#

# Apple II/II+ Documentation

Last updated August 18, 2022
Valid as of 1.31.0-UNSTABLE

Table of Contents:

- Introduction
- MAI System and Disks Configuration File
- Floppy Disk Images
- Firmware/BIOS
- Input
  - Joystick/Gamepad
  - Atari Joystick
  - Apple II/II+ Keyboard
    - Default Mappings
- Custom Palettes
- Settings Reference

## Introduction

Mednafen's "apple2" emulation module emulates an Apple II/II+. It is geared more towards running individual software releases independently of other software releases; it can be used differently, but the abstractions chosen may make it rather awkward.

## MAI System and Disks Configuration File

Single-disk single-side software can be loaded directly. Multi-disk or multi-side software will require the creation of a special configuration file, saved with the file extension "mai", to be loaded with Mednafen.

Mednafen does not write to the floppy disk image files specified via the MAI configuration file. Modified disk data is automatically saved into and loaded from files in Mednafen's nonvolatile memory/save game directory. The ID/hash used in naming these files is calculated by hashing data generated based on the contents of the disk image files and any firmware files referenced in the MAI configuration file, along with the values of settings that control the hardware configuration.

In addition to loading a naked MAI file, Mednafen supports automatically loading a MAI file from within a ZIP archive. Any referenced files(e.g. floppy disk images and override firmware) must also be in the same ZIP archive. In regards to Mednafen selecting the correct file to open, the ordering of the MAI file in the ZIP archive in relation to other files doesn't matter.

Sample MAI configuration file:

>     MEDNAFEN_SYSTEM_APPLE2
>     # Above signature must be the first line.
>     #
>     # File paths specified in this file are relative to the directory containing the MAI file.
>     #

>     #
>     # Specify available RAM, in KiB.  Can be one of: 4 8 12 16 20 24 28 32 36 40 44 48 64
>     #  Specifying "64" enables emulation of a RAM-based 16K language card.
>     #
>     #  Default: 64
>     #
>     ram 64

>     #
>     # Select Apple II/II+ firmware.  Options are: integer applesoft
>     #  Ignored if "firmware.override" is specified.
>     #
>     #  Default: applesoft
>     #
>     firmware applesoft

>     # Apple II/II+ firmware, 12KiB, located at $D000-$FFFF
>     #  Optional; specify to override the firmware loaded via Mednafen's firmware
>     #  loading system.
>     #
>     #firmware.override "apple2.rom"

>     #
>     # Select ROM card firmware.  Options are: none integer applesoft
>     #  ROM card emulation is disabled if "none" is selected(regardless of the "romcard.override" setting), or if 64K of RAM
>     #  is selected by the "ram" setting.
>     #
>     #  Default: integer
>     #
>     romcard integer

>     #
>     # (see firmware.override description)
>     #  Note: Ignored if "romcard" is set to "none".
>     #
>     #romcard.override "applesoft.rom"

>     #
>     # Select game input device(s).
>     #
>     #      none: no game I/O devices
>     #
>     #   paddles: two rotary dial paddles
>     #
>     #  joystick: 2-axis, 2-button joystick, with selected default resistance
>     #            setting(1 through 4).
>     #
>     #   gamepad: 2-axis(D-pad), 2-button gamepad, with selected default resistance
>     #            setting(1 through 4).
>     #
>     #     atari: two Atari digital joyport joysticks
>     #
>     # Examples:
>     #  gameio none
>     #  gameio paddles
>     #  gameio joystick 2
>     #  gameio gamepad 2
>     #  gameio atari
>     #
>     # Default: joystick 2
>     #
>     gameio joystick 2

>     #
>     # Specify (maximum) resistance, in Ω, for each of the four selectable
>     # resistance settings for the "joystick" and "gamepad" devices.
>     #
>     #  Default: 93551 125615 149425 164980
>     #
>     gameio.resistance 93551 125615 149425 164980

>     #
>     # Enable Disk II in Slot 6(with two 5.25" disk drives attached).
>     #
>     #   Default: 1
>     #
>     disk2.enable 1
>     disk2.drive1.enable 1
>     disk2.drive2.enable 1

>     # Select 16-sector Disk II firmware.  Options are: 13sec 16sec
>     #   Effectively ignored if "disk2.firmware.override" is set.
>     #
>     #   Default: 16sec
>     #
>     disk2.firmware 16sec

