General Category > LisaList2
Monitor format for ProFiles
D.Finni:
--- Quote from: stepleton on May 09, 2020, 08:46:18 pm ---This is a long-shot question: does anyone know anything about the hard drive format used by the Monitor?
--- End quote ---
The Monitor file system, at least on the floppy disks, is the UCSD P-System, same as on the Apple II Pascal system, except it's big-endian. I documented the format and wrote an interpreter for it just a few months ago.
stepleton:
Oh interesting! As I was trying to format a ProFile for the Monitor, one of the things I did (or at least I think I did it) was to create a disk image in Apple II Pascal in an emulator and see if that image would work when transferred directly to a ProFile emulator. The endianity issue could be one reason it didn't go anywhere :)
Have you put any of your work online? But maybe more importantly --- is there something that would suggest to you that the format would allow you to boot from the disk? For example, one clue might be that the first few blocks are not used, making room for a bootloader.
rayarachelian:
*bump* yes pls, give us a pointer to this. Not committing to anything, but perhaps I could add support for this fs in lisafsh-tool, or something else eventually.
D.Finni:
I attached two useful text files to this post. The first is an except from Apple's Monitor documentation, from a PDF on Bitsavers. It explicitly says "After the Monitor is installed [on the ProFile], you will still boot with the Monitor Boot disk."
So there's your answer from the horse's mouth regarding booting from a hard disk.
The second text file is the Apple Pascal 5.25" disk format for Apple II. You can also find a description of Apple Pascal disk format in the Call-APPLE publication called "All About Apple Pascal." It's documented in a few other sources too.
Like I said earlier, Lisa Monitor's format is exactly the same (so far as I know) as Apple II Pascal, except that word-length values are in big-endian order.
As far as code, I think that you could take DiscImageChef's Pascal FS module and modify it. Within the Apple II community, you should also find one or two projects which can read Apple II Pascal formatted disks.
D.Finni:
Oh, and by the way, last November I added Monitor format to my Vault archive site so you can click through and browse the contents of Lisa Monitor disks. And you can link directly to files within the disks. The URLs will never change.
This is neat. Take a look at some examples:
https://macgui.com/spyglass/r/7e8a7a533c8dfb56
https://macgui.com/spyglass/r/c65d7e778b0d2b79
https://macgui.com/spyglass/r/0f87d6f7c1cb821d
LisaTest is a Monitor-format disk. The feature is called "look inside with Spyglass" in the Downloads section of my site.
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