|2020.08.24:||Released the 3rd Release Candidate of 1.2.7 for macos X + source here.|
|2020.08.03:||Released the 2nd Release Candidate of 1.2.7 for macos X + source here.|
|2020.06.05:||Released the 1st Release Candidate of 1.2.7 for macos X + source here.|
|2019.11.11:||Released the first beta version of 1.2.7 for macos X + source here.|
|2020.04.12:||Released the second beta version of 1.2.7 for macos X + source here.|
|2019.11.11:||Released a 2nd alpha version of 1.2.7 for macos X here.|
|2019.10.15:||Released an alpha version of 1.2.7 for macos X here.|
|2019.10.15:||1.2.7 Alpha source code can be found at github here.|
|2015.09.03:||Released a version for Raspberry Pi off the 1.2.6 tree here.|
|2008.03.31:||Still no update just yet. 1.3.0 has some serious CPU bugs that I haven't been able to fully remove. There's one left over bug that causes Lisa Office System to get stuck in the Environments window. This seems to be CPU related and doesn't seem to have anything to do with the COPS421 emulation.|
|2007.12.13:||LisaEm 1.2.6 is now available for download.. Provides more bug fixes.|
|2007.11.25:||LisaEm 1.2.5 is now available for download.. Provides more bug fixes.|
|2007.11.11:||LisaEm 1.2.2 is now available for download.. Provides several bug fixes.|
|2007.09.23:||LisaEm 1.2.0 is now available for download.. If you don't have ROMs but wanted to try LisaEm, now's your chance. 1.2.0 is|
|2007.07.10:||LisaEm was added to the FreeBSD Ports|
|2007.07.08:||1.0.0-Release (OS X, Source) is available for download on the downloads page.|
|2007.07.05:||The LisaEm User's Guide is available for download on the downloads page.|
|2007.06.28>:||Release Candidate 2 is available for download on the downloads page.|
|2007.04.04:||Release Candidate 1 is available for download|
|2007.04.01:||Happy 30th Birthday Apple, Inc.|
|2007.03.15:||Beta 2 is up for OS X, Linux, Win32 users.|
|2007.03.14:||New Release available today! Head on over to the downloads page for LisaEm 1.0.0 Beta. This new version fixes a lot of issues, and I'm sure introduces new bugs as well. Have fun!|
|2007.03.04:||Another day, another hard drive crash. Sorry about that, took me far longer to rebuild this machine than I would have liked. Should have a new release of LisaEm fairly soon. I'm having a bit of trouble getting printing to work the way I'd like it to.|
|2007.01.28:||New preview version of LisaEm is available for downloading, as well as the first bit of source code (just libdc42 for now.). Visit the downloads section for fun and profit!|
|2007.01.24:||Happy Birthday Lisa 2. Speaking of which, you should head on over to the downloads page and see what's there today.|
I've let this web page stagnate for quite a long time. Sorry... there has been some work on the emulator, but it's not quite ready. :)
The emulator attempts to boot, but crashes in the process. I've also done some work on the Lisa File System, and the CPU core. See the [Lisa Emulator Status] page for details.
If you've found this site from a search engine (i.e. teoma) and wish to bookmark it, please bookmark it as http://lisa.sunder.net and not www.sunder.net.
To make things even more complex, there are special memory addresses that turn on or shut off various flip flops. For example a memory parity error detector, a video scan line interrupt, and the MMU. The VIA's are not identical in access. One lives in offset of two bytes, the other in an offset of 4 bytes. The 6504's 1024 bytes of memory is battery backed up (this is what the four NiCAD AA's on the I/O board are for.) The 6504's address space is available to the 68000, but in two byte skips as opposed to linearly. That is memory addresses 0,1,2,3 on the 6504 are 1,3,5,7 on the 68000.
The video circuitry is fairly simple - a dumb frame buffer that shares its memory with the Lisa's memory space. As such another memory area register can be changed to "page" through the various memory areas.
Luckily, unlike the Mac, the Lisa's (68000) ROM isn't used for much except the POST (Power On Self Test) and booting. Though it is possible for a Lisa Operating system to access the ROM, the functions it would call are limited to reading blocks off the floppy or Profile.
Yes, the Lisa does support at least three operating systems: Lisa 7/7, MacWorks (which with a bit of hardware an RAM can run upto System 7.5), and Microsoft Xenix (yes, Microsoft Xenix, not SCO: This was before Microsoft spun SCO off!) I've read on other web pages that there was a port of CP/M to the Lisa CP/M 68, but I don't have that OS. I've also seen one refrence to something called UniPlus which is supposedly a Unix SRV implementation. DTC mentioned that this later might have become A/UX... Though I'm not 100% sure, it's likely that either www.unipress.com or www.uniplus.com is the author.
As to how I got started on the project: I went on the web and searched for Lisa and Emulator and found many web pages related to the Lisa. I eventually came across one that mentioned that David T. Craig had lots and lots of Lisa documentation, and so I contacted him. He's been an invaluable resource... This project would have been close to impossible without his Docs. I just wish more people took his example and saved any technical internal docs about hardware they may have. I wish to write a Xerox Star and/or Altos emulator, but I just can't find enough detailed docs!