>     # Optionally, specify to override the firmware loaded via Mednafen's
>     # firmware loading system.
>     #
>     #disk2.firmware.override "disk2_dos33_boot.rom" "disk2_dos33_seq.rom"

>     #
>     # Define available floppy disks (or sides).  Disk identifiers(the part
>     # immediately after "disk2.disks." must only contain characters a-z, 0-9, and _)
>     #
>     # Fields are: name filepath write_protect(optional)
>     #  If the write_protect field is omitted, then the default write protect setting
>     #  for the format is used.  For WOZ disk images, write protect is explicitly
>     #  specified in the INFO header.  For other formats, write protect defaults
>     #  to off(0).
>     #
>     disk2.disks.game1 "Disk 1 - Boot" "SomeGame - Disk 1.dsk" 1
>     disk2.disks.game2 "Disk 2" "SomeGame - Disk 2.dsk" 1
>     disk2.disks.game3 "Disk 3" "SomeGame - Disk 3.dsk" 1
>     disk2.disks.save "Save Disk" "SomeGame - Save Disk.dsk" 0

>     #
>     # Specify which disks are allowed to go into which drive.
>     #
>     # Prefix the disk identifier with a * to start with that disk inserted.
>     #
>     # Don't insert the same disk (identifier) into different
>     # drives at the same time unless you're some sort of spacetime wizard.
>     #
>     disk2.drive1.disks *game1 game2 game3
>     disk2.drive2.disks *save

## Floppy Disk Images

If a virtual floppy disk image in memory has been modified(written to) during the course of emulation, the in-memory floppy disk image will be saved into a separate file under Mednafen's nonvolatile memory directory upon exit. On subsequent invocations with the same floppy disk image(or MAI file and its associated floppy disk images), this separate floppy disk image will be transparently loaded at startup and its data used in lieu of the source floppy disk image when creating the virtual floppy disk image in memory.

The following 5.25" Apple II floppy disk image formats are supported:

Extension: | Size(Bytes): | Description:
--- | --- | ---
d13 | 116480 | Apple DOS 13 sectors/track
dsk do | 143360 | Apple DOS-order 16 sectors/track
po | 143360 | Apple ProDOS-order 16 sectors/track
woz | (variable) | https://applesaucefdc.com/woz/

## Firmware/BIOS

Place the correct firmware image files in the correct location.

If you want to use custom or modified firmware, create and load a MAI configuration file.

If you make a linear dump of your Disk II P6 sequencer ROM(s) through the P5 socket via a program running on an Apple II, remember to process the resulting data to swap: A7 and A5, D4 and D7, D5 and D6.

In contrast, the required Disk II P5 boot ROM format has its data arranged how it appears to the 6502(i.e. as if it's just linearly dumped with a simple program running on an Apple II).

Filename: | Purpose: | SHA-256 Hash:
--- | --- | ---

apple2-int-auto.rom

Apple II Integer BASIC and Autostart System ROMs, concatenated(8KiB).

Consists of 2KiB ROMs(in order, with SHA-256 hashes):
(TODO: verify 341-0001, 341-0002, 341-0003 hashes)

341-0001
(3a5137fa95b0a2e4a60a975a97d04abd89425295ee352aa17a3da348764d4f27)

341-0002
(0ec63e5737b33f133166a3d55ed28a367a671f03960d9d57fb8598a9de6a437b)

341-0003
(2ba5e31366045e5f03255f147550112a5974e3a36ed21ce585917f7c5be12869)

341-0020
(29465303e7844fa56a8c846d0565e45f5ee082f98f2ccf1b261de4a7e902201b)

cb52b212a62f808c2f59600b2823491ee12bd91cab8e0260fe34b5f14c47552f
(TODO: verify)

apple2-asoft-auto.rom

Apple II+ AppleSoft BASIC and Autostart System ROMs, concatenated(12KiB).

