# MESS System Information File

# All corrections and submissions are welcome. Please zip either a patch file or the entire

# modified file and send it to:

# Hobie Troxell [ht1848@yahoo.com]

# This file contains the basic documentation for most of the drivers presented in the MESS

# distribution. Please read the readme.txt, mess.txt and messnew.txt prior to reading this

# supplementary documentation. This file should be placed in the same directory as the MESS

# executable when using the DOS version of MESS.

# Driver entries are usually divided into sections such as: Usage, Features, Links, Known Issues,

# History and Trivia, and MESS Emulation State.

# History and Trivia - This section contains various background pieces for a system. Much of the

# information in these sections was kindly provided by Thierry Schembri and Olivier Boisseau of the

# "Old-computers.com Museum". Visit the excellent site at: www.old-computers.com.

# Features - Usually a quick list of important or unique features of that system.

# Usage - This section lists any helpful commands for the computer or console in question,

# such as disk operating system and file loading BASIC commands. This information is not

# intended to replace a proper owner's manual for the system in question, and only contains

# the most simple commands that can also be found on any of dozens of websites devoted to

# the system.

# Known Issues - This section lists any known issues or bugs for the driver. These will be

# fixed as time and knowledge permit. Please be patient. If you have information that may

# help the MESS team resolve these issues go to www.mess.org.

# MESS Emulation State: This section highlights the overall status of the MESS driver. Some system

# drivers are TESTDRIVERS.

#---------------------------------------------------------------------------------------------#

$info=a2600

$bio

Atari 2600 Video Computer System

History and Trivia:

The Atari Video Computer System (VCS) was released in 1977 at a suggested retail price of

$299, which dropped quickly as sales soared; about 340,000 systems were sold the first year

alone. Joe Decuir, Steve Mayer and Ron Milner designed the VCS. The Atari VCS was

developed under the project codename "Stella". The VCS later became known, both commonly

and officially as the Atari 2600 (from the model number CX2600). It is rumored that the number

2600 was chosen because 2600 cycles was a prominent long distance access tone, and that

one of the developers had created devices that would trick pay phones into granting long

distance access as a hobby.

Features:

Resolution: 160 x 260 (horz.) at 60.00 Hz

CPU: MOS 6507 1.19 MHz

Graphics Clock: 1.19 MHz

Bits: 8

ROM: 4k max

RAM: 128 bytes, in VLSI

Video Display Processor: Stella

Sprites: 32

Colors: 256 (static)

Sound Processor: Two Channel Square or Noise (TIA)

Cartridge ROM: 2k up to 64k

Links:

Atari Age - www.atariage.com

Atari Historical Society - www.atari-history.com/a2600.html

MESS Emulation State:

1) Restricted to 2KB and 4KB carts

2) Supports NTSC games only

3) Limited compatibility

4) No support for keypad controls

5) Dip switch used to select joystick or paddles

Other emulators:

PCAE (PC Atari Emulator) - http://www.classicgaming.com/pcae/

z26 - http://www.whimsey.com/z26/

x26 (z26 front-end) - http://www.wintersolace.com/

Stella - http://stella.sourceforge.net/

StellaX - http://www.emuunlim.com/stellax/

$end

#---------------------------------------------------------------------------------------------#

$info=a400

$bio

Atari 400 Home Computer

Usage/Known Issues:

Requires full keyboard emulation. At startup, full keyboard emulation mode is enabled by

default. Whilst in full keyboard emulation mode, some key associated functionality may be

disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the

scroll_lock key.

Most disk and cartridge images should work, though some graphic issues may exist. Note that

the Atari 400 has less memory than the Atari 800, and some disk images may not work as a

consequence; this is not a bug in the emulation.

History and Trivia:

The Atari 400 and 800 were the first home computers to use custom coprocessors and the first

to use "sprites" and special video interruptions like display lists, features that will be

implemented several years after on the Commodore Amiga. It offered high graphic resolution,

lots of colors and great sound capabilities, more than other computers could do then! The

two models had same characteristics, the 400 is the low-cost version, it has only 16 KB

(instead of 48 KB), one cartridge port (two for the 800) and a membrane keyboard (a

typewriter style keyboard one for the 800).

