horst@leadsv.UUCP (John Selhorst) (05/23/85)
I have some programs that, I have been told (by the vendor), will run on
4.2BSD on a VAX in PDP-11 compatibility mode. The vendor says that there
is a utility called compat that I need. I need some quick answers and
our guru is on vacation. Here are my questions:
1) Is it possible to use compatibilty mode on a VAX without severely
hampering other users? I thought that compatibility mode was system-
wide (ie. everybody is running in compatibility mode) and that is
unacceptable.
2) What is compat and where can I get it and does it run on 4.2BSD?
3) If I am using compat, what does it look like (maybe a PDP-11 running
4.2BSD)?
I apologize if these questions seem naive. Any replies, including flames,
will be greatly appreciated. Thanks.
John Selhorst
{(ucbvax!dual!sun) (ihnp4!qubix)}!sunncal!leadsv!horst
{allegra ihnp4 dual}!fortune!amdcad!cae780!leadsv!horst
VAX and PDP-11 are probably trademarks of Digital Equipment Corp.dave@uwvax.UUCP (Dave Cohrs) (05/26/85)
> 1) Is it possible to use compatibilty mode on a VAX without severely > hampering other users? I thought that compatibility mode was system- > wide (ie. everybody is running in compatibility mode) and that is > unacceptable. No. When you run in compatability mode, all compatability-mode system calls cause 5 context switches instead of 2 as the system calls are emulated by the compat (often called v7run) program. If a number of people are using the compat programs at the same time, your system will bog down. The system-wide compatability is 4.1 compatability which is not necessary to use Pdp-11 compatability. > 2) What is compat and where can I get it and does it run on 4.2BSD? You should find the source in /usr/src/games/compat. Note that there are a couple bugs in this code which cause SIGILL to be handled incorrectly. > 3) If I am using compat, what does it look like (maybe a PDP-11 running > 4.2BSD)? V7run (compat) emulates version 7 execution. 2.8 and 2.9 executables also work, at least they do for system calls that are also on version 7. -- dave cohrs ...!{allegra,harvard,ihnp4,seismo}!uwvax!dave dave@wisc-limburger.arpa (bug? what bug? that's a feature!)
mjl@ritcv.UUCP (Mike Lutz) (05/29/85)
In article <203@uwvax.UUCP> dave@uwvax.UUCP (Dave Cohrs) writes: >V7run (compat) emulates version 7 execution. 2.8 and 2.9 executables also >work, at least they do for system calls that are also on version 7. Two caveats: separate I&D programs cannot be run under compat, and some of the older versions did not emulate floating point (or handled it incorrectly). -- Mike Lutz Rochester Institute of Technology, Rochester NY UUCP: {allegra,seismo}!rochester!ritcv!mjl CSNET: mjl%rit@csnet-relay.ARPA