I'm using a Linux OS on my laptop, and it indicates that I have more than 200GB of free space.
However it seems that PARI-GP can only use a relatively small fraction of this space :
$ gp
Reading GPRC: /etc/gprc
GPRC Done.
GP/PARI CALCULATOR Version 2.15.4 (released)
amd64 running linux (x86-64/GMP-6.3.0 kernel) 64-bit version
compiled: Apr 1 2024, gcc version 13.2.0 (Ubuntu 13.2.0-23ubuntu3)
threading engine: pthread
(readline v8.2 enabled, extended help enabled)
Copyright (C) 2000-2022 The PARI Group
PARI/GP is free software, covered by the GNU General Public License, and comes
WITHOUT ANY WARRANTY WHATSOEVER.
Type ? for help, \q to quit.
Type ?18 for how to get moral (and possibly technical) support.
parisize = 8000000, primelimit = 500000, nbthreads = 16
? default(parisizemax,40G);
*** Warning: not enough memory, new PARI stack 20000002048
*** Warning: new maximum stack size = 20000002048 (19073.488 Mbytes).