In late 1984 the Lisa was repackaged as the Macintosh XL to try and clear out poor selling inventory.
Not only that, but more important as development systems for the Mac. The original Mac had only 128 KiB of RAM and could not access a hard disk. So software development on the machine was rather cumbersome. The origin of MacWorks XL was an internal hack to emulate a Mac for software development. 512 KiB, or even 2 MiB (3rd party up to 8 MiB) did make compiling way faster despite the slower CPU. Later it became a product for Lisa owners to (also) run Mac software - but the main target was to allow smooth software development.
These machines appear to be simply regular Lisas supplied with emulation software (MacWorks?) to allow the running of Macintosh software.
Yes, usually they are all Lisa 2/10 But there are some exceptions known which seam to be after sales conversions.
MacWorks is an emulation solution to 'install' the Mac ROM images and some drivers. A (Mac) System Disk had to be booted afterwards.
As well, I think I've read that any Lisa can run the MacWorks software,
Yes, the original intention was to use a Lisa as development station for Mac software. MacWorks only later became a customer product to offer a bridge for existing Lisa owners (non developers) to tap the fast(er) growing market for Mac software. Just without a hard disk it wasn't really elegant.
so if that is correct then that could imply that the Mac XL wasn't simply a Mac 128k motherboard in a Lisa box.
No. That would been a way to waste even more money, as the Lisa hardware structure is complete different, and redesigning the Mac mainboard to fit the Lisa card cage would be way to expensive for just a few thousand possible customers. Something a software solution can do with way less cost.
You've got a Mac in Lisa clothing with probably the only noticeable outward difference being the screen and aspect ratios.
Not necessary. The factory sold Mac XL had also a modification to the screen hardware to produce square pixels. It wasn't mandatory, and MacWorks did run fine without, but was also available as an upgrade for field change.
Now the question is, was there any hardware differences with the Mac XL versus the last versions of the Lisa?
While the base was always a Lisa 2 (Lisa with 3.5" drive(s) plus changed FDC PROM and new front plate - original or converted from Lisa 1), it could come in different flavours:
- plain Lisa 2 (1 floppy) - two boot stages with successive floppies
- above with changed screen ratio
- Lisa 2/5 (1 Floppy + 5 MiB ProFile) - boots from ProFile or floppy
- above with changed screen ratio
- Lisa 2/10 (1 Floppy + 10 MiB Widget drive) - boots from HD or FD
- above with changed screen ratio
- Macintosh XL (1 Floppy + 10 MiB Widget drive, always changed screen ratio)
All of the above may bear a Macintosh XL name plate, but only the last one may be a factory made one (or field upgraded), as the name plate was separate available for licensed dealers.
The separate availability of the screen conversion kit (just a PROM) was due the inability of some LISA software (most notably the whole office suite) could not handle the changed screen. (*1)
The hardware of a Lisa vs. a MacXL can be can be detected by the suffix on the screen PROM ( 256x8 like 6309) and the CPU ROMs (a pair of 2764). I don't remember if there where also changes with the I/O ROM (a 2732) (*2). The marking is /A8 for 'original' Lisa 2 and /88 for Mac XL. If there's a different number, you might have a strange Lisa 1 conversion :)) With only the CPU ROMs changed, it can run both OS and all software, but Mac graphics may seam a bit stretched. With the PROM installed it's still possible to boot both OS, but some (let's be serious, most) Lisa Software may be unusable.
Was there anything special that the Mac XL could do that the Mac couldn't (besides RAM)?
AFAIK all Lisa I/O could be used with MacWorks. Including multiple parallel and serial interfaces. And then there is the better keyboard :))
*1 ofc, the easy solution to switch ROMs was introduced soon by third party companies like Dafax with their ROMswitcher. The Manual is a worthwhile read with quite some information around the screen issue.
*2 - The I/O ROM (2732) was most definitely swapped when a 2/5 (external ProFile HD) was changed into a 2/10 (internal Widget drive), as there was also a bord to be changed. To add complication in identifying a machine, a 2/10 still supported the external ProFile (good in the first place), so some/many(?) 2/5 without a widget drive have been upgraded later to use the 2/10's I/O ROM - and such identifying them to the software as 2/10. But that's a different story :))
Additional Info
Original MacWorks had a modified image of the original Mac. Later on Sun Remarketing did continue the Lisa support and enhanced MacWorks as MacWorks Plus, based on the Mac Plus ROMs, supporting System 6, and later updated to run up to System 7.5.
Another issue is the Lisa software, as the Lisa ROMs contain a serial number, and when the software is installed (on HD) first time, this number is copied onto the floppy, allowing from that point on only installation on machines with the same serial number. Changing the CPU-ROMs changes that number, so afterwards the installed software won't continue to work and can not be reinstalled. there was a handling note for dealers to give out just a fresh set of install disks.
Last but not least, there was also the Macintosh Professional. After Sun Remarketing (not related to SUN) took over the remaining stock and continued Lisa and Mac XL support under a licence from Apple, they sold refurbished/upgraded Lisa with 1 MiB Memory, Profile/Widget (20 MiB HD also available) and an optional 800 KiB (!) FD. First this was branded as Lisa Professional later, with the Mac Plus based MacWorks Plus renamed as Macintosh Professional. Check their 1988 Catalogue.