Under ITS I think they were just separated by a space
According to <anthk@not.dev.null>:
Under ITS I think they were just separated by a space
It was a dot on the DEC PDP-6 monitor that evolved into TOPS-10. I
believe TOPS-10 is where both CP/M and MS-DOS got their filename syntax.
According to <anthk@not.dev.null>:
Under ITS I think they were just separated by a space
It was a dot on the DEC PDP-6 monitor that evolved into TOPS-10. I believe TOPS-10 is where both CP/M and MS-DOS got their filename syntax.
On Tue, 18 Aug 2026 00:07:16 +0000, John Levine wrote:
According to <anthk@not.dev.null>:
Under ITS I think they were just separated by a space
It was a dot on the DEC PDP-6 monitor that evolved into TOPS-10. I
believe TOPS-10 is where both CP/M and MS-DOS got their filename syntax.
Also (around the same time) on the PDP-8 operating system, OS/8 (modelled
on the PDP-6 I think)
Under ITS I think they were just separated by a space
The article doesn?t mention version numbers, which are/were found on
some DEC-proprietary systems: TOPS-10/20, VMS.
On 8/23/26 00:32, Lawrence D?Oliveiro wrote:
The article doesn?t mention version numbers, which are/were found
on some DEC-proprietary systems: TOPS-10/20, VMS.
I found version numbers particularly useful. I guess there are Linux filesystems that support them, but I could never be bothered to
install them.
On 2026-08-23 08:13, Mr. Chang Man-wai wrote:
On 8/18/2026 5:57 AM, anthk@not.dev.null wrote:
Under ITS I think they were just separated by a space
The "dot separator" is just the full-stop symbol in english
language, or the decimal point in mathematics.
In Unix/Linux filesystems, that is so.
On Sun, 23 Aug 2026 07:40:25 -0700, Peter Flass wrote:
On 8/23/26 00:32, Lawrence D?Oliveiro wrote:
The article doesn?t mention version numbers, which are/were found
on some DEC-proprietary systems: TOPS-10/20, VMS.
I forgot to mention RSX ;).
I found version numbers particularly useful. I guess there are Linux
filesystems that support them, but I could never be bothered to
install them.
No. It?s not a POSIX thing.
I dallied for a while with using VCS tools (i.e. Git) for managing
versions of files. Then I came up with something more
snapshot-oriented, <https://gitlab.com/ldo/updoc>, and I have been
trying that out in some of my own content-creation projects. So for
example, I might be working on a CG model in ?example.blend?, and
every time I feel I?ve reached a critical point, I save a snapshot
into the version history file ?example.blend;?.
Note the trailing semicolon on the version history file name; that?s a
homage to DEC?s version numbers ;). Though actually the version
history file can be called what you like.
On Sun, 23 Aug 2026 11:20:45 -0700, Lars Poulsen wrote:
On 2026-08-23 08:13, Mr. Chang Man-wai wrote:
On 8/18/2026 5:57 AM, anthk@not.dev.null wrote:
Under ITS I think they were just separated by a space
The "dot separator" is just the full-stop symbol in english
language, or the decimal point in mathematics.
In Unix/Linux filesystems, that is so.
No. There is nothing in Unix/Linux/POSIX which decrees the name.ext
syntax for anything.
Some tools (e.g. Make) may assume that for determining dependencies.
But the kernel doesn?t care, and nor does most of the userland.
On 24/08/2026 6:07 AM, Lawrence D?Oliveiro wrote:
On Sun, 23 Aug 2026 07:40:25 -0700, Peter Flass wrote:
On 8/23/26 00:32, Lawrence D?Oliveiro wrote:
The article doesn?t mention version numbers, which are/were found
on some DEC-proprietary systems: TOPS-10/20, VMS.
I forgot to mention RSX ;).
I found version numbers particularly useful. I guess there are Linux
filesystems that support them, but I could never be bothered to
install them.
No. It?s not a POSIX thing.
Erm, you do know that Linux people will sometimes, on occasion, imple-
ment something not in the Posix standard?