Consists of 2KiB ROMs(in order, with SHA-256 hashes):

341-0011
(b45168834f01e11ae2cc35fc6bef153e5a13c180503c6533dff111558099df4d)

341-0012
(468d36201974ecbe22efd9164f0ead1abab00b33f1a480da525502964641f444)

341-0013
(2814de134e79213eddb6d7d7a18cba105e120a08e77c9767c46d6fc3cfcc593d)

341-0014
(6848707531d7a8934a58e743483e4ebc74bf2ded0229b42533fa20cb89ed1a23)

341-0015
(220fb70bac6839c98901cd542c3c1fbd7145d0bb9423ea8fcc8af0f16ec47d75)

341-0020
(29465303e7844fa56a8c846d0565e45f5ee082f98f2ccf1b261de4a7e902201b)

fc3e9d41e9428534a883df5aa10eb55b73ea53d2fcbb3ee4f39bed1b07a82905

disk2-13boot.rom | Disk II Interface 13-Sector P5 Boot ROM, 341-0009 | 2d2599521fc5763d4e8c308c2ee7c5c4d5c93785b8fb9a4f7d0381dfd5eb60b6 (TODO: verify)
disk2-13seq.rom | Disk II Interface 13-Sector P6 Sequencer ROM, 341-0010 | 4234aed053c622b266014c4e06ab1ce9e0e085d94a28512aa4030462be0a3cb9
disk2-16boot.rom | Disk II Interface 16-Sector P5 Boot ROM, 341-0027 | de1e3e035878bab43d0af8fe38f5839c527e9548647036598ee6fe7ec74d2a7d
disk2-16seq.rom | Disk II Interface 16-Sector P6 Sequencer ROM, 341-0028 | e5e30615040567c1e7a2d21599681f8dac820edbdcda177b816a64d74b3a12f2

## Input

### Joystick/Gamepad

Game: | Preferred Resistance Setting(1, 2, 3, or 4):
--- | ---
Boulder Dash | 3
Bouncing Kamungas | 2
Mario Bros | 2
Ms. Pac-Man | 2
Pac-Man | 2
Stargate | 1
Thexder | 2
Wavy Navy | 2
Xevious | 2
Zaxxon | 1

### Atari Joystick

The following software is known to be compatible with one or more Atari joysticks(connected via an adapter to an Apple II):

- Ardy
- Bandits (press CTRL+SHIFT+P)
- Beer Run (press CTRL+SHIFT+P on control method screen)
- Berzap
- Borg
- Borrowed Time
- Boulder Dash
- Boulder Dash II
- Bouncing Kamungas
- Bubble-Head
- Buzzard Bait
- Cyclod (press CTRL+SHIFT+P)
- Dino Eggs
- Dogfight II (virtual port 1 is player 3, virtual port 2 is player 1)
- Fly Wars
- Free Fall
- Gorgon (later version?)
- Hadron (press CTRL+SHIFT+P)
- Horizon V(press CTRL+SHIFT+P; uses both controllers simultaneously to control different aspects)
- Jawbreaker (second release/title with the same name)
- Jellyfish
- Laf-Pak, Mine Sweep (uses controller port typically used for player 2?)
- Lemmings (Sirius Software)
- Lunar Leepers (uses controller port typically used for player 2?)
- Miner 2049er
- Miner 2049er II
- Minotaur (press CTRL+SHIFT+P)
- Mouskattack
- Pest Patrol
- Pie-Man
- Plasmania
- Seadragon
- Snake Byte (press CTRL+SHIFT+P)
- Space Ark (press CTRL+N during game for config screen)
- Spy's Demise
- Star Maze (Sir-Tech) (press A on title/demo screen)
- Stellar 7
- Tass Times in Tonetown
- Twerps (press CTRL+SHIFT+P)
- Vindicator (Hal Labs) (press RETURN on level select screen one or more times; uses controller port typically used for player 2?)
- Wavy Navy
- Wayout

### Apple II/II+ Keyboard

Mednafen emulates the later II/II+ two-piece keyboard that uses the AY-5-3600 encoder.

Note that emulated keyboard key state is not updated unless input grabbing(by default, mapped to CTRL+SHIFT+Menu) is toggled on.

#### Default Mappings

Key(s): | Virtual Apple II/II+ Key:
--- | ---
A ↑ Keypad 8 | A
Z ↓ Keypad 2 | Z
B through Y | B through Y
0 through 9 | 0 through 9
- | :
= | -
Insert | RESET
Tab ESC | ESC
[ ALT | REPT
\ Enter Home | RETURN
Caps Lock CTRL | CTRL
; Keypad 4 | ;
Backspace ⭠ Keypad 5 Delete | ⭠
⭢ Keypad 6 Page Down | ⭢
SHIFT | SHIFT
, | ,
. | .
/ End | /

## Custom Palettes

Global Filename: | Description:
--- | ---
apple2.pal | RGB mode 16-color(or 32-color for TFR) palette. The presence of a custom palette will automatically enable RGB video mode if an RGB mode is not already selected via the "apple2.video.mode" setting. If the palette has 32 color entries, the text fringe reduction variant of an RGB mode is enabled. 16 or 32 RGB triplets

## Settings Reference

Caution: Any settings that change emulation behavior as seen from the emulated game are shown with the setting name bolded in the table. One should be conscious of these settings if one has changed them from the default values when using network play or movies, as they can cause desychronizations if not set the same among hosts(or between the recording emulator and the playing emulator).

