Standards Update, IEEE 1003.4: Real-time Extensions

Chuck.Phillips Chuck.Phillips at FtCollins.NCR.COM
Thu Aug 30 00:01:44 AEST 1990

From:  Chuck.Phillips at FtCollins.NCR.COM (Chuck.Phillips)

>>>>> On 28 Aug 90 11:58:40 GMT, sp at (Simon Patience) said:
>>     Finally, the group accepted abandoning the use of
>>     file descriptors for semaphore handles, but some participants
>>     wanted to keep semaphore names pathnames.
>Aargh!  Almost everyone realizes that System V IPC is a botch, largely
>because it doesn't live in the filesystem.  So what does IEEE do?
>They take IPC out of the filesystem!
>What sane reason could there be to introduce Yet Another Namespace?

Simon> The reason for semaphores not being in the file system is twofold.
Simon> Some realtime embedded systems do not have a file system but do want
Simon> semaphores...

Simon> A good reason for *not* having IPC handles in the file system is to
Simon> allow network IPC to use the same interfaces.

How about adding non-file-system-based "handles" to an mmap-like interface?
(e.g. shmmap(host,porttype,portnum,addr,len,prot,flags)?)  This could
allow the same interface to be used for network and non-network IPC,
without the overhead of a trap for every non-network IPC transaction.

`Scuse me while I don my flame retardant suit...  :-)

#include <std/disclaimer.h>
Chuck Phillips  MS440
NCR Microelectronics
2001 Danfield Ct.
Ft. Collins, CO.  80525   		uunet!ncrlnk!ncr-mpd!bach!chuckp

Volume-Number: Volume 21, Number 72

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