The meaning of su
From: [email protected] (Oliver Laumann)
Newsgroups: de.comp.lang.c
`su' steht fuer `Super-User'. Das Kommando hat urspruenglich
ausschliesslich dazu gedient, root zu werden. Die Moeglichkeit, eine
andere User-ID anzugeben, kam erst spaeter hinzu.
Die UNIX-Geschichte hat nicht mit XENIX oder Linux angefangen; merkt
Euch das mal :-)
Fuer die Unglaeubigen hier der Anfang von su.c aus UNIX V6 (es hat
also keinen Sinn, weiter zu spekulieren):
`su' stands for `Super User'. Originally, the commands's only purpose
was to become root. The possibility to add a different user id was
added later.
Keep in mind that the history of Unix did not begin with Xenix or Linux :-)
For the unbelieving here is the beginning su.c from Unix V6 (so there
is no sense in further speculation):
$ cat su.c
/* su -- become super-user */
char password[100];
char pwbuf[100];
int ttybuf[3];
main()
{
register char *p, *q;
extern fin;
if(getpw(0, pwbuf))
goto badpw;
(&fin)[1] = 0;
p = pwbuf;
while(*p != ':')
if(*p++ == '\0')
goto badpw;
if(*++p == ':')
goto ok;
The meaning of dd, again
From: [email protected] (Michael P Urban)
Newsgroups: comp.unix.misc
>I thought 'dd' was for 'device dump'.
("You young whippersnappers. When I was your age...") Anyway, dd
stands for `data definition', if it can be said to stand for anything,
because the name, and its horrifying command-line syntax, are derived
from the IBM OS/360 JCL command of the same name.
//GO EXEC PGM=IEFBR14
//SYSIN DD RECFM=FB,DISP=(NEW,,KEEP),DSN=FOOFILE
(or something like that. You think I remember _details_ of this stuff?)
I hear that people still do this sort of thing. But not on cards.
The meaning of dbx and dd
From: [email protected]
To: [email protected]
dbx is a compression/expansion scheme (roughly) similar to Dolby S.
It's put out by dbx laboratories (I believe the db is for decibel,
and the x is for expansion), which is in the bay area not too far from
Berkeley.
But what does `dd' stand for on the mainframe?
I talked to Griff Smith ([email protected]),
who wrote the System V Release 3 version of dd, about this today.
He's not sure if it was ever actually called cc in UNIX, but he is
_certain_ that the name dd comes from the jcl dd command (so does the
wreched syntax).
As far as what that's named after, neither of us has a clue.
It's possible that it was the jcl command which was originally named
'cc', and not the UNIX one.
The meaning of umask
From: [email protected] (Goran Larsson)
Newsgroups: comp.unix.misc
Date: Sat, 14 Oct 2000 21:55:25 GMT
In traditional Unix information about each process is held
in a structure called "user". This structure contains many
things (process registers, uid, gid, memory info, signals,
cwd, statistics, and the file creation mask. In SunOS 4.1.X
the file creation mask in the user structure is called u_cmask.
A pointer, traditionally called "u", is set to point to the
user structure for the current process. Device drivers and
system calls access process information in the user structure
using u (like u->u_cmask).
struct user {
...
short u_cmask; /* mask for file creation */
...
};
extern struct user *uunix;
#define u (*uunix)
Perhaps the "umask" system call got its name because it sets the
file creation mask in the "u" structure?
The meaning of the c in calloc
The meaning of the c in calloc was vividly discussed in
comp.lang.c in October 2000, with both
clear (because, unlike malloc, calloc clears the memory it
returns) and count (because, unlike malloc, calloc is passed
a count of elements to allocate) suggested as possible explanations,
however without real evidence for either. Other suggestions were
(along with several less serious ones) contiguous, core,
commit, chunk, and character,
the latter because in early versions of K&R C, calloc was the
only allocation function in the library (and had an accompanying cfree).
For the same reason, it was even suggested that the c simply
stand for the C programming language. So, the etymology of calloc
still isn't proven, and if anybody has any definite evidence as to
its meaning, I'd highly appreciate learning about it.
The meaning of the r in rmail
From: [email protected] (Jim Driscoll)
Newsgroups: comp.unix.misc
From the Unix system V/386 Release 4 Users Reference Manual, under mail(1):
" rmail only permits the sending of mail; uucp(1C) uses rmail as a security
precaution. Any application programs that generate mail messages should
be sure to invoke rmail rather than mail for message transport and/or
delivery."
Sounds pretty restricted to me. In fairness, this means that it is
also for remote mail, but I would argue on the basis of this paragraph
that it is restricted mail, since this implies that I could replace it
with mail without any lossage. In fact, they are the same program on my
system, linked with different names (/usr/bin/mail and /usr/bin/rmail).
The meaning of ping
The author of ping, Mike Muuss, writes in his "Story of the PING
Program":
From my point of view PING is not an acronym standing for Packet InterNet
Grouper, it's a sonar analogy. However, I've heard second-hand that Dave
Mills offered this expansion of the name, so perhaps we're both
right. Sheesh, and I thought the government was bad about expanding
acronyms! :-)
The complete story can be found
here.