SmartDisk II: Compatibility matrix

This page is the short answer to “will my disk work on my computer”. The details are in compatibility. How each format is made is in Create disk and image formats.

How to read it

In the tables below, R means the computer can read the image and W means the computer can write to it (the image on the card changes). “With 3.5 write” means that setting must be on. The defaults are in settings. Boot says whether a disk in that format can start the computer. Create disk makes such disks: see page 12.

1. Which computer can use which emulation

Computer	Disk II (5.25 inch)	SmartPort hard disk	Smartloader	3.5 inch drive
Apple II+	yes	only with a SmartPort card (below)	–	–
Apple II Europlus	yes	only with a SmartPort card	–	–
Apple IIe	yes	only with a SmartPort card	yes	–
Apple IIc (ROM 4)	yes	yes	–	–
Apple IIgs (ROM 01 and 03)	yes	yes	yes	yes
Macintosh with an external 800K drive port (for example the SE, DB-19 cable)	no	no	no	yes, with 3.5 Mac host on: read, write, initialize
Macintosh with a SuperDrive port	no	no	no	experimental: 1.44 MB images, read only, with 3.5 SuperDrive on

A dash means the combination is not offered or not described in this documentation.

SmartPort cards on an Apple II+ or IIe: Yellowstone works with write. Liron and SoftSP6 work. The Liron Reborn works in Liron mode (DIP switch SW1 off, SW2 on, SmartDisk II on the PRIMARY connector). An Apple II+ or IIe with no SmartPort card cannot use the SmartPort emulation.

2. The matrix: computer, emulation, file format, read, write, boot

The file lists show only the extensions of the running emulation, in any letter case.

Disk II emulation (5.25 inch) on the Apple II+, II Europlus, IIe, IIc and IIgs

The emulation is the same on every computer. The only difference is the boot limit of the IIc (section 3).

File format	R	W	Boot	Limits
.woz (WOZ 1.0, 2.0, 2.1)	yes	yes	yes, as the disk it was imaged from. IIc: ProDOS disks only	5.25 inch disks only; the tracks must lie in the first 1.25 MB of the file
.dsk, .do	yes	yes (a sector that cannot be decoded keeps its content)	yes (DOS 3.3 and ProDOS disks). IIc: ProDOS disks only	exactly 143360 bytes (35 tracks) or 163840 bytes (40 tracks), 16 sectors a track; 13 sector disks do not work
.po	yes	yes	yes (ProDOS disks)	the same sizes as .dsk
.nic	yes	yes	yes. IIc: ProDOS disks only	at least 286720 bytes
.2mg, .hdv, .dc42, .img, .moof	not in the file list of this emulation

Options: 5.25 write (default on). Off makes every image write protected for the Apple. The WOZ “write protected” flag and the FAT read-only attribute of the file are honoured too. On a IIgs, set the Control Panel speed to Normal. The Smartloader does it for you before it starts a Disk II image.

SmartPort emulation (hard disk) on the Apple IIc, IIgs, and an Apple II+ or IIe with a SmartPort card

File format	R	W	Boot	Limits
.po	yes	yes	yes, ProDOS volumes only. IIc: ProDOS only	size a non zero multiple of 512 bytes, no header; a ProDOS volume holds 32 MB at most; four units (the four volumes of the SmartPort screen)
.hdv	yes	yes	as .po	as .po
.2mg	yes	yes	as .po	the data offset of the header is 64 to 65536 bytes; the “locked” flag makes the unit write protected; a 2MG of nibbles is refused; DOS order is served as ProDOS blocks
.dsk, .do, .woz, .nic, .dc42, .img, .moof	not in the file list

Limits: the extensions .po, .hdv and .2mg work in any letter case. Restart the Apple after you change an image: the Apple is not told that the disk changed.

Smartloader on the Apple IIe and IIgs

The Smartloader is a program the board gives to the computer on a Disk II boot. It lists the card, lets you change the settings, and starts an image in another emulation.

