How to find the maximum uid that can be assgined?

[Crystal_1]

Hi,

Does any one how to find the maximum uid that can be assigned to a new user?

Tx, Crystal

[Rodney Hills]

It use to be 65535 (2^16-1)

Don't know if it has changed.

-- Rod Hills

[Steven Mertens]

hi,

I'm not sure, but is it possible its
defined by UID_MAX ?


UID_MAX
has an
HP-UX
value of
2147483647 + ,
which means that on all
HP-UX systems the smallest unattainable value for a user or group
ID
is at least 2147483647.
A particular system might be capable of supporting
more than 2147483647 user or group
IDs,
in which case its
file sets
UID_MAX
to a higher value; however, any application
assuming such a higher value is not guaranteed to be portable to all
HP-UX
systems.

regards

Steven

[harry d brown jr]

Which OS?

And even with a 64bit OS, some applications might not like large UID's, of which informix comes to mind with their older versions.

live free or die
harry

[Steven Mertens · Accepted solution]

see also :

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90682/B2355-90682_top.html&con=/hpux/onlinedocs/B2355-90682/00/03/314-con.html&toc=/hpux/onlinedocs/B2355-90682/00/03/314-toc.html&searchterms=UID_MAX&queryid=20020719-113712

The following fields have numerical limitations as noted:
The user ID is an integer value between -2 and
UID_MAX
inclusive.

The group ID is an integer value between 0 and
UID_MAX
inclusive.

Steven

[S.K. Chan]

The max amount of uids is defined by MAXINT. Check the file /usr/conf/sys/param.h and you'll see it's set to hex value 0x7fffffff which is over 2 billion, to be exact 2,147,483,647. But since root is 0, the correct number should be (MAXINT-1).

[Crystal_1]

Hi,

I am working on a script to generat a specific uid for all users.

I have found a number of 2147483647 for HP-UX. However, I am not sure :

1. if differet O/S has different max_uid?
2. if different bit O/S has different max_uid?
3. where I can find the defined max_uid on a hp-ux 11.x system?

Tx

[A. Clay Stephenson]

The value is 2^32 - 1 BUT for compatibility reasons especially in an NIS/NIS+ multi-platform environment I would keep them below 64K. At one time, SAM in 10.20 at least wouldn't allow a UID greater then 59,999.

Some versions of NFS also have problems with large uid's.

Unless you have a compelling reason to use uid's > 60K, I would avoid them.

[Steven Mertens]

here you can find all the man pages for
hpux :

http://docs.hp.com/hpux/onlinedocs/B2355-90682/B2355-90682.html

[Crystal_1]

A.Clay,

How can u know it is 2^32-1, it is not 2^31?

Crystal

[James R. Ferguson]

Hi Crystal:

Be careful if you use values > 60K. As noted in the 'tar' man pages: "tar does not
support the archival of files larger than 2GB or files that have user/group IDs greater than 60K. Files with user/group IDs greater than 60K are archived and restored under the user/group ID of the current process."

This also applies to 'cpio' and 'pax'.

Regards!

...JRF...

[A. Clay Stephenson]

You are correct! That was a typo on my part. It should be 2^31 - 1 --- the maximum value of a 32-bit two's complement integer.

[Wodisch_1]

Hi Crystal,

for quite som etime now (pre Y2K, IIRC) user-ids can be 32bit (instead of the old 16bit ones). What happens is, when the first file is owned by a user-id > 65535 the whole file-system is silently converted to use 32bits for owner/group for ALL I-nodes...

HTH,
Wodisch