0
votes
0answers
139 views

PCI Express BAR memory mapping basic understanding

I am trying to understand how PCI Express works so i can write a windows driver that can read and write to a custom PCI Express device with no on-board memory. I understand that the Base Address ...
1
vote
1answer
223 views

Auto vs Onboard/Card Dell Desktop

What is the difference between auto and onboard/card on the dell optiplex 960? The description is very lacking. As the name suggests for auto, if I do not have a video card inside, it will still use ...
1
vote
1answer
806 views

PCI Express - Memory Addressing vs Physical Memory in Memory Read/Write Transactions

I'm trying to find the link between Memory BARs (Base Address Registers) and Physical Memory in a PCI Express Transactions. In my last question I started to understand what happens when a CPU ...
2
votes
1answer
2k views

PCI Express - Clarification about BAR, Memory addressing and physical memory

I'm an absolute beginner starting to understand the PCI Express protocol and I need some clarifications about its mechanics. I understood that a PCI Express endpoint device may have some memory BAR ...
4
votes
4answers
7k views

Why aren't there PCIe RAM expansions?

Perhaps I may be overlooking some aspect that is an important cause as to why these don't exist, but I feel that having RAM expansions through PCIe would be perfectly feasible. I know that a lot of ...
0
votes
2answers
4k views

How are PCI/PCIe BARs configured to access memory on the device?

In my previous question, I established that the memory address used by PCI/PCIe devices does not have to mapped to system RAM, but could also refer to "on device" memory, e.g. RAM or registers. But ...
1
vote
1answer
2k views

What is “intel 945g pci express root port 2771”?

I find that entry in the memory allocation list of my computer (Workstation -> Device Manager -> View -> Resource by Type). It takes up 256MB of RAM and I'm wondering what's it good for.