Re: Migrating C application from VMS to LINUX

klaus1 wrote:
On Feb 19, 9:58 am, "klaus1" <klaus.s...@xxxxxxxxx> wrote:

On Feb 17, 2:19 pm, Paul Repacholi <p...@xxxxxxxxxxxxxxxx> wrote:




"klaus1" <klaus.s...@xxxxxxxxx> writes:

On Feb 16, 12:22 pm, JF Mezei <jfmezei.spam...@xxxxxxxxxxxxx> wrote:

klaus1 wrote:

I just looking for interprocess communication IPC. Does anyone have
some information for me, what kind of IPC exists in VMS and how I can
port these to Linux.

You can get a copy of a VAX or Alpha emulator to run as an app on Linux and
run VMS on linux. No need to port the apps. And you put new apps native on
Linux.

In terms of IPC on VMS:

Mailboxes
common event flags
locks
shared memory
decnet task to task
icc
tcpip

It really depends on what sort of application you have, how complex it is
and how much it relies on VMS specific systems services.

thanks for the answer, I use the following IPCs on VMS:
- Mailboxes

Easily done on an unixoid. In fact, this is an area where VMS is suckish.

- common event flags

No equivalent possible due to the process structure.

- locks

No true euivalent possible. No cross system, cluster, locks
for a start. IBM does have a DLM package that run on several
Uoids, including AIX and Linux.

- global sections

shmem can do this if you feed it the right options.

Which kind of emulator exists as an Linux app ?
I read in this thread, that "shmem" calls in linux can cover
IPCs. Is it possible to cover the whole list I mentioned before?

The problem is, the IPC system is part of the serialization and
scheduling design of the app. Change the underlying system and that
needs changes all the way up the design and possibly different IPC
needs.

any problems with file I/O handling using my c programs? fopen /
fseek / fclose?


i mean how can I port RMS spezific things in VMS to Linux ?


Write RMS for Linux!!

Seriously, if this code calls RMS directly, porting it may take extreme effort. You might be better off figuring out what it does and rewriting from scratch. RMS is built on a concept, records, that Unix/Linux simply does not have. In Unix/Linux a file is simply an ordered sequence of bytes. Any internal structure; e.g. records, is purely a figment of the programmer's imagination. This concept of a file means that ANYTHING can be treated as a file. Your process is a file; a memory resident file, and can be treated as such.

.

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