Questions tagged [unix]
For questions about the Unix operating system.
108
questions
9
votes
1
answer
1k
views
Is it true that "do ... done" blocks in Bash do not end with "od" because od existed before Bash/Bourne shell?
The Wikipedia page about od says:
Since it predates the Bourne shell, its existence causes an inconsistency in the do loop syntax. Other loops and logical blocks are opened by the name, and closed by ...
- 20.5k
8
votes
0
answers
256
views
A learning gomoku in Lisp
Years ago I played a version of gomoku that was written in Lisp that learned as you played. After a few rounds, it became nearly unbeatable. This was on Unix System III on a small PDP-11.
I have ...
- 20.5k
8
votes
2
answers
2k
views
What are the "other crontabs" that /etc/crontab refer to? [closed]
The /etc/crontab file on ubuntu has a header that reads:
# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when ...
- 199k
15
votes
1
answer
2k
views
How would old software using the SIGPIPE signal really work if it were to manage _many_ pipes?
I'm wondering what was the thinking behind having a SIGPIPE signal.
From my own experience, the first thing I do is turn off that signal (SIGIGN) and use the return value of the calls to make sure it ...
- 199k
37
votes
3
answers
5k
views
Why does make only accept tab-indentation?
The syntax for Makefiles requires that indented lines start with a tab, and not a space. So far as I can tell, this has been the case even for very early implementations of make. But even modern-day ...
- 114k
54
votes
2
answers
24k
views
Why were the /\ (min) and the \/ (max) operators abandoned in the C language?
In the UNIX V7 version of the C language (but not yet in the V6 version), there were the /\ (min) and the \/ (max) operators. In the source of the scanner part of the compiler,
case BSLASH:
if (...
- 17.9k
1
vote
1
answer
363
views
Did DEMOS have a C compiler?
DEMOS was a Soviet operating system derived from BSD Unix. The answer to this question shows that the familiar, English-derived BSD commands were essentially the same in DEMOS.
Did DEMOS have a C ...
- 36.8k
6
votes
2
answers
341
views
DEMOS commands: Cyrillic or Roman letters? Uppercase or lowercase?
DEMOS was a Soviet operating system derived from BSD Unix.
Commands in BSD are derived from English words. Did DEMOS use these same commands, develop their own commands but retain the Roman alphabet,...
- 161
26
votes
6
answers
6k
views
Was Unix ever a single-user OS?
I've been told that Unix started out as a Phone Switch OS and was not a multi-user OS at some time in its infancy.
As I'm always willing to learn new things, are there any greybeards around here ...
- 5,488
14
votes
3
answers
2k
views
What were the differences between Xenix and Unix?
According to https://en.wikipedia.org/wiki/Xenix by the beginning of the nineties, SCO was selling 32-bit 386 versions of both Xenix and Unix. According to https://news.ycombinator.com/item?id=...
- 36.8k
40
votes
1
answer
7k
views
What was "the shrinkwrap issue?"
I first read "Alice in UNIX Land" (by Lincoln Spector, Texas Computer Currents, Sept. 1989), probably around the time when it was written — and at that time didn't understand very many of ...
- 19.3k
45
votes
9
answers
8k
views
What was the point of separating stdout and stderr?
I occasionally need to work with console commands and 100% of the time I want to redirect my output to a file I fail to redirect stderr as well as stdout the first time. I can't think of a single ...
- 996
13
votes
2
answers
676
views
Unix utility "smiley" to decode emoticons: Where to get it?
I remember in the 90s, there existed a Unix command line utility named smiley that decoded emoticons. A sample use would be like this (the output is likely not the exact output the program gave):
$ ...
- 3,425
66
votes
6
answers
16k
views
Why did base64 win against uuencode?
From the the two methods of encoding 8-bit data as human-readable ASCII, for a time, uuencode format was more popular. USENET 'binaries' groups were filled with uuencoded posts with whatever goodies ...
- 20.5k
1
vote
2
answers
613
views
Does an OS, in particular Unix, need special support for terminal colors? [closed]
Also of interest, would be the first OS to support color graphics in other ways (assuming it wasn't a Unix).
Background: I'm thinking of playing around with Unix v6 due to all the material available, ...
- 279
8
votes
1
answer
930
views
Unix: Why was five (SysV) released *after* seven (V7)?
AT&T released UNIX Version 7 (seven) in 1979.
The same company released UNIX System V (five) in 1983.
Why did the later release have a lower number?
- 31.9k
17
votes
1
answer
513
views
What proprietary AT&T code/features were removed in BSD Net1 (/2), and BSD 4.4 Lite (/2) from the original 4.3BSD codebase?