I dallied for a while with using VCS tools (i.e. Git) for managing
versions of files. Then I came up with something more
snapshot-oriented, <https://gitlab.com/ldo/updoc>, and I have been
trying that out in some of my own content-creation projects. So for example, I might be working on a CG model in ?example.blend?, and
every time I feel I?ve reached a critical point, I save a snapshot
into the version history file ?example.blend;?.
You can also just save a snapshot with ZFS, you know. That also works
on Linux I'm told.
Note the trailing semicolon on the version history file name; that?s a homage to DEC?s version numbers ;). Though actually the version
history file can be called what you like.
You can also do that with Fossil. It's the version control system from
the SQLite team. You can name the /repository/ whatever you like, and
a trailing ; doesn't bother SQLite at all.
On Mon, 17 Aug 2026 23:57:34 +0200, anthk wrote:
Under ITS I think they were just separated by a space
According to Da Wiki <https://en.wikipedia.org/wiki/Filename_extension>:
The article doesn't mention version numbers, which are/were found on
some DEC-proprietary systems: TOPS-10/20, VMS.
On Sun, 23 Aug 2026 11:20:45 -0700, Lars Poulsen wrote:
On 2026-08-23 08:13, Mr. Chang Man-wai wrote:
On 8/18/2026 5:57 AM, anthk@not.dev.null wrote:
Under ITS I think they were just separated by a space
The "dot separator" is just the full-stop symbol in english
language, or the decimal point in mathematics.
In Unix/Linux filesystems, that is so.
No. There is nothing in Unix/Linux/POSIX which decrees the name.ext
syntax for anything.
Unix also copied the dot idea, but purely as a convention: the dot was
just another character that was valid in filenames, ...
Lawrence D'Oliveiro <ldo@nz.invalid> posted:
Unix also copied the dot idea, but purely as a convention: the dot
was just another character that was valid in filenames, ...
Nitpick: The File-System does need to watch out for dot, but not for extensions. It must detect the directory name ".." (and "."?).
This is especially important if the user has been chroot'ed into a
sandbox or play-pen.
On Tue, 25 Aug 2026 15:34:15 -0000 (UTC)
John Levine <johnl@taugh.com> wrote:
Microsoft famously got this wrong, by looking at the contents of the
file to decide how to process it instead of the name, so you can have
a mail attachment called CONTRACT.TXT which is in fact an executable
full of malware.
That's actually not how that works at all. Windows *does* in fact rely
on the filename extension to determine the file type, but starting in
Windows 95 they set it to hide the extension for known file types by
default, presumably because extensions were too confusing for novice
users. But the extension is still there and still counts for the OS's >purposes, even though it's not displayed - so what malevolent parties
will do is name a file e.g. InnocentDocument.txt.exe in the knowledge
that this will display to the majority of users (and especially the
novice ones) as InnocentDocument.txt even though it's actually an EXE
and recognized as such by Windows.
Real genius decision, that :/
According to Mr. Chang Man-wai <toylet.toylet@gmail.com>:
But in the naming method,
which is the file name?
Which is the file name extension? :)
I think the question doesn't make sense. The reason computer files have extensions is to describe the format of the contents: text, executables, spreadsheet, whatever. That makes it a lot easier to select the appropriate software to process them. Microsoft famously got this wrong, by looking at the contents of the file to decide how to process it instead of the name, so you can have a mail attachment called CONTRACT.TXT which is in fact an executable full of malware.
In paper files, it's generally obvious what kind of material is in the folder, or if it's not, it doesn't matter since there's only one way to process it, pull out the file and look at it.
At Mon, 24 Aug 2026 07:27:20 +0800, Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> wrote:
On 24/08/2026 6:07 AM, Lawrence D?Oliveiro wrote:
On Sun, 23 Aug 2026 07:40:25 -0700, Peter Flass wrote:
On 8/23/26 00:32, Lawrence D?Oliveiro wrote:
The article doesn?t mention version numbers, which are/were found
on some DEC-proprietary systems: TOPS-10/20, VMS.
