Without a Floppy EMU, how to get files to my Macintosh 512K?

[BPearce]

I have somehow succeeded in installing a ROM-inator Resurrections Kit in the Macintosh 512K I've been working on. (Thanks, Kay Koba!) I'm far from confident in my soldering skills -- they are still very much a work-in-progress -- but JDW's video (thanks, JDW!) went a long way toward getting me to a level of comfort with the process. (Though the idea of attaching wires to pins of the CPU was -- how shall I put this? -- terrifying.) My heart skipped a beat when I heard an unfamiliar "chime" at startup, though I soon realized that meant the ROM-inator was working!

Even better, I discovered there was nothing actually wrong with my Floppy Drive, after all. I'd cleaned and lubricated it, and had to replace the missing Pressure Pad -- but with the new ROM I was able to boot and read from and write to the 400K disk I had.

Without a Floppy EMU, what's a reasonably easy way to get files to a 400K disk? I do have a working MacSE and RaSCSI -- perhaps the 400K Floppy Drive could be moved between the two Macs on a temporary basis? Or could a spare 800K drive be used with the Macintosh 512K, with the change in ROM?

(A Floppy EMU is not at all out of the question, and I know it would make this process much easier -- I just don't have one at the moment.)

 

[retr01]

Hi @BPearce!

You can use the Apple 800k external 3.5" disk drive model A9M0106. Here are the instructions:

Mac GUI :: Using an External 800K Disk Drive with Mac 512K

Apple news, photo galleries, downloads, and discussion forums.

macgui.com

Alternatively, you may be able to use BackDown to transfer files to your Mac 512k via XMODEM:

Mac GUI :: Using the BackDown DA for XMODEM Downloading

Apple news, photo galleries, downloads, and discussion forums.

macgui.com

Cheers!

 

[SteveHere]

@BPearce Congrats on the Romulator that’s a cool upgrade!

Not sure if this helps you or not, but I‘be been able to make 400K floppies (On DS/DD disks) using my PowerMac 8600 and Disk Copy 4.2. Disk Copy can write out disk images that are not readable on the Mac OS version on the newer computer, but these disks will still boot and run on the 512K. See more details and copies of some 400k disk images that I fixed up on my bLog…
https://writtenoutput.blogspot.com/2021/01/starting-new-year-right-macintosh-512k_2.html
Not sure how to get random files into the disk images, that is an interesting challenge. There’s a version of vMac Mini for PowerPC, perhaps that could be run on the machine that is used to write out the disk images. Thanks for the interesting question, I’ve added this to my project list!

 

[BPearce]

I was ultimately able to read from and write to the (I think) 800K drive in my Mac SE — though I could only copy files, I could not copy (or even create) folders. That‘s not a distinction I came across while researching, and now I’m curious as to the technical reasons behind this. I expect it has something to do with the underlying file format, but — anybody know?

 

[SteveHere]

This article has been super helpful to me in my understanding of these things...
https://siber-sonic.com/mac/newmillfloppy.html
I believe that 400K disks used the MFS file system which did not support folders, it was a flat file system.

 

[pocketscience]

MFS was a flat file system, but it allowed "cosmetic folders" from memory... though I could be mistaken.

 

[pocketscience]

From wikipedia...

Folders exist as a concept on the original MFS-based Macintosh, but work completely differently from the way they do on modern systems. They are visible in Finder windows, but not in the open and save dialog boxes. There is always one empty folder on the volume, and if it is altered in any way (such as by adding or renaming files), a new Empty Folder appears, thus providing a way to create new folders. MFS stores all of the file and directory listing information in a single file. The Finder creates the illusion of folders, by storing all files as pairs of directory handles and file handles. To display the contents of a particular folder, MFS scans the directory for all files in that handle. There is no need to find a separate file containing the directory listing.

 

[BPearce]

Whoa. I had no idea! I‘d probably read that HFS stands for “Hierarchical File System,” but I never understood the significance…

 

[retr01]

Yes, the MFS and HFS were different. Here are some basics:

Macintosh File System (MFS) Introduced by Apple in January 1984 Flat Folders were faked, and no directories Resource Forks Graphical data stored Enabled localization Simplified application distribution Stored metadata to support GUI Filesystem limits Maximum volume size: 20 MB Maximum file size: 20 MB Maximum files: 4094 Maximum filename characters: 255 Discontinued in September 1985 MFS R/W dropped in System 7.6.1 MFS R dropped in MacOS 8

Hierarchial File System (HFS) Developed by Apple to replace MFS in September 1985 Folders, directories, tree, depth Ported Resource Fork from MFS File data Volume heard (third sector) Allocation Extents Overflow Catalog Attributes Startup Alternate volume header (second to the last sector) Filesystem Limits Maximum volume size: 2 TB Maximum file size: 2 GB Maximum number of files: 65535 Maximum filename length: 25

Cheers,