[comp.arch] on shells and os features

schwartz@shire.cs.psu.edu (Scott Schwartz) (01/12/89)

In article <5657@cbmvax.UUCP>, jesup@cbmvax (Randell Jesup) writes:
>	You're talking shells, not "Unix".  It should be possible to write
>a shell for almost any usable computer, a shell that does wildcarding 
>ala Unix.

Correct, of course.  But consider this: standard features affect how
utilities will be designed and used.  Most unix programs expect to
take a list of items on the command line. If you put a unix style
shell on VM/CMS, say, you will also have to replace lots of utilities,
like LISTFILES.  At this late stange in the evolution of these
systems, certain characteristics are so deeply ingrained that they
can't be easily changed.
-- 
Scott Schwartz		<schwartz@shire.cs.psu.edu>

ge@phoibos.UUCP (Ge Weijers) (01/12/89)

In article <4205@psuvax1.cs.psu.edu>, schwartz@shire.cs.psu.edu (Scott Schwartz) writes:
) In article <5657@cbmvax.UUCP>, jesup@cbmvax (Randell Jesup) writes:
) >	You're talking shells, not "Unix".  It should be possible to write
) >a shell for almost any usable computer, a shell that does wildcarding 
) >ala Unix.
) 
) Correct, of course.  But consider this: standard features affect how
) utilities will be designed and used.  Most unix programs expect to
) take a list of items on the command line. If you put a unix style
) shell on VM/CMS, say, you will also have to replace lots of utilities,
) like LISTFILES.  At this late stange in the evolution of these
) systems, certain characteristics are so deeply ingrained that they
) can't be easily changed.
) -- 
) Scott Schwartz		<schwartz@shire.cs.psu.edu>

You could also emulate/implement unix-style system calls, which would
make porting programs to the IBM/VM etc easy, see Eunice, which emulates
BSD 4.x on VMS (more or less, no symbolic links etc.)

Ge' Weijers, KUN Nijmegen, the Netherlands, ge@cs.kun.nl

blarson@skat.usc.edu (Bob Larson) (01/13/89)

In article <4205@psuvax1.cs.psu.edu> schwartz@shire.cs.psu.edu (Scott Schwartz) writes:
>In article <5657@cbmvax.UUCP>, jesup@cbmvax (Randell Jesup) writes:
>>	You're talking shells, not "Unix".  It should be possible to write
>>a shell for almost any usable computer, a shell that does wildcarding 
>>ala Unix.

>Correct, of course.  But consider this: standard features affect how
>utilities will be designed and used.  Most unix programs expect to
>take a list of items on the command line. If you put a unix style
>shell on VM/CMS, say, you will also have to replace lots of utilities,
>like LISTFILES.

If most programs expect single file names, wildcards ala primos would
probably be more approprate than wildcards ala unix.  Prime had exactly
this problem when they decided to implement wildcards, so their
command processor involkes the program on each file separatly.
(If the new linker is used, passing the wildcard to the program
for expantion may be specified.)

-- 
Bob Larson	Arpa: Blarson@Ecla.Usc.Edu	blarson@skat.usc.edu
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