Mark, et al. The web page does indeed describe the changes in the LE C sockets code which were delivered in z/VM 4.4.0. Actually, those C sockets changes were made late in LE 1.8 and shipped with either z/VM 4.2.0 or 4.3.0 (I don't remember exactly). The major difference between the LE 1.8 and z/VM 4.4.0 implementations of the C sockets code was the DNS resolver used by each of these sockets libraries. The older LE 1.8 code contained its own internal resolver functions. In z/VM 4.4.0, the DNS resolver was moved out of the LE C code to a separate set of callable services library (CSL) routines. These CSL routines appear in the CMS VMMT library as the EZB1xxxx routines. These routines use socket ids which are POSIX byte file system file identifiers. The latter is the cause of the increased virtual storage requirement.
In z/VM 5.1.0, PING and TRACERTE were rewritten in C in order to pick up the IPv6 support already included in the LE C sockets code. This rewrite made these two applications LE-based and this incurred the storage overhead mentioned on my little LE FAQ page. Additionally, the DNS resolver used by other, PASCAL-based clients was redone to use CMS CSL based resolver functions (EZB1xxxx). Thus, when any call is made to the resolver, you incur the storage hit described on that web page. I'm thinking I need to add this to the list of reasons for increased storage use. Hopefully this help explains why you are seeing differences when moving from z/VM 4.4.0 to z/VM 5.x.0. The LE C code changes shipped in z/VM 4.4.0, but the "exploiters" did not ship until z/VM 5.1.0. If you have any other questions, please let me know. Thanks! Mike Donovan Mark Bodenstein <[EMAIL PROTECTED] > To Sent by: The IBM IBMVM@LISTSERV.UARK.EDU z/VM Operating cc System <[EMAIL PROTECTED] Subject ARK.EDU> Re: zVM 5.3 TCPIP memory problem 09/17/2007 04:01 PM Please respond to The IBM z/VM Operating System <[EMAIL PROTECTED] ARK.EDU> Mike, Thanks for the information. I work with Jim and am also trying to understand the differences in memory use of the z/VM 5.3 TCP/IP clients compared to the z/VM 4.4 ones. The web page you reference talks about C sockets library changes, but says these were already present in z/VM 4.4. The difference we're seeing is between 4.4 and 5.3. So does this apply? I also wonder because we're seeing this with ftp and telnet, which aren't mentioned on your web page as using the C socket library. (Do they?) I've done some more testing, and find that the 5MB or so additional memory use that we're seeing only happens when there is a DNS lookup involved. So if I do "ftp cornellc.cit.cornell.edu" I see the additional memory use, but if I do "ftp 132.236.98.12" I don't. Similarly "ftp loopback" doesn't cause the additional memory use. I see the same thing for lpr: lpr profile exec (p raw at cornellc.cit.cornell.edu causes the additional memory use, while lpr profile exec (p raw at 132.236.98.12 does not. So what is there about DNS lookup that causes this memory use, while otherwise the clients don't suck up virtual storage? Thanks, Mark Bodenstein ([EMAIL PROTECTED]) Cornell University