Emulators:

Atari800 (Unix, Amiga, MS-DOS, Atari TT/Falcon, SDL, WinCE) - http://atari800.sourceforge.net/

Atari++ - http://www.math.tu-berlin.de/~thor/atari++/

Atari800Win PLus - http://www.a800win.atari-area.prv.pl/

Raibow (historical) - http://www.chrislam.co.uk/ 

PC Xformer (historical)

$end

#---------------------------------------------------------------------------------------------#

$info=a5200

$bio

Atari 5200 SuperSystem

Usage/Known Issues:

Keyboard input is a little difficult, using a joystick or mouse is recommended.

Most games are playable. See a5200.hsi for a fairly exhaustive compatibility list.

History and Trivia:

The Atari 5200 was introduced in 1982, and was actually designed to be a competitor to the

Intellivision, before ColecoVision entered the market. Developed under the name of "Pam"

(Atari, at the time, typically named projects after well-endowed female employees), Atari

considered releasing it with that moniker; PAM in this case an acronym for "Personal Arcade

Machine".

The 5200 shared much of the architecture of the Atari 400/800 computers, but featured a

different cartridge connector and completely different controllers. Non-centering analogue

joysticks which offered a full 360 degrees of mobility, were both innovative and unreliable.

Other controller features included a keypad, and a ahead-of-it's-time pause button.

The Atari 5200 suffered from it's initial incompatibility with the VCS/2600 (an adapter was later released) and fierce competition from Coleco. When Warner Communications sold Atari

Corp. to the Tramiels in 1984, they quickly removed it from the market.

Emulators:

Jum52 (Jum's A5200 Emulator) - http://www.geocities.com/james7780/emulators/emu5200.html

Because of it's hardware similarity to 400/800/XL/XE computers line - 5200 emulation is also included in:

Atari800 - http://atari800.sourceforge.net/

Atari++ - http://www.math.tu-berlin.de/~thor/atari++/

Atari800Win PLus - http://www.a800win.atari-area.prv.pl/

Raibow - http://www.chrislam.co.uk/ 

$end

#---------------------------------------------------------------------------------------------#

$info=a7800

$bio

Atari 7800 ProSystem

Known Issues:

The Pause key "P" is hard-coded and not able to be re-mapped.

Most games work fine, but a few have graphic and playability issues. See a7800.hsi for a

full compatibility list.

History and Trivia:

Originally developed in 1984 as the Atari 3600, the Atari 7800 Prosystem was released to the

US market in 1986, in an attempt to compete in a revitalized home videogame market. The 7800

was actually designed by Gencomp as part of a lawsuit settlement (Gencomp had been sued for

releasing a speedup chipset for Atari coinop Missile Command).

The 7800 was compatible with pre-existing Atari 2600 game program cartridges, without the need

for expansion modules or turning switches, but was also designed to use enhanced 7800-only

cartridges such as the pack-in "Pole Position 2". (n.b., only the 7800-specific cartridges are

currently supported in MESS.) Many peripherals, including a computer/keyboard and high score

saving cartridge were planned but never released.

Unfortunately for Atari, the system did poorly in the late 1980's market dominated by Nintendo.

www.atari-history.com has this interesting anecdote: "In the summer of 1984 the first 5,000

Atari 7800's had just been built in the new El Paso assembly plant. The production line

manager, Brad Saville was eager to meet with Jack Tramiel to show him the new flagship Atari

video game console. The meeting ended abruptly as Jack Tramiel was quoted "Get your pollution

out of here! We make computers now and we don't want your garbage." The line manager was fired

2 days later. About 8-9 months later the line manager received a phone call from Atari asking

him as to the whereabouts of the die molds for the Atari 7800. The ex-line manager responded

that he did in fact know where they were and for $50/hour for about 200 to 300 hours of his

time he would remember where they were and find them. The Atari Corp. representative who

called was infuriated and informed the former production line manager that Atari's lawyers

would be in contact with him. He never heard from Atari again."

