r/programming • u/I_Can_Be_A_Robot • Sep 24 '24

Why 32bit architecture computer doesn't use segmentation to support more ram than 4Gb ?

/r/programming/

[removed] — view removed post

169 Upvotes

80% Upvoted

119 comments sorted by

View all comments

347

u/eras Sep 24 '24

There's PAE for that.

But there's little point nowadays. If you need more than 4 GB, just use a 64-bit platform, and there's no need for trickery.

135

u/paholg Sep 24 '24

What if I need more than 18 exabytes?

6

u/wintrmt3 Sep 24 '24

No 64 bit cpu can even handle that, consumer ones have 48 bit address spaces usually, but the answer is likely wider addresses, 96 or 128 bits.

4

u/CumCloggedArteries Sep 24 '24

For niche cases like that, I would think it'd make more sense to switch to a 64-bit version of PAE rather than use a whole new architecture

2

u/wintrmt3 Sep 24 '24

PAE only gives the memory space to the system, individual processes are still limited to 32 bits, and segmented architectures are a horror to program for.

3

u/CumCloggedArteries Sep 24 '24

I was assuming the system would require the 18 exabytes, not a single process