Questions tagged [unix]
For questions about the Unix operating system.
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Origin of UNIX symbolic links?
When I search the web for information about the origin of UNIX symbolic links, I see "Symbolic links were first introduced into Unix with 4.1c-BSD". But when I go to fact check that, it ...
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Which historical Unixes supported terminal I/O with five or six bits per character, and with what character sets?
The specification for termios.h includes a facility for controlling the number of bits per character sent over the serial line, the CSIZE and CSn constants. You can request five, six, seven, or eight ...
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Why does cat with no argument read from standard input?
In advice about how to design good CLI commands I read:
If your command is expecting to have something piped to it and stdin is an interactive terminal, display help immediately and quit. This means ...
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when did command line applications start using "-h" as a "standard" way to print "help"?
I am interested to hear about the history because I have a prominent command line product that has decided to use -h for something that does not print a help message.
when did command line ...
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What is the history of SysV i386 calling convention for struct return?
I would like to understand historical roots of the quirk in the SysV calling convention for the 32-bit x86, which was inherited by the ELF standard, and so remains used on Linux to this day. Consider ...
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Why does -z and -n exist in most shells and /bin/test?
The test command on Unix-like systems provides two special syntax forms for checking whether a string is empty or not:
test -z "$foo" # the length of $foo is zero
test -n "$foo" # ...
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Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded?
Quoting from Jim Hall's "FreeDOS turns 25 years old: An origin story":
Around 1994, Microsoft announced that its next planned version of Windows would do away with MS-DOS. But I liked DOS. ...
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Correct pronunciation of `vi` (Unix editor)?
According to this video with Brian Kernighan, the correct pronunciation of the classical Unix editor ed is "Eee. Dee." — not "Edd".
So that made me wonder — what about the other ...
CommunityBot
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Circuit design tool mentioned in AT&T Unix promotion
In this video from AT&T about Unix is a circuit design tool displayed that is claimed to be based on YACC (timestamped link).
Does anyone have information about this tool?
Like:
Documentation
...
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What software stack could I use to get X10 (the version of X before X11) up and running on a modern system?
"What's the story behind the name "X11"?" showed up in the sidebar while I was browsing stackoverflow earlier and I noticed the question getting some high-signal answers, so I added a ...
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How did Bell Labs start to work on Project MAC?
Did Bell Labs approach MIT or was it the other way around? Did participating in Project MAC come from researchers requesting management at Bell Labs/MIT or did management make the decision due to ...
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Mainframe Hater's Handbook?
The famous The UNIX-HATERS Handbook claims this mailing list had been inspired by TWENEX-HATERS(1) and other *-LOVERS mailing lists, a long tradition of MIT.
Moreover, the quote below implies there ...
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When did SunOS get a graphical interface?
I understand that the first graphical user interface for SunOS was SunTools (later renamed to SunView), but I cannot find any documentation that states when it was released and for which versions of ...
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How could early UNIX OS comprise so few lines of code?
I start my journey to become a hardware / software specialist with an internship in two weeks time and decided to start studying the C language early.
I came across this video, Learn C Programming ...
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Why does UNIX ed not have a prompt by default
The line editor ed in UNIX/Linux has a "command mode" and an "insert mode" and there is no visual way to tell which mode you are in. However, there is a -p option that causes it to display a prompt ...
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What happened to all those Unix workstations in the '90s?
Around the early to mid '90s it seems there was a trend for high-end workstations running some form of Unix, and running a RISC or at least some kind of non-x86 architecture. For example:
Sun ...
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Why is the Unix epoch January 1st 1970?
In honor of this weekend being 1,600,000,000 (1.6 billion) seconds since the Unix epoch, I was wondering if anyone knows why January 1st 1970 was chosen?
According to Wikipedia,
The earliest versions ...
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Can you remember the name of a public access Unix system, around 1990/1, Spug or Spud?
Hey I recall accessing a public-access UNIX system in the UK, likely around 1990/91.
I seem to recall it gave you shell access but it might actually have only been Mail or UUCP/usenet client?
I have a ...
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Why is Windows using CR+LF and Unix just LF when Unix is the older system?
Windows and MS-DOS use the control characters CR+LF (carriage return, line feed) for new lines, while Unix uses just LF.
As far as I know CR+LF made sense for systems controlling a real teletypewriter,...
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What were the Major Public Access Unix Systems Available in the 1980s-90s?
Back in the 1980s-90s, using a UNIX system required running expensive servers or paying for timesharing service, so they were beyond the reach of most individuals, and only available to members in ...
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Was The Telemark Assembler available for the Unix or Mac Environments?
