor" program in ROM. Entering CALL-151 from the BASIC prompt puts you 'in' the monitor. Here you can view and change values in key memory locations and enter machine language routines.
Besides these built-in languages, many others can be loaded in and used (see previous Q&A).
There are several good places on the net to find out about programming:
Niel Parker's Home Page- Apple IIgs progamming information
http://axis.llx.com/~nparker/a2/
Paul Schlyter's Apple II Stuff- compilers, S-C assemblers, utilities,
Assembly Line disks, ...
http://www.stjarnhimlen.se/apple2/
Ron Kneusel's 6502 page- 6502 info, assem tutorials, and links
http://www.geocities.com/oneelkruns/65index.html
The Fridge- 6502 info, tutorials, assembly language routines
http://www.ffd2.com/fridge/
www.6502.org- 6502 info, tutorials, assembly language routines
http://www.6502.org/
Be sure to keep a look out for Apple II books, charts, software packages, etc. when you visit used book stores, swap meets, school sales, ..., or peruse comp.sys.apple2 marketplace.
Applesoft BASIC
The #1 Applesoft information source is the Basic Programming Reference Manual from Apple. Here are some other good Applesoft materials to look for ...
Apple II User's Guide by Poole, Martin, and Cook
Note: Third Edition (Apple II User's Guide for APPLE II Plus and
APPLE IIe) is completely revised to include ProDOS coverage
Apple II Reference Manual from Apple
Peeks, Pokes, and monitor routines info (see below)
DOS & ProDOS books (see below)
GSoft BASIC (New IIgs BASIC from Byte Works)
Learning to Program in GSoft BASIC by Mike Westerfield (Byte Works)
Assembly Language and Machine Language Coding
Machine coding is when you enter 6502 (65816, ...) instructions directly-- as in going to the Apple II monitor (CALL-151) and typing in hexadecimal codes at specific addresses, like 300:A9 7F (instruction to load Accumulator with the value $7F entered at address $300).
Assembly coding substitutes easy-to-remember text for the numeric codes-- as in LDA#7F to load the Accumulator with the value $7F. Assembly coding is done using assembler software (like Merlin or Orca/M). A major advantage of assembly coding is that routines and other places in your program can be tagged with text labels and referenced this way in your program. The assembler software figures out things like Jump addresses.
Assembly Lines: The Book by Wagner
Programming Manual (for 6502 from Mos Technology, 1976)
Beagle Bros "Peeks, Pokes, and Pointers" (poster)
What's Where in the Apple II? by William F. Luebbert
Programming the 65816 Including the 6502, 65C02, and 65802
by David Eyes and Ron Lichty
65816/65802 Assembly Language Programming by Fischer
Other Languages
Apple Pascal: a hands-on approach by Luehrmann & Peckham
Learn to Program in C by Mike Westerfield (Byte Works)
Learn to Program in Pascal by Mike Westerfield (Byte Works)
Logo Plus manual from Terrapin
HyperCard IIGS Script Language Guide (Apple/ Addison-Wesley)
DOS, ProDOS, and GS/OS
The DOS Manual from Apple
Beneath Apple DOS by Worth & Lechner
Beneath Apple ProDOS by Worth & Lechner
Supplement to Beneath Apple ProDOS For ProDOS8 (v1.2,1.3) by Worth & Lechner
Apple IIGS GS/OS Technical Reference (Apple/ Addison-Wesley)
Apple IIGS GS/OS Device Driver Reference (Apple/ Addison-Wesley)
Apple IIGS System 6 User's Reference (Apple/ Addison-Wesley)
The System 6 Book by Jerry Kindal (Quality Computers)
Apple IIGS ProDOS 8 Reference (Apple/ Addison-Wesley)
Apple IIGS ProDOS 16 Reference (Apple/ Addison-Wesley)
Apple IIGS Toolbox Reference v. 1-3 (Apple/ Addison-Wesley)
Exploring Apple GS/OS and ProDOS 8 by Gary Little
Toolbox Programming in C by Mike Westerfield (Byte Works)
Toolbox Programming in Pascal by Mike Westerfield (Byte Works)
One of the best ways to learn programming is to find some old game you like and experiment with customizing it. This works especially well for learning Applesoft BASIC and machine language coding.
If your Apple II is an enhanced //e or later machine, be sure to get Program Writer. It's a vintage Applesoft program editing utility from Beagle which makes writing and debugging BASIC programs much easier.
--Rubywand, Terence J. Boldt, Tony Cianfaglione, Steve Sanders, Wayne Stewart, Charles T. Turley
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003- Where can I get Apple II languages and programming software?