I forgot to mention RSX ;).
I found version numbers particularly useful. I guess there are Linux
filesystems that support them, but I could never be bothered to
install them.
No. It?s not a POSIX thing.
Erm, you do know that Linux people will sometimes, on occasion, imple-
ment something not in the Posix standard?
I dallied for a while with using VCS tools (i.e. Git) for managing
versions of files. Then I came up with something more
snapshot-oriented, <https://gitlab.com/ldo/updoc>, and I have been
trying that out in some of my own content-creation projects. So for
example, I might be working on a CG model in ?example.blend?, and
every time I feel I?ve reached a critical point, I save a snapshot
into the version history file ?example.blend;?.
You can also just save a snapshot with ZFS, you know. That also works
on Linux I'm told.
Note the trailing semicolon on the version history file name; that?s a
homage to DEC?s version numbers ;). Though actually the version
history file can be called what you like.
You can also do that with Fossil. It's the version control system from
the SQLite team. You can name the /repository/ whatever you like, and
a trailing ; doesn't bother SQLite at all.
For lightweight version control, I use RCS -- and if I need something
more heavy-duty, there's git.
By convention, a computer filename is the whole string identifying the
file, but can also be used to describe the substring that is everything
up to the extension (and its separator). The extension is everything
after the last separator.
Unix is the OS that uses "magic" (special bytes at offset 0) to
decode what a file is ... you can specify which shell is to execute
a script, for instance. (Linux has also adpted this technique.)
Microsoft is famous for trying to open a binary file in a text
editor because it has a .txt extension.
On Tue, 25 Aug 2026 11:22:58 -0700, Snidely wrote:
By convention, a computer filename is the whole string identifying the
file, but can also be used to describe the substring that is everything
up to the extension (and its separator). The extension is everything
after the last separator.
On *nix systems, there is a command called ?basename? to remove any
directory prefixes from a pathname, and also optionally any suffix.
On 8/25/2026 11:34 PM, John Levine wrote:
I think the question doesn't make sense. The reason computer files have
extensions is to describe the format of the contents: text, executables,
spreadsheet, whatever. That makes it a lot easier to select the appropriate >> ....
In paper files, it's generally obvious what kind of material is in the
folder, or if it's not, it doesn't matter since there's only one way to
process it, pull out the file and look at it.
Because computer file names are text, NOT the
actual physical objects seen with your naked
eyes. ...
You were too young as a computer users.
I lived the days when there were only
text in computers. Database files are
just texts and textual labels. :)
John Levine˙ scribbled something on Tuesday the 8/25/2026:
According to Mr. Chang Man-wai <toylet.toylet@gmail.com>:
(crossposting put on a diet)
But in the naming method,
which is the file name?
Which is the file name extension? :)
By convention, a computer filename is the whole string identifying the
file, but can also be used to describe the substring that is everything
up to the extension (and its separator).˙ The extension is everything
after the last separator.˙ In MSDOS days ... and other simple file
systems,˙ like the CP/M ancestor of FAT ... the extension was the 3 characters that fit into the directory entry structure field labeled "extension".
I think the question doesn't make sense. The reason computer files have
extensions is to describe the format of the contents: text, executables,
spreadsheet, whatever. That makes it a lot easier to select the
appropriate
software to process them. Microsoft famously got this wrong, by
looking at the contents of the file to decide how to process it
instead of the name, so you can have a mail attachment called
CONTRACT.TXT which is in fact an executable full of malware.
I don't think this is what Microsoft did.˙ Unix is the OS that uses
"magic" (special bytes at offset 0) to decode what a file is ... you can specify which shell is to execute a script, for instance.˙ (Linux has
also adpted this technique.)
Microsoft is famous for trying to open a binary file in a text editor because it has a .txt extension.
In paper files, it's generally obvious what kind of material is in the
folder, or if it's not, it doesn't matter since there's only one way to
process it, pull out the file and look at it.
There are plenty of situations where a librarian is dependent on a
subject matter expert to identify what a book or paper file is.˙ And
they may need help to identiify which expert is needed.
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