Friday, January 22, 2021

wDrive v. Floppy Emu - Comparison of the Best Apple II Disk Emulators

The 5.25" floppy disk was the principal medium of program storage for the Apple II series of computers.  Thousands of software titles were written specifically for the Apple II's Disk II drive and its successors and clones.  Using floppy disks, and more specifically disk images, is essential to using an Apple II computer.  To use a disk image is to either write the image back to a disk, a cumbersome and sometimes unreliable process, or use a disk emulator.  In a recent past blog article, I have written about the Floppy Emu, a very capable Disk II drive emulator.  I have recently acquired the wDrive, another emulator device which can simulate a Disk II drive.  While similar to the Floppy Emu in many ways, the wDrive has its own benefits and quirks, and here I will compare the two hardware floppy emulators.  

Why Accurate Floppy Emulators are Necessary

wDrive
Both wDrive and Floppy Emu are the cream of the crop of floppy emulation or simulation devices for the real Apple IIs.  Both are better than most other solutions because they support the .woz image file format.  The .woz format was specifically designed to handle Apple II protections and capture and retain the data required to make emulation pass the copy protection schemes Apple II programs used.  The .dsk, .do and .po disk formats were sector dump formats and almost useless for capturing copy protection and almost any commercial game released during the Apple II's time using those image formats has been cracked (or was never protected).  The .nib format retained some of the disk's structure and copy copy protections would be satisfied with that, but far from all.  The .edd format was released a few years ago in an effort to capture more information from the disks but it really did not gain significant traction.  

The .woz format, released in mid-2018 has gained a significant hold in the Apple II community.  A woz image is made by taking a flux-level dump of every track on a floppy disk side, which turns out to be a very large file with the .a2r extension.  This dump is made using the Applesauce hardware, which acts as an interface between a Disk II drive and a modern computer.  Then the macOS-only Applesauce Client Software can convert the a2r files into a .woz file suitable for software and hardware emulator use.  The .woz format is a chunk file format which stores every track separately and contains the information necessary to properly recreate the disk's formatting and structure as though it was an original disk.  This allows disk protections which rely on tight synchronization between tracks like half-tracks and quarter-tracks to work as they were originally intended to work.  .woz version 2 was released in late 2018 and is the current standard for accurately capturing the format and structure of 13-sector and 16-sector disks.

Floppy Emu

The Comparision

Like the Floppy Emu, the wDrive (OLED version) comes with four buttons : left, select, right and reset.  The wDrive is enclosed in a 3-D printed plastic enclosure, and this version is molded like an Apple 3.5" drive, which I found to be rather cute.  The Floppy Emu comes as a bare board but there is a plastic acrylic enclosure available which you can build around the board and screen.  

The wDrive uses a full-size SD card with a spring loading mechanism whereas the Floppy Emu uses a microSD card without the spring loader.  Because the wDrive uses a full-size SD card, you can use the locking switch on the side of the SD card to enforce write protection on disk images regardless of whether the file is marked read-only or has the write protect field set in a woz file.  You cannot do this on Floppy Emu because microSD cards do not have locking switches.  The status LED of the wDrive is red compared to the Floppy Emu's green.  When compared side by side the wDrive is significantly smaller than the Floppy Emu.

The OLED screen of the wDrive is about the same size as the Floppy Emu's.  Both devices can display seven files or folders on the screen underneath the title bar.  Both displays use a fixed-width font, but the wDrive can show 32 characters on a line while Floppy Emu makes do with 21 characters.  The extra 11 characters can make it easier to distinguish between similarly-named disk images with long file names.

When a disk image is selected, each devices does different things.  The Floppy Emu will switch to a new screen to show the status of the disk, namely whether it is being read or written and which track is active.  It will also show some status information that wDrive does not, such as the version of the woz format the disk image uses.  wDrive highlights the selected image on file browser in white, reduces the characters to 21 and shows the track being read or written with two numbers on the right side.  Other status information is shown to the left of the title bar (top row on the screen).  Floppy Emu shows the track number in decimal, wDrive in hexadecimal.  

Both devices can have their firmware updated and both have had updates as recently as November of 2020.  The latest firmware for Floppy Emu is apple-II-0.2N-F27-modelBC and for wDrive it is v1.0b8 and I upgraded both devices to their latest firmware prior to writing this blog arrticle.  Both devices come with 19-pin ribbon cables with IDC connectors on either end, which is ideal for the Disk II Controller Card but require adapters for the later controller card which used a D-shell 19-pin connector.

Menu navigation has its quirks with both Floppy Emu and wDrive.  Both devices use microswitches with plastic buttons on top of them.  If you hold down the Floppy Emu's buttons, the selector will move up or down the directory at a fixed pace.  It can take a while to get from one end of a directory to another, especially as there is no directory wrap-around.  While wDrive also suffers from a lack of directory wrap-around, if you hold down a navigation button your cursor will eventually accelerate.  Also, if you press back and select at the same time the cursor will jump back to the beginning of the directory.  If you press forward and select at the same time, the cursor will jump down to the first file using the next letter.  As the Floppy Emu's buttons are raised, they make for an easier navigating experience because they are easier to press.  

But wDrive has one other advantage over Floppy Emu and one disadvantage with file browsing.  The chief advantage for file browsing is that wDrive's ability to display files when a new directory is loaded is instant.  Floppy Emu can take up to two seconds to display the same number of files (95 or so) using an identical directory structure.  However, wDrive is officially limited to no more than 100 files per directory.  Also, this delay in showing the contents of a directory only applies to directory with .woz files located in them, with .dsk and similar format, the directory presentation is instantaneous (at least if you keep the number of files in a directory to 100 or less).