Links:

www.Atari7800.org

Emulators:

EMU7800 - http://emu7800.sourceforge.net/

$end

#---------------------------------------------------------------------------------------------#

$info=a800

$bio

Atari 800 Home Computer

Known Issues:

Requires full keyboard emulation. At startup, full keyboard emulation mode is enabled by

default. Whilst in full keyboard emulation mode, some key associated functionality may be

disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the

scroll_lock key.

The Atari800 driver now has two ROM slots. It really had two slots, so the code was modified

to optionally read the second part of a 16K ROM from the second cartridge filename provided

(right slot). The previous version had a800_cartridge_32k flag which was wrong. Cartridges

are either 8K or 16K, so that was renamed to ..._16k too ;)

Most disk and cartridge images should work, though some graphic issues may exist.

The Atari 800XL driver (a800xl) is not currently working.

History and Trivia:

The Atari 400 and 800 were the first home computers to use custom coprocessors and the first

to use "sprites" and special video interruptions like display lists, features that will be

implemented several years after on the Commodore Amiga. It offered high graphic resolution,

lots of colors and great sound capabilities, more than other computers could do then! The

two models had same characteristics, the 400 is the low-cost version, it has only 16 KB

(instead of 48 KB), one cartridge port (two for the 800) and a membrane keyboard (a

typewriter style keyboard one for the 800).

Emulators:

Atari800 (Unix, Amiga, MS-DOS, Atari TT/Falcon, SDL, WinCE) - http://atari800.sourceforge.net/

Atari++ - http://www.math.tu-berlin.de/~thor/atari++/

Atari800Win PLus - http://www.a800win.atari-area.prv.pl/

Raibow (historical) - http://www.chrislam.co.uk/ 

PC Xformer (historical)

$end

#---------------------------------------------------------------------------------------------#

$info=adam

$bio

ColecoAdam (1982)

MESS Emulation State:

$end

#---------------------------------------------------------------------------------------------#

$info=advision

$bio

Entex Adventurevision

Known Issues:

Sound is not currently supported.

All four games are playable.

History and Trivia:

The Adventure Vision was a cartridge based, electronic handheld video game that was

manufactured by Entex Industries in 1982. It measured about 13 1/4" X 10" X 9" and used

one vertical strip of 40 red LEDs and a spinning mirror to produce a screen with a 150X40

resolution drawn at 15 frames/sec. There were only four cartridges produced for it: Defender,

Turtles, Super Cobra, and an Asteroids clone, Space Force.

Visit http://www.adventurevision.com for more information.

$end

#---------------------------------------------------------------------------------------------#

$info=aim65

$bio

Rockwell AIM-65

Very early computer

Features:

Integrated 20 digit (16segment) display

Full size keyboard

Integrated printer

Connector for tty input/output

Tape interface

Known Issues:

Display and keyboard working

Usable picture of the display with its white frame as artwork would be nice.

Would suffer from support for intelligent terminals as tty equipment.

Stopped. For me it is much to cryptic to operate, and therefore not interesting for me anymore.

MESS Emulation State:

This system is a TESTDRIVER.

Contributors:

Richard A. Cini: provided help and pictures

$end

#---------------------------------------------------------------------------------------------#

$info=amiga

$bio

Commodore Amiga

Known Issues:

Sound is not currently supported.

The driver is now working fairly well, though some games may need more memory than currently

emulated.

History and Trivia:

The conceptor of the Amiga 1000 was Jay Miner, who created the Atari 800 many years before.

