28 Oct
2019
28 Oct
'19
2:31 a.m.
What is the special meaning of using / as directory
partition in UNIX? And \ as the escape character.
\ came from Multics. The first day Multics ran at Bell Labs Bob Morris
famously typed backslash-newline at the login prompt and crashed the
system.
Multics had a hierarchical file system, too, but I don't recall how
pathnames were punctuated.
Doug
7:11 a.m.
On Sun, 27 Oct 2019, Grant Taylor via TUHS wrote:
On 10/27/19 2:49 PM, Charles Anthony wrote:
I can't imagine there's any such connection. MS-DOS got it from CP/M,
which didn't even have the concept of subdirectories until after MS-DOS
did.
-uso.
/home/CAnthony
>user_dir_dir>User>CAnthony
Is there any relation between Multics'
use of ">" as a directory separator
and MS-DOS's default use of ">" at the end of the command prompt?
6 p.m.
On 27 Oct 2019 21:11 -0400, from usotsuki(a)buric.co (Steve Nickolas):
On Sun, 27 Oct 2019, Grant Taylor via TUHS wrote:
If there was such a relationship, it would probably make more sense
for the command prompt termination character to be ":", not ">",
as
DOS labelled devices as [whatever]: (like "A:" or "NUL:"). So I agree
with Steve; I imagine it's unrelated. They just had to use _something_
as a default to indicate that the computer is waiting for a command,
and ">" is as good a character as any.
In either case, since MS-DOS/PC-DOS did what CP/M already did in that
regard, the question would probably need to be posed to Kildall where
he got it from. Unless Kildall wrote it down, getting a first hand
account on the reasoning behind that particular choice would be...
nontrivial.
--
Michael Kjörling • https://michael.kjorling.se • michael(a)kjorling.se
“The most dangerous thought that you can have as a creative person
is to think you know what you’re doing.” (Bret Victor)
Is there any relation between Multics' use
of ">" as a directory
separator and MS-DOS's default use of ">" at the end of the command
prompt?
I can't imagine there's any such connection. MS-DOS got it from CP/M, which
didn't even have the concept of subdirectories until after MS-DOS did. 
9:08 p.m.
On Mon, 28 Oct 2019, Michael Kjörling wrote:
On 27 Oct 2019 21:11 -0400, from usotsuki(a)buric.co
(Steve Nickolas):
86-DOS actually did use ":" as a prompt character. This was changed for
IBM's release, for some clone releases, and for MS-DOS 2.0.
-uso.
I can't imagine there's any such connection. MS-DOS got it from CP/M, which
didn't even have the concept of subdirectories until after MS-DOS did.
If there was such a relationship, it would probably make more sense
for the command prompt termination character to be ":", not ">",
as
DOS labelled devices as [whatever]: (like "A:" or "NUL:"). So I
agree
with Steve; I imagine it's unrelated. They just had to use _something_
as a default to indicate that the computer is waiting for a command,
and ">" is as good a character as any. 
29 Oct
29 Oct
12:47 a.m.
On Mon, 28 Oct 2019, Steve Nickolas wrote:
86-DOS actually did use ":" as a prompt
character. This was changed for
IBM's release, for some clone releases, and for MS-DOS 2.0.
The best I've ever seen was RT-11's "." - talk about minimalist...
Actually this thread probably belongs on COFF by now.
-- Dave
2:43 a.m.
On 10/28/19, Dave Horsfall <dave(a)horsfall.org> wrote:
On Mon, 28 Oct 2019, Steve Nickolas wrote:
RT-11 was following standard DEC practice by using "." as its command
prompt. The "monitor dot" was the command prompt in both TOPS-10 and
TOPS-20.
Most DEC operating systems, including RT-11, TOPS-10/20, and VMS, used
"/" as a prefix on command options; "-" performs this function on
UNIX
since "/" is the directory delimiter. Back in the days of stand-alone
programs, physical switches on the console were used to set program
options. This of course won't work when you have multiprogramming. I
was told that DEC chose "/" because it looks like a toggle switch.
Command options in fact were initially called "switches".
-Paul W.
86-DOS actually did use ":" as a prompt
character. This was changed for
IBM's release, for some clone releases, and for MS-DOS 2.0.
The best I've ever seen was RT-11's "." - talk about minimalist...
Actually this thread probably belongs on COFF by now. 
28 Oct
28 Oct
2:46 a.m.
On Sun, 27 Oct 2019 16:31:28 -0400 Doug McIlroy <doug(a)cs.dartmouth.edu> wrote:
From what I read:
What is the
special meaning of using / as directory partition in UNIX? And
\ as the escape
character.
\ came from Multics. The first day Multics ran at Bell Labs Bob Morris
famously typed backslash-newline at the login prompt and crashed the
system.
Multics had a hierarchical file system, too, but I don't recall how
pathnames were punctuated. dir1>dir2>file1 -- absolute: /dir1/di2/file1
file1 -- relative: if >dir1>dir2 is the working dir
<file2 -- relative: ../file2 == >dir1>file2
<dir3>file4 -- ../dir3/file3
<<dir4>file5 -- ../../dir4/file5 == >dir4>file5
<< is more compact thant ../.. and I like the vertical symmetry of < and >!
11:36 p.m.
Bakul Shah <bakul(a)bitblocks.com> once said:
"Getting Less Than Right" would have been an
interesting title. ;)
Unix uses dot for the current directory. Was
there any notation for this in Multics?
Anthony
dir1>dir2>file1 -- absolute: /dir1/di2/file1
file1 -- relative: if
>dir1>dir2 is the working dir
<file2 -- relative: ../file2 == >dir1>file2
<dir3>file4 -- ../dir3/file3
<<dir4>file5 -- ../../dir4/file5 == >dir4>file5
<< is more compact thant ../.. and I like the vertical symmetry of < and >!
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12 comments
11 participants
participants (11)
-
Anthony Martin -
Bakul Shah -
Charles Anthony -
Clem Cole -
Dave Horsfall -
Doug McIlroy -
Grant Taylor -
Michael Kjörling -
Paul Winalski -
Richard Salz -
Steve Nickolas