C70:info-cpm (06/05/82)
>From andrew.univax@Brl-Bmd Fri Jun 4 22:10:59 1982
Message-Id: <82/06/04 1637.466@umcp-cs>
Via: Mit-Mc; 4 Jun 82 20:42-EDT
I believe that I've figured out how to integrate the normal CP/M
directory structure with a unix-like directory tree, and should have
some of the support software (mkdir, cd, elementary ls, ln) working
within a week. Is there any interest? I figure that this would have its
greatest use on a system with a hard disk, or other media that holds
large volumes of data. Any interest?
- Andy
- bandy@mit-ai
- andrew.univax@brl-bmd
- dbl!andy.univax@brl-bmdC70:info-cpm (06/05/82)
>From lauren@Ucla-Security Sat Jun 5 00:27:51 1982
Good luck. Be sure to keep in mind that once you leave the linear
directory structure, you are vulnerable to a whole new class
of problems... that's why Unix (and MARC) use a completely different
filesystem structure from CP/M. Be sure to include utilities like
icheck, dcheck, ncheck, and clri to fix the sorts of problems that
will no doubt appear frequently, given the way CP/M manages its
free space. You also might try reducing the minimum CP/M block
allocations size -- MARC uses 256 bytes which results in considerably
more useful space but (surprisingly) no measurable additional overhead
in most applications.
Interestingly, a technique such as you described was attempted and
rejected in an early pre-MARC system... the problems started to
outweigh the benefits pretty quickly. One problem that you will
certainly face is that most CP/M programs are very strict about
the sorts of filenames they will accept, so you end up stuck with the
usual CP/M limitations, which aren't much fun. There are a variety
of other pitfalls as well, all of which eventually led to the conclusion
that it was better to stop trying to build mountains on a foundation
of sand, scrap the CP/M filesystem completely, and implement a full
Unix filesystem from scratch -- which is how MARC ended up.
--Lauren--C70:info-cpm (06/05/82)
>From ARPAVAX.comay@Ucb-C70 Sat Jun 5 02:23:01 1982
Andy,
I am VERY interested in your work on creating unix-like tree
directories on CP/M systems. I would appreciate any information
you can send me.
David