Query: How to get RAM size of system
steve6375 opened this issue · 12 comments
In grub4dos I can get the total amount of RAM in a system.
How can I do this with grub2 (MBR and UEFI)?
For instance, I can automatically select a 32-bit install of Windows from a dual architecture ISO if the system has <4GB of RAM. Or run a 32-bit version of Linux if <4GB of RAM instead of the 64-bit version.
UEFI BIOS?
I can automatically select a 32-bit install of Windows from a dual architecture ISO if the system has <4GB of RAM.
You can't boot/install a 32-bit Windows if UEFI firmware is 64-bit.
Sure , in that case I was thinking of Legacy boot.
But you can run Linux 32-bit kernels from UEFI64 boot (for instance).
But you can run Linux 32-bit kernels from UEFI64 boot (for instance).
compatibility of 32-bit linux is bad. It doesn't work no some tablets with 64-bit CPU/UEFI.
besides many linux distros (eg. Ubuntu) have dropped support for 32-bit.
Sure , in that case I was thinking of Legacy boot.
How to get the total amount of RAM in grub4dos?
set /a M=*0x8298 & 0xffffffff>>10+1 > nul && set /a M1=*0x82c0>>10+1 > nul
set /a M=%M% + %M1% > nul
grub4dos has documented memory location where it is stored.
0000:8298 4 (DWORD) saved_mem_upper (extended memory size in KB)
0000:82C0 8 (QWORD) saved_mem_higher (max contiguous mem in KB starting at 4G
can do a BIOS call, int15 e820h
https://wiki.osdev.org/Detecting_Memory_(x86)#BIOS_Function:_INT_0x15.2C_EAX_.3D_0xE820
See grub4dos stage2\common.c for code.
That is showing memory above 4GB
You need to add up all conv-mem entries to get total memory?
What variable is the result returned in?
--set=VAR work ?
download latest build.
stat -q -r -s a
echo $a
Thanks. MBR result agrees with grub4dos within +/-1. 👍
Thanks - great work!