OS/2, eCS & ArcaOS - Technical > Applications

AOS RAM Disk

<< < (2/8) > >>

xynixme:

--- Quote from: Valery Sedletski on September 25, 2018, 08:00:31 pm ---I always thought, it is a 4 GB, not 4 MB limit. Am I not right?

--- End quote ---
You may not be right indeed: https://en.wikipedia.org/wiki/Gibibyte... :P

RickCHodgin:

--- Quote from: Doug Clark on September 25, 2018, 06:43:44 pm ---Does anyone know where RAM disk takes memory? And it it does use memory about the 4 GB limit, how does it do that?

--- End quote ---

According to Arca Noae's Section 6.4.3 of README


--- Code: ---6.4.3  RAM Disk

The new kernel supports a RAM disk (portion of memory which acts like a
physical disk and is assigned a drive letter). This RAM disk may be configured
to use memory above the 4GB boundary, normally limiting 32-bit operating
systems. Thus, on newer systems with large amounts of memory (8, 16, 24, 32, or
even 64GB), the space above 4GB may be configured for use as a RAM disk.

Arca Noae provides a utility for configuring up to two such RAM disks. The RAM
Disk applet located in the System Setup folder provides guidance and
configuration of such memory constructs.

--- End code ---

32-bit x86-based CPUs are able to access up to 64 GB of RAM per physical core using something called Physical Address Extensions (PAE) allowing extra information in the paging table for 36-bits of physical address space rather than just 32-bits.  Each physical process still only accesses 4 GB of virtual addresses, but they can be mapped anywhere in the 64 GB supported.

xynixme:

--- Quote from: Rick C. Hodgin on September 25, 2018, 09:25:28 pm ---Each physical process still only accesses 4 GB of virtual addresses
--- End quote ---

Not anymore, see the previous link to Wikipedia.

RickCHodgin:

--- Quote from: André Heldoorn on September 25, 2018, 10:05:40 pm ---
--- Quote from: Rick C. Hodgin on September 25, 2018, 09:25:28 pm ---Each physical process still only accesses 4 GB of virtual addresses
--- End quote ---

Not anymore, see the previous link to Wikipedia.

--- End quote ---

Do you mean it should be 4 GiB?

Dave Yeo:

--- Quote from: David Graser on September 25, 2018, 08:47:27 pm ---Feel free to correct me if I am wrong.  I believe one needs the OS/4 kernel and the QSINIT loader to utilized RAM above 4 GB.

--- End quote ---

ArcaOS comes with a modified QSINIT as os2ldr, which helps with memory holes that the IBM os2ldr can't handle and gives access to the high memory through PAE.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

Go to full version