When using Apple Pascal 1.3 (as well as versions 1.0, 1.1, and 1.2) on an
Apple II, you cannot use the Hard Disk 20SC as a volume: since Pascal stores
the volume size as a signed integer, it cannot work with volumes larger than
32767 blocks. (The HD 20SC has 39165.) The Hard Disk 20SC can be formatted
from Apple Pascal, but when you attempt to use the Pascal FILER to copy files
to the drive, you get a "NO ROOM ON VOLUME" message. Furthermore, Apple
Pascal only supports 77 files per directory, so even if you could use the
Hard Disk 20SC, you would run out of directory space before you could even
come close to running out of disk space.
The directory limitation applies to 5 meg and 10 meg ProFile drives as well.
You can use a ProFile hard drive with Pascal 1.3, but you cannot "share" the
drive with ProDos: you must dedicate the entire hard drive to a maximum of 77
Pascal files.