Multiple copies of application open...

[Quackers]

What are the pros and cons of having more than one copy of an
application open?

Being a long-time Mac user, I'm used to having only one copy open at a
time. But I notice that several apps in Windows can have multiple
copies open simultaneously. The latter seems weird, but is it poor
programming, or are there advantages?

We are developing a Java application that currently can have several
copies open at once, and I'm inclined to say this shouldn't happen.

Thanks,

Q

[Mark Schonewille]

Well, it is Windoze and thus it must be poor programming, as you
said :-)
It means that one app is loaded into memory more than once,
occupying unnessecary capacity and possibly corrupting .ini and
other files. Anyway, probably you should not ask such a question
in a Mac ng.

Mark

Quackers wrote:

>
> What are the pros and cons of having more than one copy of an
> application open?
>
> Being a long-time Mac user, I'm used to having only one copy open at a
> time. But I notice that several apps in Windoze can have multiple
> copies open simultaneously. The latter seems weird, but is it poor
> programming, or are there advantages?
>
> We are developing a Java application that currently can have several
> copies open at once, and I'm inclined to say this shouldn't happen.
>
> Thanks,
>
> Q

[Tacit]

>Well, it is Windoze and thus it must be poor programming, as you

>said :-)
>It means that one app is loaded into memory more than once,
>occupying unnessecary capacity and possibly corrupting .ini and
>other files.

That does not necessarily follow.

Some programs are specifically designed to be "reentrant." A reentrant program
is designed to be run multiple times--at least, that is how it appears to the
user.

However, the application itself is only in memory once. A reentrant program
keeps a single copy of the object code in memory; each additional instance of
the program occupies memory for its data, but the code itself is loaded only
once. If the program is running three times, what that actually means is the
code has three separate execution threads running within it, each of which has
its own data area.

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[Paul Sture]

In article <nobody-6BF932.08151319072003@news1.news.adelphia.net>, Quackers <nobody@home.now> writes:

> What are the pros and cons of having more than one copy of an
> application open?
>
> Being a long-time Mac user, I'm used to having only one copy open at a
> time. But I notice that several apps in Windows can have multiple
> copies open simultaneously. The latter seems weird, but is it poor
> programming, or are there advantages?
>

Why is this weird? If a program such as a spreadsheet supports multiple
windows so that you can see more than one file at a time within it, then
I see your point, but for those that don't, why not have multiple
instances?

The disadvantage of only having one instance open is demonstrated by
Netscape on my PC at work. I might have several windows open, but if
a rogue website makes one window barf or hang, killing Netscape kills
all the other windows too.

> We are developing a Java application that currently can have several
> copies open at once, and I'm inclined to say this shouldn't happen.
>

That depends on the application. Using OS X, I see a minimum of 2 processes
per Terminal window I have open - login and tcsh.

[Tom Stiller]

In article <9N9ITx109Y$Q@elias.decus.ch>,
[email]p_sture@elias.decus.ch[/email] (Paul Sture) wrote:

> In article <nobody-6BF932.08151319072003@news1.news.adelphia.net>, Quackers
> <nobody@home.now> writes:

> > What are the pros and cons of having more than one copy of an
> > application open?
> >
> > Being a long-time Mac user, I'm used to having only one copy open at a
> > time. But I notice that several apps in Windows can have multiple
> > copies open simultaneously. The latter seems weird, but is it poor
> > programming, or are there advantages?
> >

>
> Why is this weird? If a program such as a spreadsheet supports multiple
> windows so that you can see more than one file at a time within it, then
> I see your point, but for those that don't, why not have multiple
> instances?
>
> The disadvantage of only having one instance open is demonstrated by
> Netscape on my PC at work. I might have several windows open, but if
> a rogue website makes one window barf or hang, killing Netscape kills
> all the other windows too.

What about the multiple updates to things like cookies, bookmarks,
preferences, etc.?

>

> > We are developing a Java application that currently can have several
> > copies open at once, and I'm inclined to say this shouldn't happen.
> >

> That depends on the application. Using OS X, I see a minimum of 2 processes
> per Terminal window I have open - login and tcsh.

--
Tom Stiller

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