Setting: | Value Type: | Possible Values: | Default Value: | Description:
--- | --- | --- | --- | ---

apple2.input.port1

enum

none
paddle
joystick
gamepad
atari

joystick

Input device for Virtual Gameport 1

- none - None(all game I/O devices disabled)
  Will disable all game I/O devices if selected.
- paddle - Paddle
  1-axis, 1-button rotary dial paddle. Only usable on virtual port 2 if it's also selected on virtual port 1.
- joystick - Joystick
  2-axis, 2-button joystick, with 4-state resistance switch.
- gamepad - Gamepad
  Gamepad with D-pad and 2 buttons. Seen by emulated software as a 2-axis, 2-button analog joystick(albeit with only axis extremes), but provides more configuration options for the user.
- atari - Atari Joystick
  Atari joyport digital joystick. Only usable on virtual port 2 if it's also selected on virtual port 1. Limited compatibility with software.

apple2.input.port1.joystick.axis_scale | real | 1.00 through 1.50 | 1.00 | Analog axis scale coefficient for Joystick on Virtual Gameport 1.

apple2.input.port2

enum

paddle
atari

paddle

Input device for Virtual Gameport 2

- paddle - Paddle
  1-axis, 1-button rotary dial paddle. Only usable on virtual port 2 if it's also selected on virtual port 1.
- atari - Atari Joystick
  Atari joyport digital joystick. Only usable on virtual port 2 if it's also selected on virtual port 1. Limited compatibility with software.

apple2.video.brightness | real | -1.0 through 1.0 | 0.0 | Video brightness.
apple2.video.color_lumafilter | integer | -3 through 3 | -3 | Color video luma filter. Filters numbered closer to 0 have a stronger lowpass effect. Negative-numbered filters have ringing.
apple2.video.color_smooth | boolean | 0 1 | 0 | Enable color video smoothing. Reduces vertical stripes without making video blurrier, at the cost of some pixel irregularities. May make small text illegible in graphics mode.
apple2.video.contrast | real | -1.0 through 1.0 | 0.0 | Video contrast.
apple2.video.force_mono | integer | 0x000000 through 0xFFFFFF | 0x000000 | Force monochrome graphics color. Force monochrome graphics if non-zero, with the specified color.
apple2.video.hue | real | -1.0 through 1.0 | 0.0 | Color video hue/tint.

apple2.video.matrix

enum

custom
mednafen
la7620
cxa2025as_usa
cxa2060bs_usa
cxa2095s_usa
cxa2025as_japan
cxa2060bs_japan
cxa2095s_japan

mednafen

Color decoder matrix.

The matrixes that correspond to the nominal demodulation angles and gains for various ICs are intended to get colors within the ballpark of what consumer-oriented NTSC TVs would display, and won't exactly replicate the colors these ICs would reproduce when fed an Apple II video signal.

- custom - Custom
- mednafen - Mednafen
- la7620 - Sanyo LA7620-like.
- cxa2025as_usa - Sony CXA2025AS-like, USA setting
- cxa2060bs_usa - Sony CXA2060BS-like, USA setting.
- cxa2095s_usa - Sony CXA2095S-like, USA setting.
- cxa2025as_japan - Sony CXA2025AS-like, Japan setting.
- cxa2060bs_japan - Sony CXA2060BS-like, Japan setting.
- cxa2095s_japan - Sony CXA2095S-like, Japan setting.

