I’ve merged the Lisa floppy emulation functions into the latest Mac version firmware, to create a super universal firmware! it’s a single firmware for Floppy Emu with support for Mac and Lisa, floppy and HD20, raw disk images and Disk Copy 4.2 images. It also brings the benefits of writable DC42 disk images to the Mac. Sorry, it does not make sandwiches or wash your car, but it does nearly everything else. Press the SELECT button while the Emu is displaying version info on the LCD, you’ll enter a config menu where you can choose to operate as a hard disk, Mac floppy drive, or Lisa floppy drive. The new hd20-0.7B-F14.5 universal firmware is available now.

A few other odds and ends:

 
Checksums

After some discussion, I’ve altered the strategy for updating Disk Copy 4.2 checksums. I still don’t have a good solution for keeping the checksums updated when the disk image is modified, but instead of leaving the old (wrong) checksums in place, this new firmware sets the checksums to zero upon the first write to a DC42 image. Hopefully this will make it clearer for some future archivist who may encounter the modified image file, and he’ll understand the checksum was intentionally zeroed, rather than the image file being corrupted.

dc42cksm – I wrote this simple command line program to view the checksums in a Disk Copy 4.2 disk image file, and optionally to update the checksums if they’re not correct. If you ever have some burning need to copy a modified DC42 file off your SD Card, and import it back into Disk Copy 4.2 on the Mac, this tool can fix up the checksums for you. It’s a Windows command-line executable, but the source code is also included if you want to recompile it for OS X or Linux.

 
Blank Disks

Todd Meyer pointed out that blank 400K disks created under Lisa Office System 3.0 and 3.1 aren’t usable under Lisa Office System 2.0. The difference seems to be similar to the distinction between MFS and HFS disks on a vintage Macintosh system, except I don’t think the Mac ever used two different filesystems for the same sized disk. Thanks to Todd for providing a working LOS 2.0 blank disk image, which I’ve included with the lisa-emu-1.0S7-F11 firmware (below), and for the femu-on-Lisa photo that appears above.

 
A Spare Firmware

In case any problems are discovered with the new universal firmware hd20-0.7B, I’m also releasing an updated version of the Lisa-specific firmware, lisa-emu-1.0S7-F11. This is identical to the 1.0S6 Lisa firmware that I released yesterday, except that the checksum in the DC42 image file will be set to zero upon the first write to the disk.

 
???

The Lisa computer is a strange beast. It was the first mainstream home computer to feature a GUI instead of a text-based interface. It’s been interesting working with the Lisa while I developed the new floppy firmware, and for a time I thought maybe I’d like to get a Lisa system of my own when the time comes to return this borrowed machine. But the Lisa never really grew on me, and I can’t exactly say I’ll miss it when I need to give it back.

Running the Macintosh OS under MacWorks isn’t too bad, except that the machine has twice the bulk and weight of a contemporary Mac system. It’s just… unwieldy. That’s not meant as a dig against the Lisa – pretty much all computers of that era were unwieldy by today’s standards – but it’s impressive how much slimmer Apple was able to make the Mac 128K just a year after the Lisa, using most of the same technology except for the internal hard drive.

From the viewpoint of someone in 2015, the native Lisa OS (Lisa Office System) is truly baffling, ugly, and awkward. I’m not surprised Apple had such trouble selling Lisa systems before MacWorks came along. As the first real GUI computer, it’s no wonder Apple didn’t nail it 100% on the first attempt, so I don’t fault the Lisa or its designers for that. It’s fascinating to see this example of an early GUI, in contrast with the continuing improvements that appeared later in the Mac and other GUI systems.