He wanted to make the most powerful computer ever, then he joined a little California

company called Amiga. He used the principle of the three coprocessors (again) to help the

main processor. At the beginning, the Amiga had only 64 kilobytes of RAM!, Atari wanted to

buy the Amiga but finally, Commodore succeeded to buy it (then there was a lawsuit, which

Commodore won). It was meant to be a competitor to the Atari 520 ST. The operating system

was done by Metacomco, a British company who specialized in the 68000 processor (they also

made languages for the Sinclair QL). It is a fully multitasking system which looks like

UNIX with a graphical user interface. It was the very first personal computer with great

graphics and sound capabilities with a GUI environment. Amiga BASIC was written by

Microsoft (like most other versions of BASIC). The Amiga 1000 began to lose popularity one

year later with the creation of its two main successors: the Amiga 500 and the Amiga 2000.

There were two versions of the Amiga 1000. The first one, just called "Amiga", was sold

only in USA, had a NTSC display, and didn't have the video modes EHB and HAM, later

versions would have this built in. The second one, called "Amiga 1000" (to avoid confusion

with its successor, the Amiga 2000) had a PAL display, enhanced video modes

(HAM & EHB) and was built in Germany.

MESS Emulation State:

$end

#---------------------------------------------------------------------------------------------#

$info=apexc

$bio

APEXC (All Purpose Electronic X-Ray Computer)

Usage Notes:

You should specify a cylinder image with code to run in it. Arguably, APEXC does not require such

an image, since you may enter code in the control panel, but this would be a pain in the ass.

If the program you run use punched tape I/O, you may specify tape image files. The first unit is

read-only, the second unit is write-only.

On a CLI MESS port, the resulting MESS command line may look like this:

mess apexc -cyln ram_image.apc -ptap input.tap output.tap

Note that, when you quit MESS or the APEXC driver, the contents of the cylinder are saved

to the image you specified. This simulates the behavior of the APEXC, where the cylinder image

IS the working memory. If you don't like this behavior, you may either write-protect

the cylinder image file, or keep a backup copy elsewhere on your hard disk (highly recommended).

Note that the APEXC CPU is stopped on start-up, so that you may check the machine state and enter

the start-up program address.

On start-up, the instruction at address 0 is loaded into the Control Register, then the machine

is stopped. To run the program starting at address 0, just press the Run/stop switch

(the Run/stop switch is mapped to the Return key on the main keyboard).

To start a program at another address, you need to load the first instruction into the Control

register with the control panel. To do so, use keys 1 through 0 on the main keyboard to enter

the 10-bit address into the 10 most significant bits of the Control Panel display, and set

other bits to 0 with the three rows of keys under 1 through 0 (each key toggles a bit in the

control panel display; don't be intimidated if it sounds complicated, it should eventually

appear straight-forward when you try, provided you know what binary scale is). You have thus

generated a Stop instruction pointing to the first instruction of the program. Write this

instruction into the Control Register, by holding Left Shift pressed and pressing 1 on

the numeric keypad. You should now press the Run/stop switch twice (mapped to the Return key

on the main keyboard). First press executes the stop order, but fetches the first

instruction of the program into the control register. Second press starts running the program,

starting with the first instruction.

Control panel usage:

This is relatively simple. The Control Panel may hold and display a 32-bit value. Display is made

of 32 lamps, which show the current value in binary scale (each lamp represents one bit). Hence,

the normal usage is loading the value you want to edit into the control panel, editing it,

then saving it to the proper location.

Default key map:

Run/stop switch: Return key on main keypad

The next 6 keys may be used alone to read the register into the control panel display, or

in combination with the Left Shift key to write the value in the control panel display into the

register.

