[net.micro.cpm] CP/M 2.2 User 0 $SYS files

pdupont@Bbn-Unix.ARPA (04/09/84)

From:  Pierre duPont <pdupont@Bbn-Unix.ARPA>

According to the Glossary of Terms in the CP/M manuals I have,
it should be possible to set the $SYS attribute on .COM files
that are located in User 0, and then excute them from any other
user. (Note that this is only documented in the glossary, not
in the main body of the manual.) However, I find that this does
not work. Can someone confirm this for me? I have heard a rumor 
this feature was really only implemented in MP/M & CCP/M, and
possibly in CP/M V3.0. Clearly this is a desirable feature that
makes the User N concept extremely useful.
    - Pierre.
(Please respond directly to me only; I will
summarize to the net if needed.)

kevinw%isl@sri-unix.UUCP (04/10/84)

To clarify the attributes for cpm2 and cpm3.

attribute	cpm2			cpm3
---------	----			----
SYS		makes file invisible	for user 0 makes useable from
		to normal dir scan.	ANY user number.  WARNING: dri
		has no other effect	added the misfeature that any
		on cpm operation.	file accessed like this is a
		does not enable access	R/O file.  really screws up any
		from other user areas.	ideas of using mince from alternate
					user areas...

R/O		bdos will not allow	same as for cpm2
		this file to be
		overwritten or
		deleted.

ARCHIVE		not available		reset whenever a file is modified.
					used to flag what files are the
					same as on some archive source
					for reduced backup requirements.


Attributes for cpm2 are basically just cute additions -- r/o is nice but
there is no way other than stat to see what the attributes are.  there is
no way other than stat to even see what files are system files.  in cpm3
the attributes are much more integrated into the system and actually have
some uses.  now if only you could write a system user 0 file....  i guess
that dri has to add some screwup to what is otherwise a quite reasonable
version of os-8...

  -- Kevin
     kevinw@su-dsn

ABN.ISCAMS@Usc-Isid.ARPA (04/10/84)

Kevin (et al)

ARCHIVE is available for CP/M 2.2 - just needs a little (but well documented)
patch in the BDOS.  See SIMTEL20 (I forget which directory).  I have it,
and it works installed on my Morrow Decision I w/CP/M 2.2 just fine.  Only
undesirable effect is that D.COM no longer works correctly with wild cards.

Another simple patch (some code in the BIOS, and change one JMP in the
BDOS) gives you default access from any disk, any user area, to default disk
same user area and then to default disk user area 0 for .COM, .TXT, .HLP,
and I think everything else.  See TOADBIOS.DOC in SIMTEL20's MICRO:
<CPM.GENDOC>; source code for the patch on one of the SIGM volumes - sorry,
forget which one, but all is in TOADBIOS.DOCw.  I have that installed also
(and I have a VERY stuffed CBIOS, what with hard disk, implemented IOBYTE,
A0> CP/M prompt patch, etc., and it works fine for all but overlays (like
W*Star), where the overlays MUST be in the user area you're working in.
(However DUPUSR.COM works fine there to put the name/access in any user
area, but NOT the actual space/storage requirements.)  No undesirable effects
at all from the USER patch.

Regards,
David Kirschbaum
Toad Hall
ABN.ISCAMS@USC-ISID