[HECnet] Others DECnets

[Johnny Billquist]

Hmm, which wouldn't neccesarily result in the same thing...
Named objects use object #0, and then you specify the object name, which for instance in RSX means the task name.
Now, I don't even think numbered objects and named ones are handled the same way in RSX, since numbered objects are usually in the form NNN$$$, where $$$ is replaced by a number, for the service to be able to run several instances in parallel. I don't think this $$$ replaced by a number ever is done for named objects.
Also, the name of the task used for a service is not standardized. So, the mail service task name can be anything. All you know is that it is #27.
So, trying to talk with an named object called MAIL might cause to you to talk with just about anything.

In RSX, the known objects of my system looks like this:
.ncp sho kno obj

Known objects summary as of 4-DEC-09 16:07:24

Object   Name       Copies   User         Verification

0                             Single   Default   Off
15           TCL...   Single   Default   On
16           LSN$$$   5             Default   Off
17           FAL$$$   8             Login       On
18           HLD...   Single   Default   Off
19           NIC$$$   5             Default   Inspect
23           RMHACP   Single   Default   Off
25           MIR$$$   5             Default   Off
26           EVR$$$   5             Default   Off
27           MAL$$$   8             Default   Off
29           PHO$$$   5             Default   Off
42           RTH         Single   Default   Off
63           DTR...   Single   Default   Off

So, trying to talk to MAIL would simply just fail, unless there is a MAIL task installed, in which case that will be started. What program that might be, and what it might do is beyond guess, but most likely not what a programmer of a remote system might have expected, if he tried to talk to an object called MAIL, thinking that was the right way to talk with a MAIL-11 server accepting mails.

	Johnny



Paul Koning wrote:
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On
Behalf Of Johnny Billquist
Sent: Friday, December 04, 2009 6:45 AM
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] Others DECnets

Hi.

Ian McLaughlin wrote:
Here's where I read about hidden areas:

http://labs.hoffmanlabs.com/node/271
Hmm. Interesting article, although slightly wrong or imprecise
perhaps.
What they refer to as "named objects" are actually numbered objects.
Named objects are the ones which aren't predefined in any way, and are
for random program communications.

For instance, MAIL is never refered to by a name, but instead by it's
number, which is 27. All "well known services" have specific numbers
assigned to them.
Yes and no.   It's certainly true that well known services have object
numbers assigned to them (DEC ones are in the range 1-127, and 128-255
are reserved for customer use).   However, the object identifier in the
connect message can be either a number or a name.     So while normal
practice would be to connect to mail by connecting to object 27, it's
also valid to connect to object "MAIL".
	paul