Date   : Mon, 14 Mar 1988 11:46:02 EDT
From   : <SAGE@LL.ARPA>
Subject: CP/M Directory Entries

his is the classic problem of logical vs physical.  In one case
extent' is used to refer to the contents of one directory entry (32K or
56 logical records -- physical records probably only 32 or 64!).  The
ogical extent is always 16K, and thus there can be two logical extents
n one physical extent, just as there can be 2 or 4 or 8 logical records
128 bytes) in each physical record.  The extent number in the directory
ntry is the number of the last extent in that directory, and the record
ount is the number of logical records in that last extent.  With larger
lock sizes on a hard disk it is quite possible to have 4 or probably
ven 8 logical extents per physical extent.  The same rules apply.