Byte Works ( http://www.byteworks.org ) develops the Orca series of Apple II and IIgs languages including Pascal, C, Assembler, and the new IIgs BASIC as well as manuals, learning packages, and other language materials.
You can find very good collections of Apple II languages and related software on the net at ...
Asimov- Apple II programming software and utilities
004- I'd like to do some 'serious' Apple II programming. Where can I
find a information about soft switches (i.e. "PEEKs & POKEs"),
monitor routines, and standard names used for these?
Names shown are assembler "equate" names/labels. In a few cases, more than one label and function is associated with an address. A few soft switches have no established label.
Not all switches are present on all Apple II models. In general, the later the model, the more features and soft switches are available.
Many soft switches can be toggled via a Read or a Write. If only a Read or a Write is indicated, access the switch or indicator using the indicated method.
$FF3A -198 PRINT BELL (Destroys ACCUMULATOR & Y-REG)
$FF59 -167 ENTER MONITOR RESET, TEXT mode, "COLD START"
$FF65 -155 ENTER MONITOR, ring BELL, "WARM START"
$FF69 -151 Go to MONITOR
$FF70 -144 SCAN INPUT BUFFER (ADDRESS $200...)
--The Enforcer (on Apple Textfiles at http://www.textfiles.com/apple/ ) and Rubywand
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You can find listings of Apple II soft switches and popular monitor routines in a manual for your computer-- e.g. the Apple II Reference Manual (for II and II+), the IIe Technical Reference Manual, the Apple IIgs Firmware Reference Manual, etc..
An excellent guide to many PEEKs & POKEs and monitor routines is the famous "Peeks, Pokes, and Pointers" poster from Beagle Bros (early 1980's). A fairly exhaustive guide to important memory locations in the Apple II is What's Where in the Apple II: An Atlas to the Apple Computer by William Luebbert (1981).
On-line lists of PEEKs & POKEs + Monitor Routines are available at
Apple II Textfiles
http://www.textfiles.com/apple/
With very few exceptions, soft switches, monitor routines, and important vectors have remained stable since early Apple II models. So, although an old chart or listing may be missing some which are available on a newer Apple II, the ones shown will almost always work. --Rubywand and Mookie
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005- How can I see and edit what's in a Text file?
A handy utility for quickly viewing Text files under DOS 3.3 or ProDOS is Copy II Plus.
On the IIgs under the system Finder (the usual "desktop" display showing drives, folders, etc.) you can, probably, double-click on a text file to start up an application (program) which will display the Text and let you make changes.
Note: If you get an error message about not being able to find an application, you will want to think about setting up a link between Text type files and some Text editor program such as Teach. Some Text editor New Desk Accessories (like Shadowrite) will automatically establish a linkage.
Another way to view and edit Text files is to run a Text editor or word processor program and load in the file. On 8-bit Apple II's, some choices include Screenwriter II, AppleWriter, and, depending upon machine, some versions of Appleworks. On the IIgs you have many choices including Teach, Shadowrite NDA, CoolWriter, and Appleworks. --Rubywand
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006- How do I save a BASIC program in ASCII text form?
The following line added to the front of your Applesoft BASIC program will save it in a Text file named "LISTFILE". It works in DOS 3.3 or ProDOS.
1 HOME:PRINT CHR$(4)"OPEN LISTFILE": PRINT CHR$(4)"WRITE LISTFILE": POKE 33,33: LIST 2,: PRINT CHR$(4)"CLOSE": END
If you have a line 1 which you'd like to leave alone, you can enter the above at Line 0 and change LIST 2, to LIST 1,.
POKE 33,33 causes the text display routine to not insert any unneccessary spacing into your BASIC program listing, which cleans up the text file output nicely.
--David Cross
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007- Where and how do I get GS System 6.0.1?
You can download System 6.0.1 from several places on the net. You can also buy the set of System 6.0.1 diskettes or buy a hard disk with System 6.0.1 installed.
For details with links, go to the main Apple II FAQs at ...
009- What Operating System environments does the GS support?
The GS can support several. Some of the more popular OS environments include ...
DOS 3.3- usually Beagle's Prontodos or some other speeded version of the original DOS 3.3. This is the 5.25" diskette-based disk operating system used for years on earlier Apple II's. It's commands are designed for use from BASIC programs or from the keyboard. Many old Apple II games and other wares are on 5.25" diskettes which boot DOS 3.3.
