QNX 4.25 Free Memory

QNX USERS QNX2 and QNX4
1

Can some one please tell me why the numbers shown with sin freemem don’t agree with sin in?

In my case I have a machine with 2 gig of RAM so sin in shows:

Memory: 1712M/2048M

Sin freemem shows:
24576
8192
192512
57344
1753M
49152

Why do the individual chunks add up to more than the 1712M shown by sin in?

What is the best/most accurate way to determine system free memory?

Thanks.

Larry

2

I doubt that anyone without the source code can tell you precisely why. A common error in coding is in using one of three different meanings to a Meg.

1,000,000
1024 x 1024
1024 x 1000

I’ve seen them all appear now and then. You run into the first more often with disk space. Disk manufacturers like to make their disks sound a big as possible.

I think that there are two likely possibilities for the QNX diference.

  1. Someone made an error
  2. The two numbers are calculating slightly different things

My guess would be 2).

I do feel like the difference, 43Meg seems large, however the percentage error 43/1753 ~ %2.4 is small. If you are crowding an application in tighter than that, you are playing with fire.

3

Thanks Mitchell. Maybe someone from QNX will see this and take a look at the source …

Not a show stopper for me but management was asking for tests to check for free memory.

I mentioned sin freemem and sin in.

Unfortunately they noticed the difference and are now asking why …

Larry

4

Thanks Mitchell,

My management was asking about how to determine free memory.

I mentioned sin freemem and sin in.

Unfortunately after they used these they saw the difference between the two and are now asking why …

Hopefully someone from QNX might see this and clear up the reason for the difference.

Thanks again.

Larry

5

This is QNX 4. It is very hard to get QNX people to look at QNX 4 and QNX 2 issues. For a long time it hasn’t been possible to get them to look at QNX 6 Photon issues. So don’t get your hopes up.