As of wDrive firmware v1.0b2, things have changed remarkably.  If you put the file wdmain.dat, which is included in firmware zip file of that version and newer versions in the root of your SD card, you will be able to select a boot floppy disk image from your Apple II's screen.  You use the Apple II's Up/Down/Left/Right keys to navigate through the menu, Enter to select a directory or disk image and Esc to go back levels.  This is so much easier to use than the small OLED displays and the small buttns and you get the full 40 columns by 24 lines of the Apple II's Text Mode.  Of course this only works for the boot disk, if you need to change disks as with a multi-disk game, you will still need to revert to the wDrive's buttons and display.

Floppy Emu is more versatile in its stated ability to support floppy drives than wDrive.  Floppy Emu can support other kinds of floppy drives, including the 3.5" drives used by the Apple //gs, Apple //c+, Apple Lisa and Apple Macintosh.  wDrive can support 800KiB 3.5" .2mg images and 32MiB .hdv hard drive images, so it can do more than just simulate a 140KiB 5.25" floppy drive.

Availability and support are firmly an issue where Floppy Emu prevails.  Floppy Emu is available often, wDrive's availability is more hit and miss.  When I was building my Apple //e last September and October, wDrive was out of stock in all its variants.  On a whim one day in early January I checked the site and saw there were 5 in stock of the OLED version.  By the time I made up my mind to buy one, there were only 3 in stock.  Fortunately it came from Hong Kong in only two weeks.

Being the more popular device, Floppy Emu has more attention from users.  The documentation is also superior with a User Manual which guides you through the basics.  The wDrive's creator, Kboo, comes from Hong Kong and English is clearly not his first language.  Sometimes Floppy Emu's documentation has helped me understand the wDrive's functions better than Kboo's Engrish, the devices are rather similar.  Right now, the blog posts which talk about the wDrive on the kboohk website are down, which deprives users of much information about the improvements of never firmware.  Fortunately I was able to grab many of them from the last Wayback Machine cache of the site.

One curious deficiency that both of these devices have is their inability to format a disk image.  They require blank DOS 3.3 and ProDOS formatted disk images to use with programs which require a fresh data or save disk.  Copying from disk to disk image is supported so long as the program does not try to format and write at the same time.  Floppy Emu's User Manual has a modification to use with COPYA to get programs copied without disks being formatted.  This limitation may not apply to wDrive with woz images.


Both wDrive and Floppy Emu can write to .nib and .woz images.  wDrive and Floppy Emu respect the write protected info field in the .woz file and will show a padlock on the menu bar if the field is set to yes.  The wozardry tool will permit you to alter the "Write protected" info filed in a .woz image.  I have successfully tested the writing by saving a game with Ultima IV with the woz images from the A Woz A Day archive.

One advantage that wDrive has over Floppy Emu is its built in support for booting 13-sector disks.  By pressing the left button after selecting an image to boot, Floppy Emu will attempt to boot the disk image using 13 sector support.  I have been able to boot DOS 3.2 and The Best of MUSE, a game which requires 13 sector support.  However, the Apple II cracking machine known as 4am has released an Apple II disk image called Anti-M which can boot 13-sector disks and bypass other machine specific issues like reliance on 6502 undefined opcodes or Apple II/II+ ROM checks.  

Both devices support usage as a SmartPort drive.  SmartPort was Apple's hardware indifferent protocol which allows support for ProDOS 800KiB and hard drive images.  SmartPort can work over a Disk II-style interface but SmartPort firmware must be present in the system ROM to handle this.  SmartPort is present in all but the first ROM revisions of the Apple //c and is also always available for the //gs and //c+.  For those of us with Apple II, II+ or //e, Kboo has the SoftSP card for sale for $20.  This will add the firmware in ROM and will permit the Total Replay hard drive image to work with wDrive.  It is very dangerous to use Floppy Emu as a Smartport device with the SoftSP card without implementing the simple fix described here.  wDrive can also load the SmartPort firmware into system RAM but this solution is not compatible with Total Replay and 800KiB conversions of Ultima games.

Both devices support .dsk, .do., .po, .nib and .woz formats.  .dsk, .do and .po are sector-based formats, with the latter two specifying DOS 3.3 sector ordering and ProDOS sector ordering, respectively.  .nib and .woz use lower level imaging techniques to capture more data in a nibblized format (.nib) and timing, track width and positioning and synchronization information and metadata (.woz).  wDrive also supports images converted from edd (which is an early attempt at .a2r-flux level imaging) to edf.  The conversion utility is on kboo's website will handle this conversion.  Initially I discounted edd/edf support because edd did not exactly catch on but the only way I was able to run Ultima II (the On-line System's original version) on wDrive without cracked images was to use an edd image which kboo's utility converted into .edf until he issued a firmware update.

If you have a Disk II Controller Card with the 20-pin connectors, using a wDrive and Floppy Emu in tandem is a powerful solution for games and solutions that can use two disk drives.  The two devices work independently and their current draw should not drive the Apple II to its limits.  If you use .woz or .nib images, the wDrive is likely going to have to be Drive 2 because most programs which support two drives will expect the save disk to be in Drive 2.  However, save disks often do not have to have any special formatting and can be regular .dsk images.  Sometimes an original one or two sided disk may save high scores to itself, so you may be stuck at a high score table on Floppy Emu but not on wDrive (but you must disable write protection in the .woz file).

For $78.90, the wDrive is an easy recommendation for an floppy emulator, if you can buy one!  Right now it has taken Floppy Emu's place as my preferred Disk II emulator, but only by a hair.  I appreciate the wDrive's faster and more accessible browsing more than the Floppy Emu's versatility.  However, if you are impatient, the Floppy Emu is an excellent choice.

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