Date   : Fri, 10 Sep 1982 10:33:06-PDT
From   : UCBVAX.teklabs!azure!laurir@Ucb-C70
Subject: Re: the s1, s2, and cr fields in a CP/M disk directory

This is in response to a correspondent who would like to use the S1,
S2, and CR fields of a CP/M disk directory entry to record a file
date/time stamp.
  S2 holds the overflow bits from the extent number.  Under CP/M v1,
extent numbers were five-bit entities and are shoe-horned into the
low five bits of the EX byte.  With CP/M v2, extent numbers are lengthened,
with bits 5 and up (least significant is bit 0) stored in S2.
  The disk directory entry contains only 32 bytes, not 36 bytes as a
File Control Block does.  The CR field, the 33'rd byte, isn't stored.
  I haven't yet found a purpose for S1.  Does anyone know?

    -- Andrew Klossner  (laurir.tektronix@udel-relay)
                       (decvax!teklabs!tekmdp!laurir)