Re-use template device numbers (e.g. RTA1)

[Steve Reece_3]

Hiya,

I seem to recall in my dim and distant past that there was a SYSGEN parameter which determined whether a template device should allocate a new number to a device like RTA or whether it would reuse device numbers.

so, if I connected via SET HOST FRED, logged out, then did SET HOST FRED again, the same RTA device number wasn't reused - the system allocated RTA1: the first time, RTA2: the second, then carried on allocating new device numbers until the wrap around of 9999 was reached and then restarted at 1.

Was I dreaming this? If not, what SYSGEN parameter controlled it please?

Thanks in advance.

Steve

[RBrown_1]

>>>>
so, if I connected via SET HOST FRED, logged out, then did SET HOST FRED again, the same RTA device number wasn't reused - the system allocated RTA1: the first time, RTA2: the second, then carried on allocating new device numbers until the wrap around of 9999 was reached and then restarted at 1.
<<<<

That is the behaviour I remembered and expected, without having to do any special settings.

I am on VMS 7.1 on alpha.

This is what I found when I actually tried it:

o with RT, it reused the unit number --- I logged into RTA1 twice in a row.

o with TN (telnet), it incremented the unit number each time --- logged in to TNA44, disconnected and logged in again, this time I was on TNA45.

o with LT, it double-incremented the unit number --- first I logged in to LTA5009, next to LTA5011, and then to LTA5013!

Once again, it seems, "it depends".

[Phil.Howell]

It could be the DEVICE_NAMING parameter, but documentation on its values seems hard to find.
Phil

Also see
http://forums13.itrc.hp.com/service/forums/questionanswer.do?&threadId=1074590

[Jur van der Burg · Accepted solution]

There's no such parameter. Decnet is not using a template device (it's handled differently) so you will see a re-use of unit numbers.

Other devices like LAT and TELNET use a template device (there's a unit 0). It is used by assigning a channel to LTA0 for example, and in return a new device is created from that unit with a new unitnumber which is taken from a seed value in the template device's ucb. Normally you will get an increasing unit number, but drivers can play tricks to get the desired unit (LDdriver uses that trick).

Jur.

[Steve Reece_3]

Thanks Jur. That's what I feared but hoped wasn't the case.

[Steve Reece_3]

Jur provided the answer on this so closing the thread.
Thanks Jur.