32 bit process addressing more than 4GB


 
Thread Tools Search this Thread
Top Forums UNIX for Beginners Questions & Answers 32 bit process addressing more than 4GB
# 1  
Old 12-26-2019
32 bit process addressing more than 4GB

Hello for all,

I am testing the behavior of a 32 bit application running on Solaris 5.10 (SPARC), and realize it reaches 4GB of memory and then crashes.

It doesn't matter the amount of used memory as application is intended to perform many transactions; rather, what I want to achieve is to get the application capable to address more than 4GB without having to recompile and rebuild it in 64 bit mode.

It is possible to achieve that? if so, I am glad if you can indicate me how to do that.

Thanks in advance, and happy holidays!
# 2  
Old 12-26-2019
A 32-bit system generally cannot physically address more than 4GB of RAM.

Various systems, however, have adopted extensions that permit a 32-bit system to physically access more than 4GB of RAM.

In generally, this is implemented via "page table hacks".

For example, the x86 architecture, for example, supports a feature called Physical Address Extension (PAE) that commonly extends physically-addressable memory to 64GB.

PAE is quite common. If your system supports it, you can have more than 4GB of RAM. Otherwise you are stuck at 4GB.

You might check to see if your SPARC architecture also supports PAE and post back the results of your research.
# 3  
Old 12-27-2019
PAE was invented for 32bit kernels, in order to address more than 4GB.
It allowed many apps to consume more than 4GB, but I have my doubts that a single app could address more than 4GB.

PAE caused some severe misbehavior on Linux: for example, OOM killer was invoked if one 4GB segment was full; without knowing which process occupied most in that segment it often killed "wrong" processes before it killed a "correct" one. OpenSuSE kernels even invoked OOM killer if a single small process did continous I/O that filled a 4GB segment with only cache data - a nightmare!
Fortunately PAE is from the past - today there are 64bit kernels.

Solaris never had OOM killer, and Sparc early supported 64bit - there was no need for something like PAE.
These 2 Users Gave Thanks to MadeInGermany For This Post:
Login or Register to Ask a Question

Previous Thread | Next Thread

6 More Discussions You Might Find Interesting

1. Windows & DOS: Issues & Discussions

Which version of Windows Vista to install with a product key? 32-bit or 64-bit?

Hello everyone. I bought a dell laptop (XPS M1330) online which came without a hard drive. There is a Windows Vista Ultimate OEMAct sticker with product key at the bottom case. I checked dell website (here) for this model and it says this model supports both 32 and 64-bit version of Windows... (4 Replies)
Discussion started by: milhan
4 Replies

2. Shell Programming and Scripting

How to handle 64 bit arithmetic operation at 32 bit compiled perl interpreter?H

Hi, Here is the issue. From the program snippet I have Base: 0x1800000000, Size: 0x3FFE7FFFFFFFF which are of 40 and 56 bits. SO I used use bignum to do the math but summing them up I always failed having correct result. perl interpreter info, perl, v5.8.8 built for... (0 Replies)
Discussion started by: rrd1986
0 Replies

3. Red Hat

process fails if setuid bit is set

Hi, OS : Linux I have an executable (P1) owned by user say "abcd" and the setuid bit is set. And there is another executable (P2) which brings up the process (P1). When the setuid bit is set, the process P1 is failing, if the setuid bit is not set there is no issue. I was wondering if... (6 Replies)
Discussion started by: ahamed101
6 Replies

4. Homework & Coursework Questions

Four-Level multi-paging on x86 system with 64 bit addressing

1. The problem statement, all variables and given/known data: Hi all, I've got a huuuuuuge problem with understanding this new concept of multi-paging. I really tried to research but i could not find anything significant. I've been trying to understand this for 4 days and i cannot. The question... (0 Replies)
Discussion started by: snowboarder
0 Replies

5. AIX

fiber with 4GB

Hi, It's my first time I will use a 4BG fiber with two ports on one card. I used only one port 2GB before. What will be the drivers I need to install on my AIX5.3? Is the two ports going to be just one line? Or I can use the other ports on another connection. Thanks in advance, itik (1 Reply)
Discussion started by: itik
1 Replies

6. Programming

copying or concatinating string from 1st bit, leaving 0th bit

Hello, If i have 2 strings str1 and str2, i would like to copy/concatenate str2 to str1, from 1st bit leaving the 0th bit. How do i do it? (2 Replies)
Discussion started by: jazz
2 Replies
Login or Register to Ask a Question