CrossDOS
by David W. Martin

CROSS HERE!
	CrossMAC is a new and innovative approach to reading and writing Macintosh hard drives, CD-ROMs and diskettes using the standard Amiga hardware. It's approach is the same as it's cousin CrossDOS and this makes it a very unique program just like CrossDOS was when it first came out. This is due to the fact that CrossMAC is an actual file system for the Amiga that allows the Amiga to read and write Macintosh disks as if it were born reading them. CrossMAC handles the disk format translations transparently to the user and the Amiga.

HOW DOES IT WORK?
	CrossMAC consists of an AmigaDOS file system and device driver. The CrossMACFileSystem provided by CrossMAC allows the Amiga to access the foreign Macintosh disk format by providing a common DOS interface between the application and file system. The new file system understands the foreign disk format and must be able to use a minimum set of commands through the new DOS interface.
	By translating DOS commands the Macintosh file system reads and writes to the Macintosh device. If the device is a floppy drive then the file system is asked to open the mfm.device that will translate raw disk data into data blocks and vice versa.
	The mfm.device is used to decode and encode MFM data that is physically formatted in a standard, but non-Amiga format. It works similarly to the trackdisk.device driver that is used by AmigaDOS for Amiga format floppies and supplies answers to requests for drive control and blocks of data to be transferred.
FEATURES
	CrossMAC allows users to read and write Macintosh formatted diskettes, hard drives, and CD-ROMs. Formats compatible with CrossMAC are listed in the following table:
CrossMAC Format Compatibility Chart

Disk Size		Density		Disk Capacity	Format
3.5"			Low		800K		Amax
3.5"			Low		800K		Emplant
3.5"			Low		800K		Macintosh (1)
3.5"			High		1.44M		Macintosh (2)
Hard Drives		                All		Macintosh (3)
Hard Drives		                All		Amax or Emplant
CD-ROM			                All		Macintosh

Notes:
	(1) Requires either an Amax cartridge with an 800K Macintosh floppy, Amax II+/IV cards and standard Amiga floppies, or an AMIGA with an 800K Macintosh floppy.
	(2) High density Macintosh floppies require an Amiga high density floppy.
	(3) Macintosh hard drives and CD-ROMs are compatible with the appropriate Amiga hard drive controller (i.e. A4000	IDE).

	Once CrossMAC is installed you can access any Macintosh disk from any Amiga utility, application and file requester. Most AmigaDOS functions are supported such as reading and writing to a file, relabeling a disk name, create directories, or rename files and directories.
	CrossMac supports both Macintosh data and resource 'forks' as separate files and Macintosh icons are automatically displayed under Workbench. Other features include the ability to control ASCII file filtering, automatic disk change sensing, auto format detection, minimal memory requirements, transparent support of Macintosh binary files and a set of special utilities.

UTILITIES
	CrossMAC provides special utilities for use with the Macintosh file system. They are listed in the following chart:

CrossMAC Utilities
Name			Function
FORMAT	Extended Format command to support Macintosh disks (replaces the normal Format command)
DISKCOPY	Extended Diskcopy command to support Macintosh disks (replaced the normal Diskcopy command)
CrossMAC	Commodity the controls CrossMAC disk ejection and text translation.
DISKCHK		Checks a disk for read errors
DISKCHG		Forces a disk change on the specified device.
DR_CrossMAC	Helps diagnose possible problems with CrossMAC.
VHEX		Simple utility used to view files in HEX or ASCII.
RES_EXTRACTOR	A utility that allows you to view or extract data from Macintosh resource files.
MAC_FILE_SALV	A utility that allows you to try to recover files from a corrupted Macintosh disk. It does not repair the disk.
Finder_Manager	A utility that allows you to manage an internal CrossMac database. The database coordinates the Macintosh "Finder" information to the file extension you can assign to the file.
ConfigDisk	This utility (ConfigDisk.CrossMac) is used to configure CrossMac devices. It can create a mountfile describing the Macintosh disk to the Amiga OS. It is used primarily for Macintosh hard drives and Amax partitions.

INSTALLATION
	Installing CrossMAC was very easy and I was able to install CrossMAC using the standard Commodore Installer. Initially some bugs were discovered in the initial releases installer script so be sure that you are using at least V1.01 of CrossMAC. The installer automatically creates icons for the available floppy drives and your ready to roll in no time at all.

APPLICATIONS AND CONCLUSIONS
	Applying CrossMAC is easy. I personally use it to transfer files between Macintosh machines at friend's houses, school and work. I also use it as a good companion for my Emplant card - no Emplant owner should be without CrossMAC (more on that in a minute)! Nor should any Amiga owner who needs to read and write Macintosh formatted diskettes or hard drives! An Amiga with CrossMAC makes a fast and easy file transfer system between Amigas and Macintoshes (emulated or real).
	One thing to note I promised a story a minute ago so here it is. I also own an Emplant card which I like a great deal. However sometimes the Macintosh OS can be rather frustrating - not the Emplants fault. One day I installed RAM Doubler on my Emplant Macintosh knowing full well that it would not work since it requires an MMU that is in use by the emulation. However like most users at my skill level I thought 'Ok what the heck lets try it anyway!' Well the result was not good! No matter what I tried I could no longer get the Macintosh to boot. 
	CrossMAC to the rescue! I used the ConfigDisk.CrossMAC utility to make my Macintosh boot drive accessible by the Amiga. It popped up on Workbench like a normal Amiga drive except it had a 'cute' Macintosh icon. Next, I opened up the drive on the Workbench, opened the System Drawer folder in the drive and then opened the Extensions folder from which I removed the offending RAM Doubler extension. I dropped into a trashcan on my Workbench and it was deleted just like that! Later when I booted the Macintosh everything was fine! Talk about handy!

	CrossMAC is truly the best and only Macintosh file system I can currently recommend to Amiga users. It's a wonder that no one thought of this wonderful idea ages ago. Simplicity is sometimes the best thing that can happen and CrossMAC simply makes Macintosh disk media access easier on the Amiga. I recommend this one to anyone with the desire to access Macintosh formatted disk media.

CrossDOS
Consultron 8959 Ridge Road Plymouth, MI 48170 (313)459-7271
Cost Approx. $110.00 mail order
Any Amiga with at least 1 MB RAM and AmigaDOS 2.0 or higher.


David W. Martin is the author of numerous books and articles about Commodore computers. He is currently working on a book about the Emplant emulator and is publishing an Emplant newsletter. He resides in Houston, Texas where he works for a local Aerospace firm. He can be reached via Email at davidm@cup.portal.com.