David.Plummer@f70.n140.z1.FIDONET.ORG (David Plummer) (08/14/90)
Well, you can check the AmigaDOS manual for some old BCPL charts, or I could send you home-made include files that have structures for all the disk blocks. The only problem is that if you use structures, you are locking yourself into 512 byte sectors, which is a nono. To be right, you should use the disk blocks via offsets, which are listed in the AmigaDOS manual.Basically, what you have are the BitmapKeys, a table of twenty five sectors that each contain 127 longwords (on a floppy only one sector is needed). Each of these longwords has 32 bits. If a bit is set or clear determ,ines if the block is used or free. This scheme gives you only about 50meg of room, so FFS adds a BitmapExtension byte that points to a sector containing another list of bitmap keys, a checksum, an and so on (line noise is bad, bear with me). It's pretty confusing, but certainly more open-ended than some other filing systems I can think of.... -- David Plummer - via FidoNet node 1:140/22 UUCP: ...!alberta!herald!weyr!70!David.Plummer Domain: David.Plummer@f70.n140.z1.FIDONET.ORG Standard Disclaimers Apply...