James A. Landau JJJRLandau at AOL.COM
Thu Aug 2 00:13:41 UTC 2001

In a message dated 08/01/2001 11:23:28 AM Eastern Daylight Time,
JBaker at STRADLEY.COM writes:

>         Hmm, I was under the impression that Jesse asked for the use of
>  "dot" in computing, not just in filenames.  I guess that narrows the time
>  period down to the introduction of higher-level languages in the 1950s and
>  1960s (I don't know if the first higher-level languages used dots in
>  filenames or not), but no later than the introduction of Unix in 1969.

Nothing to do with higher-level languages.  Filenames with or without dots
are under the jursidiction of the operating systems.  Operating systems were
not widely used until the 1960's and very few of them existed until the late

Also filenames were not needed until the availability of large quantities of
DASD (direct-access storage devices, of which the floppy disk/diskette is an
example) and this did not happen until circa 1960.  Before DASD a user kept
his data as punch cards, paper tape, or magnetic tape, and did his own filing
without the use of a standardized operating system filename feature.

I have no idea whether they were called "dots", but IBM developed a
hierarchical filename system for the OS/360 operating system (I am citing a
1965 manual) in which periods/dots separated the levels of the hierarchy.
Other vendors may have done similar things; I only happen to know about IBM
because I worked with IBM systems.

DEC (Digital Equipment Corporation, now part of COMPAQ) was the leading
intellectual competitor of IBM for many years.  By "intellectual competitor"
I mean that almost everything was done either IBM-style or DEC-style, with
little mercy shown by either camp towards the other.  DEC, to the best of my
knowledge, introduced the multi-part filename, in which one part identified
the file and the other described what kind of file it was.  The two parts
were separted by a period.  UNIX is part of the DEC camp.  UNIX used a
hierarchical system, with hierarchical levels separated by slashes (/) and
then the lowest level has the DEC-style two-part name with the period
separating the two parts.  When microcomputers came out, the popular CP/M
operating system used the DEC style.  Then the IBM PC (and clones) came out,
with Bill Gates's MS-DOS operating system, which used the UNIX style except
that MS-DOS uses back-slashes (\) instead of forward slashes (/).  Again the
lowest hierarchical level used a period to separate the two parts.

The above says nothing about periods being called "dots" but does date the
period as having become important, both from the IBM and DEC camps, circa the

Another question: when did the diagonal line start being called a "slash"?
This usage is also well-nigh universal among English-speaking programmers.

I can personally attest to the exclamation point being called "bang" in 1982,
on the Hewlett-Packard 1000.

There is one term which does not yet exist but hopefully will appear soon.  I
would like a one-syllable synonym for the underscore ( _ ) character.  For
better or worse (in my personal and not-so-humble opionion, definitely worse)
the underscore has become well-established in computers since circa 1970,
with UNIX and the PASCAL language being two of the worst offendors and most
prolific perpetrators.

        - Jim Landau
          Systems Engineer
          FAA Technical Center (ACT-350/BCI)
          Atlantic City Airport NJ 08405 USA

P.S.  Air traffic controllers have their own jargon.  The forward slash (/),
widely used in the controller-computer interface, is called a "slant" (the
back-slash is not used by controllers, for the simple reason that it is not
on their keyboards).  The asterisk (*) is a "splat".

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