Min no of member?s (PDS) in one directory block?

Answer Posted / steve holton

PDS directory blocks are 256 bytes long. The first halfword
(2 bytes) are used to indicate the number of bytes used in
the block, leaving 254 bytes for directory entries.

Directory entries are variable in size, and are each at
least 12 bytes long, and up to 74 bytes long (12 byte "base"
length plus up to 62 bytes user data).

Directory blocks may have no members, so 0 is the minimum
possible members in a block. If the question is re-worded to
something like "what is the minimum number of entries in a
FULL directory block?", the answer is floor(254/74) = 3.
That is, every PDS directory block is capable of holding AT
LEAST 3 entries.

Maximum possible entries in a full directory block would be
floor(254/12) = 21.

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