mdc (04/05/83)
c R&V*[ Are there any known versions of execl that allow children to share parental d-space? Our goal is to allow multiple asynchronous processes to communicate through shared external variables. Other, lesser, operating systems seem to be able to perform this feat -- how about UNIX ?
rbk (04/06/83)
Check out 4.2bsd and Bell System V... They both allow sharing of memory space, and don't require common ancestry. Now all you have to do is get 4.2 or System V! Bob Beck Sequel Computer Systems ...teklabs!ogcvax!sequel!rbk
johnl (04/08/83)
#R:rdin:-26600:ima:20400004:000:561 ima!johnl Apr 7 12:41:00 1983 Are there any known versions of execl that allow children to share parental d-space? Our goal is to allow multiple asynchronous processes to communicate through shared external variables. System V has provision for shared "named" read/write memory segments. (I say "named" because the names are 32-bit numbers, making the name space kind of small.) It also has counting semaphores and message queues. What's more, unlike 4.2BSD, it's available right now. John Levine, decvax!yale-co!jrl, ucbvax!cbosgd!ima!johnl, {research|alice|rabbit|amd70}!ima!johnl
guy (04/09/83)
Yup, there are two operating systems that support this; they are called 4.2BSD UNIX, and USG UNIX 5.0 (d/b/a "System V"). 10,000 other people have probably also added shared memory primitives to UNIX (along with multiple-device spoolers, inter-process message mechanisms, etc.), which indicates that such a thing probably belonged there early on.... As more and more people use UNIX for applications more sophisticated than "grep" and "nroff", you will probably find its functionality grow to encompass stuff that greasier operating systems did years ago. It's too bad that to get the relative cleanliness of UNIX you have to sacrifice a lot of functionality or add on private extensions. One of the early USENIX distribution tapes had a shared-memory facility for V6 UNIX; it didn't happen through "exec" (and most of the others don't either), but by attaching to and detaching from a shared-memory segment. Guy Harris RLG Corporation {seismo,mcnc,we13}!rlgvax!guy