apple2.video.matrix.blue.i | real | -4.00 through 4.00 | -1.11 | Custom color decoder matrix; blue, I. Only used if "apple2.video.matrix" is set to "custom".
apple2.video.matrix.blue.q | real | -4.00 through 4.00 | 1.70 | Custom color decoder matrix; blue, Q. Only used if "apple2.video.matrix" is set to "custom".
apple2.video.matrix.green.i | real | -4.00 through 4.00 | -0.28 | Custom color decoder matrix; green, I. Only used if "apple2.video.matrix" is set to "custom".
apple2.video.matrix.green.q | real | -4.00 through 4.00 | -0.64 | Custom color decoder matrix; green, Q. Only used if "apple2.video.matrix" is set to "custom".
apple2.video.matrix.red.i | real | -4.00 through 4.00 | 0.96 | Custom color decoder matrix; red, I. Only used if "apple2.video.matrix" is set to "custom".
apple2.video.matrix.red.q | real | -4.00 through 4.00 | 0.62 | Custom color decoder matrix; red, Q. Only used if "apple2.video.matrix" is set to "custom".
apple2.video.mixed_text_mono | boolean | 0 1 | 0 | Enable hack to treat mixed-mode text as monochrome.

apple2.video.mode

enum

composite
rgb
rgb_tfr
rgb_alt
rgb_alt_tfr

composite

Video rendering mode.

When an RGB mode is enabled, settings "apple2.video.force_mono", "apple2.video.mixed_text_mono", "apple2.video.mono_lumafilter", "apple2.video.color_lumafilter", and "apple2.video.color_smooth" are effectively ignored.

- composite - Composite
  Internal video dimensions of 584x192.
- rgb - RGB
  Internal video dimensions of 292x192; suitable for use with scalers like hq2x.
- rgb_tfr - RGB, with HGR text fringe reduction.
  Internal video dimensions of 292x192; suitable for use with scalers like hq2x. Reduced brightness of colored pixels horizontally sandwiched between white pixels in HGR mode.
- rgb_alt - RGB (alternate algorithm)
  Internal video dimensions of 584x192.
- rgb_alt_tfr - RGB (alternate algorithm), with HGR text fringe reduction.
  Internal video dimensions of 584x192. Reduced brightness of colored pixels horizontally sandwiched between white pixels in HGR mode.

apple2.video.mono_lumafilter | integer | -3 through 7 | 5 | Monochrome video luma filter. Filters numbered closer to 0 have a stronger lowpass effect. Negative-numbered filters have ringing.
apple2.video.saturation | real | -1.0 through 1.0 | 0.0 | Color video saturation.

Setting: | Value Type: | Possible Values: | Default Value: | Description:
--- | --- | --- | --- | ---
apple2.enable | boolean | 0 1 | 1 | Enable (automatic) usage of this module.

apple2.scanlines

integer

-100 through 100

0

Enable scanlines with specified opacity.

Opacity is specified in %; IE a value of "100" will give entirely black scanlines.
Negative values are the same as positive values for non-interlaced video, but for interlaced video will cause the scanlines to be overlaid over the previous(if the video.deinterlacer setting is set to "weave", the default) field's lines.

apple2.shader

enum

none
autoip
autoipsharper
scale2x
sabr
ipsharper
ipxnoty
ipynotx
ipxnotysharper
ipynotxsharper
goat

none

Enable specified OpenGL shader.

Obviously, this will only work with the OpenGL "video.driver" setting, and only on cards and OpenGL implementations that support shaders, otherwise you will get a black screen, or Mednafen may display an error message when starting up. When a shader is enabled, the "<system>.videoip" setting is ignored.

- none - None/Disabled
- autoip - Auto Interpolation
  Will automatically interpolate on each axis if the corresponding effective scaling factor is not an integer.
- autoipsharper - Sharper Auto Interpolation
  Same as "autoip", but when interpolation is done, it is done in a manner that will reduce blurriness if possible.
- scale2x - Scale2x
- sabr - SABR v3.0
  GPU-intensive.
- ipsharper - Sharper bilinear interpolation.
- ipxnoty - Linear interpolation on X axis only.
- ipynotx - Linear interpolation on Y axis only.
- ipxnotysharper - Sharper version of "ipxnoty".
- ipynotxsharper - Sharper version of "ipynotx".
- goat - Simple approximation of a color TV CRT look.
  Intended for fullscreen modes with a vertical resolution of around 1000 to 1500 pixels. Doesn't simulate halation and electron beam energy distribution nuances.

apple2.shader.goat.fprog

boolean

0
1

0

Force interlaced video to be treated as progressive.