Read/write Control Register: 1 key on numeric keypad

Read/write Accumulator: 2 key on numeric keypad

Read/write Register: 3 key on numeric keypad

Read/write current Head Block (never used on APEXC - used for bank switching): 4 key on numeric keypad

Read/write Memory Location: 5 key on numeric keypad

Read/write memory location pointed to by ML register: 6 key on numeric keypad

write instead of reading: Left Shift key (when you press one of the 6 keys above, the

designated register is read into the control panel display, unless this key is being pressed,

in which case the value in the control panel display is written into the register)

Toggle bits 1 through 10 in display: keys 1 through 0 on the main keyboard

Toggle bits 11 through 20 in display: key row directly below the former on the main keyboard

(Q through P if your keyboard is QWERTY)

Toggle bits 21 through 30 in display: key row directly below the former on the main keyboard

(A through ; if your keyboard is QWERTY)

Toggle bits 31 and 32 in display: key row directly below the former on the main keyboard

(W and X if your keyboard is QWERTY)

Known Issues:

The driver should work correctly as of MESS .37b15. Still, it needs development tools, sample

code and usage instructions desperately. I have tons of sample code (which was the reason for

starting to write this driver), but still need to retype it. I have started work on an assembler,

too.

Since I have no description of the control panel of an actual APEXC, I implemented a common-place

control panel, so this part of the emulation is not accurate. I don't even know how an actual

APEXC was operated, and the procedures I describe above are not accurate, either.

History and Trivia:

The APEXC was designed by Andrew D. Booth at Birkbeck College, London, in the early 50's.

From 1943 on, he started working on the determination of crystal structures using X-ray diffraction

data. The computations involved were extremely tedious and there was ample incentive for automating

the process. In 1947, along with his collaborator and future spouse Kathleen Britten, he spent

a few months with von Neumann's team, which was the leading edge in computer research at the time.

Booth designed an electromechanical computer, the ARC, in the late 40's. Later on, they built

an experimental electronic computer named 'SEC' (Simple Electronic Computer), and finally the APEC

(All-Purpose Electronic Computer) series.

According to a 1956 document, the APEC series included the following machines:

* APE(X)C: Birkbeck College, London (before 1955)

* APE(N)C: Board of Mathematical Machines, Oslo ('N' must stand for 'Norway')

* APE(H)C: British Tabulating Machine Company (No idea what 'H' can stand for)

* APE(R)C: British Rayon Research Association ('R' must stand for 'Rayon')

* UCC: University College, London (circa January 1956)

* MAC (Magnetic Automatic Calculator): "built by Wharf Engineering Laboratories" (February 1955)

* The HEC (Hollerith Electronic Computer - silly name invented by BTM

directors), built by the British Tabulating Machine Company (later to become

International Computers and Tabulators (ICT), then International Computers

Limited (ICL)), a commercial machine sold in several models (I have heard of

HEC 1, HEC 2, HEC 2M (no idea what the difference with HEC 2 is) and HEC 4)

(before 1955)

Only one of each of these machines was built, with the exception of HEC (and possibly MAC)

which were commercial machines produced in small series. They were similar in design,

with various small differences, mostly in I/O equipment (either punched-card machines - APEXC,

APEHC - or teletypers (keyboard and printer, and paper tape reader and puncher) - APERC, APENC).

Also, the UCC had 8k words of storage, instead of 1k word for other machines, and the MAC

used germanium diodes in replacement of many tubes. The HEC used standard

Hollerith punch cards; the HEC 4 had a printer, too, and it featured several

instructions (divide) and registers not found on the APEXC.

I am sorry I know little more about Booth, his team, and the history of these machines.

Technical Description:

The APEXC is an incredibly simple machine.

Instruction and Data words are always 32-bit-long. The processor uses integer arithmetic with 2's

complement representation. Addresses are 10-bit-long. The APEXC has no RAM, except a 32-bit

accumulator and a 32-bit data register (used along with the 32-bit accumulator to implement 64-bit

shift instructions and hold the 64-bit result of a multiplication). Instructions and data are

stored in two magnetic drums, for a total of 32 circular magnetic tracks of 32 words. Since

the rotation rate is 3750rpm (62.5 rotations per second), the program execution speed can go

from as high as the theoretical maximum of 1 kIPS to lower than 100IPS if program instructions

and data are not contiguous. Nowadays, many a pocket calculator is faster.

One oddity is that there is no program counter: each machine instruction includes the address

of the next instruction. This design may sound weird, but it is the only way to achieve optimal

performance with this cylinder-based memory.

