Disk Format

[jeff.brielmaier@yob.com (Jeff Brielmaier)]

To: pbauer@ATHENA.MIT.EDU

PH>I am trying to find out the physical arrangement of data and directory
PH>information on a disk partition and where it is located on the disk. In
PH>particular what blocks or area contains the partition information on a hard
PH>drive. Block 0 and 1 I believe has information about the format and size of
PH>the partition and 4 thru 16 or so contains directory info? Where is the
PH>information that tells the partitioning setup?

For a ProDOS formatted disk, the following is true:

Block 00    - ProDOS Boot block
01    - SOS    Boot block (not used by ProDOS-8 / GSOS)
02-05 - Volume directory  (each block holds 13 file entries; a total of
51 are available for the user;  the 1st
entry holds the Volume label and size info)
06-?? - Volume bit-map    (Each byte hold the used/free status of 1
block of the volume [8 blocks per byte].
The # of blocks allocated to the Bit-Map
depends on the total number of blocks on the
volume. [Max number of blocks = 16])
??-?? - User data

The physical layout of a hard drive blocks to allow it to boot on an Apple // 
will vary from one interface to another.

* KingQWK 1.05 # [PK] * Let him who is stoned cast the first sin.

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