I'm trying to build the recently released Infinity Game Boy Color source code on my macOS El Capitan box. The original development environment was a Windows box, and I'm trying to modify the build ...
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What was the original unix font?
I'm looking for a font for a tattoo. I don't have any preferred font so I thought using the original Unix font could be a great reference to the great history. Can't find any reliable information ...
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Where and when did the ".s" suffix for assembly-language source files originate?
The closest I was able to find on StackOverflow is What are .S files?, in which no answerer addresses why we use .s for assembly. (And .S for preprocessor/macro assembly; and gcc -S to produce ...
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Slash versus backslash as directory separator – what/who caused this rift?
MS-DOS and derived systems use backslash \ for path separator and slash / for command parameters. Unix and a number of other systems used slash / for paths and backslash \ for escaping special ...
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What was the purpose of those special user accounts in Unix?
In a modern Linux system – modern enough to have upgraded useradd to a version from no earlier than February 2008 – it is usually the case that user accounts with UIDs no less than 1000 (other than ...
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Oldest UNIX I can run on my modern system?
What is the oldest UNIX(-like) system that can be legally downloaded and run (in a VM or emulator) on a modern PC (running Linux)?
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What does this image in Space Travel represent?
I was touching up the Space Travel article on the Wiki and realized no one had answered a question I posted some time ago. I suspect someone here knows the answer.
This image is used in the infobox to ...
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How should we interpret Dave Cutler's criticism of Unix?
Dave Cutler is well known for his contributions to operating systems, having led the effort on VAX VMS at DEC and Windows NT at Microsoft. According to his Wikipedia page, he is also known for ...
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Is the SimH emulator available on macOS?
Is the SimH emulator available for macOS? I can't find it on their website: http://simh.trailing-edge.com/
What I am specifically interested in is to run UNIX V7 on a PDP-11 emulator.
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Early implementations of the `system()` call in a consumer OS
Nowadays, it's easy to take for granted the system() call (as defined in POSIX), which allows a user program to easily execute a child process and wait for it to complete. Obviously, this is a trivial ...
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Process model in early UNIX
I heard recently that the process model in very early variants of UNIX was quite a bit different to the fork/exec model used nowadays.
How did it differ from the current state?
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Why did Dennis Ritchie write that UNIX was a modern implementation of CTSS? [closed]
At the Tenth Hawaii International Conference on the System Sciences in 1977 Dennis Ritchie presented the paper The Unix Time-sharing System: A retrospective in which he states:
...a good case can be ...
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Small format X terminal with EL screen
I remember an ad for a small-format (about as wide as a 60% keyboard) dark-ish grey colored X terminal that had a 12" (?) yellow electroluminescent screen similar to the Grid laptops but higher ...
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Nontrivial B program
I have been able to find very little about the B programming language online. the predominant resources seem incomplete, particularly in regards to standard library functions. I have not been able ...
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Which Linux or BSD distributions do still support i386, i486 or i586 CPUs?
Unfortunately Debian kicked out Pentium 1 (i586) CPU support from its 32-bit PC port (named i386 for historic circumstances) for its next stable release Debian 9 Stretch. (Then again they complain ...
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What environment was Coherent developed with?
Coherent was a Unix clone for IBM compatibles Mark Williams Company produced and sold in the 1980s and early 1990s.
What environment and tools was Coherent developed with? Was it cross-developed on ...
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Why did this joke man page use July 16, 1974 as an epoch?
This fake manual page posted to the comp.humor newsgroup jokes that
A.out accepts any option passed to it, stalls for a few
seconds, and then prints a cryptic message chosen from the
list below. The ...
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When did an overlay linker first appear in a PDP-11 UNIX OS?
On a 16-bit system with at most 64K of RAM available for a user program, one would think of having an executable overlay mechanism as an indispensable tool to maximize the amount of memory available ...
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How did early Minix represent processes
Minix, as most know, is a "Unix-like" OS originally used for teaching. Early Minix (v1 and, apparently, v2) ran on the 8088/6 series of processors. It could run on the IBM XT.
There have ...
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What is the simplest UNIX system with a MMU?
I was recently looking at a Motorola 68010 and 68451 that have been in some ESD foam on a shelf for a very, very long time. Now, things are all so huge in memory, but BSD4.4-Lite can run in only 256k ...
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How did Unix handle multiprocessing when virtual memory didn't exist?
It seems the first "real" virtual memory management system was the i386 with its powerful paging system that totally isolates processes. How did Unix work before this, ensuring no process ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 (...
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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 ...
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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,...
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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 ...
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