The machine code is made of 15 instructions only, namely addition, subtraction, multiplication,

load (3 variants), store (2 variants), conditional branch, right arithmetic bit shift,

right bit rotation, punched-card input, punched-card output, machine stop, and bank-switching

(which is never used on the APEXC, since it only has 1024 words of storage, and addresses are

10-bit-long). A so-called vector mode enables to repeat the same operation 32 times with 32

successive memory locations. Note the lack of bitwise and/or/xor and division. Also, note

the lack of indirect addressing modes: dynamic modification of opcodes is the only way one may

simulate it.

Another oddity is that the memory bus and the ALU are 1-bit-wide. There is a 64kHz bit-clock and

a 2kHz word-clock, and each word memory and arithmetic operation is decomposed into 32 1-bit

memory and arithmetic operations: this takes 32 bit cycles, for a total of 1 word cycle.

The processor is fairly efficient: most instructions take only 2 word cycles (1 for fetch,

1 for read operand and execute), with the exception of stores, shifts and multiplications.

Yes, the APEXC CPU is a RISC: there is no other adequate word.

Note there is no ROM, and therefore no 'bootstrap loader' or default start-up program whatever.

As far as I know, no executive or operating system was ever written for the APEXC, although

there were subroutine libraries of sorts for common arithmetic, I/O and debug tasks.

Operation of the machine is normally done through a control panel which allows the user to start,

stop and resume the CPU, and to alter registers and memory when the CPU is stopped. When starting

the machine, the address of the first instruction of the program to be executed must be entered

in the control panel, then the run switch must be pressed. Most programs end with a stop

instruction, which enables to check the state of the machine, possibly run some post-mortem

debugging procedures (a core dump routine is described in an APEXC programming book), then enter

the address of another program and run it.

Two I/O devices were supported: a paper tape reader, and a paper tape puncher. The puncher output

could be fed to a printer ('teletyper') unit when desirable. Printer output is emulated and is

displayed on screen. Tape input was either computer-generated by the APEXC, or hand-typed with

a special 32-key keyboard (each tape row had 5 data holes (<-> bits), which makes 32 different

values).

$end

#---------------------------------------------------------------------------------------------#

$info=apfimag

$bio

APF Imagination Machine

The APF Imagination has the same hardware as the APF-M1000, but it is a computer.

It has a keyboard and built in cassette player.

An additional disc interface was available.

In basic, pressing "FUNCTION" (currently mapped to CTRL) and a letter/number will display

a basic keyword making it easier to enter programs.

FUNCTION+Q = IF

FUNCTION+W = STEP

FUNCTION+E = STOP

FUNCTION+R = READ

FUNCTION+T = NEXT

FUNCTION+Y = PRINT

FUNCTION+U = END

FUNCTION+I = LIST

FUNCTION+O = REM

FUNCTION+P = USING

FUNCTION+1 = GOSUB

FUNCTION+2 = LET

FUNCTION+3 = DATA

FUNCTION+4 = INPUT

FUNCTION+5 = DIM

FUNCTION+6 = FOR

FUNCTION+7 = RETURN

FUNCTION+8 = THEN

FUNCTION+9 = ON

FUNCTION+0 = GOTO

FUNCTION+- = RESTORE

FUNCTION+ENTER = CLOAD

For cassette:

Use CSAVE"<filename>" to save a file, and CLOAD"" to load the file back.

For disc:

Use SAVE"<filename>" to save a file, and LOAD"<filename>" to load the file back.

You can use "DIR <drive number>" e.g. "DIR 0" and "DIR 1" to give a directory of the

disc.

Basic disk images with the ".APD" extension are supported.

Known issues:

* Cassette loading and saving is working

* Interrupts are not exact. I don't know enough about them, any info would be appreciated.

* Disc interface is working, but there may be some bugs.

