Open VMS VAx 7.1 Mailbox index number

[Rajarshi Gupta]

Do you please let me know the maximum index number of VMS mailbox in OPEN VMS VAX 7.1. The VMS mail boxes are used for inter process communications.

[Ian Miller.]

I think MBA9999 is the limit for V7.1.
I seem to remember this being raised to 32000 in a recent version of VMS but can't find the reference at present.

[Rajarshi Gupta]

Can any body please confirm in which version of Opne VMS VAX the maximum mail box number is raiesd to 32000.

[Kris Clippeleyr]

According to my info (picked it up during the TUD held in October 2004), the maximum number is 32767 starting from OpenVMS Alpha V7.3-2. I don't think engineering increased this number for any flavor of OpenVMS VAX.
Regards,
Kris (aka Qkcl)

[Rajarshi Gupta]

Hi,

Any one can please forward link for this, where the details of maximum nubmer of mail boxes in Open VMS explained

[Volker Halle · Accepted solution]

Rajarshi,

here is a pointer to the presentation from the German TUDs 2004:

http://www.decus.de/sig/vms/TUD_2004/Hints.pdf

On page 5 you'll find:

V7.3-2 Unit Limits Increasedâ ¦
â ¢Increase limit from 9999 to 32767 units
â Used for MB (mailbox) and BG (IP) devices


I could not (yet) locate a reference in the V7.3-2 release notes.

[Kris Clippeleyr]

See:
info on $CREMBX at
http://h71000.www7.hp.com/doc/732FINAL/4527/4527pro_001.html#index_x_245
and info on $GETDVI at
http://h71000.www7.hp.com/doc/732FINAL/4527/4527pro_004.html
And for additional info on the TCP/IP scalable kernel, and number of supported BG devices, see:
http://h71000.www7.hp.com/doc/732FINAL/TCP_RN/tcp_rnpro_001.html#bg_devices
Regards,
Kris (aka Qkcl)

[Ian Miller.]

To use a famous phrase "what problem are you trying to solve?" Are you just curios as to what the limit is or do you have a system which you think is running into this limit?

[Rajarshi Gupta]

Yes I have a system which has reached in this limit and necessary to increase further

[Volker Halle]

Rajarshi,

consider upgrading to OpenVMS Alpha or Itanium. Don't expect this feature to ever show up on VAX...

Volker.

[Uwe Zessin]

Interesting, I would have bet that it was 32767. 'Magic values' based on 9s are usually used in an IBM environment, but my guess is that another 'optimization' was used:

-MBA9999:
-12345678

Again, 8 characters which nicely fit in a quadword. Is that right, Volker?

[labadie_1]

Uwe

The BG device have been limited to 9999 until Tcpip 5.4, where they can reach 32767

[Uwe Zessin]

BG devices cannot be compared with MBA devices, because they get cloned by a special kernel routine from BG0: (do a SHOW DEVICE and you'll see that it is a template). That routine did limit the unit number to 9999. Same with LTA devices, for example.

[Jan van den Ende]

Uwe,


That routine did limit the unit number to 9999. Same with LTA devices, for example.


Do I mis-read that, or did you phrase it inaccurate?

I tend to conclude from your text that LAT is also extended to LTA32767:, but under V7.3-2 it really still is LTA9999: (just tested that).

(not trying to solve serious problems, just curious)

fwiw,

Proost.

Have one on me.

jpe

[Uwe Zessin]

Hello Jan, welcome back.

No, I didn't intend to suggest that the LAT unit numbers were enhanced as well. I don't know and I don't try to track such details any longer.

[Volker Halle]

Uwe,

the UNIT number of a device is stored in the UCB in UCB$W_UNIT (a WORD). This field has just been expanded to a LONGWORD (UCB$L_UNIT) in V8.2 - you need a major release to do something like this.

Unit numbers on OpenVMS have 'always' been between 0 and 9999 (just checked the VAX/VMS IDSM, which is written based on V5.2).

There is even a bit in the V8.2 DEVICE_NAMING SYSGEN parameter to limit unit numbers to 10k: SGN$M_MAX_UNITS_10K (to retain the old behaviour).

I believe TCPIP BG devices were the driving force behind this change/expansion, as customers ran into this limitation on WEB servers.

Volker.

[Kris Clippeleyr]

Good morning guys,
According to my info, the increase from 9999 to 32767 is for BG and MBA devices only.
Greetz,
Kris (aka Qkcl)

[Rajarshi Gupta]

Guys,

I found in HP OpenVMS System Services Reference Manual of OVMS7.3-2 in the section $CREMBX

Mailboxes are assigned sequentially increasing numbers (from 1 to a maximum of 9999) as they are created. When all unit numbers have been used, the system starts numbering again at unit 1. Logical names or mailbox names should be used to identify a mailbox between cooperating processes.

In the follwing Link
http://h71000.www7.hp.com/doc/732FINAL/4527/4527pro_001.html#index_x_246

Could any body know about it.

[Volker Halle]

From OpenVMS V8.2 Release Notes:

http://h71000.www7.hp.com/DOC/82FINAL/6674/6674pro_sm.html

4.6 Device Unit Number Maximum Increased
V8.2

In the past, OpenVMS would never create more than 10,000 cloned device units, and unit numbers would wrap after 9999. This had become a limitation for some devices, such as mailboxes or TCP/IP sockets.

Starting with OpenVMS Version 7.3-2, OpenVMS will create up to 32,767 devices if the DEV$V_NNM bit is clear in UCB$L_DEVCHAR2 and if bit 2 is clear in the DEVICE_NAMING system parameter. This does not require any device driver change. However, programs and command procedures that are coded to assume a maximum device number of 9999 may need to be modified.


Volker.

[Rajarshi Gupta]

Guys,
Sub: PLOYCENTER to monitor contigious disk space.

Can any body known "Is it possible to monitor the contigous disk space in VAX VMS version 7.1 using POLYCENTER Monitoring tool"

Please provide the refernce link and case details if possible

thanks in advance

[Volker Halle]

Hi,

please open a new topic for your question, as it does not belong to the subject of this entry.

Thanks,

Volker.