Re: Lisa Hardware Interface 9.1 source

> Your utility, if it does not already support this extended directory structure, may I think be more useful if it did. Key to supporting this structure is to not assume a fixed length for the directory. Use the number of allocated directory blocks to determine the max number of files supported. This will generally be a 4 block directory.

This utility never hardcoded the directory size. At first I was looking for null values, but after learning more about the structure, I started using the number of files field in the header. However, when I first added "male"/"female" disk support, I was checking against 0x06 in the header end block field, but this failed with a disk with an extended directory after I did more testing. So I changed it to check for the byte that is zero. This will work as long as the directory is shorter than 255 blocks, and I don't think we'll ever see that :)

> LisaTest

yes

> LisaGuide (not 100% sure here)
nope?

> MacWorks

on early ones, looks like it. Have to go through more disks.

> Also, also ... I recall reading in Apple's internal Lisa development materials that a Lisa could format a disk to contain both a Lisa OS and Monitor file structure. I suspect obtaining such disks would be very very very rare. Determining the low-level structure details would involve some work. The attached LISA MONITOR v10.0 release note dated July 15, 1982 discuss this extended directory structure.

I've found one disk that's got both Lisa Monitor and Mac data — intended for a Twiggy Mac.

> Thanks for your Lisa efforts, appreciated. Hope these comments are of some practical use.
You're welcome, we'll see what's needed next — probably will finish that DART to DC42 converter that I started four years ago... :)

David

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