Background
Although BSD and its source code was freely available under the original BSD licenses, but it only covered the portion of the code which copyright was owned by Regents of the University of ...
- 3,034
14
votes
6
answers
3k
views
Using only one terminal, can I interrupt a process that's hung on very early Unix versions?
Within modern shells, I am able to leave a process via one of two control sequences:
Usually Ctrl+C will directly send SIGINT to the majority of shell commands (e.g. ping, echo, cat)
A few processes ...
- 20.5k
99
votes
19
answers
21k
views
How did people use ed?
ed was the standard Unix editor, and is present on all POSIX certified systems (though it's not installed by default in Debian, FWIW).
It's a line editor (meaning, you can't see all the text at a ...
CommunityBot
- 1
20
votes
1
answer
2k
views
Identifying late 1990s embedded 486 UNIX-like system
I'm trying to identify the operating system on a Thermo-CRS C500 robot arm controller. From the specifications I know it runs on a 100 MHz 486 processor, and has 4 MB RAM and 2MB of flash/NVRAM ...
- 9,903
13
votes
2
answers
3k
views
How did the /dev file system work in early Unix?
UNIX did not have support for virtual file systems (vnodes) until 1986.
S.R. Kleiman, “Vnodes: An Architecture for Multiple File System Types in Sun UNIX,” Summer USENIX 1986
I remember this quite ...
- 114k
44
votes
1
answer
8k
views
What warning was given on attempting to post to USENET, circa 1990?
I recall a confirmation/warning message that read something like
"this will post to thousands of sites... are you sure?"
What was a typical such message in the days of pay-per-minute dialup access?
- 111
0
votes
2
answers
283
views
Role of Termcap under contemporary unices
A word of caution regarding this question: I'm more a userland than kernel person but have this nagging concern which I think belongs to kernel.
When configuring a system one decides on peripherals ...
- 427
5
votes
1
answer
257
views
How to test a chat script with a uucp linux and uucp(server) unix?
I like to play with old networks, uucp is really and advanced(is from the 1978) for that time.
I have setup a uucp server in a tru64 unix server.
On tru64 server
I have edit /etc/inetd.conf
uucp ...
- 427
7
votes
1
answer
428
views
Does the TELCOM program on the Tandy Model 100 support any Unix terminal–like control codes?
I've been connecting my Tandy Model 100 to a serial port on a Linux box via the TELCOM program with some success. The main downside is that in whatever the default terminfo/$TERM setting it gets, a ...
- 2,853
13
votes
0
answers
384
views
Unix on the H11?
I'm curious if anyone is aware of actual uses of Unix on the Heathkit H11? I don't see any technical reason a memory-expanded H11 couldn't run Unix, but can't find any examples of it doing so.
- 18.5k
61
votes
1
answer
15k
views
When was the famous "sudo warning" introduced? Under what background? By whom?
On all Unix-like operating systems, sudo is often provided as the standard package for executing commands as superuser (or an alternative user). When sudo is invoked by the user for the first time, ...
- 105
13
votes
2
answers
3k
views
Could you use uppercase or special characters in a password in early Unix?
This article is about Ken Thompson's old Unix password hash being cracked. One line in the article intrigues:
"Even an exhaustive search over all lower-case letters and digits took several days (...
- 114k
11
votes
2
answers
1k
views
Does "Unix" and "UNIX" represent the same thing?
In some articles I see the word Unix written as "Unix", while in other articles I see the word Unix written as "UNIX".
Does "Unix" and "UNIX" represent the same thing?
- 171
7
votes
2
answers
722
views
How to setup a teletype to a unix shell
So, recently I've been researching old tech because I want to write some fiction about some typewriter that can access the command line(yep) that shows up in many youtube videos like This one. I want ...
CommunityBot
- 1
8
votes
1
answer
375
views
WEGA operating system origins
I just recently stumbled across information about DDR minicomputer P8000 and its unixoid operating system WEGA. The website above as well as Wikipedia seem to claim some compatibility or even ...
- 199k
11
votes
6
answers
2k
views
What happens when a terminal (like a VT100) is connected to a computer?
I'm wondering what's the sequence of actions when a terminal (like a VT100) is plugged into a serial port of a computer? Especially, how the connection of this terminal is detected, and how the ...
CommunityBot
- 1
66
votes
1
answer
10k
views
What's the story behind the name "X11"?
To this day on Linux configs and startup scripts for the GUI system are stored in /etc/X11. I remember this name appearing alone, or alongside others - XFree86, X.org, X - for as long as I had contact ...