ProDOS 8- e.g. ProDOS v2.0.3. This is a disk operating system which supports a variety of devices (e.g. 3.5" drives, hard drives, etc.) and allows sub-directories. Commands are very similar to DOS 3.3 and are designed for use in BASIC programs or from the keyboard. BASIC and 'system' programs can also utilize direct CALLs to well-defined ProDOS Machine Language Interface routines.
Apple Pascal- This is an early 1980's implementation of UCSD Pascal which can run on 40-column and 80-column Apple II's.
System- Originally called "ProDOS 16" and later "GS/OS", the collection of 'system stuff' (which includes GS/OS) is today called "System". The System Finder utilizes Toolbox routines to supply a super-res desktop, Windows-like environment. Both ProDOS 8 programs and 'GS Applications' (i.e. wares that need GS/OS to run) can be started from the desktop. Depending upon factors such as installed RAM and presence of a hard disk, System will usually be System 5.0.4 or System 6.0.1. System 5.0.4 is appropriate fo
r 1.25MB or smaller non-hard disk GS's. System 6.0.1 is recommended for larger memory GS's with a hard disk.
--Rubywand and David Empson
GNO- GNO is a UNIX-like multitasking environment for the Apple IIgs which runs on top of the native operating system, GS/OS.
--Rubywand, David Empson, Devin Reade, Jeffrey Iverson
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010- How do I write programs for the Apple Graphics Tablet?
The Apple Graphics Tablet I know of is rather large and heavy; its pen is attached to it with a (too short) cable; it makes funny sounds that change when the pen is moved in/out the reach of of the tablet.
A long time ago I patched a few programs to make use of this tablet. To make it clear in the first place - I don't have these patched versions available anymore :-(. But I found a listing from which I can tell you this:
To detect the interface card, I looped over all slots to check in its firmware for
$B0 at location $Cx01 and
$20 at location $Cx09
x being the slot number. I never found this 'signature' in any other firmware.
To check for the pen position one has to poll the tablet (again x being the slot number):
LDA $CFFF ; switch off all extension ROMS
LDA $Cx00 ; switch on the extension ROM of the tablet
LDA #$Cx
STA $07F8 ; initialize some hidden text screen data area for the tablet firmware
JSR $CBB9 ; call well known location ;-) in tablet firmware
When the pen is in reach of the tablet (up or down) this routine will return immediately. Else it will block - fortunately, the routine checks the keyboard strobe ($C010) too and will also return if a key is pressed, even if the pen remains out of tablet's reach.
After the routine has returned one can get the information:
$0280 contains the state of the pen (up or down), I don't recall which bit it is nor if one can distinguish between 'pen up' and 'pen out of reach but key pressed'
$0281, $0282 contains the absolute X position of the pen
$0283, $0284 contains the absolute Y position of the pen
As far as I can remember the values have about 12 bit resolution (!). Usually I needed screen coordinates (280 x 192), so I dropped the 4 least significant bits and did some additional adjustment. Unfortunately, I don't recall what coordinates will be there in the 'out of reach but key pressed' case.
--Oliver Schmidt
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011- A while ago someone posted about how to read the joystick on
a GS in native mode. They said that it was possible to read
both paddles at once and therefore get much more accurate
readings?
Only the high bit of these locations is valid. When the high bit of either location becomes 0 then the corresponding analog input has timed out.
You will actually get more accurate results by reading them one after the other with the accumulator set to 8 bits wide and the index registers used to hold the counts (16 bits wide). This allows for a much faster loop, giving better resolution. Assuming that this routine is called from full native mode, the following code will do the trick:
strobe equ $C070 ; analog input timing reset
pdl0 equ $C064 ; analog input 0
pdl1 equ $C065 ; analog input 1
start php ; save processor status register
phb ; and data bank register
sep #%100000 ; make accumulator 8 bits wide
lda #0 ; make data bank = 0
pha
plb
ldx #0 ; initialize the counters
txy
lda strobe ; strobe the timing reset
loop1 inx ; increment pdl0 count
lda pdl0 ; is high bit = 0?
bmi loop1 ; no, keep checking
lda strobe ; yes, strobe the timing reset again
loop2 iny ; increment pdl1 counter
lda pdl1 ; is high bit = 0?
bmi loop2 ; no, keep checking
plb ; yes, restore data bank
plp ; and processor status register
rts ; return to caller (could be RTL)
Notice that the actual counting loops are only 9 cycles long. This gives the best possible resolution. You will need your counters to be 16 bits wide as the results will easily overflow the capacity of an 8 bit counter.
