gpw@ihuxa.UUCP (George Wilkin) (06/07/84)
I know little of UNIX internals but somehow got lassoed into doing a study of 11/70's vs 11/780's. Hopefully someone out there can help, thanks in advance. I am in need of information on the differences between System V UNIX* on an 11/70 versus an 11/780 (VAX). Specifically the following: Is an 11/70 capable of performing the full impelmentation of System V UNIX ? If it is not capable, what can't be done. Are there hardware problems involved? Does an 11/70 have any specific advantages/disadvantages when running System V, can they be overcome? Time differences between machines on file copies etc... Please send information by mail, if possible I will summorize on the net. G. P. Wilkin (AT&T NETWORK SYSTEMS) ihnp4!ihuxa!gpw *System V and UNIX are trrademarks of AT&T
gwyn@brl-vgr.UUCP (06/08/84)
Sorry, I can't readily mail to UUCP sites...
The performance of UNIX System V on the supported CPUs is given in the SRD.
The PDP-11/70 is shown as having about 55% of the throughput of a VAX-11/780.
If you're going to run UNIX System V on a VAX-11/780 you are advised to get
a KMC11-B to drive your DZ11s for much improved terminal i/o.
Also from the SRD: The PDP-11/70 is "fully supported" but does not have:
- flexnames and corresponding object/archive format
- job control ("shl", sxt)
I have also found that (at least in Release 1) the PDP-11 "f77" is an older
version, since the newer version was too big for the PDP-11 (recall that
AT&T UNIX does not support user-mode text overlays). Indeed, the main
problem with the PDP-11 is its limited (64Kb I + 64Kb D) process address
space. It is also supposed to be out of production by DEC.jab@uokvax.UUCP (06/16/84)
#R:ihuxa:-54400:uokvax:6200029:000:1239 uokvax!jab Jun 16 03:09:00 1984 /***** uokvax:net.unix-wizar / ihuxa!gpw / 7:51 pm Jun 7, 1984 */ I am in need of information on the differences between System V UNIX* on an 11/70 versus an 11/780 (VAX). Specifically the following: Is an 11/70 capable of performing the full implementation of System V UNIX ? G. P. Wilkin (AT&T NETWORK SYSTEMS) ihnp4!ihuxa!gpw /* ---------- */ Doug Gwyn pointed to the newer "features" such as the "shell layers" facility. A lot of "add-on" packages, such as the Ethernet package from AT&T that runs on top of System V, ignore the PDP-11 entirely. It would be up to YOU to port such things over and make it work, and it's not clear that it's worth the effort. Also, the 1024 bytes/block filesystem isn't honored on the PDP-11 under System V, probably because they don't want to play games with the size of SABUFS that count against the precious kernel D space. The game of fitting a lot of things into a 64K address space gets old; even with text overlays, you can only put so many things into the kernel D space. (George Goble at Purdue and Peter Staubach here at OU have done a little work with data overlays, but it's not fun and not feasible (possible?) to do in a general way.) Jeff Bowles Lisle, IL