* Keyboard is mostly working but some keys may be missing

* Keypad is not emulated

* The M6847 emulation is very advanced *BUT* I don't think I have set it up correctly for the APF Imagination, therefore the graphics are wrong.

* Memory emulation is not complete

$end

#---------------------------------------------------------------------------------------------#

$info=apfm1000

$bio

APF M-1000

The APF M-1000 is a console. It has a built-in game. The emulation is not exact and the

built in game does not work.

Known issues:

* internal game does not work

* keypad is not emulated

$end

#---------------------------------------------------------------------------------------------#

$info=apple1

$bio

Apple 1

Usage:

Upon boot or reset, the system displays a "\" and a blinking "@" cursor on the next

line. The blinking "@" is the Apple 1's video cursor. The "\" is the prompt for the

Monitor program. From the Monitor, you can examine or change memory or execute another

program.

You can always interrupt a program and return to the Monitor by pressing the Apple 1's

RESET switch (F12). This will not clear the screen or disturb memory contents.

To cold-boot the system, clearing the screen and memory, press the MESS Reset key

(F3, in partial emulation mode only).

The Apple 1's CLEAR SCREEN switch (F2) will clear the screen and place the cursor at

the upper left corner. This only clears the video hardware, not the computer's memory,

so you can use it whenever you like.

To start the cassette interface's mini-monitor from the Monitor, type the Monitor command:

C100R

This mini-monitor will let you write memory regions to a cassette image or read a cassette

image into memory. It will only execute a single line of commands, and will then return you

to the main Monitor, but this line can contain several write or read commands.

Cassette write command, writing data from memory at $xxxx-$yyyy:

xxxx.yyyyW

Cassette read command, reading data into memory at $xxxx-$yyyy:

xxxx.yyyyR

The starting and ending addresses xxxx and yyyy should be 4-digit hexadecimal addresses.

The starting address can actually be shorter than 4 digits, but to be safe, the ending address

should be exactly 4 digits. (A bug in the cassette mini-monitor will cause digits missing

from the ending address to be replaced by the trailing digits of the starting address, and

if the starting address does not end with zeroes, much more data will be written or read than

expected.)

If a command line contains multiple write or read commands, the corresponding memory regions

will be written or read in sequence. These commands may be separated by spaces, which are

ignored.

When a region is written, its data is preceded by a 10-second leader. When a region is read,

the leader can vary in length but should be at least 4-5 seconds.

If the cassette image doesn't contain enough data to fill a region, the mini-monitor will hang

waiting for the remaining data, and the system must be reset.

When all the cassette commands have been executed, the mini-monitor will return to the Monitor,

which will display a "\" prompt.

Some cassette command examples:

To read Apple 1 BASIC from cassette:

E000.EFFFR

To write a BASIC program to cassette, with BASIC's default LOMEM= setting of 2048:

4A.00FFW800.FFFW

To read a BASIC program from cassette, with LOMEM=768:

4A.00FFR300.FFFR

Once Apple 1 BASIC is loaded into memory, it can be started with the Monitor command:

E000R

This will start BASIC from scratch, removing any existing BASIC program and data.

To return to BASIC from the monitor while preserving the current program and data,

use the command:

E2B3R

The BASIC prompt is a ">". Apple 1 BASIC is generally similar to Apple II Integer BASIC,

but without the latter's graphics commands.

MESS Emulation State:

Optional cassette interface is included and emulated.

4 KB of DRAM is mapped to $E000-$EFFF. This is required for Apple 1 BASIC.

Known Issues:

The cassette interface and $E000-$EFFF DRAM are always included; they cannot be switched off.

The DRAM at $E000-$EFFF is not included in the RAM configured by MESS's -ram option, due

to limitations in how MESS presently manages configurable RAM.

History and Trivia:

The Apple 1 was a kit computer that was introduced and sold in small quantities in 1976.