- 114k
70
votes
3
answers
9k
views
Why did Unix use slash as the directory separator?
The Unix designers came from the GE/MIT Multics project, and Multics inspired some Unix features. In particular, Multics has a hierarchical filesystem, and so does Unix.
On Multics, pathnames were of ...
- 5,196
15
votes
1
answer
855
views
Why does AT&T syntax use * and $?
In a comment to an answer about AT&T assembly syntax, another-dave asked the following:
DEC used #foo for an immediate operand in -11 assemblers; the Unix guys apparently preferred $foo, which ...
- 745
5
votes
1
answer
507
views
What was the first publication documenting AT&T syntax assembly language?
What was the first publication to document what is (now) known as AT&T syntax assembly language?
- 18.1k
52
votes
10
answers
10k
views
Why was preemptive multitasking so slow in coming to consumer OS's?
Preemptive (rather than cooperative) multitasking was a highly-touted feature for PC's in 1996, with its inclusion in Windows 95 for the first time. It was also highly-touted for 2001 Macs when ...
CommunityBot
- 1
1
vote
1
answer
293
views
Netscape has detected a /.netscape/lock file
My computer is saying that my netscape file is being used by a host that says it is located in Boulder Colorodo. It is coming from a wierd IP address. I just plugged my ethernet cable to use the ...
- 18.1k
13
votes
2
answers
1k
views
Origin of "tarball"
It seems to be common (at least among my section of the world's *NIX users) to refer to "tape archives" made with GNU tar or similar as "tarballs". I always thought this was a slightly odd choice, ...
- 375
6
votes
1
answer
696
views
On the use of the "Code Improver"
Very early C compilers, (mostly K&R C, as seen in UNIX V6, or this compiler for the Atari ST called "Megamax C") came with a "code improver". This was apparently a separate binary, named c2, and ...
- 114k
16
votes
4
answers
3k
views
What determines which architecture an a.out executable runs on?
The ELF file format has an e_machine field in the header, which specifies which ISA the executable expects. And the e_ident structure also has an EI_OSABI field that specifies which ABI the executable ...
CommunityBot
- 1
33
votes
2
answers
5k
views
Why was UNIX never backported to the PDP-7?
Originally, UNIX was written in PDP-7 assembly, and then in PDP-11 assembly, but then when UNIX V4 began to be re-written in C in 1973 and was run mostly on the PDP-11.
So far as I can tell, there ...
- 12.7k
4
votes
2
answers
583
views
Setting up and using UUCP (with analog modems)
These days, of course, we have the Internet, but back in the day, there was Unix to Unix Copy - UUCP. In its heyday it was a terrific way to get email and other simple data moving across the world, ...
- 1,151
2
votes
1
answer
651
views
File system performance and the Unix API
A 1994 book called 'The Design and Implementation of a Log-structured file system' contains the claim "We have implemented a prototype log-structured file system called Sprite LFS; it outperforms ...
- 114k
17
votes
1
answer
5k
views
How many lines of code were in the first Unix version (with the Thompson shell)?
How many lines of code were in the first Unix version (with the Thompson shell)?
Given that the modern Linux kernel has about 15 million lines of code, I do wonder of the amount with the first Unix ...
- 114k
7
votes
2
answers
804
views
Does ancient UNIX create a new shell process for each terminal?
In Linux, each terminal is associated with a new shell process. For example, here I have two xterm terminals, and each xterm terminal has an associated shell process:
I am wondering if in the old ...
- 375
5
votes
2
answers
394
views
Could we change the baud rate for the two serial ports on a terminal and on a computer?
Say we have a terminal (for example: VT100) that is connected to a computer (for example: PDP-11), and UNIX V7 is installed on the computer.
The terminal will have a serial port that is connected ...
- 211
8
votes
2
answers
546
views
Is there anything special about /dev/console?
I am using the SimH emulator to emulate a PDP-11 computer with UNIX V7 installed on it. So basically I am emulating something like this:
I issued the tty command to see on which TTY port my terminal ...
- 7,923
12
votes
2
answers
2k
views
What is the version of Unix and the name of the computer it run on in this 1982 video?
I am learning about the history of computers, and based on what I know so far, Unix was run on a large computer, and in order to use it, you have to use a computer terminal.
Does anybody knows what ...
- 496
6
votes
1
answer
481
views
Can you get the file descriptors of a process in UNIX V7?
In Linux, if I want to get the file descriptors of a process, I would go to the following directory:
/proc/<pid>/fd
But in UNIX V7, the /proc directory does not exist.
- 11.3k