When disabled, the default, the "video.deinterlacer" setting is effectively ignored with respect to what appears on the screen, unless it's set to "blend" or "blend_rg". When enabled, it may be prudent to disable the scanlines effect controlled by the *.goat.slen setting, or else the scanline effect may look objectionable.

apple2.shader.goat.hdiv | real | -2.00 through 2.00 | 0.50 | Constant RGB horizontal divergence.

apple2.shader.goat.pat

enum

goatron
borg
slenderman

goatron

Mask pattern.

- goatron - Goatron
  Brightest.
- borg - Borg
  Darkest.
- slenderman - Slenderman
  Spookiest?

apple2.shader.goat.slen | boolean | 0 1 | 1 | Enable scanlines effect.
apple2.shader.goat.tp | real | 0.00 through 1.00 | 0.50 | Transparency of otherwise-opaque mask areas.
apple2.shader.goat.vdiv | real | -2.00 through 2.00 | 0.50 | Constant RGB vertical divergence.

apple2.special

enum

none
hq2x
hq3x
hq4x
scale2x
scale3x
scale4x
2xsai
super2xsai
supereagle
nn2x
nn3x
nn4x
nny2x
nny3x
nny4x

none

Enable specified special video scaler.

The destination rectangle is NOT altered by this setting, so if you have xscale and yscale set to "2", and try to use a 3x scaling filter like hq3x, the image is not going to look that great. The nearest-neighbor scalers are intended for use with bilinear interpolation enabled, for a sharper image, though the "autoipsharper" shader may provide better results.

- none - None/Disabled
- hq2x - hq2x
- hq3x - hq3x
- hq4x - hq4x
- scale2x - scale2x
- scale3x - scale3x
- scale4x - scale4x
- 2xsai - 2xSaI
- super2xsai - Super 2xSaI
- supereagle - Super Eagle
- nn2x - Nearest-neighbor 2x
- nn3x - Nearest-neighbor 3x
- nn4x - Nearest-neighbor 4x
- nny2x - Nearest-neighbor 2x, y axis only
- nny3x - Nearest-neighbor 3x, y axis only
- nny4x - Nearest-neighbor 4x, y axis only

apple2.stretch

enum

0
full
aspect
aspect_int
aspect_mult2

aspect_mult2

Stretch to fill screen.

- 0 - Disabled
- full - Full
  Full-screen stretch, disregarding aspect ratio.
- aspect - Aspect Preserve
  Full-screen stretch as far as the aspect ratio(in this sense, the equivalent xscalefs == yscalefs) can be maintained.
- aspect_int - Aspect Preserve + Integer Scale
  Full-screen stretch, same as "aspect" except that the equivalent xscalefs and yscalefs are rounded down to the nearest integer.
- aspect_mult2 - Aspect Preserve + Integer Multiple-of-2 Scale
  Full-screen stretch, same as "aspect_int", but rounds down to the nearest multiple of 2.

apple2.tblur | boolean | 0 1 | 0 | Enable video temporal blur(50/50 previous/current frame by default).
apple2.tblur.accum | boolean | 0 1 | 0 | Accumulate color data rather than discarding it.
apple2.tblur.accum.amount | real | 0 through 100 | 50 | Blur amount in accumulation mode, specified in percentage of accumulation buffer to mix with the current frame.

apple2.videoip

enum

0
1
x
y

x

Enable (bi)linear interpolation.

- 0 - Disabled
- 1 - Bilinear
- x - Linear (X)
  Interpolation only on the X axis.
- y - Linear (Y)
  Interpolation only on the Y axis.

apple2.xres | integer | 0 through 65536 | 0 | Full-screen horizontal resolution. A value of "0" will cause the current desktop horizontal resolution to be used.
apple2.xscale | real | 0.01 through 256 | 4.000000 | Scaling factor for the X axis in windowed mode.
apple2.xscalefs | real | 0.01 through 256 | 1.000000 | Scaling factor for the X axis in fullscreen mode. For this setting to have any effect, the "<system>.stretch" setting must be set to "0".
apple2.yres | integer | 0 through 65536 | 0 | Full-screen vertical resolution. A value of "0" will cause the current desktop vertical resolution to be used.
apple2.yscale | real | 0.01 through 256 | 4.000000 | Scaling factor for the Y axis in windowed mode.
apple2.yscalefs | real | 0.01 through 256 | 1.000000 | Scaling factor for the Y axis in fullscreen mode. For this setting to have any effect, the "<system>.stretch" setting must be set to "0".