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From: Paul Winalski <paul.winalski@gmail.com>
To: tuhs@tuhs.org
Subject: [TUHS] Re: Pipes (was Re: After 50 years, what has the Impact of Unix been?)
Date: Thu, 5 Dec 2024 12:22:05 -0500	[thread overview]
Message-ID: <CABH=_VTq9a8LSf+CE6dQ2wXL3es6A=JCUaY_zSfTtiPV9w-Jew@mail.gmail.com> (raw)
In-Reply-To: <c9e880b1-e9b6-430d-ba95-8bad10607cbf@osta.com>

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Regarding pipes and pipe-like interprocess communications facilities in
other operating systems, VMS has always had a pipe-like communications
pseudo-devices called mailboxes.  The main difference between Unix pipes
and VMS mailboxes is that pipes have distinct read-only and write-only file
descriptors.  Mailboxes do not--channels (VMS-speak for file descriptors)
assigned to a mailbox can be used for both reading and writing.  This means
that it is not possible to do "broken pipe"-type detection on a mailbox.
This very much restricts the usefulness of mailboxes.

I wrote a true pipe device driver for VMS as part of the DEC Shell product
(a port of the Unix Bourne shell to VMS).

-Paul W.

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  parent reply	other threads:[~2024-12-05 17:22 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-04  3:17 [TUHS] After 50 years, what has the Impact of Unix been? sjenkin
2024-12-04 13:05 ` [TUHS] " Marc Donner
2024-12-04 13:40   ` William Cheswick
2024-12-04 15:02   ` Rich Salz
2024-12-05  3:08   ` John Levine
2024-12-05 15:19     ` [TUHS] Re: Pipes (was Re: After 50 years, what has the Impact of Unix been?) Dan Cross
2024-12-05 16:00       ` John R Levine
2024-12-05 16:17         ` Heinz Lycklama
2024-12-05 17:06           ` Marc Rochkind
2024-12-05 17:53             ` John Cowan
2024-12-05 18:05             ` John Levine
2024-12-05 17:22           ` Paul Winalski [this message]
2024-12-05 18:19         ` Ron Natalie
2024-12-06  2:29           ` Adam Thornton
2024-12-07 20:38             ` Ron Natalie
2024-12-05 16:55       ` Adam Thornton
2024-12-05 17:35       ` Chet Ramey via TUHS
2024-12-05 20:55         ` arnold
2024-12-05 21:12           ` Dan Cross
2024-12-05 21:50             ` Marc Rochkind
2024-12-05 22:03             ` Warner Losh
2024-12-05 22:19               ` Chet Ramey via TUHS
2024-12-05 23:07                 ` Marc Rochkind
2024-12-06  8:16                   ` Diomidis Spinellis
2024-12-06  0:46                 ` Alexis
2024-12-06 21:46                   ` Chet Ramey via TUHS
2024-12-05 23:07               ` arnold
2024-12-06  1:09                 ` G. Branden Robinson
2024-12-06  1:31                   ` Greg A. Woods
2024-12-06  2:05                     ` Steve Nickolas
2024-12-06 16:44                     ` arnold
2024-12-05 22:05             ` Bakul Shah via TUHS
2024-12-06  2:02             ` John Levine
2024-12-06  2:21               ` Dan Cross
2024-12-06 16:46                 ` arnold
2024-12-06  2:26 Douglas McIlroy

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