Using memory locations as counters will only serve to slow the counting loop down. If X and Y contain valid data before entry, you will need to save them off to the stack and pull them back in after interpreting the joystick results. I have used this exact method to read the analog inputs on my Science Toolkit box which connects to the joystick port.
The results have been extremely accurate (much more than would be needed for a game which reads the joystick). --tgeer@pro-gumbo.cts.com (System Administrator)
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012- How do I write programs which use the mouse?
The assembly language interface to the mouse firmware is documented in the reference material that was supplied with the IIe AppleMouse card, the IIc Technical Reference Manual, and the IIgs Firmware Reference Manual.
For a 'how to' discussion, see csa2 FAQs Resource file R034MOUSEPRG.TXT at ...
I've asked Michael Haardt, author of cpmtools, to incorporate some code changes that would allow his package to work on apple II cpm images (both in dos and prodos order). This package allows one to manipulate cpm disk images - extract, copy, delete, etc, etc from a unix command line. With version 1.6, cpmtools can now handle apple II cpm images.
With cpmtools, I've been able to create Apple II images with the generic software obtained from
http://www.retroarchive.org/cpm
These images I've been able to download to an Apple II via ADT without any problems. I feel that they would be of use to Apple II CP/M users.
--Bart, Celt, Raoul Golan, Paul Schlyter, Charles T. Turley
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014- How can I view and enter code using the "monitor"?
Every Apple II has a built in "System Monitor", which lets you play around with memory contents.
To get into it, start in BASIC and type CALL-151.
You then get an * prompt to indicate you are in the monitor. To get back to BASIC at a later point, press Control-C then return (on a line by itself).
The monitor has a lot of commands and the syntax is rather cryptic. Everything is entered and displayed in hexadecimal (base 16).
The simplest commands are a single letter. For example, the "I" command sets the display to inverse, and "N" sets it to normal.
The next level up in complexity are commands which expect a single address parameter. The address must be entered first, followed by the command letter. In some cases, the monitor remembers the last address used, so you can continue where you left off by using the command letter by itself.
An example of this is the "L" command (list) which disassembles 20 instructions. The normal usage is to enter the start address followed by an "L". After you've seen one screenful, type "L" by itself and you get another screenful continuing from the next address.
e.g.
E000L
L
The first command will list the first page of code for the Applesoft BASIC interpreter, and the second command will list the second page.
You can use multiple commands on the same line, as long as you know what you are doing. If you don't mind pausing and resuming the scrolling output (use Ctrl-S to pause, any key to resume), you can do something like:
E000LLLLLLL
to get several pages of disassembly at once.
Moving up another step are commands that accept a range of addresses. The address range is entered, with the start and end address separated by a period (fullstop), and the command letter (if any) goes on the end.
The best example of this is a memory dump, which doesn't have a command letter. If you want to display a range of bytes as a hex dump, use something like this:
E000.E07F
The monitor displays eight bytes per line, with the address at the beginning of each line. If you don't start on a multiple of eight, then the first line will have less than eight bytes and subsequent lines will be aligned on eight byte boundaries.
There are variations on the memory dump that can be used for special cases:
1. You can press return on a blank line to display the next eight bytes.
2. If you enter an address and press return, one location is displayed.
3. You can continue from the end of the previous dump to a specified address by entering a dot followed by the end address.
You can also display scattered locations by entering them as separate commands. For example:
E000 E003 E006
will display the three specified locations, one per line.
The third layer of command complexity are the commands which expect a destination address and a source address range. The destination address goes first, then a less-than sign, then the source range (with a dot in the middle), and finally the command letter. The main example of this is a memory move ("M"):
4000<6000.7FFFM
This will move 8192 (2000 hex) bytes from locations 6000 through 7FFF down to 4000.
If your source and destination ranges overlap, the move will work correctly if you are moving data to a lower memory location, but if moving to a higher location you will get a repeating pattern of the data from the start of the source range.
There is one major command that breaks the rules above: the "set memory" command. The general syntax for this is the start address followed by a colon, then a space-separated list of bytes to be entered into memory. If you enter more than two digits for the data bytes, only the low order two digits are used.
If you are entering a lot of data, you can continue the command on subsequent lines by starting the command with a colon (no address).
The rest of the command line after the colon is regarded as part of the data to be entered, unless the monitor encounters a single letter command first.
For example, the following single line command will enter a short machine code program and disassemble it. The "N" command (normal) is used as a dummy command to force the data entry to terminate.
300:20 58 FC A9 C8 20 ED FD A9 E9 20 ED FD 20 8E FD 60 N 300L
Having got all that out of the way, here are the major monitor commands, each given in example form.