Target of the loader	What it starts	Boot of the computer from it	Limits
Disk II	a .woz, .dsk, .do, .po, .nic	yes	the same as the Disk II emulation
SmartPort	a .po, .hdv, .2mg	yes, ProDOS volumes	the loader jumps to the boot ROM of slot 5 on every machine but the IIgs: a SmartPort card must sit in slot 5
3.5 inch drive	a .2mg, .po, .img, .dc42, .dc, .moof	restarts the IIgs from it	offered only on a IIgs

3.5 inch drive emulation on the Apple IIgs and on a Macintosh

File format	R	W	Boot	Limits
.2mg	yes	yes with 3.5 write	IIgs: yes	ProDOS block order only (DOS order and nibbles are refused); exactly 800 blocks (400K, one side) or 1600 blocks (800K, two sides); the “locked” flag makes it write protected
.po, .img	yes	yes with 3.5 write	IIgs: yes	raw blocks, 400K or 800K, no header
.dc42, .dc (DiskCopy 4.2)	yes	yes with 3.5 write	IIgs: yes	the data must match the disk format of the header; the tags are not used; the header checksums are not updated by a write
.moof (Applesauce)	yes	yes with 3.5 write, in place; a file marked write protected stays so	IIgs: yes	GCR disks of 400K (one side) or 800K (two sides); MFM (1.44 MB), Twiggy and flux are refused; the first write clears the header CRC32; a sector or a cylinder the file does not hold is not written
1440K (2880 blocks) as .img, .2mg, .dc42	yes, Macintosh host only	no		experimental SuperDrive mode
.dsk, .do, .woz, .nic, .hdv	not in the file list

Limits for every format of this emulation:

• 3.5 write is off by default. The disk is write protected until you turn the option on.
• A 400K disk has one side.
• The 12 tag bytes of a sector read as zeros and are not kept when the host writes.
• 3.5 Mac host must be on for a Macintosh. The board restarts when you change that setting.
• The card needs 32 KB clusters. The mount refuses an image otherwise.

3. Limits that decide whether a disk boots

Computer	Limit
Apple IIc	A disk starts the IIc only if it is a ProDOS disk.
Apple IIgs	The ROM 03 looks for a SmartPort device before it boots a 5.25 inch disk; the SmartDisk II ignores that look. The Disk II emulation needs Normal speed. A 3.5 inch image boots from a .2mg, .po, .img, .dc42, .dc or .moof file.
Apple II+ and IIe with a card	The card boots from its slot. The SmartPort image must be a ProDOS volume. The Smartloader’s SmartPort start assumes slot 5. On an unenhanced IIe, type PR# and the slot number after power up.
Apple IIe, II+ (Disk II)	A DOS 3.3 or a ProDOS disk boots as it does from a real Disk II. For copy protected disks see compatibility section 4.
Macintosh	Start the board in Macintosh mode (3.5 Mac host). 400K and 800K GCR disks. A blank 800K image can be initialized from the Macintosh.
Any computer, accelerator in 1 MHz mode	A CPU accelerator that writes the Apple’s write loop one cycle late corrupts writes (the Smartloader fails with ERR:E2). The SmartDisk II is not at fault. Ask about accelerators first.
Hardware before revision 3	Not compatible with the IIgs and the IIc: cut the trace between IDC pins 5 and 7.
Any computer	The SD card must be FAT32 with 32 KB clusters, and in the board at power up.

HD20 emulation (Macintosh): upcoming. It is not available in this firmware yet.

4. What decides the format you should use

You want to	Use	On
boot a DOS 3.3 or ProDOS game with its copy protection	.woz	Disk II emulation, any computer (the IIc boots ProDOS disks only)
boot a plain DOS 3.3 or ProDOS 5.25 inch disk	.dsk, .do or .po (143360 bytes)	Disk II emulation
a hard disk of up to 32 MB	.po, .hdv or .2mg	SmartPort emulation (IIc, IIgs, card)
a 3.5 inch disk on a IIgs	.2mg, .po, .img, .dc42 or .moof	3.5 inch emulation
a 3.5 inch disk on a Macintosh	.dc42, .img, .2mg (HFS volume: Create disk) or .moof of an 800K disk	3.5 inch emulation, 3.5 Mac host on, 3.5 write on to save
an exact copy of a 3.5 inch disk with its timing	.moof	3.5 inch emulation

See also: compatibility (copy protection, SD card, folder limits), Create disk and image formats, Disk II, SmartPort, Smartloader, 3.5 inch drive, settings.

---

SmartDisk II user documentation · latest firmware · Documentation home