Re: tli vs sockets

Art S. Kagel said >Informix supports whichever library, sockets or streams (TLI) is more >efficient on a particular platform. "Efficient" according to who? :-) >Although many UNIXs provide both >libraries the underlying OS only supports one and the other is >implemented as a layer over the other an inherently less efficient. >UNIX variants based on Berkley 4.x support sockets natively and TLI as >an addon. UNIX variants derived from the System V Rel 5.4 code stream >support Streams natively and sockets as an add on. Careful when talking about TLI/sockets. The typical STREAMS network stack used a combined TLI and socket approach in the module with socket calls simply packing their arguments into an array and passing it down the STREAMS stack with an ioctl/STREAMS message. Many vendors actually added one or more system call entry points for socket calls for performance reasons - Wyse did it when they were selling Wyse V/386 _years_ ago, SCO have done it much more recently. In general socket calls are at least as fast as the TLI equivalent and frequently faster - they can have fewer message exchanges, bypass the upper part of the STREAMS stack, and the user level API is much closer to the kernel level API. If you want a laugh run a system call trace on a simple TLI program that does a listen...accept and gaze in wonder at the amount of work that goes on (yeah, the SCO libnsl_s at least is, ah, unoptimized :-) ) >If you recently >upgraded your UNIX, or your Informix version from one originally >written for an earlier version of your OS, the code base may have >changed. SUN OS and SCO for example each changed in the last few years >from a BSD base to a SystemV base. Sun OS didn't change - it was replaced by Solaris which went STREAMS for political reasons. SCO has always been STREAMS based - they used SVR3 with the Lachman stack. More recently (OpenServer 5.0.0 + net100) they added the bypass system call for socket operations. And even more recently they bought Unixware... >You've just got to trust that >Informix made the product better in this way. I have never met anyone who knew what they were talking about who would assert that TLI over STREAMS was more "efficient"! With the way Informix has gone recently they'll have to work hard to win back blind trust anyway :-). Mike -- .----------------------------------------------------------------------. | Mike Jagdis | Internet: mailto:mike@roan.co.uk | | Roan Technology Ltd. | | | 54A Peach Street, Wokingham | Telephone: +44 118 989 0403 |