<return> Display next line of hex dump
1000 Hex dump one location
1000.101F Hex dump a range of locations
.102F Continue hex dump to specified address
1000:1 2 3 50 Set memory
:51 52 53 Continue set memory
300G Go - call subroutine at specified location
G Go again - call same address as last time
I Inverse
300L List - disassemble 20 lines
L List again - continue disassembly
1000<2000.207FM Move - copy range to destination address
N Normal
1000<2000.207FV Verify - compare range to destination address
There are also several commands that use control characters:
Ctrl-B Cold start BASIC (avoid this)
Ctrl-C Warm start BASIC
Ctrl-E Display the saved CPU registers
Ctrl-K Set input to specified slot (preceded by slot number)
Ctrl-P Set output to specified slot (preceded by slot number)
Ctrl-Y User command
The Ctrl-E command also lets you set the saved CPU registers, which will be used on a subsequent G (go) command. Type Ctrl-E then a colon, followed by the data to place into the A, X and Y registers.
The Ctrl-K and Ctrl-P commands should be avoided if you are running under DOS 3.3 or ProDOS, because they may cause DOS to be disconnected from the I/O. Use PR#n or IN#n instead.
Ctrl-Y is an "escape hatch", which allows third-party code to hook into the monitor for this one command.
On the Apple IIgs, IIc (with UniDisk ROM or later), and enhanced IIe there is also a mini-assembler which can be accessed from the monitor by typing an exclamation mark as a monitor command. While in the mini-assembler you enter lines of the form Address:Instruction, or to enter instructions in sequence, type a space then the instruction. (You must specify the address for the first instruction, or you could be writing anywhere.) Press <return> on a blank line to get back to the monitor.
e.g. starting in the monitor, type in the following:
!
1000:JSR FC58
LDA #C8
JSR FDED
LDA #E9
JSR FDED
JSR FD8E
RTS
<return>
1000L
1000G
This is the same program I gave above as an example of the set memory command, loaded at a different location.
--David Empson
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015- What parts of Apple II memory should a user be careful about
modifying when using the monitor?
It is important to keep in mind that you can do all sorts of nasty things to the computer if you play around in the monitor and don't know where things are located in memory.
The safest bet if you want to have a play would be to start the computer with no disk in the drive, then get into the monitor.
Don't play around with the following memory areas at all (unless you know exactly what you are doing):
0020-004F Zero page memory area used by the monitor
0100-01FF Stack
0200-02FF Input buffer
03D0-03FF System vectors
C000-C0FF I/O space. Don't even read memory in this area
unless you know what you are doing.
C100-C7FF I/O firmware (usually ROM on cards in slots, or
emultated slots). Some I/O cards may have I/O
ports in this area (but not for the IIc).
C800-CFFF Bank-switched area used by I/O cards. It is safe
to read this area in the IIc, but it has to be
handled carefully in other machines.
The following areas must be handled carefully to avoid problems:
0050-00FF Zero page memory area used by Applesoft BASIC
0400-07FF Text screen and "screen holes", which contain
system data
D000-FFFF ROM and bank-switched RAM ("language card").
Don't write anything into this area, especially
if you are running under ProDOS.
Other memory areas that you may need to be aware of:
0800-???? Applesoft BASIC programs normally go here,
followed by variables
2000-3FFF Hires graphics buffer for page 1
4000-5FFF Hires graphics buffer for page 2
9600-BFFF Normally used by DOS 3.3 or ProDOS
????-95FF Normally used for strings in Applesoft BASIC
The hires graphics buffers are only an issue if you need to use them. Under DOS 3.3 or ProDOS, the upper memory limit (9600) may change depending on the use of the MAXFILES command under DOS or the number of open files under ProDOS.
This leaves you with the following areas that you can usually play with to your heart's content. There are _some_ exceptions, but I've covered enough for one article.
0000-001F This isn't entirely free, but is usually OK.
0300-03CF Often used for small machine code programs.
1000(ish)-7FFF(ish)
The last area varies wildly depending on the size of any BASIC program and its variables.
--David Empson
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016- Can I do multi-tasking on a IIgs? or What is GNO/ME?
GNO/ME is a programming shell (a command line environment) for the Apple IIgs. Designed as a replacement for the ORCA Shell, GNO/ME works in a manner similar to the Unix operating system, providing preemptive multitasking of multiple text programs, as well as many Unix commands and library functions.
For more information about GNO/ME, see
GNO/ME USENET newsgroup (comp.sys.apple2.gno) and FAQs at
