A Bit Of A Rarity

[blusnowkitty]

As a side note, does anyone have a schematic of the ROM adapter? If the ROM gets released I might burn it to some real ROMs and throw it in my retail Mac 128 for a laugh

 

[Dog Cow]

Good luck!

Any idea if those ROMs are on the Web somewhere?

They've been on Mac GUI Vault for a few years: Twiggy Mac prototype ROM

I also did some write-ups back in 2014, investigating the file format and ROM:

Twiggy Mac ROM disassembly

Report on Twiggy Mac disks

As a side note, does anyone have a schematic of the ROM adapter? If the ROM gets released I might burn it to some real ROMs 

It isn't necessary to have the adapter. You can merge the contents into a Hi and Lo ROM as used on the production Macintosh board. Some people have already done it a few years ago with the newer Twiggy ROM version.

 

[blusnowkitty]

It isn't necessary to have the adapter. You can merge the contents into a Hi and Lo ROM as used on the production Macintosh board. Some people have already done it a few years ago with the newer Twiggy ROM version.

Ah cool; so 

copy /b high1.bin + high2.bin combined_hi.bin
copy /b low1.bin + low2.bin combined_lo.bin

or for *nix

cat high1.bin high2.bin > combined_hi.bin
cat low1.bin low2.bin > combined_lo.bin


Burn to a pair of 27256 EPROMs and enjoy? Sounds easy enough.

 

[jake18125]

I wonder if the PALs have the security fuses blown.
I'm guessing as it is a prototype and still very much a development system there is a minor chance that they would still be readable by a programmer.
If so, that's probably the only way to get at least some of the PAL equations for the macintosh!

 

[Paralel]

Now that this thread has been brought back to life, where did this all end up? Were the ROMs backed up? Was the disk recoverable?