Date   : Fri, 22 Aug 1986 14:08:19 EDT
From   : SAGE@LL.ARPA
Subject: DateStamper Information

   Below is a description of DateStamper that appeared earlier on the net by
one of its authors, Bridger Mitchell.  I would add the following comments.
 
   The original version poked changes into the BDOS and might have failed to
work with a modified BDOS.  However, the current release includes a version
that will work with any kind of CP/M2.2-compatible BDOS, such as ZRDOS or,
presumably, P2DOS.
 
   There are two ways to install DateStamper.  The easy way is as an RSX
(resident system extension) below the CCP.  In that case you are right that
it takes up quite a bit of TPA (2K for the CCP plus about 1K more for
DateStamper itself).  If you can move your CCP, BDOS, and BIOS down by about
1K, you can install DateStamper above the BIOS.  Then the TPA space you lose
is only that required for the DateStamper code.  This TPA loss, however, is
permanent; you cannot recover it by not loading DateStamper (you can, of
course, boot from a vanilla CP/M disk).  With DateStamper running as an RSX,
it can be removed from memory when its presence is causing a problem.  Bruce
Morgen and I wrote a program (not yet distributed) called CLRRSX that will
remove DateStamper and any other RSXs present.
 
   It is very impressive how unobtrusively DateStamper functions.  I had
worried that all the accesses to the time/date file would slow things down,
but it turns out not to be noticeable.  I am very pleased with it.  The only
problem I have encountered is that when files are copied with standard
utilities, the destination file is given the current date/time rather than
the date/time of the source file.  This is, of course, not a defect of
DateStamper but of the utilities.  Gradually, as more of us use DateStamper,
utilities will be modified to support it.  I plan to add it to the next
release of VFILER and would like to add it to some general copy program like
PPIP, MCOPY, and/or AC.
 
                                        Jay Sage
                                        MIT Lincoln Lab
 
 
DateStamper is a CP/M 2.2 system extension for time-and-date-stamping of
files.  It occupies under 1K of high memory, either above/in the bios
or below the CCP and stamps the created, accessed and modified date-and-time
of each file.  Each directory entry has a corresponding 16-byte
entry in the special datestamper file, which is the first directory entry
and occupies the first unreserved groups on a disk.  A disk is prepared,
once, for datestamping with the PUTDS utility, which creates the file,
moving existing entries/groups if necessary.
 
Except for the use of the one directory entry and space for the file
(1K per 64 directory entries) DateStamper and non-datestamper disks
are totally compatible.  All disk i/o is done at the bios level,
with little overhead.
 
DateStamper runs with most any type of real-time clock. Or with none,
in which case it keeps the date plus  "relative time" - one tick per
file access.  The clock interface is portable - applications programs
can read the current time with an extended bdos-getversion call.
 
The major utilities supplied with DateStamper are SDD - an extension
of Super Directory to include created/accessed/modified dates/times,
and DATSWEEP - a many-featured file-maintenance program that supports
incremental file backup, etc. by date and time.  Applications programs
can obtain a file's datestamps through a specified interface.
 
DateStamper runs with the standard Digital Research CP/m 2.2 bdos,
with various Apple 2/2e z80 look-alikes, Magnolia-H/Z 89/90, ZRDOS,
and some other variants.  Not, however, with 3.0 or TurboDos.
 
For more information contact:
 
PluPerfect Systems (714) 659-4432
Box 1494
Idyllwild CA 92349
 
--bridger mitchell (I am a co-author).