SVR3.0 vs BSD4.3

[Joe Buck]

In article <7514 at brl-smoke.ARPA> gwyn at brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>In article <2423 at bsu-cs.UUCP> dhesi at bsu-cs.UUCP (Rahul Dhesi) writes:
>> [ what's missing from Sys V ]
>>   job control (stop/restart jobs, get status of jobs and know
>>                one is stopped for tty input)
>
>As I mentioned, the System V equivalent is "shell layers", which is
>not quite as nice from the user's perspective but it sure disrupts the
>system internals less than the 4BSD approach.

shl isn't anywhere NEAR as nice from the user's perspective as job
control and isn't an adequate replacement.  This is the number one
reason that I, and a vast number of other users, will not consider
a Sys V environment.  Windows are also not an adequate replacement;
I use both windows and job control.  You can explain why I'm
technically foolish to have this attitude.  But I use it and I like
it.  If the internal implementation is inelegant, that's unfortunate;
I'd tolerate slight changes in the user interface if it would result
in cleaner internals, but we do the internals to get the nice user
interface, not the other way around!

>>   support for multiple command interpreters with #! as first line of script
>
>This is totally unnecessary; if all scripts are executed by a Bourne
>shell, it is easy to simulate the #! feature, in fact to generalize
>on it.  Nevertheless I think AT&T may be adding this kludge to the
>kernel exec code in a future release, alas.

The reason Dennis Ritchie invented #!  (that's right, it's not a
Berkeleyism) was for the Pascal p-code interpreter.  It wasn't
originally designed for csh shell scripts at all!  It makes programs
like Larry Wall's "perl" much more wonderful as well.  While it's
unsafe to write a set-uid shell script, it's perfectly safe to write
a set-uid perl script, and this can only be done with #!.  There are
things #! gives you that you can't get any other way, and
implementing it isn't ugly at all -- it simply generalizes the
concept of the "magic number" at the beginning of an executable.  
csh is not the reason for #!.

>>   dbm library--fast /etc/passwd and /usr/lib/news/history access etc.
>
>There are other ways to speed up /etc/passwd access that don't have
>the drawback of maintaining a separate index file.  A good, standard
>ISAM would be useful, but dbm ain't it.

Here I agree with you.  dbm sucks, in many ways.  I was extremely
peturbed once when I found you can't have two dbm databases open in
the same program -- I ended up forking off a second program to do
part of the job.


>>   context diffs from diff
>
>This could be added easily enough, and I considered adding it to my
>System V emulation package but decided it wasn't particularly useful.

Context diffs are the safest way to transmit small source code
changes in a distributed environment, and are easier both for
programs and for people to deal with.

Oh, by the way, Sys V versions of many utilities are vastly superior:
lint and make especially come to mind.
-- 
- Joe Buck  {uunet,ucbvax,sun,<smart-site>}!epimass.epi.com!jbuck
	    Old Internet mailers: jbuck%epimass.epi.com at uunet.uu.net