Steve Wozniak ("Woz"), who worked for Hewlett-Packard at the time, wanted to build his own

computer. He could afford neither the Intel 8080 (the most popular microprocessor at the

time) nor the Motorola 6800 (his own preference). Therefore, he decided to build his computer

around MOS Technology's new 6502 chip, which was quite compatible with the Motorola 6800 but

far less expensive. He proceeded to write a BASIC interpreter for the chip, and then turned

to designing the computer that would run it, using an earlier paper design for the Motorola

6800.

The resulting computer was easier to use and more affordable than many other kit computers

of the time, sporting a keyboard interface and TV-compatible video terminal circuitry, all

on a single circuit board. To keep costs down, the video memory was implemented using shift

registers rather than RAM, with the downside being a slow display rate (60 characters per

second). However, this was still much faster than the 10-character-per-second electromechanical

Teletypes used with many early home computers. Wozniak's computer also used new, more compact

4-kilobit dynamic RAM chips instead of the 1-kilobit static RAMs used by most other designs.

Wozniak promoted his computer and enhancements for it at the Homebrew Computer Club in Palo

Alto, California.

Steve Jobs, who had worked with Woz on the game "Breakout" for Atari, convinced Woz to try

to market and sell the computer. Together they formed the Apple Computer Company. Paul

Terrell, the owner of The Byte Shop, a new local computer store, was interested in this

computer, but only if it was fully assembled and came with a cassette interface, so

Wozniak designed one.

Normally, the Apple 1 was sold "naked", simply as a circuit board, without a monitor, power

supply, keyboard, tape drive, etc. These would be added by the owner. Wozniak and Jobs

assembled about 200 systems and sold about 170 of them. Most of these were later traded in

to Apple for Apple IIs and were destroyed. About 30 to 50 are still in existence.

Features:

CPU: MOS Technology 6502, 1 MHz

Memory: 4 kB DRAM, expandable to 8 kB on board, or up to 52 kB with third-party expansion

hardware

Screen: 40x24 characters

Storage: Optional cassette interface

Links:

Apple I Owners Club -- http://www.applefritter.com/apple1

Apple History -- http://www.apple-history.com/

Apple ][ History -- http://apple2history.org/history/ah02.html

Apple 1 Manual -- http://emulation.net/apple1/manual/apple1manx.html

$end

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$info=apple2

$bio

Apple ][

Known issues:

Optional cassette drive not yet supported; in fact, no peripherals are supported

(bug #477)

Colors are incorrect (bug #475).

Requires full keyboard emulation. At startup, full keyboard emulation mode is enabled by

default. Whilst in full keyboard emulation mode, some key associated functionality may be

disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the

scroll_lock key.

Usage:

Upon booting, you'll get the ROM monitor prompt ('*'), from which you can

examine/modify/run at different memory locations. (Note: you would normally need to press

RESET to get to the prompt, but this doesn't seem to be necessary in MESS.)

From the Monitor, press control-B then ENTER to get to Integer BASIC, which uses the

greater than prompt ('>').

You can invoke the mini-assembler by entering 'F666G' at the Monitor.

To backspace, use the left arrow key. The "Backspace" key is mapped to the Apple ][

"DEL".

History and Trivia:

The Apple ][ is an improved version of the Apple 1 kit computer first released in 1977.

Along with the TRS-80 and the PET, it constituted one of the "second-generation" of

computers, aimed at the general user rather than the specialized hobbyist.

The Apple ][ featured a beige plastic case, color graphics, and seven (eight?) expansion

slots. It included a version of BASIC called "Integer BASIC" on the ROM which came with

the machine.

It was an excellent home gaming platform. It shipped with two game paddles (various

models were used) and supports up to four. It also included a built-in speaker.

The cassette interface required a cassette recording deck and was quite finicky. The

treble and bass on the cassette deck had to be fiddled with in just the right way.

Features:

CPU: MOS 6502 1MHz

Memory: RAM 4kB expandable to 48kB, 12kB ROM

Screen: 6 colors at 280x192, 4-bit color at 40x48

Data path: 8-bit

Links:

Apple History -- http://www.apple-history.com/